There are 7 function definitions in trace_probe_tmpl.h, they are:
1, process_fetch_insn
2, fetch_store_strlen
3, fetch_store_string
4, fetch_store_strlen_user
5, fetch_store_string_user
6, probe_mem_read
7, probe_mem_read_user
Every C file which includes trace_probe_tmpl.h has to implement them,
otherwise it gets warnings and errors. However, some of them are identical,
like kprobe and eprobe, as a result, there is a lot redundant code in those
2 files.
This patch would like to provide default behaviors for those functions
which kprobe and eprobe can share by just including trace_probe_kernel.h
with trace_probe_tmpl.h together.
It removes redundant code, increases readability, and more importantly,
makes it easier to introduce a new feature based on trace probe
(it's possible).
Signed-off-by: Song Chen <[email protected]>
Reported-by: kernel test robot <[email protected]>
---
v2:
1, reorganize patchset
v3:
1, mark nokprobe_inline for get_event_field
2, remove warnings reported from kernel test robot
3, fix errors reported from kernel test robot
v4:
1, reset changes in v3(2) and v3(3), they are not reasonable fix.
2, I intended to introduce a new header file to exclude
trace_events_synth.c out of the patch. However, after looking
further, i found the errors in [1] are introduced by this patch,
but the warning in [1] are not. The errors can be fixed by adding
"#ifdef CONFIG_HAVE_REGS_AND_STACK_ACCESS_API".
[1]:https://lore.kernel.org/lkml/[email protected]/
---
kernel/trace/trace_eprobe.c | 144 ------------------------------
kernel/trace/trace_events_synth.c | 7 +-
kernel/trace/trace_kprobe.c | 102 ---------------------
kernel/trace/trace_probe_kernel.h | 143 +++++++++++++++++++++++++++--
4 files changed, 141 insertions(+), 255 deletions(-)
diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c
index bdb26eee7a0c..60ced4a7a25d 100644
--- a/kernel/trace/trace_eprobe.c
+++ b/kernel/trace/trace_eprobe.c
@@ -319,64 +319,6 @@ print_eprobe_event(struct trace_iterator *iter, int flags,
return trace_handle_return(s);
}
-static unsigned long get_event_field(struct fetch_insn *code, void *rec)
-{
- struct ftrace_event_field *field = code->data;
- unsigned long val;
- void *addr;
-
- addr = rec + field->offset;
-
- if (is_string_field(field)) {
- switch (field->filter_type) {
- case FILTER_DYN_STRING:
- val = (unsigned long)(rec + (*(unsigned int *)addr & 0xffff));
- break;
- case FILTER_RDYN_STRING:
- val = (unsigned long)(addr + (*(unsigned int *)addr & 0xffff));
- break;
- case FILTER_STATIC_STRING:
- val = (unsigned long)addr;
- break;
- case FILTER_PTR_STRING:
- val = (unsigned long)(*(char *)addr);
- break;
- default:
- WARN_ON_ONCE(1);
- return 0;
- }
- return val;
- }
-
- switch (field->size) {
- case 1:
- if (field->is_signed)
- val = *(char *)addr;
- else
- val = *(unsigned char *)addr;
- break;
- case 2:
- if (field->is_signed)
- val = *(short *)addr;
- else
- val = *(unsigned short *)addr;
- break;
- case 4:
- if (field->is_signed)
- val = *(int *)addr;
- else
- val = *(unsigned int *)addr;
- break;
- default:
- if (field->is_signed)
- val = *(long *)addr;
- else
- val = *(unsigned long *)addr;
- break;
- }
- return val;
-}
-
static int get_eprobe_size(struct trace_probe *tp, void *rec)
{
struct fetch_insn *code;
@@ -419,92 +361,6 @@ static int get_eprobe_size(struct trace_probe *tp, void *rec)
return ret;
}
-/* Kprobe specific fetch functions */
-
-/* Note that we don't verify it, since the code does not come from user space */
-static int
-process_fetch_insn(struct fetch_insn *code, void *rec, void *dest,
- void *base)
-{
- unsigned long val;
-
- retry:
- switch (code->op) {
- case FETCH_OP_TP_ARG:
- val = get_event_field(code, rec);
- break;
- case FETCH_OP_IMM:
- val = code->immediate;
- break;
- case FETCH_OP_COMM:
- val = (unsigned long)current->comm;
- break;
- case FETCH_OP_DATA:
- val = (unsigned long)code->data;
- break;
- case FETCH_NOP_SYMBOL: /* Ignore a place holder */
- code++;
- goto retry;
- default:
- return -EILSEQ;
- }
- code++;
- return process_fetch_insn_bottom(code, val, dest, base);
-}
-NOKPROBE_SYMBOL(process_fetch_insn)
-
-/* Return the length of string -- including null terminal byte */
-static nokprobe_inline int
-fetch_store_strlen_user(unsigned long addr)
-{
- return kern_fetch_store_strlen_user(addr);
-}
-
-/* Return the length of string -- including null terminal byte */
-static nokprobe_inline int
-fetch_store_strlen(unsigned long addr)
-{
- return kern_fetch_store_strlen(addr);
-}
-
-/*
- * Fetch a null-terminated string from user. Caller MUST set *(u32 *)buf
- * with max length and relative data location.
- */
-static nokprobe_inline int
-fetch_store_string_user(unsigned long addr, void *dest, void *base)
-{
- return kern_fetch_store_string_user(addr, dest, base);
-}
-
-/*
- * Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max
- * length and relative data location.
- */
-static nokprobe_inline int
-fetch_store_string(unsigned long addr, void *dest, void *base)
-{
- return kern_fetch_store_string(addr, dest, base);
-}
-
-static nokprobe_inline int
-probe_mem_read_user(void *dest, void *src, size_t size)
-{
- const void __user *uaddr = (__force const void __user *)src;
-
- return copy_from_user_nofault(dest, uaddr, size);
-}
-
-static nokprobe_inline int
-probe_mem_read(void *dest, void *src, size_t size)
-{
-#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
- if ((unsigned long)src < TASK_SIZE)
- return probe_mem_read_user(dest, src, size);
-#endif
- return copy_from_kernel_nofault(dest, src, size);
-}
-
/* eprobe handler */
static inline void
__eprobe_trace_func(struct eprobe_data *edata, void *rec)
diff --git a/kernel/trace/trace_events_synth.c b/kernel/trace/trace_events_synth.c
index e310052dc83c..7460f18ba973 100644
--- a/kernel/trace/trace_events_synth.c
+++ b/kernel/trace/trace_events_synth.c
@@ -18,6 +18,7 @@
#include <linux/trace_events.h>
#include <trace/events/mmflags.h>
#include "trace_probe.h"
+#include "trace_probe_tmpl.h"
#include "trace_probe_kernel.h"
#include "trace_synth.h"
@@ -420,12 +421,12 @@ static unsigned int trace_string(struct synth_trace_event *entry,
data_offset += event->n_u64 * sizeof(u64);
data_offset += data_size;
- len = kern_fetch_store_strlen((unsigned long)str_val);
+ len = fetch_store_strlen((unsigned long)str_val);
data_offset |= len << 16;
*(u32 *)&entry->fields[*n_u64] = data_offset;
- ret = kern_fetch_store_string((unsigned long)str_val, &entry->fields[*n_u64], entry);
+ ret = fetch_store_string((unsigned long)str_val, &entry->fields[*n_u64], entry);
(*n_u64)++;
} else {
@@ -473,7 +474,7 @@ static notrace void trace_event_raw_event_synth(void *__data,
val_idx = var_ref_idx[field_pos];
str_val = (char *)(long)var_ref_vals[val_idx];
- len = kern_fetch_store_strlen((unsigned long)str_val);
+ len = fetch_store_strlen((unsigned long)str_val);
fields_size += len;
}
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index a4ffa864dbb7..c2e0b741ae82 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -1218,108 +1218,6 @@ static const struct file_operations kprobe_profile_ops = {
.release = seq_release,
};
-/* Kprobe specific fetch functions */
-
-/* Return the length of string -- including null terminal byte */
-static nokprobe_inline int
-fetch_store_strlen_user(unsigned long addr)
-{
- return kern_fetch_store_strlen_user(addr);
-}
-
-/* Return the length of string -- including null terminal byte */
-static nokprobe_inline int
-fetch_store_strlen(unsigned long addr)
-{
- return kern_fetch_store_strlen(addr);
-}
-
-/*
- * Fetch a null-terminated string from user. Caller MUST set *(u32 *)buf
- * with max length and relative data location.
- */
-static nokprobe_inline int
-fetch_store_string_user(unsigned long addr, void *dest, void *base)
-{
- return kern_fetch_store_string_user(addr, dest, base);
-}
-
-/*
- * Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max
- * length and relative data location.
- */
-static nokprobe_inline int
-fetch_store_string(unsigned long addr, void *dest, void *base)
-{
- return kern_fetch_store_string(addr, dest, base);
-}
-
-static nokprobe_inline int
-probe_mem_read_user(void *dest, void *src, size_t size)
-{
- const void __user *uaddr = (__force const void __user *)src;
-
- return copy_from_user_nofault(dest, uaddr, size);
-}
-
-static nokprobe_inline int
-probe_mem_read(void *dest, void *src, size_t size)
-{
-#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
- if ((unsigned long)src < TASK_SIZE)
- return probe_mem_read_user(dest, src, size);
-#endif
- return copy_from_kernel_nofault(dest, src, size);
-}
-
-/* Note that we don't verify it, since the code does not come from user space */
-static int
-process_fetch_insn(struct fetch_insn *code, void *rec, void *dest,
- void *base)
-{
- struct pt_regs *regs = rec;
- unsigned long val;
-
-retry:
- /* 1st stage: get value from context */
- switch (code->op) {
- case FETCH_OP_REG:
- val = regs_get_register(regs, code->param);
- break;
- case FETCH_OP_STACK:
- val = regs_get_kernel_stack_nth(regs, code->param);
- break;
- case FETCH_OP_STACKP:
- val = kernel_stack_pointer(regs);
- break;
- case FETCH_OP_RETVAL:
- val = regs_return_value(regs);
- break;
- case FETCH_OP_IMM:
- val = code->immediate;
- break;
- case FETCH_OP_COMM:
- val = (unsigned long)current->comm;
- break;
- case FETCH_OP_DATA:
- val = (unsigned long)code->data;
- break;
-#ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
- case FETCH_OP_ARG:
- val = regs_get_kernel_argument(regs, code->param);
- break;
-#endif
- case FETCH_NOP_SYMBOL: /* Ignore a place holder */
- code++;
- goto retry;
- default:
- return -EILSEQ;
- }
- code++;
-
- return process_fetch_insn_bottom(code, val, dest, base);
-}
-NOKPROBE_SYMBOL(process_fetch_insn)
/* Kprobe handler */
static nokprobe_inline void
diff --git a/kernel/trace/trace_probe_kernel.h b/kernel/trace/trace_probe_kernel.h
index 77dbd9ff9782..39f44513ec4e 100644
--- a/kernel/trace/trace_probe_kernel.h
+++ b/kernel/trace/trace_probe_kernel.h
@@ -12,7 +12,7 @@
*/
/* Return the length of string -- including null terminal byte */
static nokprobe_inline int
-kern_fetch_store_strlen_user(unsigned long addr)
+fetch_store_strlen_user(unsigned long addr)
{
const void __user *uaddr = (__force const void __user *)addr;
int ret;
@@ -29,14 +29,14 @@ kern_fetch_store_strlen_user(unsigned long addr)
/* Return the length of string -- including null terminal byte */
static nokprobe_inline int
-kern_fetch_store_strlen(unsigned long addr)
+fetch_store_strlen(unsigned long addr)
{
int ret, len = 0;
u8 c;
#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
if (addr < TASK_SIZE)
- return kern_fetch_store_strlen_user(addr);
+ return fetch_store_strlen_user(addr);
#endif
do {
@@ -63,7 +63,7 @@ static nokprobe_inline void set_data_loc(int ret, void *dest, void *__dest, void
* with max length and relative data location.
*/
static nokprobe_inline int
-kern_fetch_store_string_user(unsigned long addr, void *dest, void *base)
+fetch_store_string_user(unsigned long addr, void *dest, void *base)
{
const void __user *uaddr = (__force const void __user *)addr;
int maxlen = get_loc_len(*(u32 *)dest);
@@ -86,7 +86,7 @@ kern_fetch_store_string_user(unsigned long addr, void *dest, void *base)
* length and relative data location.
*/
static nokprobe_inline int
-kern_fetch_store_string(unsigned long addr, void *dest, void *base)
+fetch_store_string(unsigned long addr, void *dest, void *base)
{
int maxlen = get_loc_len(*(u32 *)dest);
void *__dest;
@@ -94,7 +94,7 @@ kern_fetch_store_string(unsigned long addr, void *dest, void *base)
#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
if ((unsigned long)addr < TASK_SIZE)
- return kern_fetch_store_string_user(addr, dest, base);
+ return fetch_store_string_user(addr, dest, base);
#endif
if (unlikely(!maxlen))
@@ -112,4 +112,135 @@ kern_fetch_store_string(unsigned long addr, void *dest, void *base)
return ret;
}
+static nokprobe_inline int
+probe_mem_read_user(void *dest, void *src, size_t size)
+{
+ const void __user *uaddr = (__force const void __user *)src;
+
+ return copy_from_user_nofault(dest, uaddr, size);
+}
+
+static nokprobe_inline int
+probe_mem_read(void *dest, void *src, size_t size)
+{
+#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
+ if ((unsigned long)src < TASK_SIZE)
+ return probe_mem_read_user(dest, src, size);
+#endif
+ return copy_from_kernel_nofault(dest, src, size);
+}
+
+static nokprobe_inline unsigned long
+get_event_field(struct fetch_insn *code, void *rec)
+{
+ struct ftrace_event_field *field = code->data;
+ unsigned long val;
+ void *addr;
+
+ addr = rec + field->offset;
+
+ if (is_string_field(field)) {
+ switch (field->filter_type) {
+ case FILTER_DYN_STRING:
+ val = (unsigned long)(rec + (*(unsigned int *)addr & 0xffff));
+ break;
+ case FILTER_RDYN_STRING:
+ val = (unsigned long)(addr + (*(unsigned int *)addr & 0xffff));
+ break;
+ case FILTER_STATIC_STRING:
+ val = (unsigned long)addr;
+ break;
+ case FILTER_PTR_STRING:
+ val = (unsigned long)(*(char *)addr);
+ break;
+ default:
+ WARN_ON_ONCE(1);
+ return 0;
+ }
+ return val;
+ }
+
+ switch (field->size) {
+ case 1:
+ if (field->is_signed)
+ val = *(char *)addr;
+ else
+ val = *(unsigned char *)addr;
+ break;
+ case 2:
+ if (field->is_signed)
+ val = *(short *)addr;
+ else
+ val = *(unsigned short *)addr;
+ break;
+ case 4:
+ if (field->is_signed)
+ val = *(int *)addr;
+ else
+ val = *(unsigned int *)addr;
+ break;
+ default:
+ if (field->is_signed)
+ val = *(long *)addr;
+ else
+ val = *(unsigned long *)addr;
+ break;
+ }
+ return val;
+}
+
+/* Note that we don't verify it, since the code does not come from user space */
+static int
+process_fetch_insn(struct fetch_insn *code, void *rec, void *dest,
+ void *base)
+{
+ struct pt_regs *regs = rec;
+ unsigned long val;
+
+retry:
+ /* 1st stage: get value from context */
+ switch (code->op) {
+#ifdef CONFIG_HAVE_REGS_AND_STACK_ACCESS_API
+ case FETCH_OP_REG:
+ val = regs_get_register(regs, code->param);
+ break;
+ case FETCH_OP_STACK:
+ val = regs_get_kernel_stack_nth(regs, code->param);
+ break;
+ case FETCH_OP_STACKP:
+ val = kernel_stack_pointer(regs);
+ break;
+ case FETCH_OP_RETVAL:
+ val = regs_return_value(regs);
+ break;
+#endif
+ case FETCH_OP_IMM:
+ val = code->immediate;
+ break;
+ case FETCH_OP_COMM:
+ val = (unsigned long)current->comm;
+ break;
+ case FETCH_OP_DATA:
+ val = (unsigned long)code->data;
+ break;
+#ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
+ case FETCH_OP_ARG:
+ val = regs_get_kernel_argument(regs, code->param);
+ break;
+#endif
+ case FETCH_NOP_SYMBOL: /* Ignore a place holder */
+ code++;
+ goto retry;
+ case FETCH_OP_TP_ARG:
+ val = get_event_field(code, rec);
+ break;
+ default:
+ return -EILSEQ;
+ }
+ code++;
+
+ return process_fetch_insn_bottom(code, val, dest, base);
+}
+NOKPROBE_SYMBOL(process_fetch_insn)
+
#endif /* __TRACE_PROBE_KERNEL_H_ */
--
2.25.1
On Wed, 28 Dec 2022 15:08:25 +0800
Song Chen <[email protected]> wrote:
> There are 7 function definitions in trace_probe_tmpl.h, they are:
>
> 1, process_fetch_insn
Other functions except for this are OK for me.
But I think this function should have different instance for kprobe
and eprobe, because the passed 'void *rec' is completely different.
For the kprobe's process_fetch_insn() will take a 'pt_regs *', on the
other hand, the eprobe's process_fetch_insn() will take a
'ftrace_event_field *'.
I also, don't want to expose get_event_field() function because
it is only for the eprobes.
What about making a new common function and call it in default case
from both process_fetch_insn()? Your goal is reducing the redundant
code, then it is enough to share only the common code. :)
For example, in trace_probe_kernel.h,
process_common_fetch_insn(struct fetch_insn *code, void *dest, void *base, unsigned long *val)
{
switch (code->op) {
case FETCH_OP_IMM:
*val = code->immediate;
break;
case FETCH_OP_COMM:
*val = (unsigned long)current->comm;
break;
case FETCH_OP_DATA:
*val = (unsigned long)code->data;
break;
default:
return -EILSEQ;
}
return 0;
}
For kprobe events:
process_fetch_insn(struct fetch_insn *code, void *rec, void *dest, void *base)
{
while (code->op == FETCH_NOP_SYMBOL)
code++;
switch (code->op) {
case FETCH_OP_REG:
val = regs_get_register(regs, code->param);
...
default:
ret = process_common_fetch_insn(code, dest, base, &val);
if (ret < 0)
return ret;
}
...
}
For eprobe events:
process_fetch_insn(struct fetch_insn *code, void *rec, void *dest, void *base)
{
while (code->op == FETCH_NOP_SYMBOL)
code++;
if (code->op == FETCH_OP_TP_ARG) {
val = get_event_field(code, rec);
} else {
ret = process_common_fetch_insn(code, dest, base, &val);
if (ret < 0)
return ret;
}
...
}
You also don't see the error related to CONFIG_HAVE_REGS_AND_STACK_ACCESS_API. :)
Thank you,
> 2, fetch_store_strlen
> 3, fetch_store_string
> 4, fetch_store_strlen_user
> 5, fetch_store_string_user
> 6, probe_mem_read
> 7, probe_mem_read_user
>
> Every C file which includes trace_probe_tmpl.h has to implement them,
> otherwise it gets warnings and errors. However, some of them are identical,
> like kprobe and eprobe, as a result, there is a lot redundant code in those
> 2 files.
>
> This patch would like to provide default behaviors for those functions
> which kprobe and eprobe can share by just including trace_probe_kernel.h
> with trace_probe_tmpl.h together.
>
> It removes redundant code, increases readability, and more importantly,
> makes it easier to introduce a new feature based on trace probe
> (it's possible).
>
> Signed-off-by: Song Chen <[email protected]>
> Reported-by: kernel test robot <[email protected]>
>
> ---
> v2:
> 1, reorganize patchset
>
> v3:
> 1, mark nokprobe_inline for get_event_field
> 2, remove warnings reported from kernel test robot
> 3, fix errors reported from kernel test robot
>
> v4:
> 1, reset changes in v3(2) and v3(3), they are not reasonable fix.
> 2, I intended to introduce a new header file to exclude
> trace_events_synth.c out of the patch. However, after looking
> further, i found the errors in [1] are introduced by this patch,
> but the warning in [1] are not. The errors can be fixed by adding
> "#ifdef CONFIG_HAVE_REGS_AND_STACK_ACCESS_API".
>
> [1]:https://lore.kernel.org/lkml/[email protected]/
> ---
> kernel/trace/trace_eprobe.c | 144 ------------------------------
> kernel/trace/trace_events_synth.c | 7 +-
> kernel/trace/trace_kprobe.c | 102 ---------------------
> kernel/trace/trace_probe_kernel.h | 143 +++++++++++++++++++++++++++--
> 4 files changed, 141 insertions(+), 255 deletions(-)
>
> diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c
> index bdb26eee7a0c..60ced4a7a25d 100644
> --- a/kernel/trace/trace_eprobe.c
> +++ b/kernel/trace/trace_eprobe.c
> @@ -319,64 +319,6 @@ print_eprobe_event(struct trace_iterator *iter, int flags,
> return trace_handle_return(s);
> }
>
> -static unsigned long get_event_field(struct fetch_insn *code, void *rec)
> -{
> - struct ftrace_event_field *field = code->data;
> - unsigned long val;
> - void *addr;
> -
> - addr = rec + field->offset;
> -
> - if (is_string_field(field)) {
> - switch (field->filter_type) {
> - case FILTER_DYN_STRING:
> - val = (unsigned long)(rec + (*(unsigned int *)addr & 0xffff));
> - break;
> - case FILTER_RDYN_STRING:
> - val = (unsigned long)(addr + (*(unsigned int *)addr & 0xffff));
> - break;
> - case FILTER_STATIC_STRING:
> - val = (unsigned long)addr;
> - break;
> - case FILTER_PTR_STRING:
> - val = (unsigned long)(*(char *)addr);
> - break;
> - default:
> - WARN_ON_ONCE(1);
> - return 0;
> - }
> - return val;
> - }
> -
> - switch (field->size) {
> - case 1:
> - if (field->is_signed)
> - val = *(char *)addr;
> - else
> - val = *(unsigned char *)addr;
> - break;
> - case 2:
> - if (field->is_signed)
> - val = *(short *)addr;
> - else
> - val = *(unsigned short *)addr;
> - break;
> - case 4:
> - if (field->is_signed)
> - val = *(int *)addr;
> - else
> - val = *(unsigned int *)addr;
> - break;
> - default:
> - if (field->is_signed)
> - val = *(long *)addr;
> - else
> - val = *(unsigned long *)addr;
> - break;
> - }
> - return val;
> -}
> -
> static int get_eprobe_size(struct trace_probe *tp, void *rec)
> {
> struct fetch_insn *code;
> @@ -419,92 +361,6 @@ static int get_eprobe_size(struct trace_probe *tp, void *rec)
> return ret;
> }
>
> -/* Kprobe specific fetch functions */
> -
> -/* Note that we don't verify it, since the code does not come from user space */
> -static int
> -process_fetch_insn(struct fetch_insn *code, void *rec, void *dest,
> - void *base)
> -{
> - unsigned long val;
> -
> - retry:
> - switch (code->op) {
> - case FETCH_OP_TP_ARG:
> - val = get_event_field(code, rec);
> - break;
> - case FETCH_OP_IMM:
> - val = code->immediate;
> - break;
> - case FETCH_OP_COMM:
> - val = (unsigned long)current->comm;
> - break;
> - case FETCH_OP_DATA:
> - val = (unsigned long)code->data;
> - break;
> - case FETCH_NOP_SYMBOL: /* Ignore a place holder */
> - code++;
> - goto retry;
> - default:
> - return -EILSEQ;
> - }
> - code++;
> - return process_fetch_insn_bottom(code, val, dest, base);
> -}
> -NOKPROBE_SYMBOL(process_fetch_insn)
> -
> -/* Return the length of string -- including null terminal byte */
> -static nokprobe_inline int
> -fetch_store_strlen_user(unsigned long addr)
> -{
> - return kern_fetch_store_strlen_user(addr);
> -}
> -
> -/* Return the length of string -- including null terminal byte */
> -static nokprobe_inline int
> -fetch_store_strlen(unsigned long addr)
> -{
> - return kern_fetch_store_strlen(addr);
> -}
> -
> -/*
> - * Fetch a null-terminated string from user. Caller MUST set *(u32 *)buf
> - * with max length and relative data location.
> - */
> -static nokprobe_inline int
> -fetch_store_string_user(unsigned long addr, void *dest, void *base)
> -{
> - return kern_fetch_store_string_user(addr, dest, base);
> -}
> -
> -/*
> - * Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max
> - * length and relative data location.
> - */
> -static nokprobe_inline int
> -fetch_store_string(unsigned long addr, void *dest, void *base)
> -{
> - return kern_fetch_store_string(addr, dest, base);
> -}
> -
> -static nokprobe_inline int
> -probe_mem_read_user(void *dest, void *src, size_t size)
> -{
> - const void __user *uaddr = (__force const void __user *)src;
> -
> - return copy_from_user_nofault(dest, uaddr, size);
> -}
> -
> -static nokprobe_inline int
> -probe_mem_read(void *dest, void *src, size_t size)
> -{
> -#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
> - if ((unsigned long)src < TASK_SIZE)
> - return probe_mem_read_user(dest, src, size);
> -#endif
> - return copy_from_kernel_nofault(dest, src, size);
> -}
> -
> /* eprobe handler */
> static inline void
> __eprobe_trace_func(struct eprobe_data *edata, void *rec)
> diff --git a/kernel/trace/trace_events_synth.c b/kernel/trace/trace_events_synth.c
> index e310052dc83c..7460f18ba973 100644
> --- a/kernel/trace/trace_events_synth.c
> +++ b/kernel/trace/trace_events_synth.c
> @@ -18,6 +18,7 @@
> #include <linux/trace_events.h>
> #include <trace/events/mmflags.h>
> #include "trace_probe.h"
> +#include "trace_probe_tmpl.h"
> #include "trace_probe_kernel.h"
>
> #include "trace_synth.h"
> @@ -420,12 +421,12 @@ static unsigned int trace_string(struct synth_trace_event *entry,
> data_offset += event->n_u64 * sizeof(u64);
> data_offset += data_size;
>
> - len = kern_fetch_store_strlen((unsigned long)str_val);
> + len = fetch_store_strlen((unsigned long)str_val);
>
> data_offset |= len << 16;
> *(u32 *)&entry->fields[*n_u64] = data_offset;
>
> - ret = kern_fetch_store_string((unsigned long)str_val, &entry->fields[*n_u64], entry);
> + ret = fetch_store_string((unsigned long)str_val, &entry->fields[*n_u64], entry);
>
> (*n_u64)++;
> } else {
> @@ -473,7 +474,7 @@ static notrace void trace_event_raw_event_synth(void *__data,
> val_idx = var_ref_idx[field_pos];
> str_val = (char *)(long)var_ref_vals[val_idx];
>
> - len = kern_fetch_store_strlen((unsigned long)str_val);
> + len = fetch_store_strlen((unsigned long)str_val);
>
> fields_size += len;
> }
> diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
> index a4ffa864dbb7..c2e0b741ae82 100644
> --- a/kernel/trace/trace_kprobe.c
> +++ b/kernel/trace/trace_kprobe.c
> @@ -1218,108 +1218,6 @@ static const struct file_operations kprobe_profile_ops = {
> .release = seq_release,
> };
>
> -/* Kprobe specific fetch functions */
> -
> -/* Return the length of string -- including null terminal byte */
> -static nokprobe_inline int
> -fetch_store_strlen_user(unsigned long addr)
> -{
> - return kern_fetch_store_strlen_user(addr);
> -}
> -
> -/* Return the length of string -- including null terminal byte */
> -static nokprobe_inline int
> -fetch_store_strlen(unsigned long addr)
> -{
> - return kern_fetch_store_strlen(addr);
> -}
> -
> -/*
> - * Fetch a null-terminated string from user. Caller MUST set *(u32 *)buf
> - * with max length and relative data location.
> - */
> -static nokprobe_inline int
> -fetch_store_string_user(unsigned long addr, void *dest, void *base)
> -{
> - return kern_fetch_store_string_user(addr, dest, base);
> -}
> -
> -/*
> - * Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max
> - * length and relative data location.
> - */
> -static nokprobe_inline int
> -fetch_store_string(unsigned long addr, void *dest, void *base)
> -{
> - return kern_fetch_store_string(addr, dest, base);
> -}
> -
> -static nokprobe_inline int
> -probe_mem_read_user(void *dest, void *src, size_t size)
> -{
> - const void __user *uaddr = (__force const void __user *)src;
> -
> - return copy_from_user_nofault(dest, uaddr, size);
> -}
> -
> -static nokprobe_inline int
> -probe_mem_read(void *dest, void *src, size_t size)
> -{
> -#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
> - if ((unsigned long)src < TASK_SIZE)
> - return probe_mem_read_user(dest, src, size);
> -#endif
> - return copy_from_kernel_nofault(dest, src, size);
> -}
> -
> -/* Note that we don't verify it, since the code does not come from user space */
> -static int
> -process_fetch_insn(struct fetch_insn *code, void *rec, void *dest,
> - void *base)
> -{
> - struct pt_regs *regs = rec;
> - unsigned long val;
> -
> -retry:
> - /* 1st stage: get value from context */
> - switch (code->op) {
> - case FETCH_OP_REG:
> - val = regs_get_register(regs, code->param);
> - break;
> - case FETCH_OP_STACK:
> - val = regs_get_kernel_stack_nth(regs, code->param);
> - break;
> - case FETCH_OP_STACKP:
> - val = kernel_stack_pointer(regs);
> - break;
> - case FETCH_OP_RETVAL:
> - val = regs_return_value(regs);
> - break;
> - case FETCH_OP_IMM:
> - val = code->immediate;
> - break;
> - case FETCH_OP_COMM:
> - val = (unsigned long)current->comm;
> - break;
> - case FETCH_OP_DATA:
> - val = (unsigned long)code->data;
> - break;
> -#ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
> - case FETCH_OP_ARG:
> - val = regs_get_kernel_argument(regs, code->param);
> - break;
> -#endif
> - case FETCH_NOP_SYMBOL: /* Ignore a place holder */
> - code++;
> - goto retry;
> - default:
> - return -EILSEQ;
> - }
> - code++;
> -
> - return process_fetch_insn_bottom(code, val, dest, base);
> -}
> -NOKPROBE_SYMBOL(process_fetch_insn)
>
> /* Kprobe handler */
> static nokprobe_inline void
> diff --git a/kernel/trace/trace_probe_kernel.h b/kernel/trace/trace_probe_kernel.h
> index 77dbd9ff9782..39f44513ec4e 100644
> --- a/kernel/trace/trace_probe_kernel.h
> +++ b/kernel/trace/trace_probe_kernel.h
> @@ -12,7 +12,7 @@
> */
> /* Return the length of string -- including null terminal byte */
> static nokprobe_inline int
> -kern_fetch_store_strlen_user(unsigned long addr)
> +fetch_store_strlen_user(unsigned long addr)
> {
> const void __user *uaddr = (__force const void __user *)addr;
> int ret;
> @@ -29,14 +29,14 @@ kern_fetch_store_strlen_user(unsigned long addr)
>
> /* Return the length of string -- including null terminal byte */
> static nokprobe_inline int
> -kern_fetch_store_strlen(unsigned long addr)
> +fetch_store_strlen(unsigned long addr)
> {
> int ret, len = 0;
> u8 c;
>
> #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
> if (addr < TASK_SIZE)
> - return kern_fetch_store_strlen_user(addr);
> + return fetch_store_strlen_user(addr);
> #endif
>
> do {
> @@ -63,7 +63,7 @@ static nokprobe_inline void set_data_loc(int ret, void *dest, void *__dest, void
> * with max length and relative data location.
> */
> static nokprobe_inline int
> -kern_fetch_store_string_user(unsigned long addr, void *dest, void *base)
> +fetch_store_string_user(unsigned long addr, void *dest, void *base)
> {
> const void __user *uaddr = (__force const void __user *)addr;
> int maxlen = get_loc_len(*(u32 *)dest);
> @@ -86,7 +86,7 @@ kern_fetch_store_string_user(unsigned long addr, void *dest, void *base)
> * length and relative data location.
> */
> static nokprobe_inline int
> -kern_fetch_store_string(unsigned long addr, void *dest, void *base)
> +fetch_store_string(unsigned long addr, void *dest, void *base)
> {
> int maxlen = get_loc_len(*(u32 *)dest);
> void *__dest;
> @@ -94,7 +94,7 @@ kern_fetch_store_string(unsigned long addr, void *dest, void *base)
>
> #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
> if ((unsigned long)addr < TASK_SIZE)
> - return kern_fetch_store_string_user(addr, dest, base);
> + return fetch_store_string_user(addr, dest, base);
> #endif
>
> if (unlikely(!maxlen))
> @@ -112,4 +112,135 @@ kern_fetch_store_string(unsigned long addr, void *dest, void *base)
> return ret;
> }
>
> +static nokprobe_inline int
> +probe_mem_read_user(void *dest, void *src, size_t size)
> +{
> + const void __user *uaddr = (__force const void __user *)src;
> +
> + return copy_from_user_nofault(dest, uaddr, size);
> +}
> +
> +static nokprobe_inline int
> +probe_mem_read(void *dest, void *src, size_t size)
> +{
> +#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
> + if ((unsigned long)src < TASK_SIZE)
> + return probe_mem_read_user(dest, src, size);
> +#endif
> + return copy_from_kernel_nofault(dest, src, size);
> +}
> +
> +static nokprobe_inline unsigned long
> +get_event_field(struct fetch_insn *code, void *rec)
> +{
> + struct ftrace_event_field *field = code->data;
> + unsigned long val;
> + void *addr;
> +
> + addr = rec + field->offset;
> +
> + if (is_string_field(field)) {
> + switch (field->filter_type) {
> + case FILTER_DYN_STRING:
> + val = (unsigned long)(rec + (*(unsigned int *)addr & 0xffff));
> + break;
> + case FILTER_RDYN_STRING:
> + val = (unsigned long)(addr + (*(unsigned int *)addr & 0xffff));
> + break;
> + case FILTER_STATIC_STRING:
> + val = (unsigned long)addr;
> + break;
> + case FILTER_PTR_STRING:
> + val = (unsigned long)(*(char *)addr);
> + break;
> + default:
> + WARN_ON_ONCE(1);
> + return 0;
> + }
> + return val;
> + }
> +
> + switch (field->size) {
> + case 1:
> + if (field->is_signed)
> + val = *(char *)addr;
> + else
> + val = *(unsigned char *)addr;
> + break;
> + case 2:
> + if (field->is_signed)
> + val = *(short *)addr;
> + else
> + val = *(unsigned short *)addr;
> + break;
> + case 4:
> + if (field->is_signed)
> + val = *(int *)addr;
> + else
> + val = *(unsigned int *)addr;
> + break;
> + default:
> + if (field->is_signed)
> + val = *(long *)addr;
> + else
> + val = *(unsigned long *)addr;
> + break;
> + }
> + return val;
> +}
> +
> +/* Note that we don't verify it, since the code does not come from user space */
> +static int
> +process_fetch_insn(struct fetch_insn *code, void *rec, void *dest,
> + void *base)
> +{
> + struct pt_regs *regs = rec;
> + unsigned long val;
> +
> +retry:
> + /* 1st stage: get value from context */
> + switch (code->op) {
> +#ifdef CONFIG_HAVE_REGS_AND_STACK_ACCESS_API
> + case FETCH_OP_REG:
> + val = regs_get_register(regs, code->param);
> + break;
> + case FETCH_OP_STACK:
> + val = regs_get_kernel_stack_nth(regs, code->param);
> + break;
> + case FETCH_OP_STACKP:
> + val = kernel_stack_pointer(regs);
> + break;
> + case FETCH_OP_RETVAL:
> + val = regs_return_value(regs);
> + break;
> +#endif
> + case FETCH_OP_IMM:
> + val = code->immediate;
> + break;
> + case FETCH_OP_COMM:
> + val = (unsigned long)current->comm;
> + break;
> + case FETCH_OP_DATA:
> + val = (unsigned long)code->data;
> + break;
> +#ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
> + case FETCH_OP_ARG:
> + val = regs_get_kernel_argument(regs, code->param);
> + break;
> +#endif
> + case FETCH_NOP_SYMBOL: /* Ignore a place holder */
> + code++;
> + goto retry;
> + case FETCH_OP_TP_ARG:
> + val = get_event_field(code, rec);
> + break;
> + default:
> + return -EILSEQ;
> + }
> + code++;
> +
> + return process_fetch_insn_bottom(code, val, dest, base);
> +}
> +NOKPROBE_SYMBOL(process_fetch_insn)
> +
> #endif /* __TRACE_PROBE_KERNEL_H_ */
> --
> 2.25.1
>
--
Masami Hiramatsu (Google) <[email protected]>
Hi,
在 2022/12/29 17:30, Masami Hiramatsu (Google) 写道:
> On Wed, 28 Dec 2022 15:08:25 +0800
> Song Chen <[email protected]> wrote:
>
>> There are 7 function definitions in trace_probe_tmpl.h, they are:
>>
>> 1, process_fetch_insn
>
> Other functions except for this are OK for me.
> But I think this function should have different instance for kprobe
> and eprobe, because the passed 'void *rec' is completely different.
> For the kprobe's process_fetch_insn() will take a 'pt_regs *', on the
> other hand, the eprobe's process_fetch_insn() will take a
> 'ftrace_event_field *'.
> I also, don't want to expose get_event_field() function because
> it is only for the eprobes.
>
> What about making a new common function and call it in default case
> from both process_fetch_insn()? Your goal is reducing the redundant
> code, then it is enough to share only the common code. :)
>
> For example, in trace_probe_kernel.h,
>
> process_common_fetch_insn(struct fetch_insn *code, void *dest, void *base, unsigned long *val)
> {
> switch (code->op) {
> case FETCH_OP_IMM:
> *val = code->immediate;
> break;
> case FETCH_OP_COMM:
> *val = (unsigned long)current->comm;
> break;
> case FETCH_OP_DATA:
> *val = (unsigned long)code->data;
> break;
> default:
> return -EILSEQ;
> }
> return 0;
> }
>
> For kprobe events:
>
> process_fetch_insn(struct fetch_insn *code, void *rec, void *dest, void *base)
> {
> while (code->op == FETCH_NOP_SYMBOL)
> code++;
> switch (code->op) {
> case FETCH_OP_REG:
> val = regs_get_register(regs, code->param);
> ...
> default:
> ret = process_common_fetch_insn(code, dest, base, &val);
> if (ret < 0)
> return ret;
> }
> ...
> }
>
> For eprobe events:
>
> process_fetch_insn(struct fetch_insn *code, void *rec, void *dest, void *base)
> {
> while (code->op == FETCH_NOP_SYMBOL)
> code++;
> if (code->op == FETCH_OP_TP_ARG) {
> val = get_event_field(code, rec);
> } else {
> ret = process_common_fetch_insn(code, dest, base, &val);
> if (ret < 0)
> return ret;
> }
> ...
> }
>
> You also don't see the error related to CONFIG_HAVE_REGS_AND_STACK_ACCESS_API. :)
>
> Thank you,
>
Thanks a lot for the good idea and so specific demo code, i accept it
and will submit a new one based on it.
If we think about it further, we can implement process_common_fetch_insn
in trace_probe_tmpl.h, uprobe can benefit from it as well, what do you
think? i will include it in the next submit and you can have a look.
Thanks again.
Song
>> 2, fetch_store_strlen
>> 3, fetch_store_string
>> 4, fetch_store_strlen_user
>> 5, fetch_store_string_user
>> 6, probe_mem_read
>> 7, probe_mem_read_user
>>
>> Every C file which includes trace_probe_tmpl.h has to implement them,
>> otherwise it gets warnings and errors. However, some of them are identical,
>> like kprobe and eprobe, as a result, there is a lot redundant code in those
>> 2 files.
>>
>> This patch would like to provide default behaviors for those functions
>> which kprobe and eprobe can share by just including trace_probe_kernel.h
>> with trace_probe_tmpl.h together.
>>
>> It removes redundant code, increases readability, and more importantly,
>> makes it easier to introduce a new feature based on trace probe
>> (it's possible).
>>
>> Signed-off-by: Song Chen <[email protected]>
>> Reported-by: kernel test robot <[email protected]>
>>
>> ---
>> v2:
>> 1, reorganize patchset
>>
>> v3:
>> 1, mark nokprobe_inline for get_event_field
>> 2, remove warnings reported from kernel test robot
>> 3, fix errors reported from kernel test robot
>>
>> v4:
>> 1, reset changes in v3(2) and v3(3), they are not reasonable fix.
>> 2, I intended to introduce a new header file to exclude
>> trace_events_synth.c out of the patch. However, after looking
>> further, i found the errors in [1] are introduced by this patch,
>> but the warning in [1] are not. The errors can be fixed by adding
>> "#ifdef CONFIG_HAVE_REGS_AND_STACK_ACCESS_API".
>>
>> [1]:https://lore.kernel.org/lkml/[email protected]/
>> ---
>> kernel/trace/trace_eprobe.c | 144 ------------------------------
>> kernel/trace/trace_events_synth.c | 7 +-
>> kernel/trace/trace_kprobe.c | 102 ---------------------
>> kernel/trace/trace_probe_kernel.h | 143 +++++++++++++++++++++++++++--
>> 4 files changed, 141 insertions(+), 255 deletions(-)
>>
>> diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c
>> index bdb26eee7a0c..60ced4a7a25d 100644
>> --- a/kernel/trace/trace_eprobe.c
>> +++ b/kernel/trace/trace_eprobe.c
>> @@ -319,64 +319,6 @@ print_eprobe_event(struct trace_iterator *iter, int flags,
>> return trace_handle_return(s);
>> }
>>
>> -static unsigned long get_event_field(struct fetch_insn *code, void *rec)
>> -{
>> - struct ftrace_event_field *field = code->data;
>> - unsigned long val;
>> - void *addr;
>> -
>> - addr = rec + field->offset;
>> -
>> - if (is_string_field(field)) {
>> - switch (field->filter_type) {
>> - case FILTER_DYN_STRING:
>> - val = (unsigned long)(rec + (*(unsigned int *)addr & 0xffff));
>> - break;
>> - case FILTER_RDYN_STRING:
>> - val = (unsigned long)(addr + (*(unsigned int *)addr & 0xffff));
>> - break;
>> - case FILTER_STATIC_STRING:
>> - val = (unsigned long)addr;
>> - break;
>> - case FILTER_PTR_STRING:
>> - val = (unsigned long)(*(char *)addr);
>> - break;
>> - default:
>> - WARN_ON_ONCE(1);
>> - return 0;
>> - }
>> - return val;
>> - }
>> -
>> - switch (field->size) {
>> - case 1:
>> - if (field->is_signed)
>> - val = *(char *)addr;
>> - else
>> - val = *(unsigned char *)addr;
>> - break;
>> - case 2:
>> - if (field->is_signed)
>> - val = *(short *)addr;
>> - else
>> - val = *(unsigned short *)addr;
>> - break;
>> - case 4:
>> - if (field->is_signed)
>> - val = *(int *)addr;
>> - else
>> - val = *(unsigned int *)addr;
>> - break;
>> - default:
>> - if (field->is_signed)
>> - val = *(long *)addr;
>> - else
>> - val = *(unsigned long *)addr;
>> - break;
>> - }
>> - return val;
>> -}
>> -
>> static int get_eprobe_size(struct trace_probe *tp, void *rec)
>> {
>> struct fetch_insn *code;
>> @@ -419,92 +361,6 @@ static int get_eprobe_size(struct trace_probe *tp, void *rec)
>> return ret;
>> }
>>
>> -/* Kprobe specific fetch functions */
>> -
>> -/* Note that we don't verify it, since the code does not come from user space */
>> -static int
>> -process_fetch_insn(struct fetch_insn *code, void *rec, void *dest,
>> - void *base)
>> -{
>> - unsigned long val;
>> -
>> - retry:
>> - switch (code->op) {
>> - case FETCH_OP_TP_ARG:
>> - val = get_event_field(code, rec);
>> - break;
>> - case FETCH_OP_IMM:
>> - val = code->immediate;
>> - break;
>> - case FETCH_OP_COMM:
>> - val = (unsigned long)current->comm;
>> - break;
>> - case FETCH_OP_DATA:
>> - val = (unsigned long)code->data;
>> - break;
>> - case FETCH_NOP_SYMBOL: /* Ignore a place holder */
>> - code++;
>> - goto retry;
>> - default:
>> - return -EILSEQ;
>> - }
>> - code++;
>> - return process_fetch_insn_bottom(code, val, dest, base);
>> -}
>> -NOKPROBE_SYMBOL(process_fetch_insn)
>> -
>> -/* Return the length of string -- including null terminal byte */
>> -static nokprobe_inline int
>> -fetch_store_strlen_user(unsigned long addr)
>> -{
>> - return kern_fetch_store_strlen_user(addr);
>> -}
>> -
>> -/* Return the length of string -- including null terminal byte */
>> -static nokprobe_inline int
>> -fetch_store_strlen(unsigned long addr)
>> -{
>> - return kern_fetch_store_strlen(addr);
>> -}
>> -
>> -/*
>> - * Fetch a null-terminated string from user. Caller MUST set *(u32 *)buf
>> - * with max length and relative data location.
>> - */
>> -static nokprobe_inline int
>> -fetch_store_string_user(unsigned long addr, void *dest, void *base)
>> -{
>> - return kern_fetch_store_string_user(addr, dest, base);
>> -}
>> -
>> -/*
>> - * Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max
>> - * length and relative data location.
>> - */
>> -static nokprobe_inline int
>> -fetch_store_string(unsigned long addr, void *dest, void *base)
>> -{
>> - return kern_fetch_store_string(addr, dest, base);
>> -}
>> -
>> -static nokprobe_inline int
>> -probe_mem_read_user(void *dest, void *src, size_t size)
>> -{
>> - const void __user *uaddr = (__force const void __user *)src;
>> -
>> - return copy_from_user_nofault(dest, uaddr, size);
>> -}
>> -
>> -static nokprobe_inline int
>> -probe_mem_read(void *dest, void *src, size_t size)
>> -{
>> -#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
>> - if ((unsigned long)src < TASK_SIZE)
>> - return probe_mem_read_user(dest, src, size);
>> -#endif
>> - return copy_from_kernel_nofault(dest, src, size);
>> -}
>> -
>> /* eprobe handler */
>> static inline void
>> __eprobe_trace_func(struct eprobe_data *edata, void *rec)
>> diff --git a/kernel/trace/trace_events_synth.c b/kernel/trace/trace_events_synth.c
>> index e310052dc83c..7460f18ba973 100644
>> --- a/kernel/trace/trace_events_synth.c
>> +++ b/kernel/trace/trace_events_synth.c
>> @@ -18,6 +18,7 @@
>> #include <linux/trace_events.h>
>> #include <trace/events/mmflags.h>
>> #include "trace_probe.h"
>> +#include "trace_probe_tmpl.h"
>> #include "trace_probe_kernel.h"
>>
>> #include "trace_synth.h"
>> @@ -420,12 +421,12 @@ static unsigned int trace_string(struct synth_trace_event *entry,
>> data_offset += event->n_u64 * sizeof(u64);
>> data_offset += data_size;
>>
>> - len = kern_fetch_store_strlen((unsigned long)str_val);
>> + len = fetch_store_strlen((unsigned long)str_val);
>>
>> data_offset |= len << 16;
>> *(u32 *)&entry->fields[*n_u64] = data_offset;
>>
>> - ret = kern_fetch_store_string((unsigned long)str_val, &entry->fields[*n_u64], entry);
>> + ret = fetch_store_string((unsigned long)str_val, &entry->fields[*n_u64], entry);
>>
>> (*n_u64)++;
>> } else {
>> @@ -473,7 +474,7 @@ static notrace void trace_event_raw_event_synth(void *__data,
>> val_idx = var_ref_idx[field_pos];
>> str_val = (char *)(long)var_ref_vals[val_idx];
>>
>> - len = kern_fetch_store_strlen((unsigned long)str_val);
>> + len = fetch_store_strlen((unsigned long)str_val);
>>
>> fields_size += len;
>> }
>> diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
>> index a4ffa864dbb7..c2e0b741ae82 100644
>> --- a/kernel/trace/trace_kprobe.c
>> +++ b/kernel/trace/trace_kprobe.c
>> @@ -1218,108 +1218,6 @@ static const struct file_operations kprobe_profile_ops = {
>> .release = seq_release,
>> };
>>
>> -/* Kprobe specific fetch functions */
>> -
>> -/* Return the length of string -- including null terminal byte */
>> -static nokprobe_inline int
>> -fetch_store_strlen_user(unsigned long addr)
>> -{
>> - return kern_fetch_store_strlen_user(addr);
>> -}
>> -
>> -/* Return the length of string -- including null terminal byte */
>> -static nokprobe_inline int
>> -fetch_store_strlen(unsigned long addr)
>> -{
>> - return kern_fetch_store_strlen(addr);
>> -}
>> -
>> -/*
>> - * Fetch a null-terminated string from user. Caller MUST set *(u32 *)buf
>> - * with max length and relative data location.
>> - */
>> -static nokprobe_inline int
>> -fetch_store_string_user(unsigned long addr, void *dest, void *base)
>> -{
>> - return kern_fetch_store_string_user(addr, dest, base);
>> -}
>> -
>> -/*
>> - * Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max
>> - * length and relative data location.
>> - */
>> -static nokprobe_inline int
>> -fetch_store_string(unsigned long addr, void *dest, void *base)
>> -{
>> - return kern_fetch_store_string(addr, dest, base);
>> -}
>> -
>> -static nokprobe_inline int
>> -probe_mem_read_user(void *dest, void *src, size_t size)
>> -{
>> - const void __user *uaddr = (__force const void __user *)src;
>> -
>> - return copy_from_user_nofault(dest, uaddr, size);
>> -}
>> -
>> -static nokprobe_inline int
>> -probe_mem_read(void *dest, void *src, size_t size)
>> -{
>> -#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
>> - if ((unsigned long)src < TASK_SIZE)
>> - return probe_mem_read_user(dest, src, size);
>> -#endif
>> - return copy_from_kernel_nofault(dest, src, size);
>> -}
>> -
>> -/* Note that we don't verify it, since the code does not come from user space */
>> -static int
>> -process_fetch_insn(struct fetch_insn *code, void *rec, void *dest,
>> - void *base)
>> -{
>> - struct pt_regs *regs = rec;
>> - unsigned long val;
>> -
>> -retry:
>> - /* 1st stage: get value from context */
>> - switch (code->op) {
>> - case FETCH_OP_REG:
>> - val = regs_get_register(regs, code->param);
>> - break;
>> - case FETCH_OP_STACK:
>> - val = regs_get_kernel_stack_nth(regs, code->param);
>> - break;
>> - case FETCH_OP_STACKP:
>> - val = kernel_stack_pointer(regs);
>> - break;
>> - case FETCH_OP_RETVAL:
>> - val = regs_return_value(regs);
>> - break;
>> - case FETCH_OP_IMM:
>> - val = code->immediate;
>> - break;
>> - case FETCH_OP_COMM:
>> - val = (unsigned long)current->comm;
>> - break;
>> - case FETCH_OP_DATA:
>> - val = (unsigned long)code->data;
>> - break;
>> -#ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
>> - case FETCH_OP_ARG:
>> - val = regs_get_kernel_argument(regs, code->param);
>> - break;
>> -#endif
>> - case FETCH_NOP_SYMBOL: /* Ignore a place holder */
>> - code++;
>> - goto retry;
>> - default:
>> - return -EILSEQ;
>> - }
>> - code++;
>> -
>> - return process_fetch_insn_bottom(code, val, dest, base);
>> -}
>> -NOKPROBE_SYMBOL(process_fetch_insn)
>>
>> /* Kprobe handler */
>> static nokprobe_inline void
>> diff --git a/kernel/trace/trace_probe_kernel.h b/kernel/trace/trace_probe_kernel.h
>> index 77dbd9ff9782..39f44513ec4e 100644
>> --- a/kernel/trace/trace_probe_kernel.h
>> +++ b/kernel/trace/trace_probe_kernel.h
>> @@ -12,7 +12,7 @@
>> */
>> /* Return the length of string -- including null terminal byte */
>> static nokprobe_inline int
>> -kern_fetch_store_strlen_user(unsigned long addr)
>> +fetch_store_strlen_user(unsigned long addr)
>> {
>> const void __user *uaddr = (__force const void __user *)addr;
>> int ret;
>> @@ -29,14 +29,14 @@ kern_fetch_store_strlen_user(unsigned long addr)
>>
>> /* Return the length of string -- including null terminal byte */
>> static nokprobe_inline int
>> -kern_fetch_store_strlen(unsigned long addr)
>> +fetch_store_strlen(unsigned long addr)
>> {
>> int ret, len = 0;
>> u8 c;
>>
>> #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
>> if (addr < TASK_SIZE)
>> - return kern_fetch_store_strlen_user(addr);
>> + return fetch_store_strlen_user(addr);
>> #endif
>>
>> do {
>> @@ -63,7 +63,7 @@ static nokprobe_inline void set_data_loc(int ret, void *dest, void *__dest, void
>> * with max length and relative data location.
>> */
>> static nokprobe_inline int
>> -kern_fetch_store_string_user(unsigned long addr, void *dest, void *base)
>> +fetch_store_string_user(unsigned long addr, void *dest, void *base)
>> {
>> const void __user *uaddr = (__force const void __user *)addr;
>> int maxlen = get_loc_len(*(u32 *)dest);
>> @@ -86,7 +86,7 @@ kern_fetch_store_string_user(unsigned long addr, void *dest, void *base)
>> * length and relative data location.
>> */
>> static nokprobe_inline int
>> -kern_fetch_store_string(unsigned long addr, void *dest, void *base)
>> +fetch_store_string(unsigned long addr, void *dest, void *base)
>> {
>> int maxlen = get_loc_len(*(u32 *)dest);
>> void *__dest;
>> @@ -94,7 +94,7 @@ kern_fetch_store_string(unsigned long addr, void *dest, void *base)
>>
>> #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
>> if ((unsigned long)addr < TASK_SIZE)
>> - return kern_fetch_store_string_user(addr, dest, base);
>> + return fetch_store_string_user(addr, dest, base);
>> #endif
>>
>> if (unlikely(!maxlen))
>> @@ -112,4 +112,135 @@ kern_fetch_store_string(unsigned long addr, void *dest, void *base)
>> return ret;
>> }
>>
>> +static nokprobe_inline int
>> +probe_mem_read_user(void *dest, void *src, size_t size)
>> +{
>> + const void __user *uaddr = (__force const void __user *)src;
>> +
>> + return copy_from_user_nofault(dest, uaddr, size);
>> +}
>> +
>> +static nokprobe_inline int
>> +probe_mem_read(void *dest, void *src, size_t size)
>> +{
>> +#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
>> + if ((unsigned long)src < TASK_SIZE)
>> + return probe_mem_read_user(dest, src, size);
>> +#endif
>> + return copy_from_kernel_nofault(dest, src, size);
>> +}
>> +
>> +static nokprobe_inline unsigned long
>> +get_event_field(struct fetch_insn *code, void *rec)
>> +{
>> + struct ftrace_event_field *field = code->data;
>> + unsigned long val;
>> + void *addr;
>> +
>> + addr = rec + field->offset;
>> +
>> + if (is_string_field(field)) {
>> + switch (field->filter_type) {
>> + case FILTER_DYN_STRING:
>> + val = (unsigned long)(rec + (*(unsigned int *)addr & 0xffff));
>> + break;
>> + case FILTER_RDYN_STRING:
>> + val = (unsigned long)(addr + (*(unsigned int *)addr & 0xffff));
>> + break;
>> + case FILTER_STATIC_STRING:
>> + val = (unsigned long)addr;
>> + break;
>> + case FILTER_PTR_STRING:
>> + val = (unsigned long)(*(char *)addr);
>> + break;
>> + default:
>> + WARN_ON_ONCE(1);
>> + return 0;
>> + }
>> + return val;
>> + }
>> +
>> + switch (field->size) {
>> + case 1:
>> + if (field->is_signed)
>> + val = *(char *)addr;
>> + else
>> + val = *(unsigned char *)addr;
>> + break;
>> + case 2:
>> + if (field->is_signed)
>> + val = *(short *)addr;
>> + else
>> + val = *(unsigned short *)addr;
>> + break;
>> + case 4:
>> + if (field->is_signed)
>> + val = *(int *)addr;
>> + else
>> + val = *(unsigned int *)addr;
>> + break;
>> + default:
>> + if (field->is_signed)
>> + val = *(long *)addr;
>> + else
>> + val = *(unsigned long *)addr;
>> + break;
>> + }
>> + return val;
>> +}
>> +
>> +/* Note that we don't verify it, since the code does not come from user space */
>> +static int
>> +process_fetch_insn(struct fetch_insn *code, void *rec, void *dest,
>> + void *base)
>> +{
>> + struct pt_regs *regs = rec;
>> + unsigned long val;
>> +
>> +retry:
>> + /* 1st stage: get value from context */
>> + switch (code->op) {
>> +#ifdef CONFIG_HAVE_REGS_AND_STACK_ACCESS_API
>> + case FETCH_OP_REG:
>> + val = regs_get_register(regs, code->param);
>> + break;
>> + case FETCH_OP_STACK:
>> + val = regs_get_kernel_stack_nth(regs, code->param);
>> + break;
>> + case FETCH_OP_STACKP:
>> + val = kernel_stack_pointer(regs);
>> + break;
>> + case FETCH_OP_RETVAL:
>> + val = regs_return_value(regs);
>> + break;
>> +#endif
>> + case FETCH_OP_IMM:
>> + val = code->immediate;
>> + break;
>> + case FETCH_OP_COMM:
>> + val = (unsigned long)current->comm;
>> + break;
>> + case FETCH_OP_DATA:
>> + val = (unsigned long)code->data;
>> + break;
>> +#ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
>> + case FETCH_OP_ARG:
>> + val = regs_get_kernel_argument(regs, code->param);
>> + break;
>> +#endif
>> + case FETCH_NOP_SYMBOL: /* Ignore a place holder */
>> + code++;
>> + goto retry;
>> + case FETCH_OP_TP_ARG:
>> + val = get_event_field(code, rec);
>> + break;
>> + default:
>> + return -EILSEQ;
>> + }
>> + code++;
>> +
>> + return process_fetch_insn_bottom(code, val, dest, base);
>> +}
>> +NOKPROBE_SYMBOL(process_fetch_insn)
>> +
>> #endif /* __TRACE_PROBE_KERNEL_H_ */
>> --
>> 2.25.1
>>
>
>
On Fri, 30 Dec 2022 09:59:31 +0800
Song Chen <[email protected]> wrote:
> Hi,
>
> 在 2022/12/29 17:30, Masami Hiramatsu (Google) 写道:
> > On Wed, 28 Dec 2022 15:08:25 +0800
> > Song Chen <[email protected]> wrote:
> >
> >> There are 7 function definitions in trace_probe_tmpl.h, they are:
> >>
> >> 1, process_fetch_insn
> >
> > Other functions except for this are OK for me.
> > But I think this function should have different instance for kprobe
> > and eprobe, because the passed 'void *rec' is completely different.
> > For the kprobe's process_fetch_insn() will take a 'pt_regs *', on the
> > other hand, the eprobe's process_fetch_insn() will take a
> > 'ftrace_event_field *'.
> > I also, don't want to expose get_event_field() function because
> > it is only for the eprobes.
> >
> > What about making a new common function and call it in default case
> > from both process_fetch_insn()? Your goal is reducing the redundant
> > code, then it is enough to share only the common code. :)
> >
> > For example, in trace_probe_kernel.h,
> >
> > process_common_fetch_insn(struct fetch_insn *code, void *dest, void *base, unsigned long *val)
> > {
> > switch (code->op) {
> > case FETCH_OP_IMM:
> > *val = code->immediate;
> > break;
> > case FETCH_OP_COMM:
> > *val = (unsigned long)current->comm;
> > break;
> > case FETCH_OP_DATA:
> > *val = (unsigned long)code->data;
> > break;
> > default:
> > return -EILSEQ;
> > }
> > return 0;
> > }
> >
> > For kprobe events:
> >
> > process_fetch_insn(struct fetch_insn *code, void *rec, void *dest, void *base)
> > {
> > while (code->op == FETCH_NOP_SYMBOL)
> > code++;
> > switch (code->op) {
> > case FETCH_OP_REG:
> > val = regs_get_register(regs, code->param);
> > ...
> > default:
> > ret = process_common_fetch_insn(code, dest, base, &val);
> > if (ret < 0)
> > return ret;
> > }
> > ...
> > }
> >
> > For eprobe events:
> >
> > process_fetch_insn(struct fetch_insn *code, void *rec, void *dest, void *base)
> > {
> > while (code->op == FETCH_NOP_SYMBOL)
> > code++;
> > if (code->op == FETCH_OP_TP_ARG) {
> > val = get_event_field(code, rec);
> > } else {
> > ret = process_common_fetch_insn(code, dest, base, &val);
> > if (ret < 0)
> > return ret;
> > }
> > ...
> > }
> >
> > You also don't see the error related to CONFIG_HAVE_REGS_AND_STACK_ACCESS_API. :)
> >
> > Thank you,
> >
>
> Thanks a lot for the good idea and so specific demo code, i accept it
> and will submit a new one based on it.
>
> If we think about it further, we can implement process_common_fetch_insn
> in trace_probe_tmpl.h, uprobe can benefit from it as well, what do you
> think? i will include it in the next submit and you can have a look.
Agreed. It sounds good to me. :)
Thank you!
>
> Thanks again.
>
> Song
>
> >> 2, fetch_store_strlen
> >> 3, fetch_store_string
> >> 4, fetch_store_strlen_user
> >> 5, fetch_store_string_user
> >> 6, probe_mem_read
> >> 7, probe_mem_read_user
> >>
> >> Every C file which includes trace_probe_tmpl.h has to implement them,
> >> otherwise it gets warnings and errors. However, some of them are identical,
> >> like kprobe and eprobe, as a result, there is a lot redundant code in those
> >> 2 files.
> >>
> >> This patch would like to provide default behaviors for those functions
> >> which kprobe and eprobe can share by just including trace_probe_kernel.h
> >> with trace_probe_tmpl.h together.
> >>
> >> It removes redundant code, increases readability, and more importantly,
> >> makes it easier to introduce a new feature based on trace probe
> >> (it's possible).
> >>
> >> Signed-off-by: Song Chen <[email protected]>
> >> Reported-by: kernel test robot <[email protected]>
> >>
> >> ---
> >> v2:
> >> 1, reorganize patchset
> >>
> >> v3:
> >> 1, mark nokprobe_inline for get_event_field
> >> 2, remove warnings reported from kernel test robot
> >> 3, fix errors reported from kernel test robot
> >>
> >> v4:
> >> 1, reset changes in v3(2) and v3(3), they are not reasonable fix.
> >> 2, I intended to introduce a new header file to exclude
> >> trace_events_synth.c out of the patch. However, after looking
> >> further, i found the errors in [1] are introduced by this patch,
> >> but the warning in [1] are not. The errors can be fixed by adding
> >> "#ifdef CONFIG_HAVE_REGS_AND_STACK_ACCESS_API".
> >>
> >> [1]:https://lore.kernel.org/lkml/[email protected]/
> >> ---
> >> kernel/trace/trace_eprobe.c | 144 ------------------------------
> >> kernel/trace/trace_events_synth.c | 7 +-
> >> kernel/trace/trace_kprobe.c | 102 ---------------------
> >> kernel/trace/trace_probe_kernel.h | 143 +++++++++++++++++++++++++++--
> >> 4 files changed, 141 insertions(+), 255 deletions(-)
> >>
> >> diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c
> >> index bdb26eee7a0c..60ced4a7a25d 100644
> >> --- a/kernel/trace/trace_eprobe.c
> >> +++ b/kernel/trace/trace_eprobe.c
> >> @@ -319,64 +319,6 @@ print_eprobe_event(struct trace_iterator *iter, int flags,
> >> return trace_handle_return(s);
> >> }
> >>
> >> -static unsigned long get_event_field(struct fetch_insn *code, void *rec)
> >> -{
> >> - struct ftrace_event_field *field = code->data;
> >> - unsigned long val;
> >> - void *addr;
> >> -
> >> - addr = rec + field->offset;
> >> -
> >> - if (is_string_field(field)) {
> >> - switch (field->filter_type) {
> >> - case FILTER_DYN_STRING:
> >> - val = (unsigned long)(rec + (*(unsigned int *)addr & 0xffff));
> >> - break;
> >> - case FILTER_RDYN_STRING:
> >> - val = (unsigned long)(addr + (*(unsigned int *)addr & 0xffff));
> >> - break;
> >> - case FILTER_STATIC_STRING:
> >> - val = (unsigned long)addr;
> >> - break;
> >> - case FILTER_PTR_STRING:
> >> - val = (unsigned long)(*(char *)addr);
> >> - break;
> >> - default:
> >> - WARN_ON_ONCE(1);
> >> - return 0;
> >> - }
> >> - return val;
> >> - }
> >> -
> >> - switch (field->size) {
> >> - case 1:
> >> - if (field->is_signed)
> >> - val = *(char *)addr;
> >> - else
> >> - val = *(unsigned char *)addr;
> >> - break;
> >> - case 2:
> >> - if (field->is_signed)
> >> - val = *(short *)addr;
> >> - else
> >> - val = *(unsigned short *)addr;
> >> - break;
> >> - case 4:
> >> - if (field->is_signed)
> >> - val = *(int *)addr;
> >> - else
> >> - val = *(unsigned int *)addr;
> >> - break;
> >> - default:
> >> - if (field->is_signed)
> >> - val = *(long *)addr;
> >> - else
> >> - val = *(unsigned long *)addr;
> >> - break;
> >> - }
> >> - return val;
> >> -}
> >> -
> >> static int get_eprobe_size(struct trace_probe *tp, void *rec)
> >> {
> >> struct fetch_insn *code;
> >> @@ -419,92 +361,6 @@ static int get_eprobe_size(struct trace_probe *tp, void *rec)
> >> return ret;
> >> }
> >>
> >> -/* Kprobe specific fetch functions */
> >> -
> >> -/* Note that we don't verify it, since the code does not come from user space */
> >> -static int
> >> -process_fetch_insn(struct fetch_insn *code, void *rec, void *dest,
> >> - void *base)
> >> -{
> >> - unsigned long val;
> >> -
> >> - retry:
> >> - switch (code->op) {
> >> - case FETCH_OP_TP_ARG:
> >> - val = get_event_field(code, rec);
> >> - break;
> >> - case FETCH_OP_IMM:
> >> - val = code->immediate;
> >> - break;
> >> - case FETCH_OP_COMM:
> >> - val = (unsigned long)current->comm;
> >> - break;
> >> - case FETCH_OP_DATA:
> >> - val = (unsigned long)code->data;
> >> - break;
> >> - case FETCH_NOP_SYMBOL: /* Ignore a place holder */
> >> - code++;
> >> - goto retry;
> >> - default:
> >> - return -EILSEQ;
> >> - }
> >> - code++;
> >> - return process_fetch_insn_bottom(code, val, dest, base);
> >> -}
> >> -NOKPROBE_SYMBOL(process_fetch_insn)
> >> -
> >> -/* Return the length of string -- including null terminal byte */
> >> -static nokprobe_inline int
> >> -fetch_store_strlen_user(unsigned long addr)
> >> -{
> >> - return kern_fetch_store_strlen_user(addr);
> >> -}
> >> -
> >> -/* Return the length of string -- including null terminal byte */
> >> -static nokprobe_inline int
> >> -fetch_store_strlen(unsigned long addr)
> >> -{
> >> - return kern_fetch_store_strlen(addr);
> >> -}
> >> -
> >> -/*
> >> - * Fetch a null-terminated string from user. Caller MUST set *(u32 *)buf
> >> - * with max length and relative data location.
> >> - */
> >> -static nokprobe_inline int
> >> -fetch_store_string_user(unsigned long addr, void *dest, void *base)
> >> -{
> >> - return kern_fetch_store_string_user(addr, dest, base);
> >> -}
> >> -
> >> -/*
> >> - * Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max
> >> - * length and relative data location.
> >> - */
> >> -static nokprobe_inline int
> >> -fetch_store_string(unsigned long addr, void *dest, void *base)
> >> -{
> >> - return kern_fetch_store_string(addr, dest, base);
> >> -}
> >> -
> >> -static nokprobe_inline int
> >> -probe_mem_read_user(void *dest, void *src, size_t size)
> >> -{
> >> - const void __user *uaddr = (__force const void __user *)src;
> >> -
> >> - return copy_from_user_nofault(dest, uaddr, size);
> >> -}
> >> -
> >> -static nokprobe_inline int
> >> -probe_mem_read(void *dest, void *src, size_t size)
> >> -{
> >> -#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
> >> - if ((unsigned long)src < TASK_SIZE)
> >> - return probe_mem_read_user(dest, src, size);
> >> -#endif
> >> - return copy_from_kernel_nofault(dest, src, size);
> >> -}
> >> -
> >> /* eprobe handler */
> >> static inline void
> >> __eprobe_trace_func(struct eprobe_data *edata, void *rec)
> >> diff --git a/kernel/trace/trace_events_synth.c b/kernel/trace/trace_events_synth.c
> >> index e310052dc83c..7460f18ba973 100644
> >> --- a/kernel/trace/trace_events_synth.c
> >> +++ b/kernel/trace/trace_events_synth.c
> >> @@ -18,6 +18,7 @@
> >> #include <linux/trace_events.h>
> >> #include <trace/events/mmflags.h>
> >> #include "trace_probe.h"
> >> +#include "trace_probe_tmpl.h"
> >> #include "trace_probe_kernel.h"
> >>
> >> #include "trace_synth.h"
> >> @@ -420,12 +421,12 @@ static unsigned int trace_string(struct synth_trace_event *entry,
> >> data_offset += event->n_u64 * sizeof(u64);
> >> data_offset += data_size;
> >>
> >> - len = kern_fetch_store_strlen((unsigned long)str_val);
> >> + len = fetch_store_strlen((unsigned long)str_val);
> >>
> >> data_offset |= len << 16;
> >> *(u32 *)&entry->fields[*n_u64] = data_offset;
> >>
> >> - ret = kern_fetch_store_string((unsigned long)str_val, &entry->fields[*n_u64], entry);
> >> + ret = fetch_store_string((unsigned long)str_val, &entry->fields[*n_u64], entry);
> >>
> >> (*n_u64)++;
> >> } else {
> >> @@ -473,7 +474,7 @@ static notrace void trace_event_raw_event_synth(void *__data,
> >> val_idx = var_ref_idx[field_pos];
> >> str_val = (char *)(long)var_ref_vals[val_idx];
> >>
> >> - len = kern_fetch_store_strlen((unsigned long)str_val);
> >> + len = fetch_store_strlen((unsigned long)str_val);
> >>
> >> fields_size += len;
> >> }
> >> diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
> >> index a4ffa864dbb7..c2e0b741ae82 100644
> >> --- a/kernel/trace/trace_kprobe.c
> >> +++ b/kernel/trace/trace_kprobe.c
> >> @@ -1218,108 +1218,6 @@ static const struct file_operations kprobe_profile_ops = {
> >> .release = seq_release,
> >> };
> >>
> >> -/* Kprobe specific fetch functions */
> >> -
> >> -/* Return the length of string -- including null terminal byte */
> >> -static nokprobe_inline int
> >> -fetch_store_strlen_user(unsigned long addr)
> >> -{
> >> - return kern_fetch_store_strlen_user(addr);
> >> -}
> >> -
> >> -/* Return the length of string -- including null terminal byte */
> >> -static nokprobe_inline int
> >> -fetch_store_strlen(unsigned long addr)
> >> -{
> >> - return kern_fetch_store_strlen(addr);
> >> -}
> >> -
> >> -/*
> >> - * Fetch a null-terminated string from user. Caller MUST set *(u32 *)buf
> >> - * with max length and relative data location.
> >> - */
> >> -static nokprobe_inline int
> >> -fetch_store_string_user(unsigned long addr, void *dest, void *base)
> >> -{
> >> - return kern_fetch_store_string_user(addr, dest, base);
> >> -}
> >> -
> >> -/*
> >> - * Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max
> >> - * length and relative data location.
> >> - */
> >> -static nokprobe_inline int
> >> -fetch_store_string(unsigned long addr, void *dest, void *base)
> >> -{
> >> - return kern_fetch_store_string(addr, dest, base);
> >> -}
> >> -
> >> -static nokprobe_inline int
> >> -probe_mem_read_user(void *dest, void *src, size_t size)
> >> -{
> >> - const void __user *uaddr = (__force const void __user *)src;
> >> -
> >> - return copy_from_user_nofault(dest, uaddr, size);
> >> -}
> >> -
> >> -static nokprobe_inline int
> >> -probe_mem_read(void *dest, void *src, size_t size)
> >> -{
> >> -#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
> >> - if ((unsigned long)src < TASK_SIZE)
> >> - return probe_mem_read_user(dest, src, size);
> >> -#endif
> >> - return copy_from_kernel_nofault(dest, src, size);
> >> -}
> >> -
> >> -/* Note that we don't verify it, since the code does not come from user space */
> >> -static int
> >> -process_fetch_insn(struct fetch_insn *code, void *rec, void *dest,
> >> - void *base)
> >> -{
> >> - struct pt_regs *regs = rec;
> >> - unsigned long val;
> >> -
> >> -retry:
> >> - /* 1st stage: get value from context */
> >> - switch (code->op) {
> >> - case FETCH_OP_REG:
> >> - val = regs_get_register(regs, code->param);
> >> - break;
> >> - case FETCH_OP_STACK:
> >> - val = regs_get_kernel_stack_nth(regs, code->param);
> >> - break;
> >> - case FETCH_OP_STACKP:
> >> - val = kernel_stack_pointer(regs);
> >> - break;
> >> - case FETCH_OP_RETVAL:
> >> - val = regs_return_value(regs);
> >> - break;
> >> - case FETCH_OP_IMM:
> >> - val = code->immediate;
> >> - break;
> >> - case FETCH_OP_COMM:
> >> - val = (unsigned long)current->comm;
> >> - break;
> >> - case FETCH_OP_DATA:
> >> - val = (unsigned long)code->data;
> >> - break;
> >> -#ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
> >> - case FETCH_OP_ARG:
> >> - val = regs_get_kernel_argument(regs, code->param);
> >> - break;
> >> -#endif
> >> - case FETCH_NOP_SYMBOL: /* Ignore a place holder */
> >> - code++;
> >> - goto retry;
> >> - default:
> >> - return -EILSEQ;
> >> - }
> >> - code++;
> >> -
> >> - return process_fetch_insn_bottom(code, val, dest, base);
> >> -}
> >> -NOKPROBE_SYMBOL(process_fetch_insn)
> >>
> >> /* Kprobe handler */
> >> static nokprobe_inline void
> >> diff --git a/kernel/trace/trace_probe_kernel.h b/kernel/trace/trace_probe_kernel.h
> >> index 77dbd9ff9782..39f44513ec4e 100644
> >> --- a/kernel/trace/trace_probe_kernel.h
> >> +++ b/kernel/trace/trace_probe_kernel.h
> >> @@ -12,7 +12,7 @@
> >> */
> >> /* Return the length of string -- including null terminal byte */
> >> static nokprobe_inline int
> >> -kern_fetch_store_strlen_user(unsigned long addr)
> >> +fetch_store_strlen_user(unsigned long addr)
> >> {
> >> const void __user *uaddr = (__force const void __user *)addr;
> >> int ret;
> >> @@ -29,14 +29,14 @@ kern_fetch_store_strlen_user(unsigned long addr)
> >>
> >> /* Return the length of string -- including null terminal byte */
> >> static nokprobe_inline int
> >> -kern_fetch_store_strlen(unsigned long addr)
> >> +fetch_store_strlen(unsigned long addr)
> >> {
> >> int ret, len = 0;
> >> u8 c;
> >>
> >> #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
> >> if (addr < TASK_SIZE)
> >> - return kern_fetch_store_strlen_user(addr);
> >> + return fetch_store_strlen_user(addr);
> >> #endif
> >>
> >> do {
> >> @@ -63,7 +63,7 @@ static nokprobe_inline void set_data_loc(int ret, void *dest, void *__dest, void
> >> * with max length and relative data location.
> >> */
> >> static nokprobe_inline int
> >> -kern_fetch_store_string_user(unsigned long addr, void *dest, void *base)
> >> +fetch_store_string_user(unsigned long addr, void *dest, void *base)
> >> {
> >> const void __user *uaddr = (__force const void __user *)addr;
> >> int maxlen = get_loc_len(*(u32 *)dest);
> >> @@ -86,7 +86,7 @@ kern_fetch_store_string_user(unsigned long addr, void *dest, void *base)
> >> * length and relative data location.
> >> */
> >> static nokprobe_inline int
> >> -kern_fetch_store_string(unsigned long addr, void *dest, void *base)
> >> +fetch_store_string(unsigned long addr, void *dest, void *base)
> >> {
> >> int maxlen = get_loc_len(*(u32 *)dest);
> >> void *__dest;
> >> @@ -94,7 +94,7 @@ kern_fetch_store_string(unsigned long addr, void *dest, void *base)
> >>
> >> #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
> >> if ((unsigned long)addr < TASK_SIZE)
> >> - return kern_fetch_store_string_user(addr, dest, base);
> >> + return fetch_store_string_user(addr, dest, base);
> >> #endif
> >>
> >> if (unlikely(!maxlen))
> >> @@ -112,4 +112,135 @@ kern_fetch_store_string(unsigned long addr, void *dest, void *base)
> >> return ret;
> >> }
> >>
> >> +static nokprobe_inline int
> >> +probe_mem_read_user(void *dest, void *src, size_t size)
> >> +{
> >> + const void __user *uaddr = (__force const void __user *)src;
> >> +
> >> + return copy_from_user_nofault(dest, uaddr, size);
> >> +}
> >> +
> >> +static nokprobe_inline int
> >> +probe_mem_read(void *dest, void *src, size_t size)
> >> +{
> >> +#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
> >> + if ((unsigned long)src < TASK_SIZE)
> >> + return probe_mem_read_user(dest, src, size);
> >> +#endif
> >> + return copy_from_kernel_nofault(dest, src, size);
> >> +}
> >> +
> >> +static nokprobe_inline unsigned long
> >> +get_event_field(struct fetch_insn *code, void *rec)
> >> +{
> >> + struct ftrace_event_field *field = code->data;
> >> + unsigned long val;
> >> + void *addr;
> >> +
> >> + addr = rec + field->offset;
> >> +
> >> + if (is_string_field(field)) {
> >> + switch (field->filter_type) {
> >> + case FILTER_DYN_STRING:
> >> + val = (unsigned long)(rec + (*(unsigned int *)addr & 0xffff));
> >> + break;
> >> + case FILTER_RDYN_STRING:
> >> + val = (unsigned long)(addr + (*(unsigned int *)addr & 0xffff));
> >> + break;
> >> + case FILTER_STATIC_STRING:
> >> + val = (unsigned long)addr;
> >> + break;
> >> + case FILTER_PTR_STRING:
> >> + val = (unsigned long)(*(char *)addr);
> >> + break;
> >> + default:
> >> + WARN_ON_ONCE(1);
> >> + return 0;
> >> + }
> >> + return val;
> >> + }
> >> +
> >> + switch (field->size) {
> >> + case 1:
> >> + if (field->is_signed)
> >> + val = *(char *)addr;
> >> + else
> >> + val = *(unsigned char *)addr;
> >> + break;
> >> + case 2:
> >> + if (field->is_signed)
> >> + val = *(short *)addr;
> >> + else
> >> + val = *(unsigned short *)addr;
> >> + break;
> >> + case 4:
> >> + if (field->is_signed)
> >> + val = *(int *)addr;
> >> + else
> >> + val = *(unsigned int *)addr;
> >> + break;
> >> + default:
> >> + if (field->is_signed)
> >> + val = *(long *)addr;
> >> + else
> >> + val = *(unsigned long *)addr;
> >> + break;
> >> + }
> >> + return val;
> >> +}
> >> +
> >> +/* Note that we don't verify it, since the code does not come from user space */
> >> +static int
> >> +process_fetch_insn(struct fetch_insn *code, void *rec, void *dest,
> >> + void *base)
> >> +{
> >> + struct pt_regs *regs = rec;
> >> + unsigned long val;
> >> +
> >> +retry:
> >> + /* 1st stage: get value from context */
> >> + switch (code->op) {
> >> +#ifdef CONFIG_HAVE_REGS_AND_STACK_ACCESS_API
> >> + case FETCH_OP_REG:
> >> + val = regs_get_register(regs, code->param);
> >> + break;
> >> + case FETCH_OP_STACK:
> >> + val = regs_get_kernel_stack_nth(regs, code->param);
> >> + break;
> >> + case FETCH_OP_STACKP:
> >> + val = kernel_stack_pointer(regs);
> >> + break;
> >> + case FETCH_OP_RETVAL:
> >> + val = regs_return_value(regs);
> >> + break;
> >> +#endif
> >> + case FETCH_OP_IMM:
> >> + val = code->immediate;
> >> + break;
> >> + case FETCH_OP_COMM:
> >> + val = (unsigned long)current->comm;
> >> + break;
> >> + case FETCH_OP_DATA:
> >> + val = (unsigned long)code->data;
> >> + break;
> >> +#ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
> >> + case FETCH_OP_ARG:
> >> + val = regs_get_kernel_argument(regs, code->param);
> >> + break;
> >> +#endif
> >> + case FETCH_NOP_SYMBOL: /* Ignore a place holder */
> >> + code++;
> >> + goto retry;
> >> + case FETCH_OP_TP_ARG:
> >> + val = get_event_field(code, rec);
> >> + break;
> >> + default:
> >> + return -EILSEQ;
> >> + }
> >> + code++;
> >> +
> >> + return process_fetch_insn_bottom(code, val, dest, base);
> >> +}
> >> +NOKPROBE_SYMBOL(process_fetch_insn)
> >> +
> >> #endif /* __TRACE_PROBE_KERNEL_H_ */
> >> --
> >> 2.25.1
> >>
> >
> >
--
Masami Hiramatsu (Google) <[email protected]>
Hi,
在 2023/1/3 18:33, Masami Hiramatsu (Google) 写道:
> On Fri, 30 Dec 2022 09:59:31 +0800
> Song Chen <[email protected]> wrote:
>
>> Hi,
>>
>> 在 2022/12/29 17:30, Masami Hiramatsu (Google) 写道:
>>> On Wed, 28 Dec 2022 15:08:25 +0800
>>> Song Chen <[email protected]> wrote:
>>>
>>>> There are 7 function definitions in trace_probe_tmpl.h, they are:
>>>>
>>>> 1, process_fetch_insn
>>>
>>> Other functions except for this are OK for me.
>>> But I think this function should have different instance for kprobe
>>> and eprobe, because the passed 'void *rec' is completely different.
>>> For the kprobe's process_fetch_insn() will take a 'pt_regs *', on the
>>> other hand, the eprobe's process_fetch_insn() will take a
>>> 'ftrace_event_field *'.
>>> I also, don't want to expose get_event_field() function because
>>> it is only for the eprobes.
>>>
>>> What about making a new common function and call it in default case
>>> from both process_fetch_insn()? Your goal is reducing the redundant
>>> code, then it is enough to share only the common code. :)
>>>
>>> For example, in trace_probe_kernel.h,
>>>
>>> process_common_fetch_insn(struct fetch_insn *code, void *dest, void *base, unsigned long *val)
>>> {
>>> switch (code->op) {
>>> case FETCH_OP_IMM:
>>> *val = code->immediate;
>>> break;
>>> case FETCH_OP_COMM:
>>> *val = (unsigned long)current->comm;
>>> break;
>>> case FETCH_OP_DATA:
>>> *val = (unsigned long)code->data;
>>> break;
>>> default:
>>> return -EILSEQ;
>>> }
>>> return 0;
>>> }
>>>
>>> For kprobe events:
>>>
>>> process_fetch_insn(struct fetch_insn *code, void *rec, void *dest, void *base)
>>> {
>>> while (code->op == FETCH_NOP_SYMBOL)
>>> code++;
>>> switch (code->op) {
>>> case FETCH_OP_REG:
>>> val = regs_get_register(regs, code->param);
>>> ...
>>> default:
>>> ret = process_common_fetch_insn(code, dest, base, &val);
>>> if (ret < 0)
>>> return ret;
>>> }
>>> ...
>>> }
>>>
>>> For eprobe events:
>>>
>>> process_fetch_insn(struct fetch_insn *code, void *rec, void *dest, void *base)
>>> {
>>> while (code->op == FETCH_NOP_SYMBOL)
>>> code++;
>>> if (code->op == FETCH_OP_TP_ARG) {
>>> val = get_event_field(code, rec);
>>> } else {
>>> ret = process_common_fetch_insn(code, dest, base, &val);
>>> if (ret < 0)
>>> return ret;
>>> }
>>> ...
>>> }
>>>
>>> You also don't see the error related to CONFIG_HAVE_REGS_AND_STACK_ACCESS_API. :)
>>>
>>> Thank you,
>>>
>>
>> Thanks a lot for the good idea and so specific demo code, i accept it
>> and will submit a new one based on it.
>>
>> If we think about it further, we can implement process_common_fetch_insn
>> in trace_probe_tmpl.h, uprobe can benefit from it as well, what do you
>> think? i will include it in the next submit and you can have a look.
>
> Agreed. It sounds good to me. :)
>
> Thank you!
>
That's so kind, many thanks :)
Song
>>
>> Thanks again.
>>
>> Song
>>
>>>> 2, fetch_store_strlen
>>>> 3, fetch_store_string
>>>> 4, fetch_store_strlen_user
>>>> 5, fetch_store_string_user
>>>> 6, probe_mem_read
>>>> 7, probe_mem_read_user
>>>>
>>>> Every C file which includes trace_probe_tmpl.h has to implement them,
>>>> otherwise it gets warnings and errors. However, some of them are identical,
>>>> like kprobe and eprobe, as a result, there is a lot redundant code in those
>>>> 2 files.
>>>>
>>>> This patch would like to provide default behaviors for those functions
>>>> which kprobe and eprobe can share by just including trace_probe_kernel.h
>>>> with trace_probe_tmpl.h together.
>>>>
>>>> It removes redundant code, increases readability, and more importantly,
>>>> makes it easier to introduce a new feature based on trace probe
>>>> (it's possible).
>>>>
>>>> Signed-off-by: Song Chen <[email protected]>
>>>> Reported-by: kernel test robot <[email protected]>
>>>>
>>>> ---
>>>> v2:
>>>> 1, reorganize patchset
>>>>
>>>> v3:
>>>> 1, mark nokprobe_inline for get_event_field
>>>> 2, remove warnings reported from kernel test robot
>>>> 3, fix errors reported from kernel test robot
>>>>
>>>> v4:
>>>> 1, reset changes in v3(2) and v3(3), they are not reasonable fix.
>>>> 2, I intended to introduce a new header file to exclude
>>>> trace_events_synth.c out of the patch. However, after looking
>>>> further, i found the errors in [1] are introduced by this patch,
>>>> but the warning in [1] are not. The errors can be fixed by adding
>>>> "#ifdef CONFIG_HAVE_REGS_AND_STACK_ACCESS_API".
>>>>
>>>> [1]:https://lore.kernel.org/lkml/[email protected]/
>>>> ---
>>>> kernel/trace/trace_eprobe.c | 144 ------------------------------
>>>> kernel/trace/trace_events_synth.c | 7 +-
>>>> kernel/trace/trace_kprobe.c | 102 ---------------------
>>>> kernel/trace/trace_probe_kernel.h | 143 +++++++++++++++++++++++++++--
>>>> 4 files changed, 141 insertions(+), 255 deletions(-)
>>>>
>>>> diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c
>>>> index bdb26eee7a0c..60ced4a7a25d 100644
>>>> --- a/kernel/trace/trace_eprobe.c
>>>> +++ b/kernel/trace/trace_eprobe.c
>>>> @@ -319,64 +319,6 @@ print_eprobe_event(struct trace_iterator *iter, int flags,
>>>> return trace_handle_return(s);
>>>> }
>>>>
>>>> -static unsigned long get_event_field(struct fetch_insn *code, void *rec)
>>>> -{
>>>> - struct ftrace_event_field *field = code->data;
>>>> - unsigned long val;
>>>> - void *addr;
>>>> -
>>>> - addr = rec + field->offset;
>>>> -
>>>> - if (is_string_field(field)) {
>>>> - switch (field->filter_type) {
>>>> - case FILTER_DYN_STRING:
>>>> - val = (unsigned long)(rec + (*(unsigned int *)addr & 0xffff));
>>>> - break;
>>>> - case FILTER_RDYN_STRING:
>>>> - val = (unsigned long)(addr + (*(unsigned int *)addr & 0xffff));
>>>> - break;
>>>> - case FILTER_STATIC_STRING:
>>>> - val = (unsigned long)addr;
>>>> - break;
>>>> - case FILTER_PTR_STRING:
>>>> - val = (unsigned long)(*(char *)addr);
>>>> - break;
>>>> - default:
>>>> - WARN_ON_ONCE(1);
>>>> - return 0;
>>>> - }
>>>> - return val;
>>>> - }
>>>> -
>>>> - switch (field->size) {
>>>> - case 1:
>>>> - if (field->is_signed)
>>>> - val = *(char *)addr;
>>>> - else
>>>> - val = *(unsigned char *)addr;
>>>> - break;
>>>> - case 2:
>>>> - if (field->is_signed)
>>>> - val = *(short *)addr;
>>>> - else
>>>> - val = *(unsigned short *)addr;
>>>> - break;
>>>> - case 4:
>>>> - if (field->is_signed)
>>>> - val = *(int *)addr;
>>>> - else
>>>> - val = *(unsigned int *)addr;
>>>> - break;
>>>> - default:
>>>> - if (field->is_signed)
>>>> - val = *(long *)addr;
>>>> - else
>>>> - val = *(unsigned long *)addr;
>>>> - break;
>>>> - }
>>>> - return val;
>>>> -}
>>>> -
>>>> static int get_eprobe_size(struct trace_probe *tp, void *rec)
>>>> {
>>>> struct fetch_insn *code;
>>>> @@ -419,92 +361,6 @@ static int get_eprobe_size(struct trace_probe *tp, void *rec)
>>>> return ret;
>>>> }
>>>>
>>>> -/* Kprobe specific fetch functions */
>>>> -
>>>> -/* Note that we don't verify it, since the code does not come from user space */
>>>> -static int
>>>> -process_fetch_insn(struct fetch_insn *code, void *rec, void *dest,
>>>> - void *base)
>>>> -{
>>>> - unsigned long val;
>>>> -
>>>> - retry:
>>>> - switch (code->op) {
>>>> - case FETCH_OP_TP_ARG:
>>>> - val = get_event_field(code, rec);
>>>> - break;
>>>> - case FETCH_OP_IMM:
>>>> - val = code->immediate;
>>>> - break;
>>>> - case FETCH_OP_COMM:
>>>> - val = (unsigned long)current->comm;
>>>> - break;
>>>> - case FETCH_OP_DATA:
>>>> - val = (unsigned long)code->data;
>>>> - break;
>>>> - case FETCH_NOP_SYMBOL: /* Ignore a place holder */
>>>> - code++;
>>>> - goto retry;
>>>> - default:
>>>> - return -EILSEQ;
>>>> - }
>>>> - code++;
>>>> - return process_fetch_insn_bottom(code, val, dest, base);
>>>> -}
>>>> -NOKPROBE_SYMBOL(process_fetch_insn)
>>>> -
>>>> -/* Return the length of string -- including null terminal byte */
>>>> -static nokprobe_inline int
>>>> -fetch_store_strlen_user(unsigned long addr)
>>>> -{
>>>> - return kern_fetch_store_strlen_user(addr);
>>>> -}
>>>> -
>>>> -/* Return the length of string -- including null terminal byte */
>>>> -static nokprobe_inline int
>>>> -fetch_store_strlen(unsigned long addr)
>>>> -{
>>>> - return kern_fetch_store_strlen(addr);
>>>> -}
>>>> -
>>>> -/*
>>>> - * Fetch a null-terminated string from user. Caller MUST set *(u32 *)buf
>>>> - * with max length and relative data location.
>>>> - */
>>>> -static nokprobe_inline int
>>>> -fetch_store_string_user(unsigned long addr, void *dest, void *base)
>>>> -{
>>>> - return kern_fetch_store_string_user(addr, dest, base);
>>>> -}
>>>> -
>>>> -/*
>>>> - * Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max
>>>> - * length and relative data location.
>>>> - */
>>>> -static nokprobe_inline int
>>>> -fetch_store_string(unsigned long addr, void *dest, void *base)
>>>> -{
>>>> - return kern_fetch_store_string(addr, dest, base);
>>>> -}
>>>> -
>>>> -static nokprobe_inline int
>>>> -probe_mem_read_user(void *dest, void *src, size_t size)
>>>> -{
>>>> - const void __user *uaddr = (__force const void __user *)src;
>>>> -
>>>> - return copy_from_user_nofault(dest, uaddr, size);
>>>> -}
>>>> -
>>>> -static nokprobe_inline int
>>>> -probe_mem_read(void *dest, void *src, size_t size)
>>>> -{
>>>> -#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
>>>> - if ((unsigned long)src < TASK_SIZE)
>>>> - return probe_mem_read_user(dest, src, size);
>>>> -#endif
>>>> - return copy_from_kernel_nofault(dest, src, size);
>>>> -}
>>>> -
>>>> /* eprobe handler */
>>>> static inline void
>>>> __eprobe_trace_func(struct eprobe_data *edata, void *rec)
>>>> diff --git a/kernel/trace/trace_events_synth.c b/kernel/trace/trace_events_synth.c
>>>> index e310052dc83c..7460f18ba973 100644
>>>> --- a/kernel/trace/trace_events_synth.c
>>>> +++ b/kernel/trace/trace_events_synth.c
>>>> @@ -18,6 +18,7 @@
>>>> #include <linux/trace_events.h>
>>>> #include <trace/events/mmflags.h>
>>>> #include "trace_probe.h"
>>>> +#include "trace_probe_tmpl.h"
>>>> #include "trace_probe_kernel.h"
>>>>
>>>> #include "trace_synth.h"
>>>> @@ -420,12 +421,12 @@ static unsigned int trace_string(struct synth_trace_event *entry,
>>>> data_offset += event->n_u64 * sizeof(u64);
>>>> data_offset += data_size;
>>>>
>>>> - len = kern_fetch_store_strlen((unsigned long)str_val);
>>>> + len = fetch_store_strlen((unsigned long)str_val);
>>>>
>>>> data_offset |= len << 16;
>>>> *(u32 *)&entry->fields[*n_u64] = data_offset;
>>>>
>>>> - ret = kern_fetch_store_string((unsigned long)str_val, &entry->fields[*n_u64], entry);
>>>> + ret = fetch_store_string((unsigned long)str_val, &entry->fields[*n_u64], entry);
>>>>
>>>> (*n_u64)++;
>>>> } else {
>>>> @@ -473,7 +474,7 @@ static notrace void trace_event_raw_event_synth(void *__data,
>>>> val_idx = var_ref_idx[field_pos];
>>>> str_val = (char *)(long)var_ref_vals[val_idx];
>>>>
>>>> - len = kern_fetch_store_strlen((unsigned long)str_val);
>>>> + len = fetch_store_strlen((unsigned long)str_val);
>>>>
>>>> fields_size += len;
>>>> }
>>>> diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
>>>> index a4ffa864dbb7..c2e0b741ae82 100644
>>>> --- a/kernel/trace/trace_kprobe.c
>>>> +++ b/kernel/trace/trace_kprobe.c
>>>> @@ -1218,108 +1218,6 @@ static const struct file_operations kprobe_profile_ops = {
>>>> .release = seq_release,
>>>> };
>>>>
>>>> -/* Kprobe specific fetch functions */
>>>> -
>>>> -/* Return the length of string -- including null terminal byte */
>>>> -static nokprobe_inline int
>>>> -fetch_store_strlen_user(unsigned long addr)
>>>> -{
>>>> - return kern_fetch_store_strlen_user(addr);
>>>> -}
>>>> -
>>>> -/* Return the length of string -- including null terminal byte */
>>>> -static nokprobe_inline int
>>>> -fetch_store_strlen(unsigned long addr)
>>>> -{
>>>> - return kern_fetch_store_strlen(addr);
>>>> -}
>>>> -
>>>> -/*
>>>> - * Fetch a null-terminated string from user. Caller MUST set *(u32 *)buf
>>>> - * with max length and relative data location.
>>>> - */
>>>> -static nokprobe_inline int
>>>> -fetch_store_string_user(unsigned long addr, void *dest, void *base)
>>>> -{
>>>> - return kern_fetch_store_string_user(addr, dest, base);
>>>> -}
>>>> -
>>>> -/*
>>>> - * Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max
>>>> - * length and relative data location.
>>>> - */
>>>> -static nokprobe_inline int
>>>> -fetch_store_string(unsigned long addr, void *dest, void *base)
>>>> -{
>>>> - return kern_fetch_store_string(addr, dest, base);
>>>> -}
>>>> -
>>>> -static nokprobe_inline int
>>>> -probe_mem_read_user(void *dest, void *src, size_t size)
>>>> -{
>>>> - const void __user *uaddr = (__force const void __user *)src;
>>>> -
>>>> - return copy_from_user_nofault(dest, uaddr, size);
>>>> -}
>>>> -
>>>> -static nokprobe_inline int
>>>> -probe_mem_read(void *dest, void *src, size_t size)
>>>> -{
>>>> -#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
>>>> - if ((unsigned long)src < TASK_SIZE)
>>>> - return probe_mem_read_user(dest, src, size);
>>>> -#endif
>>>> - return copy_from_kernel_nofault(dest, src, size);
>>>> -}
>>>> -
>>>> -/* Note that we don't verify it, since the code does not come from user space */
>>>> -static int
>>>> -process_fetch_insn(struct fetch_insn *code, void *rec, void *dest,
>>>> - void *base)
>>>> -{
>>>> - struct pt_regs *regs = rec;
>>>> - unsigned long val;
>>>> -
>>>> -retry:
>>>> - /* 1st stage: get value from context */
>>>> - switch (code->op) {
>>>> - case FETCH_OP_REG:
>>>> - val = regs_get_register(regs, code->param);
>>>> - break;
>>>> - case FETCH_OP_STACK:
>>>> - val = regs_get_kernel_stack_nth(regs, code->param);
>>>> - break;
>>>> - case FETCH_OP_STACKP:
>>>> - val = kernel_stack_pointer(regs);
>>>> - break;
>>>> - case FETCH_OP_RETVAL:
>>>> - val = regs_return_value(regs);
>>>> - break;
>>>> - case FETCH_OP_IMM:
>>>> - val = code->immediate;
>>>> - break;
>>>> - case FETCH_OP_COMM:
>>>> - val = (unsigned long)current->comm;
>>>> - break;
>>>> - case FETCH_OP_DATA:
>>>> - val = (unsigned long)code->data;
>>>> - break;
>>>> -#ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
>>>> - case FETCH_OP_ARG:
>>>> - val = regs_get_kernel_argument(regs, code->param);
>>>> - break;
>>>> -#endif
>>>> - case FETCH_NOP_SYMBOL: /* Ignore a place holder */
>>>> - code++;
>>>> - goto retry;
>>>> - default:
>>>> - return -EILSEQ;
>>>> - }
>>>> - code++;
>>>> -
>>>> - return process_fetch_insn_bottom(code, val, dest, base);
>>>> -}
>>>> -NOKPROBE_SYMBOL(process_fetch_insn)
>>>>
>>>> /* Kprobe handler */
>>>> static nokprobe_inline void
>>>> diff --git a/kernel/trace/trace_probe_kernel.h b/kernel/trace/trace_probe_kernel.h
>>>> index 77dbd9ff9782..39f44513ec4e 100644
>>>> --- a/kernel/trace/trace_probe_kernel.h
>>>> +++ b/kernel/trace/trace_probe_kernel.h
>>>> @@ -12,7 +12,7 @@
>>>> */
>>>> /* Return the length of string -- including null terminal byte */
>>>> static nokprobe_inline int
>>>> -kern_fetch_store_strlen_user(unsigned long addr)
>>>> +fetch_store_strlen_user(unsigned long addr)
>>>> {
>>>> const void __user *uaddr = (__force const void __user *)addr;
>>>> int ret;
>>>> @@ -29,14 +29,14 @@ kern_fetch_store_strlen_user(unsigned long addr)
>>>>
>>>> /* Return the length of string -- including null terminal byte */
>>>> static nokprobe_inline int
>>>> -kern_fetch_store_strlen(unsigned long addr)
>>>> +fetch_store_strlen(unsigned long addr)
>>>> {
>>>> int ret, len = 0;
>>>> u8 c;
>>>>
>>>> #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
>>>> if (addr < TASK_SIZE)
>>>> - return kern_fetch_store_strlen_user(addr);
>>>> + return fetch_store_strlen_user(addr);
>>>> #endif
>>>>
>>>> do {
>>>> @@ -63,7 +63,7 @@ static nokprobe_inline void set_data_loc(int ret, void *dest, void *__dest, void
>>>> * with max length and relative data location.
>>>> */
>>>> static nokprobe_inline int
>>>> -kern_fetch_store_string_user(unsigned long addr, void *dest, void *base)
>>>> +fetch_store_string_user(unsigned long addr, void *dest, void *base)
>>>> {
>>>> const void __user *uaddr = (__force const void __user *)addr;
>>>> int maxlen = get_loc_len(*(u32 *)dest);
>>>> @@ -86,7 +86,7 @@ kern_fetch_store_string_user(unsigned long addr, void *dest, void *base)
>>>> * length and relative data location.
>>>> */
>>>> static nokprobe_inline int
>>>> -kern_fetch_store_string(unsigned long addr, void *dest, void *base)
>>>> +fetch_store_string(unsigned long addr, void *dest, void *base)
>>>> {
>>>> int maxlen = get_loc_len(*(u32 *)dest);
>>>> void *__dest;
>>>> @@ -94,7 +94,7 @@ kern_fetch_store_string(unsigned long addr, void *dest, void *base)
>>>>
>>>> #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
>>>> if ((unsigned long)addr < TASK_SIZE)
>>>> - return kern_fetch_store_string_user(addr, dest, base);
>>>> + return fetch_store_string_user(addr, dest, base);
>>>> #endif
>>>>
>>>> if (unlikely(!maxlen))
>>>> @@ -112,4 +112,135 @@ kern_fetch_store_string(unsigned long addr, void *dest, void *base)
>>>> return ret;
>>>> }
>>>>
>>>> +static nokprobe_inline int
>>>> +probe_mem_read_user(void *dest, void *src, size_t size)
>>>> +{
>>>> + const void __user *uaddr = (__force const void __user *)src;
>>>> +
>>>> + return copy_from_user_nofault(dest, uaddr, size);
>>>> +}
>>>> +
>>>> +static nokprobe_inline int
>>>> +probe_mem_read(void *dest, void *src, size_t size)
>>>> +{
>>>> +#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
>>>> + if ((unsigned long)src < TASK_SIZE)
>>>> + return probe_mem_read_user(dest, src, size);
>>>> +#endif
>>>> + return copy_from_kernel_nofault(dest, src, size);
>>>> +}
>>>> +
>>>> +static nokprobe_inline unsigned long
>>>> +get_event_field(struct fetch_insn *code, void *rec)
>>>> +{
>>>> + struct ftrace_event_field *field = code->data;
>>>> + unsigned long val;
>>>> + void *addr;
>>>> +
>>>> + addr = rec + field->offset;
>>>> +
>>>> + if (is_string_field(field)) {
>>>> + switch (field->filter_type) {
>>>> + case FILTER_DYN_STRING:
>>>> + val = (unsigned long)(rec + (*(unsigned int *)addr & 0xffff));
>>>> + break;
>>>> + case FILTER_RDYN_STRING:
>>>> + val = (unsigned long)(addr + (*(unsigned int *)addr & 0xffff));
>>>> + break;
>>>> + case FILTER_STATIC_STRING:
>>>> + val = (unsigned long)addr;
>>>> + break;
>>>> + case FILTER_PTR_STRING:
>>>> + val = (unsigned long)(*(char *)addr);
>>>> + break;
>>>> + default:
>>>> + WARN_ON_ONCE(1);
>>>> + return 0;
>>>> + }
>>>> + return val;
>>>> + }
>>>> +
>>>> + switch (field->size) {
>>>> + case 1:
>>>> + if (field->is_signed)
>>>> + val = *(char *)addr;
>>>> + else
>>>> + val = *(unsigned char *)addr;
>>>> + break;
>>>> + case 2:
>>>> + if (field->is_signed)
>>>> + val = *(short *)addr;
>>>> + else
>>>> + val = *(unsigned short *)addr;
>>>> + break;
>>>> + case 4:
>>>> + if (field->is_signed)
>>>> + val = *(int *)addr;
>>>> + else
>>>> + val = *(unsigned int *)addr;
>>>> + break;
>>>> + default:
>>>> + if (field->is_signed)
>>>> + val = *(long *)addr;
>>>> + else
>>>> + val = *(unsigned long *)addr;
>>>> + break;
>>>> + }
>>>> + return val;
>>>> +}
>>>> +
>>>> +/* Note that we don't verify it, since the code does not come from user space */
>>>> +static int
>>>> +process_fetch_insn(struct fetch_insn *code, void *rec, void *dest,
>>>> + void *base)
>>>> +{
>>>> + struct pt_regs *regs = rec;
>>>> + unsigned long val;
>>>> +
>>>> +retry:
>>>> + /* 1st stage: get value from context */
>>>> + switch (code->op) {
>>>> +#ifdef CONFIG_HAVE_REGS_AND_STACK_ACCESS_API
>>>> + case FETCH_OP_REG:
>>>> + val = regs_get_register(regs, code->param);
>>>> + break;
>>>> + case FETCH_OP_STACK:
>>>> + val = regs_get_kernel_stack_nth(regs, code->param);
>>>> + break;
>>>> + case FETCH_OP_STACKP:
>>>> + val = kernel_stack_pointer(regs);
>>>> + break;
>>>> + case FETCH_OP_RETVAL:
>>>> + val = regs_return_value(regs);
>>>> + break;
>>>> +#endif
>>>> + case FETCH_OP_IMM:
>>>> + val = code->immediate;
>>>> + break;
>>>> + case FETCH_OP_COMM:
>>>> + val = (unsigned long)current->comm;
>>>> + break;
>>>> + case FETCH_OP_DATA:
>>>> + val = (unsigned long)code->data;
>>>> + break;
>>>> +#ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
>>>> + case FETCH_OP_ARG:
>>>> + val = regs_get_kernel_argument(regs, code->param);
>>>> + break;
>>>> +#endif
>>>> + case FETCH_NOP_SYMBOL: /* Ignore a place holder */
>>>> + code++;
>>>> + goto retry;
>>>> + case FETCH_OP_TP_ARG:
>>>> + val = get_event_field(code, rec);
>>>> + break;
>>>> + default:
>>>> + return -EILSEQ;
>>>> + }
>>>> + code++;
>>>> +
>>>> + return process_fetch_insn_bottom(code, val, dest, base);
>>>> +}
>>>> +NOKPROBE_SYMBOL(process_fetch_insn)
>>>> +
>>>> #endif /* __TRACE_PROBE_KERNEL_H_ */
>>>> --
>>>> 2.25.1
>>>>
>>>
>>>
>
>