2022-12-30 07:00:20

by Song Chen

Subject: [PATCH v5 3/3] kernel/trace: extract common part in process_fetch_insn

Each probe has an instance of process_fetch_insn respectively,
but they have something in common.

This patch aims to extract the common part into
process_common_fetch_insn which can be shared by each probe,
and they only need to focus on their special cases.

Signed-off-by: Song Chen <[email protected]>
Suggested-by: Masami Hiramatsu <[email protected]>
---
kernel/trace/trace_eprobe.c | 26 ++++++--------------------
kernel/trace/trace_kprobe.c | 14 ++++----------
kernel/trace/trace_probe_tmpl.h | 20 ++++++++++++++++++++
kernel/trace/trace_uprobe.c | 11 ++++-------
4 files changed, 34 insertions(+), 37 deletions(-)

diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c
index ca5d097eec4f..bff0f48f4b44 100644
--- a/kernel/trace/trace_eprobe.c
+++ b/kernel/trace/trace_eprobe.c
@@ -395,20 +395,12 @@ static int get_eprobe_size(struct trace_probe *tp, void *rec)
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:
- continue;
+ if (process_common_fetch_insn(code, &val) < 0)
+ continue;
}
code++;
len = process_fetch_insn_bottom(code, val, NULL, NULL);
@@ -428,26 +420,20 @@ process_fetch_insn(struct fetch_insn *code, void *rec, void *dest,
void *base)
{
unsigned long val;
+ int ret;

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;
+ ret = process_common_fetch_insn(code, &val);
+ if (ret < 0)
+ return ret;
}
code++;
return process_fetch_insn_bottom(code, val, dest, base);
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 714fe9c04eb6..af8b2023a76b 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -1225,6 +1225,7 @@ process_fetch_insn(struct fetch_insn *code, void *rec, void *dest,
{
struct pt_regs *regs = rec;
unsigned long val;
+ int ret;

retry:
/* 1st stage: get value from context */
@@ -1241,15 +1242,6 @@ process_fetch_insn(struct fetch_insn *code, void *rec, void *dest,
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);
@@ -1259,7 +1251,9 @@ process_fetch_insn(struct fetch_insn *code, void *rec, void *dest,
code++;
goto retry;
default:
- return -EILSEQ;
+ ret = process_common_fetch_insn(code, &val);
+ if (ret < 0)
+ return ret;
}
code++;

diff --git a/kernel/trace/trace_probe_tmpl.h b/kernel/trace/trace_probe_tmpl.h
index 1b57420857e1..17258eca0125 100644
--- a/kernel/trace/trace_probe_tmpl.h
+++ b/kernel/trace/trace_probe_tmpl.h
@@ -67,6 +67,26 @@ probe_mem_read(void *dest, void *src, size_t size);
static nokprobe_inline int
probe_mem_read_user(void *dest, void *src, size_t size);

+/* common part of process_fetch_insn*/
+static nokprobe_inline int
+process_common_fetch_insn(struct fetch_insn *code, 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;
+}
+
/* From the 2nd stage, routine is same */
static nokprobe_inline int
process_fetch_insn_bottom(struct fetch_insn *code, unsigned long val,
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index 1ff8f87211a6..c53b0752533f 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -220,6 +220,7 @@ process_fetch_insn(struct fetch_insn *code, void *rec, void *dest,
{
struct pt_regs *regs = rec;
unsigned long val;
+ int ret;

/* 1st stage: get value from context */
switch (code->op) {
@@ -235,20 +236,16 @@ process_fetch_insn(struct fetch_insn *code, void *rec, void *dest,
case FETCH_OP_RETVAL:
val = regs_return_value(regs);
break;
- case FETCH_OP_IMM:
- val = code->immediate;
- break;
case FETCH_OP_COMM:
val = FETCH_TOKEN_COMM;
break;
- case FETCH_OP_DATA:
- val = (unsigned long)code->data;
- break;
case FETCH_OP_FOFFS:
val = translate_user_vaddr(code->immediate);
break;
default:
- return -EILSEQ;
+ ret = process_common_fetch_insn(code, &val);
+ if (ret < 0)
+ return ret;
}
code++;

--
2.25.1

2023-01-03 13:51:07

by Masami Hiramatsu

Subject: Re: [PATCH v5 3/3] kernel/trace: extract common part in process_fetch_insn

On Fri, 30 Dec 2022 14:33:53 +0800
Song Chen <[email protected]> wrote:

> Each probe has an instance of process_fetch_insn respectively,
> but they have something in common.
>
> This patch aims to extract the common part into
> process_common_fetch_insn which can be shared by each probe,
> and they only need to focus on their special cases.
>
> Signed-off-by: Song Chen <[email protected]>
> Suggested-by: Masami Hiramatsu <[email protected]>

This looks good to me.

Acked-by: Masami Hiramatsu (Google) <[email protected]>

Thanks!


> ---
> kernel/trace/trace_eprobe.c | 26 ++++++--------------------
> kernel/trace/trace_kprobe.c | 14 ++++----------
> kernel/trace/trace_probe_tmpl.h | 20 ++++++++++++++++++++
> kernel/trace/trace_uprobe.c | 11 ++++-------
> 4 files changed, 34 insertions(+), 37 deletions(-)
>
> diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c
> index ca5d097eec4f..bff0f48f4b44 100644
> --- a/kernel/trace/trace_eprobe.c
> +++ b/kernel/trace/trace_eprobe.c
> @@ -395,20 +395,12 @@ static int get_eprobe_size(struct trace_probe *tp, void *rec)
> 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:
> - continue;
> + if (process_common_fetch_insn(code, &val) < 0)
> + continue;
> }
> code++;
> len = process_fetch_insn_bottom(code, val, NULL, NULL);
> @@ -428,26 +420,20 @@ process_fetch_insn(struct fetch_insn *code, void *rec, void *dest,
> void *base)
> {
> unsigned long val;
> + int ret;
>
> 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;
> + ret = process_common_fetch_insn(code, &val);
> + if (ret < 0)
> + return ret;
> }
> code++;
> return process_fetch_insn_bottom(code, val, dest, base);
> diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
> index 714fe9c04eb6..af8b2023a76b 100644
> --- a/kernel/trace/trace_kprobe.c
> +++ b/kernel/trace/trace_kprobe.c
> @@ -1225,6 +1225,7 @@ process_fetch_insn(struct fetch_insn *code, void *rec, void *dest,
> {
> struct pt_regs *regs = rec;
> unsigned long val;
> + int ret;
>
> retry:
> /* 1st stage: get value from context */
> @@ -1241,15 +1242,6 @@ process_fetch_insn(struct fetch_insn *code, void *rec, void *dest,
> 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);
> @@ -1259,7 +1251,9 @@ process_fetch_insn(struct fetch_insn *code, void *rec, void *dest,
> code++;
> goto retry;
> default:
> - return -EILSEQ;
> + ret = process_common_fetch_insn(code, &val);
> + if (ret < 0)
> + return ret;
> }
> code++;
>
> diff --git a/kernel/trace/trace_probe_tmpl.h b/kernel/trace/trace_probe_tmpl.h
> index 1b57420857e1..17258eca0125 100644
> --- a/kernel/trace/trace_probe_tmpl.h
> +++ b/kernel/trace/trace_probe_tmpl.h
> @@ -67,6 +67,26 @@ probe_mem_read(void *dest, void *src, size_t size);
> static nokprobe_inline int
> probe_mem_read_user(void *dest, void *src, size_t size);
>
> +/* common part of process_fetch_insn*/
> +static nokprobe_inline int
> +process_common_fetch_insn(struct fetch_insn *code, 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;
> +}
> +
> /* From the 2nd stage, routine is same */
> static nokprobe_inline int
> process_fetch_insn_bottom(struct fetch_insn *code, unsigned long val,
> diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
> index 1ff8f87211a6..c53b0752533f 100644
> --- a/kernel/trace/trace_uprobe.c
> +++ b/kernel/trace/trace_uprobe.c
> @@ -220,6 +220,7 @@ process_fetch_insn(struct fetch_insn *code, void *rec, void *dest,
> {
> struct pt_regs *regs = rec;
> unsigned long val;
> + int ret;
>
> /* 1st stage: get value from context */
> switch (code->op) {
> @@ -235,20 +236,16 @@ process_fetch_insn(struct fetch_insn *code, void *rec, void *dest,
> case FETCH_OP_RETVAL:
> val = regs_return_value(regs);
> break;
> - case FETCH_OP_IMM:
> - val = code->immediate;
> - break;
> case FETCH_OP_COMM:
> val = FETCH_TOKEN_COMM;
> break;
> - case FETCH_OP_DATA:
> - val = (unsigned long)code->data;
> - break;
> case FETCH_OP_FOFFS:
> val = translate_user_vaddr(code->immediate);
> break;
> default:
> - return -EILSEQ;
> + ret = process_common_fetch_insn(code, &val);
> + if (ret < 0)
> + return ret;
> }
> code++;
>
> --
> 2.25.1
>


--
Masami Hiramatsu (Google) <[email protected]>