Vivek found some problems with old kexec-tools.
We keep the old crashkernel=X to old behavoir, so it will not break
old kexec-tools.
Add crashkernel=X,high to support new kexec-tools that supports loading high.
when high is used, memblock will search from top to low.
if the allocated one is above 4G, kernel will try to auto allocate
72M under 4G for swiotlb.
user could crashkernel=Y,low to change 72M to other value.
-v2: reorder the patch sequences
crashkernel=X,high, crashkernel=Y,low only handle simple form.
crashkernel=X will override crashkernel=X;high crashkernel=Y;low
-v3: update description in kernel-parameters.txt
update get_last_crashkernel and _simple checking about suffix.
-v4: update to use ,high again, and also not abuse parse_crashkernel_simple
Thanks
Yinghai
We can extend kexec-tools to support multiple "Crash kernel" in /proc/iomem
instead.
So we can use "Crash kernel" instead of "Crash kernel low" in /proc/iomem.
Suggested-by: Vivek Goyal <[email protected]>
Signed-off-by: Yinghai Lu <[email protected]>
---
kernel/kexec.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
Index: linux-2.6/kernel/kexec.c
===================================================================
--- linux-2.6.orig/kernel/kexec.c
+++ linux-2.6/kernel/kexec.c
@@ -55,7 +55,7 @@ struct resource crashk_res = {
.flags = IORESOURCE_BUSY | IORESOURCE_MEM
};
struct resource crashk_low_res = {
- .name = "Crash kernel low",
+ .name = "Crash kernel",
.start = 0,
.end = 0,
.flags = IORESOURCE_BUSY | IORESOURCE_MEM
Per hpa, use crashkernel=X,high crashkernel=Y,low instead of
crashkernel_hign=X crashkernel_low=Y. As that could be extensible.
-v2: according to Vivek, change delimiter to ;
-v3: let hign and low only handle simple form and it conforms to
description in kernel-parameters.txt
still keep crashkernel=X override any crashkernel=X,high
crashkernel=Y,low
-v4: update get_last_crashkernel returning and add more strict
checking in parse_crashkernel_simple() found by HATAYAMA.
-v5: Change delimiter back to , according to HPA.
also separate parse_suffix from parse_simper according to vivek.
so we can avoid @pos in that path.
Cc: HATAYAMA Daisuke <[email protected]>
Signed-off-by: Yinghai Lu <[email protected]>
---
Documentation/kernel-parameters.txt | 10 +--
arch/x86/kernel/setup.c | 6 +-
kernel/kexec.c | 103 +++++++++++++++++++++++++++++++-----
3 files changed, 98 insertions(+), 21 deletions(-)
Index: linux-2.6/Documentation/kernel-parameters.txt
===================================================================
--- linux-2.6.orig/Documentation/kernel-parameters.txt
+++ linux-2.6/Documentation/kernel-parameters.txt
@@ -603,16 +603,16 @@ bytes respectively. Such letter suffixes
a memory unit (amount[KMG]). See also
Documentation/kdump/kdump.txt for an example.
- crashkernel_high=size[KMG]
+ crashkernel=size[KMG],high
[KNL, x86_64] range could be above 4G. Allow kernel
to allocate physical memory region from top, so could
be above 4G if system have more than 4G ram installed.
Otherwise memory region will be allocated below 4G, if
available.
It will be ignored if crashkernel=X is specified.
- crashkernel_low=size[KMG]
- [KNL, x86_64] range under 4G. When crashkernel_high= is
- passed, kernel could allocate physical memory region
+ crashkernel=size[KMG],low
+ [KNL, x86_64] range under 4G. When crashkernel=X,high
+ is passed, kernel could allocate physical memory region
above 4G, that cause second kernel crash on system
that require some amount of low memory, e.g. swiotlb
requires at least 64M+32K low memory. Kernel would
@@ -620,7 +620,7 @@ bytes respectively. Such letter suffixes
This one let user to specify own low range under 4G
for second kernel instead.
0: to disable low allocation.
- It will be ignored when crashkernel_high=X is not used
+ It will be ignored when crashkernel=X,high is not used
or memory reserved is below 4G.
cs89x0_dma= [HW,NET]
Index: linux-2.6/arch/x86/kernel/setup.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/setup.c
+++ linux-2.6/arch/x86/kernel/setup.c
@@ -526,7 +526,7 @@ static void __init reserve_crashkernel_l
int ret;
total_low_mem = memblock_mem_size(1UL<<(32-PAGE_SHIFT));
- /* crashkernel_low=YM */
+ /* crashkernel=Y,low */
ret = parse_crashkernel_low(boot_command_line, total_low_mem,
&low_size, &base);
if (ret != 0) {
@@ -539,7 +539,7 @@ static void __init reserve_crashkernel_l
low_size = swiotlb_size_or_default() + (8UL<<20);
auto_set = true;
} else {
- /* passed with crashkernel_low=0 ? */
+ /* passed with crashkernel=0,low ? */
if (!low_size)
return;
}
@@ -579,7 +579,7 @@ static void __init reserve_crashkernel(v
ret = parse_crashkernel(boot_command_line, total_mem,
&crash_size, &crash_base);
if (ret != 0 || crash_size <= 0) {
- /* crashkernel_high=XM */
+ /* crashkernel=X,high */
ret = parse_crashkernel_high(boot_command_line, total_mem,
&crash_size, &crash_base);
if (ret != 0 || crash_size <= 0)
Index: linux-2.6/kernel/kexec.c
===================================================================
--- linux-2.6.orig/kernel/kexec.c
+++ linux-2.6/kernel/kexec.c
@@ -1368,35 +1368,108 @@ static int __init parse_crashkernel_simp
return 0;
}
+#define SUFFIX_HIGH 0
+#define SUFFIX_LOW 1
+#define SUFFIX_NULL 2
+static __initdata char *suffix_tbl[] = {
+ [SUFFIX_HIGH] = ",high",
+ [SUFFIX_LOW] = ",low",
+ [SUFFIX_NULL] = NULL,
+};
+
/*
- * That function is the entry point for command line parsing and should be
- * called from the arch-specific code.
+ * That function parses "suffix" crashkernel command lines like
+ *
+ * crashkernel=size,[high|low]
+ *
+ * It returns 0 on success and -EINVAL on failure.
*/
+static int __init parse_crashkernel_suffix(char *cmdline,
+ unsigned long long *crash_size,
+ unsigned long long *crash_base,
+ const char *suffix)
+{
+ char *cur = cmdline;
+
+ *crash_size = memparse(cmdline, &cur);
+ if (cmdline == cur) {
+ pr_warn("crashkernel: memory value expected\n");
+ return -EINVAL;
+ }
+
+ /* check with suffix */
+ if (!strncmp(cur, suffix, strlen(suffix)))
+ return 0;
+
+ pr_warn("crashkernel: unrecognized char\n");
+ return -EINVAL;
+}
+
+static __init char *get_last_crashkernel(char *cmdline,
+ const char *name,
+ const char *suffix)
+{
+ char *p = cmdline, *ck_cmdline = NULL;
+
+ /* find crashkernel and use the last one if there are more */
+ p = strstr(p, name);
+ while (p) {
+ char *end_p = strchr(p, ' ');
+ char *q;
+
+ if (!end_p)
+ end_p = p + strlen(p);
+
+ if (!suffix) {
+ int i;
+
+ /* skip the one with any known suffix */
+ for (i = 0; suffix_tbl[i]; i++) {
+ q = end_p - strlen(suffix_tbl[i]);
+ if (!strncmp(q, suffix_tbl[i],
+ strlen(suffix_tbl[i])))
+ goto next;
+ }
+ ck_cmdline = p;
+ } else {
+ q = end_p - strlen(suffix);
+ if (!strncmp(q, suffix, strlen(suffix)))
+ ck_cmdline = p;
+ }
+next:
+ p = strstr(p+1, name);
+ }
+
+ if (!ck_cmdline)
+ return NULL;
+
+ return ck_cmdline;
+}
+
static int __init __parse_crashkernel(char *cmdline,
unsigned long long system_ram,
unsigned long long *crash_size,
unsigned long long *crash_base,
- const char *name)
+ const char *name,
+ const char *suffix)
{
- char *p = cmdline, *ck_cmdline = NULL;
char *first_colon, *first_space;
+ char *ck_cmdline;
BUG_ON(!crash_size || !crash_base);
*crash_size = 0;
*crash_base = 0;
- /* find crashkernel and use the last one if there are more */
- p = strstr(p, name);
- while (p) {
- ck_cmdline = p;
- p = strstr(p+1, name);
- }
+ ck_cmdline = get_last_crashkernel(cmdline, name, suffix);
if (!ck_cmdline)
return -EINVAL;
ck_cmdline += strlen(name);
+ if (suffix)
+ return parse_crashkernel_suffix(ck_cmdline, crash_size,
+ crash_base, suffix);
/*
* if the commandline contains a ':', then that's the extended
* syntax -- if not, it must be the classic syntax
@@ -1413,13 +1486,17 @@ static int __init __parse_crashkernel(ch
return 0;
}
+/*
+ * That function is the entry point for command line parsing and should be
+ * called from the arch-specific code.
+ */
int __init parse_crashkernel(char *cmdline,
unsigned long long system_ram,
unsigned long long *crash_size,
unsigned long long *crash_base)
{
return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base,
- "crashkernel=");
+ "crashkernel=", NULL);
}
int __init parse_crashkernel_high(char *cmdline,
@@ -1428,7 +1505,7 @@ int __init parse_crashkernel_high(char *
unsigned long long *crash_base)
{
return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base,
- "crashkernel_high=");
+ "crashkernel=", suffix_tbl[SUFFIX_HIGH]);
}
int __init parse_crashkernel_low(char *cmdline,
@@ -1437,7 +1514,7 @@ int __init parse_crashkernel_low(char *c
unsigned long long *crash_base)
{
return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base,
- "crashkernel_low=");
+ "crashkernel=", suffix_tbl[SUFFIX_LOW]);
}
static void update_vmcoreinfo_note(void)
Vivek found old kexec-tools does not work new kernel anymore.
So change back crashkernel= back to old behavoir, and add crashkernel_high=
to let user decide if buffer could be above 4G, and also new kexec-tools will
be needed.
-v2: let crashkernel=X override crashkernel_high=
update description about _high will be ignored by crashkernel=X
-v3: update description about kernel-parameters.txt according to Vivek.
Signed-off-by: Yinghai Lu <[email protected]>
---
Documentation/kernel-parameters.txt | 13 +++++++++++--
arch/x86/kernel/setup.c | 24 +++++++++++++++++++-----
include/linux/kexec.h | 2 ++
kernel/kexec.c | 9 +++++++++
4 files changed, 41 insertions(+), 7 deletions(-)
Index: linux-2.6/Documentation/kernel-parameters.txt
===================================================================
--- linux-2.6.orig/Documentation/kernel-parameters.txt
+++ linux-2.6/Documentation/kernel-parameters.txt
@@ -603,9 +603,16 @@ bytes respectively. Such letter suffixes
a memory unit (amount[KMG]). See also
Documentation/kdump/kdump.txt for an example.
+ crashkernel_high=size[KMG]
+ [KNL, x86_64] range could be above 4G. Allow kernel
+ to allocate physical memory region from top, so could
+ be above 4G if system have more than 4G ram installed.
+ Otherwise memory region will be allocated below 4G, if
+ available.
+ It will be ignored if crashkernel=X is specified.
crashkernel_low=size[KMG]
- [KNL, x86_64] range under 4G. When crashkernel= is
- passed, kernel allocate physical memory region
+ [KNL, x86_64] range under 4G. When crashkernel_high= is
+ passed, kernel could allocate physical memory region
above 4G, that cause second kernel crash on system
that require some amount of low memory, e.g. swiotlb
requires at least 64M+32K low memory. Kernel would
@@ -613,6 +620,8 @@ bytes respectively. Such letter suffixes
This one let user to specify own low range under 4G
for second kernel instead.
0: to disable low allocation.
+ It will be ignored when crashkernel_high=X is not used
+ or memory reserved is below 4G.
cs89x0_dma= [HW,NET]
Format: <dma>
Index: linux-2.6/arch/x86/kernel/setup.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/setup.c
+++ linux-2.6/arch/x86/kernel/setup.c
@@ -505,11 +505,14 @@ static void __init memblock_x86_reserve_
/*
* Keep the crash kernel below this limit. On 32 bits earlier kernels
* would limit the kernel to the low 512 MiB due to mapping restrictions.
+ * On 64bit, old kexec-tools need to under 896MiB.
*/
#ifdef CONFIG_X86_32
-# define CRASH_KERNEL_ADDR_MAX (512 << 20)
+# define CRASH_KERNEL_ADDR_LOW_MAX (512 << 20)
+# define CRASH_KERNEL_ADDR_HIGH_MAX (512 << 20)
#else
-# define CRASH_KERNEL_ADDR_MAX MAXMEM
+# define CRASH_KERNEL_ADDR_LOW_MAX (896UL<<20)
+# define CRASH_KERNEL_ADDR_HIGH_MAX MAXMEM
#endif
static void __init reserve_crashkernel_low(void)
@@ -523,6 +526,7 @@ static void __init reserve_crashkernel_l
int ret;
total_low_mem = memblock_mem_size(1UL<<(32-PAGE_SHIFT));
+ /* crashkernel_low=YM */
ret = parse_crashkernel_low(boot_command_line, total_low_mem,
&low_size, &base);
if (ret != 0) {
@@ -566,14 +570,22 @@ static void __init reserve_crashkernel(v
const unsigned long long alignment = 16<<20; /* 16M */
unsigned long long total_mem;
unsigned long long crash_size, crash_base;
+ bool high = false;
int ret;
total_mem = memblock_phys_mem_size();
+ /* crashkernel=XM */
ret = parse_crashkernel(boot_command_line, total_mem,
&crash_size, &crash_base);
- if (ret != 0 || crash_size <= 0)
- return;
+ if (ret != 0 || crash_size <= 0) {
+ /* crashkernel_high=XM */
+ ret = parse_crashkernel_high(boot_command_line, total_mem,
+ &crash_size, &crash_base);
+ if (ret != 0 || crash_size <= 0)
+ return;
+ high = true;
+ }
/* 0 means: find the address automatically */
if (crash_base <= 0) {
@@ -581,7 +593,9 @@ static void __init reserve_crashkernel(v
* kexec want bzImage is below CRASH_KERNEL_ADDR_MAX
*/
crash_base = memblock_find_in_range(alignment,
- CRASH_KERNEL_ADDR_MAX, crash_size, alignment);
+ high ? CRASH_KERNEL_ADDR_HIGH_MAX :
+ CRASH_KERNEL_ADDR_LOW_MAX,
+ crash_size, alignment);
if (!crash_base) {
pr_info("crashkernel reservation failed - No suitable area found.\n");
Index: linux-2.6/include/linux/kexec.h
===================================================================
--- linux-2.6.orig/include/linux/kexec.h
+++ linux-2.6/include/linux/kexec.h
@@ -200,6 +200,8 @@ extern size_t vmcoreinfo_max_size;
int __init parse_crashkernel(char *cmdline, unsigned long long system_ram,
unsigned long long *crash_size, unsigned long long *crash_base);
+int parse_crashkernel_high(char *cmdline, unsigned long long system_ram,
+ unsigned long long *crash_size, unsigned long long *crash_base);
int parse_crashkernel_low(char *cmdline, unsigned long long system_ram,
unsigned long long *crash_size, unsigned long long *crash_base);
int crash_shrink_memory(unsigned long new_size);
Index: linux-2.6/kernel/kexec.c
===================================================================
--- linux-2.6.orig/kernel/kexec.c
+++ linux-2.6/kernel/kexec.c
@@ -1422,6 +1422,15 @@ int __init parse_crashkernel(char *cmdli
"crashkernel=");
}
+int __init parse_crashkernel_high(char *cmdline,
+ unsigned long long system_ram,
+ unsigned long long *crash_size,
+ unsigned long long *crash_base)
+{
+ return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base,
+ "crashkernel_high=");
+}
+
int __init parse_crashkernel_low(char *cmdline,
unsigned long long system_ram,
unsigned long long *crash_size,
Chao said that kdump does does work well on his system on 3.8
without extra parameter, even iommu does not work with kdump.
And now have to append crashkernel_low=Y in first kernel to make
kdump work.
We have now modified crashkernel=X to allocate memory beyong 4G (if
available) and do not allocate low range for crashkernel if the user
does not specify that with crashkernel_low=Y. This causes regression
if iommu is not enabled. Without iommu, swiotlb needs to be setup in
first 4G and there is no low memory available to second kernel.
Set crashkernel_low automatically if the user does not specify that.
For system that does support IOMMU with kdump properly, user could
specify crashkernel_low=0 to save that 72M low ram.
-v3: add swiotlb_size() according to Konrad.
-v4: add comments what 8M is for according to hpa.
also update more crashkernel_low= in kernel-parameters.txt
-v5: update changelog according to Vivek.
-v6: Change description about swiotlb referring according to HATAYAMA.
Reported-by: WANG Chao <[email protected]>
Tested-by: WANG Chao <[email protected]>
Signed-off-by: Yinghai Lu <[email protected]>
---
Documentation/kernel-parameters.txt | 14 +++++++++++---
arch/x86/kernel/setup.c | 20 +++++++++++++++++---
include/linux/swiotlb.h | 1 +
lib/swiotlb.c | 19 +++++++++++++++----
4 files changed, 44 insertions(+), 10 deletions(-)
Index: linux-2.6/arch/x86/kernel/setup.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/setup.c
+++ linux-2.6/arch/x86/kernel/setup.c
@@ -519,19 +519,33 @@ static void __init reserve_crashkernel_l
unsigned long long low_base = 0, low_size = 0;
unsigned long total_low_mem;
unsigned long long base;
+ bool auto_set = false;
int ret;
total_low_mem = memblock_mem_size(1UL<<(32-PAGE_SHIFT));
ret = parse_crashkernel_low(boot_command_line, total_low_mem,
&low_size, &base);
- if (ret != 0 || low_size <= 0)
- return;
+ if (ret != 0) {
+ /*
+ * two parts from lib/swiotlb.c:
+ * swiotlb size: user specified with swiotlb= or default.
+ * swiotlb overflow buffer: now is hardcoded to 32k,
+ * round to 8M to cover more others.
+ */
+ low_size = swiotlb_size_or_default() + (8UL<<20);
+ auto_set = true;
+ } else {
+ /* passed with crashkernel_low=0 ? */
+ if (!low_size)
+ return;
+ }
low_base = memblock_find_in_range(low_size, (1ULL<<32),
low_size, alignment);
if (!low_base) {
- pr_info("crashkernel low reservation failed - No suitable area found.\n");
+ if (!auto_set)
+ pr_info("crashkernel low reservation failed - No suitable area found.\n");
return;
}
Index: linux-2.6/include/linux/swiotlb.h
===================================================================
--- linux-2.6.orig/include/linux/swiotlb.h
+++ linux-2.6/include/linux/swiotlb.h
@@ -25,6 +25,7 @@ extern int swiotlb_force;
extern void swiotlb_init(int verbose);
int swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose);
extern unsigned long swiotlb_nr_tbl(void);
+unsigned long swiotlb_size_or_default(void);
extern int swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs);
/*
Index: linux-2.6/lib/swiotlb.c
===================================================================
--- linux-2.6.orig/lib/swiotlb.c
+++ linux-2.6/lib/swiotlb.c
@@ -105,9 +105,9 @@ setup_io_tlb_npages(char *str)
if (!strcmp(str, "force"))
swiotlb_force = 1;
- return 1;
+ return 0;
}
-__setup("swiotlb=", setup_io_tlb_npages);
+early_param("swiotlb", setup_io_tlb_npages);
/* make io_tlb_overflow tunable too? */
unsigned long swiotlb_nr_tbl(void)
@@ -115,6 +115,18 @@ unsigned long swiotlb_nr_tbl(void)
return io_tlb_nslabs;
}
EXPORT_SYMBOL_GPL(swiotlb_nr_tbl);
+
+/* default to 64MB */
+#define IO_TLB_DEFAULT_SIZE (64UL<<20)
+unsigned long swiotlb_size_or_default(void)
+{
+ unsigned long size;
+
+ size = io_tlb_nslabs << IO_TLB_SHIFT;
+
+ return size ? size : (IO_TLB_DEFAULT_SIZE);
+}
+
/* Note that this doesn't work with highmem page */
static dma_addr_t swiotlb_virt_to_bus(struct device *hwdev,
volatile void *address)
@@ -188,8 +200,7 @@ int __init swiotlb_init_with_tbl(char *t
void __init
swiotlb_init(int verbose)
{
- /* default to 64MB */
- size_t default_size = 64UL<<20;
+ size_t default_size = IO_TLB_DEFAULT_SIZE;
unsigned char *vstart;
unsigned long bytes;
Index: linux-2.6/Documentation/kernel-parameters.txt
===================================================================
--- linux-2.6.orig/Documentation/kernel-parameters.txt
+++ linux-2.6/Documentation/kernel-parameters.txt
@@ -596,9 +596,6 @@ bytes respectively. Such letter suffixes
is selected automatically. Check
Documentation/kdump/kdump.txt for further details.
- crashkernel_low=size[KMG]
- [KNL, x86] parts under 4G.
-
crashkernel=range1:size1[,range2:size2,...][@offset]
[KNL] Same as above, but depends on the memory
in the running system. The syntax of range is
@@ -606,6 +603,17 @@ bytes respectively. Such letter suffixes
a memory unit (amount[KMG]). See also
Documentation/kdump/kdump.txt for an example.
+ crashkernel_low=size[KMG]
+ [KNL, x86_64] range under 4G. When crashkernel= is
+ passed, kernel allocate physical memory region
+ above 4G, that cause second kernel crash on system
+ that require some amount of low memory, e.g. swiotlb
+ requires at least 64M+32K low memory. Kernel would
+ try to allocate 72M below 4G automatically.
+ This one let user to specify own low range under 4G
+ for second kernel instead.
+ 0: to disable low allocation.
+
cs89x0_dma= [HW,NET]
Format: <dma>
On Wed, Apr 10, 2013 at 12:39:15PM -0700, Yinghai Lu wrote:
> Vivek found some problems with old kexec-tools.
>
> We keep the old crashkernel=X to old behavoir, so it will not break
> old kexec-tools.
> Add crashkernel=X,high to support new kexec-tools that supports loading high.
> when high is used, memblock will search from top to low.
> if the allocated one is above 4G, kernel will try to auto allocate
> 72M under 4G for swiotlb.
> user could crashkernel=Y,low to change 72M to other value.
>
> -v2: reorder the patch sequences
> crashkernel=X,high, crashkernel=Y,low only handle simple form.
> crashkernel=X will override crashkernel=X;high crashkernel=Y;low
> -v3: update description in kernel-parameters.txt
> update get_last_crashkernel and _simple checking about suffix.
> -v4: update to use ,high again, and also not abuse parse_crashkernel_simple
>
This series looks good to me.
Acked-by: Vivek Goyal <[email protected]>
Vivek
(2013/04/11 4:39), Yinghai Lu wrote:
<cut>
> Index: linux-2.6/kernel/kexec.c
> ===================================================================
> --- linux-2.6.orig/kernel/kexec.c
> +++ linux-2.6/kernel/kexec.c
> @@ -1368,35 +1368,108 @@ static int __init parse_crashkernel_simp
> return 0;
> }
>
> +#define SUFFIX_HIGH 0
> +#define SUFFIX_LOW 1
> +#define SUFFIX_NULL 2
> +static __initdata char *suffix_tbl[] = {
> + [SUFFIX_HIGH] = ",high",
> + [SUFFIX_LOW] = ",low",
> + [SUFFIX_NULL] = NULL,
> +};
> +
> /*
> - * That function is the entry point for command line parsing and should be
> - * called from the arch-specific code.
> + * That function parses "suffix" crashkernel command lines like
> + *
> + * crashkernel=size,[high|low]
> + *
> + * It returns 0 on success and -EINVAL on failure.
> */
> +static int __init parse_crashkernel_suffix(char *cmdline,
> + unsigned long long *crash_size,
> + unsigned long long *crash_base,
> + const char *suffix)
> +{
> + char *cur = cmdline;
> +
> + *crash_size = memparse(cmdline, &cur);
> + if (cmdline == cur) {
> + pr_warn("crashkernel: memory value expected\n");
> + return -EINVAL;
> + }
> +
> + /* check with suffix */
> + if (!strncmp(cur, suffix, strlen(suffix)))
> + return 0;
What kind of strings do you intend to be passed here? The syntax that
matches this check would be
[0-9]+[kmgKMG]?(,low|,high){.*(,low|,high)}*
though memparse() part might be less precise. For example, the following
one passes the check since it ends with ",low" and ",high" follows
"12345K" to be parsed by memparse(). Is this within your intension for
ease of implementation?
crashkernel=12345K,highfoobar,highabcd,low
> +
> + pr_warn("crashkernel: unrecognized char\n");
> + return -EINVAL;
> +}
I like functions checking errornous cases in the middle and ends with
successful case. How about:
/* check with suffix */
if (strncmp(cur, suffix, strlen(suffix)) {
pr_warn("crashkernel: unrecognized char\n");
return -EINVAL;
}
return 0;
--
Thanks.
HATAYAMA, Daisuke
On Thu, Apr 11, 2013 at 10:46 PM, HATAYAMA Daisuke
<[email protected]> wrote:
> (2013/04/11 4:39), Yinghai Lu wrote:
> <cut>
>> Index: linux-2.6/kernel/kexec.c
>> ===================================================================
>> --- linux-2.6.orig/kernel/kexec.c
>> +++ linux-2.6/kernel/kexec.c
>> @@ -1368,35 +1368,108 @@ static int __init parse_crashkernel_simp
>> return 0;
>> }
>>
>> +#define SUFFIX_HIGH 0
>> +#define SUFFIX_LOW 1
>> +#define SUFFIX_NULL 2
>> +static __initdata char *suffix_tbl[] = {
>> + [SUFFIX_HIGH] = ",high",
>> + [SUFFIX_LOW] = ",low",
>> + [SUFFIX_NULL] = NULL,
>> +};
>> +
>> /*
>> - * That function is the entry point for command line parsing and should be
>> - * called from the arch-specific code.
>> + * That function parses "suffix" crashkernel command lines like
>> + *
>> + * crashkernel=size,[high|low]
>> + *
>> + * It returns 0 on success and -EINVAL on failure.
>> */
>> +static int __init parse_crashkernel_suffix(char *cmdline,
>> + unsigned long long *crash_size,
>> + unsigned long long *crash_base,
>> + const char *suffix)
>> +{
>> + char *cur = cmdline;
>> +
>> + *crash_size = memparse(cmdline, &cur);
>> + if (cmdline == cur) {
>> + pr_warn("crashkernel: memory value expected\n");
>> + return -EINVAL;
>> + }
>> +
>> + /* check with suffix */
>> + if (!strncmp(cur, suffix, strlen(suffix)))
>> + return 0;
>
> What kind of strings do you intend to be passed here? The syntax that
> matches this check would be
>
> [0-9]+[kmgKMG]?(,low|,high){.*(,low|,high)}*
should be
[0-9]+[kmgKMG](,low|,high)
will tight the checking.
>
> though memparse() part might be less precise. For example, the following
> one passes the check since it ends with ",low" and ",high" follows
> "12345K" to be parsed by memparse(). Is this within your intension for
> ease of implementation?
>
> crashkernel=12345K,highfoobar,highabcd,low
it will be rejected.
crashkernel=12345K,highfoobar,highabcd,high
should be rejected too.
>
>> +
>> + pr_warn("crashkernel: unrecognized char\n");
>> + return -EINVAL;
>> +}
>
> I like functions checking errornous cases in the middle and ends with
> successful case. How about:
>
> /* check with suffix */
> if (strncmp(cur, suffix, strlen(suffix)) {
> pr_warn("crashkernel: unrecognized char\n");
> return -EINVAL;
> }
>
> return 0;
ok.