[PATCH v4 3/4] x86, kdump: Change crashkernel_high/low= to crashkernel=,high/low

[PATCH v4 3/4] x86, kdump: Change crashkernel_high/low= to crashkernel=,high/low

[Yinghai Lu]

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 <d.hatayama@jp.fujitsu.com>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>

---
 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)

Re: [PATCH v4 3/4] x86, kdump: Change crashkernel_high/low= to crashkernel=,high/low

[Vivek Goyal]

On Tue, Apr 09, 2013 at 01:01:50PM -0700, Yinghai Lu wrote:
> 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 <d.hatayama@jp.fujitsu.com>
> Signed-off-by: Yinghai Lu <yinghai@kernel.org>

This one looks good to me. Looks like you posted this one independet of
previous series.

Can you repost the final version in a series again. I will do some
more testing and ack it.

Thanks
Vivek

> 
> ---
>  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)

[PATCH -v4 0/4] x86, kdump: Fix crashkernel high with old kexec-tools

[Yinghai Lu]

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

[PATCH v4 3/4] x86, kdump: Change crashkernel_high/low= to crashkernel=,high/low

[Yinghai Lu]

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 <d.hatayama@jp.fujitsu.com>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>

---
 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)

Re: [PATCH v4 3/4] x86, kdump: Change crashkernel_high/low= to crashkernel=,high/low

[HATAYAMA Daisuke]

(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

Re: [PATCH v4 3/4] x86, kdump: Change crashkernel_high/low= to crashkernel=,high/low

[Yinghai Lu]

On Thu, Apr 11, 2013 at 10:46 PM, HATAYAMA Daisuke
<d.hatayama@jp.fujitsu.com> 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.