[RFC][x86_64] Introducing the memmap= kernel command line option

[RFC][x86_64] Introducing the memmap= kernel command line option

[Hariprasad Nellitheertha]

[-- Attachment #1: Type: text/plain, Size: 457 bytes --]

Hi Andi,

In order to port kdump to x86_64, we need to have the 
memmap= kernel command line option available. This is so 
that the dump-capture kernel can be booted with a custom 
memory map.

The attached patch adds the memmap= functionality to the 
x86_64 kernel. It is against 2.6.12-rc2-mm3. I have done 
some amount of testing and it is working fine.

Could you kindly review this patch and let me know your 
thoughts on it.

Thanks and Regards,
Hari

[-- Attachment #2: x8664-memmap-command-line-option.patch --]
[-- Type: text/plain, Size: 3449 bytes --]


This patch adds the 'memmap=' kernel command line option for the
x86_64 kernel.

Signed-off-by: Hariprasad Nellitheertha <hari@in.ibm.com>
---

 linux-2.6.12-rc2-hari/Documentation/kernel-parameters.txt |    2 -
 linux-2.6.12-rc2-hari/arch/x86_64/kernel/e820.c           |   25 ++++++++++++++
 linux-2.6.12-rc2-hari/arch/x86_64/kernel/setup.c          |    3 +
 linux-2.6.12-rc2-hari/include/asm-x86_64/e820.h           |    2 +
 4 files changed, 31 insertions(+), 1 deletion(-)

diff -puN arch/x86_64/kernel/e820.c~x8664-memmap-command-line-option arch/x86_64/kernel/e820.c
--- linux-2.6.12-rc2/arch/x86_64/kernel/e820.c~x8664-memmap-command-line-option	2005-04-15 10:15:04.000000000 +0530
+++ linux-2.6.12-rc2-hari/arch/x86_64/kernel/e820.c	2005-04-15 10:17:23.000000000 +0530
@@ -513,6 +513,31 @@ void __init parse_memopt(char *p, char *
 	end_user_pfn >>= PAGE_SHIFT;	
 } 
 
+void __init parse_memmapopt(char *p, char **from)
+{
+	if (!memcmp(p, "exactmap", 8)) {
+		p += 8;
+		e820.nr_map = 0;
+	} else {
+		unsigned long long start_at, mem_size;
+
+		mem_size = memparse(p, from);
+		p = *from;
+		if (*p == '@') {
+			start_at = memparse(p+1, from);
+			add_memory_region(start_at, mem_size, E820_RAM);
+		} else if (*p == '#') {
+			start_at = memparse(p+1, from);
+			add_memory_region(start_at, mem_size, E820_ACPI);
+		} else if (*p == '$') {
+			start_at = memparse(p+1, from);
+			add_memory_region(start_at, mem_size, E820_RESERVED);
+		} else {
+			end_user_pfn = (mem_size >> PAGE_SHIFT);
+		}
+	}
+}
+
 unsigned long pci_mem_start = 0xaeedbabe;
 
 /*
diff -puN arch/x86_64/kernel/setup.c~x8664-memmap-command-line-option arch/x86_64/kernel/setup.c
--- linux-2.6.12-rc2/arch/x86_64/kernel/setup.c~x8664-memmap-command-line-option	2005-04-15 10:15:04.000000000 +0530
+++ linux-2.6.12-rc2-hari/arch/x86_64/kernel/setup.c	2005-04-15 10:15:04.000000000 +0530
@@ -349,6 +349,9 @@ static __init void parse_cmdline_early (
 		if (!memcmp(from, "mem=", 4))
 			parse_memopt(from+4, &from); 
 
+		if (!memcmp(from, "memmap=", 7))
+			parse_memmapopt(from+7, &from);
+
 #ifdef CONFIG_DISCONTIGMEM
 		if (!memcmp(from, "numa=", 5))
 			numa_setup(from+5); 
diff -puN include/asm-x86_64/e820.h~x8664-memmap-command-line-option include/asm-x86_64/e820.h
--- linux-2.6.12-rc2/include/asm-x86_64/e820.h~x8664-memmap-command-line-option	2005-04-15 10:15:04.000000000 +0530
+++ linux-2.6.12-rc2-hari/include/asm-x86_64/e820.h	2005-04-15 10:15:04.000000000 +0530
@@ -54,6 +54,8 @@ extern void e820_setup_gap(void);
 
 extern void __init parse_memopt(char *p, char **end);
 
+extern void __init parse_memmapopt(char *p, char **end);
+
 extern struct e820map e820;
 #endif/*!__ASSEMBLY__*/
 
diff -puN Documentation/kernel-parameters.txt~x8664-memmap-command-line-option Documentation/kernel-parameters.txt
--- linux-2.6.12-rc2/Documentation/kernel-parameters.txt~x8664-memmap-command-line-option	2005-04-15 10:19:37.000000000 +0530
+++ linux-2.6.12-rc2-hari/Documentation/kernel-parameters.txt	2005-04-15 10:19:56.000000000 +0530
@@ -794,7 +794,7 @@ running once the system is up.
 	mem=nopentium	[BUGS=IA-32] Disable usage of 4MB pages for kernel
 			memory.
 
-	memmap=exactmap	[KNL,IA-32] Enable setting of an exact
+	memmap=exactmap	[KNL,IA-32,X86-64] Enable setting of an exact
 			E820 memory map, as specified by the user.
 			Such memmap=exactmap lines can be constructed based on
 			BIOS output or other requirements. See the memmap=nn@ss
_

Re: [RFC][x86_64] Introducing the memmap= kernel command line option

[Andi Kleen]

On Fri, Apr 15, 2005 at 11:43:55AM +0530, Hariprasad Nellitheertha wrote:
> Hi Andi,
> 
> In order to port kdump to x86_64, we need to have the 
> memmap= kernel command line option available. This is so 
> that the dump-capture kernel can be booted with a custom 
> memory map.
> 
> The attached patch adds the memmap= functionality to the 
> x86_64 kernel. It is against 2.6.12-rc2-mm3. I have done 
> some amount of testing and it is working fine.
> 
> Could you kindly review this patch and let me know your 
> thoughts on it.

You should add a __setup somewhere, otherwise the kernel
will complain about unknown arguments or generate a memmap
variable in inits environment. 

Comma parsing would be nice.

Otherwise it looks ok.

-Andi

Re: [RFC][x86_64] Introducing the memmap= kernel command line option

[Hariprasad Nellitheertha]

Andi Kleen wrote:
> On Fri, Apr 15, 2005 at 11:43:55AM +0530, Hariprasad Nellitheertha wrote:
> 
>>Hi Andi,
>>
>>In order to port kdump to x86_64, we need to have the 
>>memmap= kernel command line option available. This is so 
>>that the dump-capture kernel can be booted with a custom 
>>memory map.
>>
>>The attached patch adds the memmap= functionality to the 
>>x86_64 kernel. It is against 2.6.12-rc2-mm3. I have done 
>>some amount of testing and it is working fine.
>>
>>Could you kindly review this patch and let me know your 
>>thoughts on it.
> 
> 
> You should add a __setup somewhere, otherwise the kernel
> will complain about unknown arguments or generate a memmap
> variable in inits environment. 

Sure. Will add that.

> 
> Comma parsing would be nice.

Will add this for i386 as well and send out another patch

> 
> Otherwise it looks ok.

Thanks!

- Hari

Re: [RFC][x86_64] Introducing the memmap= kernel command line option

[Hariprasad Nellitheertha]

[-- Attachment #1: Type: text/plain, Size: 1154 bytes --]

Hi Andi,

Andi Kleen wrote:
> On Fri, Apr 15, 2005 at 11:43:55AM +0530, Hariprasad Nellitheertha wrote:
> 
>>Hi Andi,
>>
>>In order to port kdump to x86_64, we need to have the 
>>memmap= kernel command line option available. This is so 
>>that the dump-capture kernel can be booted with a custom 
>>memory map.
>>
>>The attached patch adds the memmap= functionality to the 
>>x86_64 kernel. It is against 2.6.12-rc2-mm3. I have done 
>>some amount of testing and it is working fine.
>>
>>Could you kindly review this patch and let me know your 
>>thoughts on it.
> 
> 
> You should add a __setup somewhere, otherwise the kernel
> will complain about unknown arguments or generate a memmap
> variable in inits environment. 

The memmap= option does not introduce any new variables that 
we would need at a later point of time. Its very similar in 
the way it handles the maps to the "mem=" option. Hence I 
have not added the __setup in the attached patch.

> 
> Comma parsing would be nice.

I have introduced comma parsing. The patch for doing the 
same in i386 follows in a separate patch.

Please review and let me know your comments.

Regards, Hari

[-- Attachment #2: x8664-memmap-command-line-option.patch --]
[-- Type: text/plain, Size: 3552 bytes --]


This patch adds the 'memmap=' kernel command line option for the
x86_64 kernel.

Signed-off-by: Hariprasad Nellitheertha <hari@in.ibm.com>
---

 linux-2.6.12-rc2-hari/Documentation/kernel-parameters.txt |    2 
 linux-2.6.12-rc2-hari/arch/x86_64/kernel/e820.c           |   32 ++++++++++++++
 linux-2.6.12-rc2-hari/arch/x86_64/kernel/setup.c          |    3 +
 linux-2.6.12-rc2-hari/include/asm-x86_64/e820.h           |    2 
 4 files changed, 38 insertions(+), 1 deletion(-)

diff -puN arch/x86_64/kernel/e820.c~x8664-memmap-command-line-option arch/x86_64/kernel/e820.c
--- linux-2.6.12-rc2/arch/x86_64/kernel/e820.c~x8664-memmap-command-line-option	2005-04-15 10:15:04.000000000 +0530
+++ linux-2.6.12-rc2-hari/arch/x86_64/kernel/e820.c	2005-04-27 16:27:45.000000000 +0530
@@ -513,6 +513,38 @@ void __init parse_memopt(char *p, char *
 	end_user_pfn >>= PAGE_SHIFT;	
 } 
 
+void __init parse_memmapopt(char *p, char **from)
+{
+	do {
+		if (!memcmp(p, "exactmap", 8)) {
+			p += 8;
+			e820.nr_map = 0;
+		} else {
+			unsigned long long start_at, mem_size;
+
+			mem_size = memparse(p, from);
+			p = *from;
+			if (*p == '@') {
+				start_at = memparse(p+1, from);
+				add_memory_region(start_at, mem_size, E820_RAM);
+			} else if (*p == '#') {
+				start_at = memparse(p+1, from);
+				add_memory_region(start_at, mem_size, E820_ACPI);
+			} else if (*p == '$') {
+				start_at = memparse(p+1, from);
+				add_memory_region(start_at, mem_size, E820_RESERVED);
+			} else {
+				end_user_pfn = (mem_size >> PAGE_SHIFT);
+			}
+			p = *from;
+		}
+		if (*p != ',')
+			break;
+		else
+			p += 1;
+	} while(1);
+}
+
 unsigned long pci_mem_start = 0xaeedbabe;
 
 /*
diff -puN arch/x86_64/kernel/setup.c~x8664-memmap-command-line-option arch/x86_64/kernel/setup.c
--- linux-2.6.12-rc2/arch/x86_64/kernel/setup.c~x8664-memmap-command-line-option	2005-04-15 10:15:04.000000000 +0530
+++ linux-2.6.12-rc2-hari/arch/x86_64/kernel/setup.c	2005-04-15 10:15:04.000000000 +0530
@@ -349,6 +349,9 @@ static __init void parse_cmdline_early (
 		if (!memcmp(from, "mem=", 4))
 			parse_memopt(from+4, &from); 
 
+		if (!memcmp(from, "memmap=", 7))
+			parse_memmapopt(from+7, &from);
+
 #ifdef CONFIG_DISCONTIGMEM
 		if (!memcmp(from, "numa=", 5))
 			numa_setup(from+5); 
diff -puN include/asm-x86_64/e820.h~x8664-memmap-command-line-option include/asm-x86_64/e820.h
--- linux-2.6.12-rc2/include/asm-x86_64/e820.h~x8664-memmap-command-line-option	2005-04-15 10:15:04.000000000 +0530
+++ linux-2.6.12-rc2-hari/include/asm-x86_64/e820.h	2005-04-15 10:15:04.000000000 +0530
@@ -54,6 +54,8 @@ extern void e820_setup_gap(void);
 
 extern void __init parse_memopt(char *p, char **end);
 
+extern void __init parse_memmapopt(char *p, char **end);
+
 extern struct e820map e820;
 #endif/*!__ASSEMBLY__*/
 
diff -puN Documentation/kernel-parameters.txt~x8664-memmap-command-line-option Documentation/kernel-parameters.txt
--- linux-2.6.12-rc2/Documentation/kernel-parameters.txt~x8664-memmap-command-line-option	2005-04-15 10:19:37.000000000 +0530
+++ linux-2.6.12-rc2-hari/Documentation/kernel-parameters.txt	2005-04-15 10:19:56.000000000 +0530
@@ -794,7 +794,7 @@ running once the system is up.
 	mem=nopentium	[BUGS=IA-32] Disable usage of 4MB pages for kernel
 			memory.
 
-	memmap=exactmap	[KNL,IA-32] Enable setting of an exact
+	memmap=exactmap	[KNL,IA-32,X86-64] Enable setting of an exact
 			E820 memory map, as specified by the user.
 			Such memmap=exactmap lines can be constructed based on
 			BIOS output or other requirements. See the memmap=nn@ss
_

Re: [RFC][i386] Comma parsing for the memmap= kernel command line option

[Hariprasad Nellitheertha]

[-- Attachment #1: Type: text/plain, Size: 14 bytes --]

Regards, Hari

[-- Attachment #2: i386-memmap-comma-parsing.patch --]
[-- Type: text/plain, Size: 3302 bytes --]


This patch adds comma parsing ability to the i386
memmap= kernel command line option. With this, multiple
entries to memmap can be separated by a comma instead of
separate entries.

For example, memmap=exactmap,640k@0M,1024M@1M

Signed-off-by: Hariprasad Nellitheertha <hari@in.ibm.com>
---

 linux-2.6.12-rc2-hari/arch/i386/kernel/setup.c |   79 +++++++++++++------------
 1 files changed, 43 insertions(+), 36 deletions(-)

diff -puN arch/i386/kernel/setup.c~i386-memmap-comma-parsing arch/i386/kernel/setup.c
--- linux-2.6.12-rc2/arch/i386/kernel/setup.c~i386-memmap-comma-parsing	2005-04-27 16:30:05.000000000 +0530
+++ linux-2.6.12-rc2-hari/arch/i386/kernel/setup.c	2005-04-28 15:04:42.000000000 +0530
@@ -716,45 +716,52 @@ static void __init parse_cmdline_early (
 		}
 
 		else if (!memcmp(from, "memmap=", 7)) {
-			if (to != command_line)
-				to--;
-			if (!memcmp(from+7, "exactmap", 8)) {
+			from += 7;
+			do {
+				if (to != command_line)
+					to--;
+				if (!memcmp(from, "exactmap", 8)) {
 #ifdef CONFIG_CRASH_DUMP
-				/* If we are doing a crash dump, we
-				 * still need to know the real mem
-				 * size before original memory map is
-				 * reset.
-				 */
-				find_max_pfn();
-				saved_max_pfn = max_pfn;
-#endif
-				from += 8+7;
-				e820.nr_map = 0;
-				userdef = 1;
-			} else {
-				/* If the user specifies memory size, we
-				 * limit the BIOS-provided memory map to
-				 * that size. exactmap can be used to specify
-				 * the exact map. mem=number can be used to
-				 * trim the existing memory map.
-				 */
-				unsigned long long start_at, mem_size;
- 
-				mem_size = memparse(from+7, &from);
-				if (*from == '@') {
-					start_at = memparse(from+1, &from);
-					add_memory_region(start_at, mem_size, E820_RAM);
-				} else if (*from == '#') {
-					start_at = memparse(from+1, &from);
-					add_memory_region(start_at, mem_size, E820_ACPI);
-				} else if (*from == '$') {
-					start_at = memparse(from+1, &from);
-					add_memory_region(start_at, mem_size, E820_RESERVED);
+					/* If we are doing a crash dump, we
+					 * still need to know the real mem
+					 * size before original memory map is
+					 * reset.
+					 */
+					find_max_pfn();
+					saved_max_pfn = max_pfn;
+#endif
+					from += 8;
+					e820.nr_map = 0;
+					userdef = 1;
 				} else {
-					limit_regions(mem_size);
-					userdef=1;
+					/* If the user specifies memory size, we
+					 * limit the BIOS-provided memory map to
+					 * that size. exactmap can be used to specify
+					 * the exact map. mem=number can be used to
+					 * trim the existing memory map.
+					 */
+					unsigned long long start_at, mem_size;
+
+					mem_size = memparse(from, &from);
+					if (*from == '@') {
+						start_at = memparse(from+1, &from);
+						add_memory_region(start_at, mem_size, E820_RAM);
+					} else if (*from == '#') {
+						start_at = memparse(from+1, &from);
+						add_memory_region(start_at, mem_size, E820_ACPI);
+					} else if (*from == '$') {
+						start_at = memparse(from+1, &from);
+						add_memory_region(start_at, mem_size, E820_RESERVED);
+					} else {
+						limit_regions(mem_size);
+						userdef=1;
+					}
 				}
-			}
+				if (*from != ',')
+					break;
+				else
+					from += 1;
+			} while(1);
 		}
 
 		else if (!memcmp(from, "noexec=", 7))
_