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SubjectRe: [PATCH] Increase number of e820 entries hard limit from 32 to 128

This is a very good idea.

Jeff

Venkatesh Pallipadi wrote:

>The specifications that talk about E820 map doesn't have an upper limit
>on the number of E820 entries. But, today's kernel has a hard limit of 32.
>With increase in memory size, we are seeing the number of E820 entries
>reaching close to 32. Patch below bumps the number upto 128.
>
>Patch does it for both i386 and x86-64.
>
>Side-effect:
>bss increases by ~ 2K and init.data increases by ~7.5K
>on all systems, due to increase in size of static arrays.
>
>Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
>
>diff -purN linux-2.6.11/Documentation/i386/zero-page.txt.orig linux-2.6.11/Documentation/i386/zero-page.txt
>--- linux-2.6.11/Documentation/i386/zero-page.txt.orig 2005-04-21 17:09:08.059184904 -0700
>+++ linux-2.6.11/Documentation/i386/zero-page.txt 2005-04-21 17:09:14.955136560 -0700
>@@ -79,6 +79,6 @@ Offset Type Description
> 0x22c unsigned long ramdisk_max
> 0x230 16 bytes trampoline
> 0x290 - 0x2cf EDD_MBR_SIG_BUFFER (edd.S)
>-0x2d0 - 0x600 E820MAP
>-0x600 - 0x7ff EDDBUF (edd.S) for disk signature read sector
>-0x600 - 0x7eb EDDBUF (edd.S) for edd data
>+0x2d0 - 0xd00 E820MAP
>+0xd00 - 0xeff EDDBUF (edd.S) for disk signature read sector
>+0xd00 - 0xeeb EDDBUF (edd.S) for edd data
>diff -purN linux-2.6.11/include/linux/edd.h.orig linux-2.6.11/include/linux/edd.h
>--- linux-2.6.11/include/linux/edd.h.orig 2005-04-21 17:09:08.059184904 -0700
>+++ linux-2.6.11/include/linux/edd.h 2005-04-21 17:09:14.956136408 -0700
>@@ -32,7 +32,7 @@
>
> #define EDDNR 0x1e9 /* addr of number of edd_info structs at EDDBUF
> in boot_params - treat this as 1 byte */
>-#define EDDBUF 0x600 /* addr of edd_info structs in boot_params */
>+#define EDDBUF 0xd00 /* addr of edd_info structs in boot_params */
> #define EDDMAXNR 6 /* number of edd_info structs starting at EDDBUF */
> #define EDDEXTSIZE 8 /* change these if you muck with the structures */
> #define EDDPARMSIZE 74
>diff -purN linux-2.6.11/include/asm-i386/e820.h.orig linux-2.6.11/include/asm-i386/e820.h
>--- linux-2.6.11/include/asm-i386/e820.h.orig 2005-04-21 17:09:08.060184752 -0700
>+++ linux-2.6.11/include/asm-i386/e820.h 2005-04-21 17:09:14.956136408 -0700
>@@ -13,7 +13,7 @@
> #define __E820_HEADER
>
> #define E820MAP 0x2d0 /* our map */
>-#define E820MAX 32 /* number of entries in E820MAP */
>+#define E820MAX 128 /* number of entries in E820MAP */
> #define E820NR 0x1e8 /* # entries in E820MAP */
>
> #define E820_RAM 1
>diff -purN linux-2.6.11/include/asm-i386/setup.h.orig linux-2.6.11/include/asm-i386/setup.h
>--- linux-2.6.11/include/asm-i386/setup.h.orig 2005-04-21 17:09:08.060184752 -0700
>+++ linux-2.6.11/include/asm-i386/setup.h 2005-04-21 17:09:14.957136256 -0700
>@@ -16,7 +16,7 @@
> #define MAXMEM_PFN PFN_DOWN(MAXMEM)
> #define MAX_NONPAE_PFN (1 << 20)
>
>-#define PARAM_SIZE 2048
>+#define PARAM_SIZE 4096
> #define COMMAND_LINE_SIZE 256
>
> #define OLD_CL_MAGIC_ADDR 0x90020
>diff -purN linux-2.6.11/arch/i386/boot/setup.S.orig linux-2.6.11/arch/i386/boot/setup.S
>--- linux-2.6.11/arch/i386/boot/setup.S.orig 2005-04-21 17:09:08.061184600 -0700
>+++ linux-2.6.11/arch/i386/boot/setup.S 2005-04-21 17:09:14.957136256 -0700
>@@ -164,7 +164,7 @@ ramdisk_max: .long (-__PAGE_OFFSET-(512
> trampoline: call start_of_setup
> .align 16
> # The offset at this point is 0x240
>- .space (0x7ff-0x240+1) # E820 & EDD space (ending at 0x7ff)
>+ .space (0xeff-0x240+1) # E820 & EDD space (ending at 0xeff)
> # End of setup header #####################################################
>
> start_of_setup:
>@@ -333,9 +333,9 @@ jmpe820:
> # sizeof(e820rec).
> #
> good820:
>- movb (E820NR), %al # up to 32 entries
>+ movb (E820NR), %al # up to 128 entries
> cmpb $E820MAX, %al
>- jnl bail820
>+ jae bail820
>
> incb (E820NR)
> movw %di, %ax
>diff -purN linux-2.6.11/include/asm-x86_64/e820.h.orig linux-2.6.11/include/asm-x86_64/e820.h
>--- linux-2.6.11/include/asm-x86_64/e820.h.orig 2005-04-21 17:09:08.061184600 -0700
>+++ linux-2.6.11/include/asm-x86_64/e820.h 2005-04-21 17:09:14.958136104 -0700
>@@ -14,7 +14,7 @@
> #include <linux/mmzone.h>
>
> #define E820MAP 0x2d0 /* our map */
>-#define E820MAX 32 /* number of entries in E820MAP */
>+#define E820MAX 128 /* number of entries in E820MAP */
> #define E820NR 0x1e8 /* # entries in E820MAP */
>
> #define E820_RAM 1
>diff -purN linux-2.6.11/include/asm-x86_64/bootsetup.h.orig linux-2.6.11/include/asm-x86_64/bootsetup.h
>--- linux-2.6.11/include/asm-x86_64/bootsetup.h.orig 2005-04-21 17:09:08.061184600 -0700
>+++ linux-2.6.11/include/asm-x86_64/bootsetup.h 2005-04-22 14:38:39.793893360 -0700
>@@ -2,7 +2,8 @@
> #ifndef _X86_64_BOOTSETUP_H
> #define _X86_64_BOOTSETUP_H 1
>
>-extern char x86_boot_params[2048];
>+#define BOOT_PARAM_SIZE 4096
>+extern char x86_boot_params[BOOT_PARAM_SIZE];
>
> /*
> * This is set up by the setup-routine at boot-time
>diff -purN linux-2.6.11/arch/x86_64/boot/setup.S.orig linux-2.6.11/arch/x86_64/boot/setup.S
>--- linux-2.6.11/arch/x86_64/boot/setup.S.orig 2005-04-21 17:09:08.062184448 -0700
>+++ linux-2.6.11/arch/x86_64/boot/setup.S 2005-04-22 15:32:57.074711408 -0700
>@@ -160,7 +160,7 @@ ramdisk_max: .long 0xffffffff
> trampoline: call start_of_setup
> .align 16
> # The offset at this point is 0x240
>- .space (0x7ff-0x240+1) # E820 & EDD space (ending at 0x7ff)
>+ .space (0xeff-0x240+1) # E820 & EDD space (ending at 0xeff)
> # End of setup header #####################################################
>
> start_of_setup:
>@@ -412,9 +412,9 @@ jmpe820:
> # sizeof(e820rec).
> #
> good820:
>- movb (E820NR), %al # up to 32 entries
>+ movb (E820NR), %al # up to 128 entries
> cmpb $E820MAX, %al
>- jnl bail820
>+ jae bail820
>
> incb (E820NR)
> movw %di, %ax
>diff -purN linux-2.6.11/arch/x86_64/kernel/setup64.c.orig linux-2.6.11/arch/x86_64/kernel/setup64.c
>--- linux-2.6.11/arch/x86_64/kernel/setup64.c.orig 2005-04-22 15:29:38.304929008 -0700
>+++ linux-2.6.11/arch/x86_64/kernel/setup64.c 2005-04-21 17:12:15.529685056 -0700
>@@ -12,6 +12,7 @@
> #include <linux/string.h>
> #include <linux/bootmem.h>
> #include <linux/bitops.h>
>+#include <asm/bootsetup.h>
> #include <asm/pda.h>
> #include <asm/pgtable.h>
> #include <asm/processor.h>
>@@ -26,7 +27,7 @@
> #include <asm/mman.h>
> #include <asm/numa.h>
>
>-char x86_boot_params[2048] __initdata = {0,};
>+char x86_boot_params[BOOT_PARAM_SIZE] __initdata = {0,};
>
> cpumask_t cpu_initialized __initdata = CPU_MASK_NONE;
>
>diff -purN linux-2.6.11/arch/x86_64/kernel/head64.c.orig linux-2.6.11/arch/x86_64/kernel/head64.c
>--- linux-2.6.11/arch/x86_64/kernel/head64.c.orig 2005-04-22 15:29:22.004407064 -0700
>+++ linux-2.6.11/arch/x86_64/kernel/head64.c 2005-04-22 15:32:37.295718272 -0700
>@@ -29,8 +29,6 @@ static void __init clear_bss(void)
> (unsigned long) __bss_end - (unsigned long) __bss_start);
> }
>
>-extern char x86_boot_params[2048];
>-
> #define NEW_CL_POINTER 0x228 /* Relative to real mode data */
> #define OLD_CL_MAGIC_ADDR 0x90020
> #define OLD_CL_MAGIC 0xA33F
>@@ -44,7 +42,7 @@ static void __init copy_bootdata(char *r
> int new_data;
> char * command_line;
>
>- memcpy(x86_boot_params, real_mode_data, 2048);
>+ memcpy(x86_boot_params, real_mode_data, BOOT_PARAM_SIZE);
> new_data = *(int *) (x86_boot_params + NEW_CL_POINTER);
> if (!new_data) {
> if (OLD_CL_MAGIC != * (u16 *) OLD_CL_MAGIC_ADDR) {
>-
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