Commit f9ba7053 authored by Venkatesh Pallipadi's avatar Venkatesh Pallipadi Committed by Linus Torvalds
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[PATCH] Increase number of e820 entries hard limit from 32 to 128 



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.

The patch changes the location of EDDBUF in zero-page (as it comes after E820).
As, EDDBUF is not used by boot loaders, this patch should not have any effect
on bootloader-setup code interface.

Patch covers both i386 and x86-64.

Tested on:
* grub booting bzImage
* lilo booting bzImage with EDID info enabled
* pxeboot of bzImage

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: default avatarVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent be9e6870

Documentation/i386/zero-page.txt

+3 −3
Original line number Diff line number Diff line
@@ -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

arch/i386/boot/setup.S

+3 −3
Original line number Diff line number Diff line
@@ -164,7 +164,7 @@ ramdisk_max: .long (-__PAGE_OFFSET-(512 << 20)-1) & 0x7fffffff 
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

arch/x86_64/boot/setup.S

+3 −3
Original line number Diff line number Diff line
@@ -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

arch/x86_64/kernel/head64.c

+1 −3
Original line number Diff line number Diff line
@@ -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 *real_mode_data) 
	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) {

arch/x86_64/kernel/setup64.c

+2 −1
Original line number Diff line number Diff line
@@ -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;

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