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Commit 9c9cb143 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'x86/setup' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 

* 'x86/setup' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86, setup: ACPI 3, BIOS workaround for E820-probing code
  x86, setup: preemptively save/restore edi and ebp around INT 15 E820
  x86, setup: mark %esi as clobbered in E820 BIOS call
parents 4fe70410 c549e71d

arch/x86/boot/memory.c

+24 −9
Original line number Diff line number Diff line
@@ -2,6 +2,7 @@ 
 *

 *   Copyright (C) 1991, 1992 Linus Torvalds

 *   Copyright 2007 rPath, Inc. - All Rights Reserved

 *   Copyright 2009 Intel Corporation; author H. Peter Anvin

 *

 *   This file is part of the Linux kernel, and is made available under

 *   the terms of the GNU General Public License version 2.
@@ -16,24 +17,32 @@ 


#define SMAP	0x534d4150	/* ASCII "SMAP" */



struct e820_ext_entry {

	struct e820entry std;

	u32 ext_flags;

} __attribute__((packed));



static int detect_memory_e820(void)

{

	int count = 0;

	u32 next = 0;

	u32 size, id;

	u32 size, id, edi;

	u8 err;

	struct e820entry *desc = boot_params.e820_map;

	static struct e820_ext_entry buf; /* static so it is zeroed */



	do {

		size = sizeof(struct e820entry);

		size = sizeof buf;



		/* Important: %edx is clobbered by some BIOSes,

		   so it must be either used for the error output

		   or explicitly marked clobbered. */

		asm("int $0x15; setc %0"

		/* Important: %edx and %esi are clobbered by some BIOSes,

		   so they must be either used for the error output

		   or explicitly marked clobbered.  Given that, assume there

		   is something out there clobbering %ebp and %edi, too. */

		asm("pushl %%ebp; int $0x15; popl %%ebp; setc %0"

		    : "=d" (err), "+b" (next), "=a" (id), "+c" (size),

		      "=m" (*desc)

		    : "D" (desc), "d" (SMAP), "a" (0xe820));

		      "=D" (edi), "+m" (buf)

		    : "D" (&buf), "d" (SMAP), "a" (0xe820)

		    : "esi");



		/* BIOSes which terminate the chain with CF = 1 as opposed

		   to %ebx = 0 don't always report the SMAP signature on
@@ -51,8 +60,14 @@ static int detect_memory_e820(void) 
			break;

		}



		/* ACPI 3.0 added the extended flags support.  If bit 0

		   in the extended flags is zero, we're supposed to simply

		   ignore the entry -- a backwards incompatible change! */

		if (size > 20 && !(buf.ext_flags & 1))

			continue;



		*desc++ = buf.std;

		count++;

		desc++;

	} while (next && count < ARRAY_SIZE(boot_params.e820_map));



	return boot_params.e820_entries = count;