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linux-sg2042
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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
This commit is contained in:
Linus Torvalds 2009-04-01 11:13:31 -07:00
parent 4fe70410d9 c549e71d07
commit 9c9cb14387
1 changed files with 24 additions and 9 deletions
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33
arch/x86/boot/memory.c
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@ -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;