linux/arch/x86/boot/memory.c
Andi Kleen 1b72691ce3 x86: fix build warnings in real mode code
This recent patch

commit c3965bd151
Author: Paul Jackson <pj@sgi.com>
Date:   Wed May 14 08:15:34 2008 -0700

    x86 boot: proper use of ARRAY_SIZE instead of repeated E820MAX constant

caused these new warnings during a normal build:

In file included from linux-2.6/arch/x86/boot/memory.c:17:
linux-2.6/include/linux/log2.h: In function '__ilog2_u32':
linux-2.6/include/linux/log2.h:34: warning: implicit declaration of function 'fls'
linux-2.6/include/linux/log2.h: In function '__ilog2_u64':
linux-2.6/include/linux/log2.h:42: warning: implicit declaration of function 'fls64'
linux-2.6/include/linux/log2.h: In function '__roundup_pow_of_two ':
linux-2.6/include/linux/log2.h:63: warning: implicit declaration of function 'fls_long'

I tried to fix them in log2.h, but it's difficult because the real mode
environment is completely different from a normal kernel environment. Instead
define an own ARRAY_SIZE macro in boot.h, similar to the other private
macros there.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-18 09:20:14 +02:00

119 lines
2.5 KiB
C

/* -*- linux-c -*- ------------------------------------------------------- *
*
* Copyright (C) 1991, 1992 Linus Torvalds
* Copyright 2007 rPath, Inc. - All Rights Reserved
*
* This file is part of the Linux kernel, and is made available under
* the terms of the GNU General Public License version 2.
*
* ----------------------------------------------------------------------- */
/*
* Memory detection code
*/
#include "boot.h"
#define SMAP 0x534d4150 /* ASCII "SMAP" */
static int detect_memory_e820(void)
{
int count = 0;
u32 next = 0;
u32 size, id;
u8 err;
struct e820entry *desc = boot_params.e820_map;
do {
size = sizeof(struct e820entry);
/* 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"
: "=d" (err), "+b" (next), "=a" (id), "+c" (size),
"=m" (*desc)
: "D" (desc), "d" (SMAP), "a" (0xe820));
/* BIOSes which terminate the chain with CF = 1 as opposed
to %ebx = 0 don't always report the SMAP signature on
the final, failing, probe. */
if (err)
break;
/* Some BIOSes stop returning SMAP in the middle of
the search loop. We don't know exactly how the BIOS
screwed up the map at that point, we might have a
partial map, the full map, or complete garbage, so
just return failure. */
if (id != SMAP) {
count = 0;
break;
}
count++;
desc++;
} while (next && count < ARRAY_SIZE(boot_params.e820_map));
return boot_params.e820_entries = count;
}
static int detect_memory_e801(void)
{
u16 ax, bx, cx, dx;
u8 err;
bx = cx = dx = 0;
ax = 0xe801;
asm("stc; int $0x15; setc %0"
: "=m" (err), "+a" (ax), "+b" (bx), "+c" (cx), "+d" (dx));
if (err)
return -1;
/* Do we really need to do this? */
if (cx || dx) {
ax = cx;
bx = dx;
}
if (ax > 15*1024)
return -1; /* Bogus! */
/* This ignores memory above 16MB if we have a memory hole
there. If someone actually finds a machine with a memory
hole at 16MB and no support for 0E820h they should probably
generate a fake e820 map. */
boot_params.alt_mem_k = (ax == 15*1024) ? (dx << 6)+ax : ax;
return 0;
}
static int detect_memory_88(void)
{
u16 ax;
u8 err;
ax = 0x8800;
asm("stc; int $0x15; setc %0" : "=bcdm" (err), "+a" (ax));
boot_params.screen_info.ext_mem_k = ax;
return -err;
}
int detect_memory(void)
{
int err = -1;
if (detect_memory_e820() > 0)
err = 0;
if (!detect_memory_e801())
err = 0;
if (!detect_memory_88())
err = 0;
return err;
}