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authorH. Peter Anvin <hpa@linux.intel.com>2009-04-01 18:13:46 -0700
committerH. Peter Anvin <hpa@zytor.com>2009-04-09 16:08:11 -0700
commitdf7699c56421c0476704f24a43409ac8c505f3d2 (patch)
treec8d5935a5bd7dd59b0ce70db1a53999090be938b /arch/x86/boot/memory.c
parent7a734e7dd93b9aea08ed51036a9a0e2c9dfd8dac (diff)
downloadlinux-df7699c56421c0476704f24a43409ac8c505f3d2.tar.gz
x86, setup: "glove box" BIOS interrupts in the core boot code
Impact: BIOS proofing "Glove box" off BIOS interrupts in the core boot code. LKML-Reference: <49DE7F79.4030106@zytor.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Diffstat (limited to 'arch/x86/boot/memory.c')
-rw-r--r--arch/x86/boot/memory.c81
1 files changed, 40 insertions, 41 deletions
diff --git a/arch/x86/boot/memory.c b/arch/x86/boot/memory.c
index 5054c2ddd1a0..d989de810cac 100644
--- a/arch/x86/boot/memory.c
+++ b/arch/x86/boot/memory.c
@@ -25,12 +25,16 @@ struct e820_ext_entry {
static int detect_memory_e820(void)
{
int count = 0;
- u32 next = 0;
- u32 size, id, edi;
- u8 err;
+ struct biosregs ireg, oreg;
struct e820entry *desc = boot_params.e820_map;
static struct e820_ext_entry buf; /* static so it is zeroed */
+ initregs(&ireg);
+ ireg.ax = 0xe820;
+ ireg.cx = sizeof buf;
+ ireg.edx = SMAP;
+ ireg.di = (size_t)&buf;
+
/*
* Set this here so that if the BIOS doesn't change this field
* but still doesn't change %ecx, we're still okay...
@@ -38,22 +42,13 @@ static int detect_memory_e820(void)
buf.ext_flags = 1;
do {
- size = sizeof buf;
-
- /* 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),
- "=D" (edi), "+m" (buf)
- : "D" (&buf), "d" (SMAP), "a" (0xe820)
- : "esi");
+ intcall(0x15, &ireg, &oreg);
+ ireg.ebx = oreg.ebx; /* for next iteration... */
/* 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)
+ if (oreg.eflags & X86_EFLAGS_CF)
break;
/* Some BIOSes stop returning SMAP in the middle of
@@ -61,7 +56,7 @@ static int detect_memory_e820(void)
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) {
+ if (oreg.eax != SMAP) {
count = 0;
break;
}
@@ -69,58 +64,62 @@ static int detect_memory_e820(void)
/* 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))
+ if (oreg.cx > 20 && !(buf.ext_flags & 1))
continue;
*desc++ = buf.std;
count++;
- } while (next && count < ARRAY_SIZE(boot_params.e820_map));
+ } while (ireg.ebx && 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;
+ struct biosregs ireg, oreg;
- bx = cx = dx = 0;
- ax = 0xe801;
- asm("stc; int $0x15; setc %0"
- : "=m" (err), "+a" (ax), "+b" (bx), "+c" (cx), "+d" (dx));
+ initregs(&ireg);
+ ireg.ax = 0xe801;
+ intcall(0x15, &ireg, &oreg);
- if (err)
+ if (oreg.eflags & X86_EFLAGS_CF)
return -1;
/* Do we really need to do this? */
- if (cx || dx) {
- ax = cx;
- bx = dx;
+ if (oreg.cx || oreg.dx) {
+ oreg.ax = oreg.cx;
+ oreg.bx = oreg.dx;
}
- if (ax > 15*1024)
+ if (oreg.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;
+ } else if (oreg.ax == 15*1024) {
+ boot_params.alt_mem_k = (oreg.dx << 6) + oreg.ax;
+ } else {
+ /*
+ * 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 = oreg.ax;
+ }
return 0;
}
static int detect_memory_88(void)
{
- u16 ax;
- u8 err;
+ struct biosregs ireg, oreg;
- ax = 0x8800;
- asm("stc; int $0x15; setc %0" : "=bcdm" (err), "+a" (ax));
+ initregs(&ireg);
+ ireg.ah = 0x88;
+ intcall(0x15, &ireg, &oreg);
- boot_params.screen_info.ext_mem_k = ax;
+ boot_params.screen_info.ext_mem_k = oreg.ax;
- return -err;
+ return -(oreg.eflags & X86_EFLAGS_CF); /* 0 or -1 */
}
int detect_memory(void)