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author | H. Peter Anvin <hpa@zytor.com> | 2009-03-28 13:53:26 -0700 |
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committer | H. Peter Anvin <hpa@zytor.com> | 2009-03-28 18:18:20 -0700 |
commit | 32ec7fd08b597586774b92ac1cd2678021ccac1b (patch) | |
tree | 532ec12d24a1c7c17d3250ccdb2b66ddc8804cff /arch/x86/boot | |
parent | 01522df346f846906eaf6ca57148641476209909 (diff) | |
download | op-kernel-dev-32ec7fd08b597586774b92ac1cd2678021ccac1b.zip op-kernel-dev-32ec7fd08b597586774b92ac1cd2678021ccac1b.tar.gz |
x86, setup: preemptively save/restore edi and ebp around INT 15 E820
Impact: BIOS bugproofing
Since there are BIOSes known to clobber %ebx and %esi for INT 15 E820,
assume there is something out there clobbering %edi and/or %ebp too,
and don't wait for it to fail.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Diffstat (limited to 'arch/x86/boot')
-rw-r--r-- | arch/x86/boot/memory.c | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/arch/x86/boot/memory.c b/arch/x86/boot/memory.c index a99dbbe..fcdb10ad 100644 --- a/arch/x86/boot/memory.c +++ b/arch/x86/boot/memory.c @@ -20,7 +20,7 @@ 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; @@ -29,10 +29,11 @@ static int detect_memory_e820(void) /* Important: %edx and %esi are clobbered by some BIOSes, so they must be either used for the error output - or explicitly marked clobbered. */ - asm("int $0x15; setc %0" + 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" (edi), "=m" (*desc) : "D" (desc), "d" (SMAP), "a" (0xe820) : "esi"); |