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| author | H. Peter Anvin <hpa@zytor.com> | 2008-10-13 12:35:42 -0700 |
|---|---|---|
| committer | H. Peter Anvin <hpa@zytor.com> | 2008-10-13 12:35:42 -0700 |
| commit | e5c9012ac933f95aee0cd0da11451a7c0986b84d (patch) | |
| tree | bcbf6b0cd2df2784152f958861b9afc1a185e1cb | |
| parent | e6f38a11e398dd934d567178174fbc3a6ebcbc1a (diff) | |
| download | syslinux-elf-e5c9012ac933f95aee0cd0da11451a7c0986b84d.tar.gz syslinux-elf-e5c9012ac933f95aee0cd0da11451a7c0986b84d.tar.xz syslinux-elf-e5c9012ac933f95aee0cd0da11451a7c0986b84d.zip | |
e820: pre-initialize buffer
Pre-initialize the e820 buffer to all zero, except for the active bit;
we have found that BIOSes will make assumptions about the pre-existing
value of the buffer and this seems the most conservative value.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
| -rw-r--r-- | com32/lib/syslinux/memmap.c | 2 | ||||
| -rw-r--r-- | core/highmem.inc | 5 | ||||
| -rw-r--r-- | memdisk/msetup.c | 2 |
3 files changed, 9 insertions, 0 deletions
diff --git a/com32/lib/syslinux/memmap.c b/com32/lib/syslinux/memmap.c index e14dd70b..105c9473 100644 --- a/com32/lib/syslinux/memmap.c +++ b/com32/lib/syslinux/memmap.c @@ -78,6 +78,8 @@ struct syslinux_memmap *syslinux_memory_map(void) ireg.ecx.l = sizeof(*e820buf); ireg.es = SEG(e820buf); ireg.edi.w[0] = OFFS(e820buf); + memset(e820buf, 0, sizeof *e820buf); + e820buf->extattr = 1; do { __intcall(0x15, &ireg, &oreg); diff --git a/core/highmem.inc b/core/highmem.inc index 7341bf27..69652b7f 100644 --- a/core/highmem.inc +++ b/core/highmem.inc @@ -40,6 +40,11 @@ get_e820: mov dword [E820Max],-(1 << 20) ; Max amount of high memory mov dword [E820Mem],(1 << 20) ; End of detected high memory .start_over: + mov di,E820Buf + xor ax,ax + mov cx,12 + rep stosw ; Clear buffer + mov byte [di-4],01h ; Initial extattr value xor ebx,ebx ; Start with first record jmp short .do_e820 ; Skip "at end" check first time! .int_loop: and ebx,ebx ; If we're back at beginning... diff --git a/memdisk/msetup.c b/memdisk/msetup.c index 60149c3b..a2067011 100644 --- a/memdisk/msetup.c +++ b/memdisk/msetup.c @@ -45,6 +45,8 @@ static inline int get_e820(void) com32sys_t regs; memset(®s, 0, sizeof regs); + memset(buf, 0, sizeof *buf); + buf->extattr = 1; do { regs.eax.l = 0x0000e820; |