Re: [PATCH 3.17 100/141] x86, microcode: Fix accessing dis_ucode_ldr on 32-bit

Borislav Petkov
2014-11-26T14:45:05Z

On Wed, Nov 26, 2014 at 07:39:26AM -0500, boris ostrovsky wrote:
> https://lkml.org/lkml/2014/11/25/973 is all I have right now.

Ok, so the Code: section from this splat says:

25: 55 push %ebp
26: 89 e5 mov %esp,%ebp
28: 83 ec 08 sub $0x8,%esp
2b:* 80 3d c0 ee 97 01 00 cmpb $0x0,0x197eec0 <-- trapping instruction
32: 89 1c 24 mov %ebx,(%esp)
35: 89 74 24 04 mov %esi,0x4(%esp)
39: 74 12 je 0x4d
3b: 8b 1c 24 mov (%esp),%ebx
3e: 8b .byte 0x8b
3f: 74 .byte 0x74

which I can correlate to the dis_ucode_ldr test here:

.loc 1 134 0
.loc 1 137 0
cmpb $0, dis_ucode_ldr+1073741824 #, *_11
je .L46 #,

so we must be faulting when accessing that dis_ucode_ldr thing. But you
said that accessing it through its virtual address doesn't fix the issue
either. Which is very very strange...

Hmmm.

--
Regards/Gruss,
Boris.

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