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i386: Enable CX8/PGE CPUID bits early on VIA C3 

Fix boot failures with the early CPUID checking on VIA C3

Includes fixes from Christian Volkmann

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Andi Kleen 2007-05-21 14:31:50 +02:00 committed by Linus Torvalds
parent 4c1f59d8be
commit 39427d6e59
1 changed files with 27 additions and 0 deletions
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27
arch/i386/kernel/verify_cpu.S
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@ -2,6 +2,7 @@
This runs in 16bit mode so that the caller can still use the BIOS
to output errors on the screen */
#include <asm/cpufeature.h>
#include <asm/msr.h>
verify_cpu:
pushfl # Save caller passed flags
@ -45,6 +46,32 @@ verify_cpu:
cmpl $0x1,%eax
jb bad # no cpuid 1
#if REQUIRED_MASK1 & NEED_CMPXCHG64
/* Some VIA C3s need magic MSRs to enable CX64. Do this here */
cmpl $0x746e6543,%ebx # Cent
jne 1f
cmpl $0x48727561,%edx # aurH
jne 1f
cmpl $0x736c7561,%ecx # auls
jne 1f
movl $1,%eax # check model
cpuid
movl %eax,%ebx
shr $8,%ebx
andl $0xf,%ebx
cmp $6,%ebx # check family == 6
jne 1f
shr $4,%eax
andl $0xf,%eax
cmpl $6,%eax # check model >= 6
jb 1f
# assume models >= 6 all support this MSR
movl $MSR_VIA_FCR,%ecx
rdmsr
orl $((1<<1)|(1<<7)),%eax # enable CMPXCHG64 and PGE
wrmsr
1:
#endif
movl $0x1,%eax # Does the cpu have what it takes
cpuid