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>

diff --git a/arch/i386/kernel/verify_cpu.S b/arch/i386/kernel/verify_cpu.S
index b2a9d80..f1d1eac 100644 (file)
--- a/arch/i386/kernel/verify_cpu.S
+++ b/arch/i386/kernel/verify_cpu.S
@@ -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