diff options
Diffstat (limited to 'arch/i386/kernel/verify_cpu.S')
| -rw-r--r-- | arch/i386/kernel/verify_cpu.S | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/arch/i386/kernel/verify_cpu.S b/arch/i386/kernel/verify_cpu.S index b2a9d80b6421..f1d1eacf4ab0 100644 --- 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 |