Messages in this thread Patch in this message | | | Date | Sat, 30 Jul 2005 10:55:50 -0700 | From | Zachary Amsden <> | Subject | Re: [PATCH] 2/6 i386 serialize-msr |
| |
'Apparently' I need to make some coffee :)
Zwane Mwaikambo wrote:
> wrmsr(MSR_IA32_UCODE_REV, 0, 0); >- __asm__ __volatile__ ("cpuid" : : : "ax", "bx", "cx", "dx"); >+ /* see 1.07. Apprent chip bug */ >+ serialize_cpu(); > >1.07 in which document? Also, please just spell 'apparent' correctly, >saving 1 byte really just looks lazy. > > >
i386 arch cleanup. Introduce the serialize macro to serialize processor state. Why the microcode update needs it I am not quite sure, since wrmsr() is already a serializing instruction, but it is a microcode update, so I will keep the semantic the same, since this could be a timing workaround. As far as I can tell, this has always been there since the original microcode update source.
Signed-off-by: Zachary Amsden <zach@vmware.com> Index: linux-2.6.13/arch/i386/kernel/microcode.c =================================================================== --- linux-2.6.13.orig/arch/i386/kernel/microcode.c 2005-07-29 15:26:04.000000000 -0700 +++ linux-2.6.13/arch/i386/kernel/microcode.c 2005-07-30 10:55:02.000000000 -0700 @@ -164,7 +164,8 @@ } wrmsr(MSR_IA32_UCODE_REV, 0, 0); - __asm__ __volatile__ ("cpuid" : : : "ax", "bx", "cx", "dx"); + /* see notes above for revision 1.07. Apparent chip bug */ + serialize_cpu(); /* get the current revision from MSR 0x8B */ rdmsr(MSR_IA32_UCODE_REV, val[0], uci->rev); pr_debug("microcode: collect_cpu_info : sig=0x%x, pf=0x%x, rev=0x%x\n", @@ -377,7 +378,9 @@ (unsigned long) uci->mc->bits >> 16 >> 16); wrmsr(MSR_IA32_UCODE_REV, 0, 0); - __asm__ __volatile__ ("cpuid" : : : "ax", "bx", "cx", "dx"); + /* see notes above for revision 1.07. Apparent chip bug */ + serialize_cpu(); + /* get the current revision from MSR 0x8B */ rdmsr(MSR_IA32_UCODE_REV, val[0], val[1]); Index: linux-2.6.13/include/asm-i386/processor.h =================================================================== --- linux-2.6.13.orig/include/asm-i386/processor.h 2005-07-29 15:26:53.000000000 -0700 +++ linux-2.6.13/include/asm-i386/processor.h 2005-07-30 10:32:44.000000000 -0700 @@ -277,6 +277,11 @@ outb((data), 0x23); \ } while (0) +static inline void serialize_cpu(void) +{ + __asm__ __volatile__ ("cpuid" : : : "ax", "bx", "cx", "dx"); +} + static inline void __monitor(const void *eax, unsigned long ecx, unsigned long edx) { | |