Messages in this thread Patch in this message | | | Date | Fri, 29 Jul 2005 21:04:16 -0700 | From | zach@vmware ... | Subject | [PATCH] 2/6 i386 serialize-msr |
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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 11:14:33.000000000 -0700 +++ linux-2.6.13/arch/i386/kernel/microcode.c 2005-07-29 11:16:18.000000000 -0700 @@ -164,7 +164,8 @@ } wrmsr(MSR_IA32_UCODE_REV, 0, 0); - __asm__ __volatile__ ("cpuid" : : : "ax", "bx", "cx", "dx"); + /* XXX needed? wrmsr should serialize unless a chip bug */ + serialize(); /* 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"); + /* XXX needed? wrmsr should serialize unless a chip bug */ + serialize(); + /* 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 11:16:10.000000000 -0700 +++ linux-2.6.13/include/asm-i386/processor.h 2005-07-29 11:16:28.000000000 -0700 @@ -277,6 +277,11 @@ outb((data), 0x23); \ } while (0) +static inline void serialize(void) +{ + __asm__ __volatile__ ("cpuid" : : : "ax", "bx", "cx", "dx"); +} + static inline void __monitor(const void *eax, unsigned long ecx, unsigned long edx) { - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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