From 245067d1674d451855692fcd4647daf9fd47f82d Mon Sep 17 00:00:00 2001 From: Zachary Amsden Date: Sat, 3 Sep 2005 15:56:37 -0700 Subject: [PATCH] [PATCH] i386: cleanup serialize msr 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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/i386/kernel/microcode.c | 7 +++++-- include/asm-i386/processor.h | 5 +++++ include/asm-x86_64/processor.h | 5 +++++ 3 files changed, 15 insertions(+), 2 deletions(-) diff --git a/arch/i386/kernel/microcode.c b/arch/i386/kernel/microcode.c index a77c612aad00..165f13158c60 100644 --- a/arch/i386/kernel/microcode.c +++ b/arch/i386/kernel/microcode.c @@ -164,7 +164,8 @@ static void collect_cpu_info (void *unused) } 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 @@ static void do_update_one (void * unused) (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]); diff --git a/include/asm-i386/processor.h b/include/asm-i386/processor.h index 7e17d3b4f65a..a0489b222702 100644 --- a/include/asm-i386/processor.h +++ b/include/asm-i386/processor.h @@ -277,6 +277,11 @@ static inline void clear_in_cr4 (unsigned long mask) 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) { diff --git a/include/asm-x86_64/processor.h b/include/asm-x86_64/processor.h index 85549e656eeb..194160f6a43f 100644 --- a/include/asm-x86_64/processor.h +++ b/include/asm-x86_64/processor.h @@ -437,6 +437,11 @@ static inline void prefetchw(void *x) 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) { -- 2.20.1