From: Zachary Amsden <zach@vmware.com>
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>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
arch/i386/kernel/microcode.c | 7 +++++--
include/asm-i386/processor.h | 5 +++++
2 files changed, 10 insertions(+), 2 deletions(-)
diff -puN arch/i386/kernel/microcode.c~i386-arch-cleanup-seralize-msr arch/i386/kernel/microcode.c
--- devel/arch/i386/kernel/microcode.c~i386-arch-cleanup-seralize-msr 2005-07-30 11:15:44.000000000 -0700
+++ devel-akpm/arch/i386/kernel/microcode.c 2005-07-30 11:15:44.000000000 -0700
@@ -164,7 +164,8 @@ static void collect_cpu_info (void *unus
}
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 -puN include/asm-i386/processor.h~i386-arch-cleanup-seralize-msr include/asm-i386/processor.h
--- devel/include/asm-i386/processor.h~i386-arch-cleanup-seralize-msr 2005-07-30 11:15:44.000000000 -0700
+++ devel-akpm/include/asm-i386/processor.h 2005-07-30 11:15:44.000000000 -0700
@@ -277,6 +277,11 @@ static inline void clear_in_cr4 (unsigne
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)
{
_