[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 <zach@vmware.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/i386/kernel/microcode.c b/arch/i386/kernel/microcode.c
index a77c612..165f131 100644
--- a/arch/i386/kernel/microcode.c
+++ b/arch/i386/kernel/microcode.c
@@ -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]);
diff --git a/include/asm-i386/processor.h b/include/asm-i386/processor.h
index 7e17d3b..a0489b2 100644
--- a/include/asm-i386/processor.h
+++ b/include/asm-i386/processor.h
@@ -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)
{
diff --git a/include/asm-x86_64/processor.h b/include/asm-x86_64/processor.h
index 85549e6..194160f 100644
--- a/include/asm-x86_64/processor.h
+++ b/include/asm-x86_64/processor.h
@@ -437,6 +437,11 @@
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)
{
