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authorRudolf Marek <r.marek@assembler.cz>2010-05-16 21:51:34 +0000
committerRudolf Marek <r.marek@assembler.cz>2010-05-16 21:51:34 +0000
commitbeba99045c7e7af21481d359384d06c77e636d53 (patch)
treefa8f248eea176e182b4fe8f85e3a08ab134b6550 /src/include
parent4bb368cc73446240ea4c6d6aa6de4c5c867be3bf (diff)
Following patch reworks car_disable into C. Tested, works here. I compared
also the GCC generated code and it looks all right. Please test on some multicore CPU. I added the "memory" clobber to read_cr0 / write_cr0 function as it is in Linux Kernel. Seems that if this is missing, GCC is too smart and messes the order of reads/writes to CR0 (not tested if really a problem here, but be safe for future users of this function ;) Signed-off-by: Rudolf Marek <r.marek@assembler.cz> Acked-by: Stefan Reinauer <stepan@coresystems.de> git-svn-id: svn://svn.coreboot.org/coreboot/trunk@5562 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1
Diffstat (limited to 'src/include')
-rw-r--r--src/include/cpu/x86/cache.h9
1 files changed, 6 insertions, 3 deletions
diff --git a/src/include/cpu/x86/cache.h b/src/include/cpu/x86/cache.h
index f3ac2ed11f..14538592e9 100644
--- a/src/include/cpu/x86/cache.h
+++ b/src/include/cpu/x86/cache.h
@@ -20,16 +20,19 @@
#ifndef CPU_X86_CACHE
#define CPU_X86_CACHE
+/* the memory clobber prevents the GCC from reordering the read/write order
+ of CR0 */
+
static inline unsigned long read_cr0(void)
{
unsigned long cr0;
- asm volatile ("movl %%cr0, %0" : "=r" (cr0));
+ asm volatile ("movl %%cr0, %0" : "=r" (cr0) :: "memory");
return cr0;
}
static inline void write_cr0(unsigned long cr0)
{
- asm volatile ("movl %0, %%cr0" : : "r" (cr0));
+ asm volatile ("movl %0, %%cr0" : : "r" (cr0) : "memory");
}
static inline void invd(void)
@@ -39,7 +42,7 @@ static inline void invd(void)
static inline void wbinvd(void)
{
- asm volatile ("wbinvd");
+ asm volatile ("wbinvd" ::: "memory");
}
static inline void enable_cache(void)