diff options
| author | Zachary Amsden <zach@vmware.com> | 2005-09-03 15:56:36 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@evo.osdl.org> | 2005-09-05 00:06:11 -0700 |
| commit | 4bb0d3ec3e5b1e9e2399cdc641b3b6521ac9cdaa (patch) | |
| tree | 5e8d7646f5c6a2cec990b6d591f230d496b20664 /arch/i386/power | |
| parent | 2a0694d15d55d0deed928786a6393d5e45e37d76 (diff) | |
[PATCH] i386: inline asm cleanup
i386 Inline asm cleanup. Use cr/dr accessor functions.
Also, a potential bugfix. Also, some CR accessors really should be volatile.
Reads from CR0 (numeric state may change in an exception handler), writes to
CR4 (flipping CR4.TSD) and reads from CR2 (page fault) prevent instruction
re-ordering. I did not add memory clobber to CR3 / CR4 / CR0 updates, as it
was not there to begin with, and in no case should kernel memory be clobbered,
except when doing a TLB flush, which already has memory clobber.
I noticed that page invalidation does not have a memory clobber. I can't find
a bug as a result, but there is definitely a potential for a bug here:
#define __flush_tlb_single(addr) \
__asm__ __volatile__("invlpg %0": :"m" (*(char *) addr))
Signed-off-by: Zachary Amsden <zach@vmware.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch/i386/power')
| -rw-r--r-- | arch/i386/power/cpu.c | 16 |
1 files changed, 8 insertions, 8 deletions
diff --git a/arch/i386/power/cpu.c b/arch/i386/power/cpu.c index c547c1af6fa..4e19c43e095 100644 --- a/arch/i386/power/cpu.c +++ b/arch/i386/power/cpu.c @@ -57,10 +57,10 @@ void __save_processor_state(struct saved_context *ctxt) /* * control registers */ - asm volatile ("movl %%cr0, %0" : "=r" (ctxt->cr0)); - asm volatile ("movl %%cr2, %0" : "=r" (ctxt->cr2)); - asm volatile ("movl %%cr3, %0" : "=r" (ctxt->cr3)); - asm volatile ("movl %%cr4, %0" : "=r" (ctxt->cr4)); + ctxt->cr0 = read_cr0(); + ctxt->cr2 = read_cr2(); + ctxt->cr3 = read_cr3(); + ctxt->cr4 = read_cr4(); } void save_processor_state(void) @@ -109,10 +109,10 @@ void __restore_processor_state(struct saved_context *ctxt) /* * control registers */ - asm volatile ("movl %0, %%cr4" :: "r" (ctxt->cr4)); - asm volatile ("movl %0, %%cr3" :: "r" (ctxt->cr3)); - asm volatile ("movl %0, %%cr2" :: "r" (ctxt->cr2)); - asm volatile ("movl %0, %%cr0" :: "r" (ctxt->cr0)); + write_cr4(ctxt->cr4); + write_cr3(ctxt->cr3); + write_cr2(ctxt->cr2); + write_cr2(ctxt->cr0); /* * now restore the descriptor tables to their proper values |