From 4bb0d3ec3e5b1e9e2399cdc641b3b6521ac9cdaa Mon Sep 17 00:00:00 2001 From: Zachary Amsden Date: Sat, 3 Sep 2005 15:56:36 -0700 Subject: [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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/i386/kernel/efi.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'arch/i386/kernel/efi.c') diff --git a/arch/i386/kernel/efi.c b/arch/i386/kernel/efi.c index 850648ae8305..921fdb15fc9b 100644 --- a/arch/i386/kernel/efi.c +++ b/arch/i386/kernel/efi.c @@ -79,7 +79,7 @@ static void efi_call_phys_prelog(void) * directory. If I have PSE, I just need to duplicate one entry in * page directory. */ - __asm__ __volatile__("movl %%cr4, %0":"=r"(cr4)); + cr4 = read_cr4(); if (cr4 & X86_CR4_PSE) { efi_bak_pg_dir_pointer[0].pgd = @@ -115,7 +115,7 @@ static void efi_call_phys_epilog(void) cpu_gdt_descr[0].address = (unsigned long) __va(cpu_gdt_descr[0].address); __asm__ __volatile__("lgdt %0":"=m"(cpu_gdt_descr)); - __asm__ __volatile__("movl %%cr4, %0":"=r"(cr4)); + cr4 = read_cr4(); if (cr4 & X86_CR4_PSE) { swapper_pg_dir[pgd_index(0)].pgd = -- cgit v1.2.3