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authorH. J. Lu <hjl@lucon.org>2005-05-01 08:58:48 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-05-01 08:58:48 -0700
commitfd51f666fa591294bd7462447512666e61c56ea0 (patch)
tree0addf0006900152975c38bd75fdfd238c9179013 /arch/i386/kernel/process.c
parentd5b63d78f1e75f6c6f04862dfb2f2a4aeffafd4c (diff)
[PATCH] i386/x86_64 segment register access update
The new i386/x86_64 assemblers no longer accept instructions for moving between a segment register and a 32bit memory location, i.e., movl (%eax),%ds movl %ds,(%eax) To generate instructions for moving between a segment register and a 16bit memory location without the 16bit operand size prefix, 0x66, mov (%eax),%ds mov %ds,(%eax) should be used. It will work with both new and old assemblers. The assembler starting from 2.16.90.0.1 will also support movw (%eax),%ds movw %ds,(%eax) without the 0x66 prefix. I am enclosing patches for 2.4 and 2.6 kernels here. The resulting kernel binaries should be unchanged as before, with old and new assemblers, if gcc never generates memory access for unsigned gsindex; asm volatile("movl %%gs,%0" : "=g" (gsindex)); If gcc does generate memory access for the code above, the upper bits in gsindex are undefined and the new assembler doesn't allow it. Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch/i386/kernel/process.c')
-rw-r--r--arch/i386/kernel/process.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/i386/kernel/process.c b/arch/i386/kernel/process.c
index b2203e21acb3..85bd56d44314 100644
--- a/arch/i386/kernel/process.c
+++ b/arch/i386/kernel/process.c
@@ -611,8 +611,8 @@ struct task_struct fastcall * __switch_to(struct task_struct *prev_p, struct tas
* Save away %fs and %gs. No need to save %es and %ds, as
* those are always kernel segments while inside the kernel.
*/
- asm volatile("movl %%fs,%0":"=m" (*(int *)&prev->fs));
- asm volatile("movl %%gs,%0":"=m" (*(int *)&prev->gs));
+ asm volatile("mov %%fs,%0":"=m" (prev->fs));
+ asm volatile("mov %%gs,%0":"=m" (prev->gs));
/*
* Restore %fs and %gs if needed.