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x86/entry/64: Use native swapgs in asm_load_gs_index() 

When PARAVIRT_XXL is in use, then load_gs_index() uses xen_load_gs_index()
and asm_load_gs_index() is unused.

It's therefore pointless to use the paravirtualized SWAPGS implementation
in asm_load_gs_index(). Switch it to a plain swapgs.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Acked-by: Juergen Gross <jgross@suse.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200512213809.583980272@linutronix.de
This commit is contained in:
Thomas Gleixner 2020-05-12 14:54:14 +02:00
parent 410367e321
commit c9317202af
1 changed files with 3 additions and 3 deletions
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6
arch/x86/entry/entry_64.S
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@ -1043,11 +1043,11 @@ idtentry simd_coprocessor_error do_simd_coprocessor_error has_error_code=0
*/
SYM_FUNC_START(asm_load_gs_index)
FRAME_BEGIN
SWAPGS
swapgs
.Lgs_change:
movl %edi, %gs
2: ALTERNATIVE "", "mfence", X86_BUG_SWAPGS_FENCE
SWAPGS
swapgs
FRAME_END
ret
SYM_FUNC_END(asm_load_gs_index)
@ -1057,7 +1057,7 @@ EXPORT_SYMBOL(asm_load_gs_index)
.section .fixup, "ax"
/* running with kernelgs */
SYM_CODE_START_LOCAL_NOALIGN(.Lbad_gs)
SWAPGS /* switch back to user gs */
swapgs /* switch back to user gs */
.macro ZAP_GS
/* This can't be a string because the preprocessor needs to see it. */
movl $__USER_DS, %eax