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x86/entry: Disable interrupts for native_load_gs_index() in C code 

There is absolutely no point in doing this in ASM code. Move it to C.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lkml.kernel.org/r/20200505134903.531534675@linutronix.de
This commit is contained in:
Thomas Gleixner 2020-03-04 23:32:15 +01:00
parent daf7a69787
commit 410367e321
2 changed files with 15 additions and 10 deletions
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11
arch/x86/entry/entry_64.S
View File

@ -1041,22 +1041,17 @@ idtentry simd_coprocessor_error do_simd_coprocessor_error has_error_code=0
*
* Is in entry.text as it shouldn't be instrumented.
*/
SYM_FUNC_START(native_load_gs_index)
SYM_FUNC_START(asm_load_gs_index)
FRAME_BEGIN
pushfq
DISABLE_INTERRUPTS(CLBR_ANY & ~CLBR_RDI)
TRACE_IRQS_OFF
SWAPGS
.Lgs_change:
movl %edi, %gs
2: ALTERNATIVE "", "mfence", X86_BUG_SWAPGS_FENCE
SWAPGS
TRACE_IRQS_FLAGS (%rsp)
popfq
FRAME_END
ret
SYM_FUNC_END(native_load_gs_index)
EXPORT_SYMBOL(native_load_gs_index)
SYM_FUNC_END(asm_load_gs_index)
EXPORT_SYMBOL(asm_load_gs_index)
_ASM_EXTABLE(.Lgs_change, .Lbad_gs)
.section .fixup, "ax"

14
arch/x86/include/asm/special_insns.h
View File

@ -7,6 +7,7 @@
#include <asm/nops.h>
#include <asm/processor-flags.h>
#include <linux/irqflags.h>
#include <linux/jump_label.h>
/*
@ -129,7 +130,16 @@ static inline void native_wbinvd(void)
asm volatile("wbinvd": : :"memory");
}
extern asmlinkage void native_load_gs_index(unsigned);
extern asmlinkage void asm_load_gs_index(unsigned int selector);
static inline void native_load_gs_index(unsigned int selector)
{
unsigned long flags;
local_irq_save(flags);
asm_load_gs_index(selector);
local_irq_restore(flags);
}
static inline unsigned long __read_cr4(void)
{
@ -186,7 +196,7 @@ static inline void wbinvd(void)
#ifdef CONFIG_X86_64
static inline void load_gs_index(unsigned selector)
static inline void load_gs_index(unsigned int selector)
{
native_load_gs_index(selector);
}