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/* SPDX-License-Identifier: GPL-2.0-only */
#ifndef _ASM_X86_GSSEG_H
#define _ASM_X86_GSSEG_H
#include <linux/types.h>
#include <asm/asm.h>
#include <asm/cpufeature.h>
#include <asm/alternative.h>
#include <asm/processor.h>
#include <asm/nops.h>
#ifdef CONFIG_X86_64
extern asmlinkage void asm_load_gs_index(u16 selector);
/* Replace with "lkgs %di" once binutils support LKGS instruction */
#define LKGS_DI _ASM_BYTES(0xf2,0x0f,0x00,0xf7)
static inline void native_lkgs(unsigned int selector)
{
u16 sel = selector;
asm_inline volatile("1: " LKGS_DI
_ASM_EXTABLE_TYPE_REG(1b, 1b, EX_TYPE_ZERO_REG, %k[sel])
: [sel] "+D" (sel));
}
static inline void native_load_gs_index(unsigned int selector)
{
if (cpu_feature_enabled(X86_FEATURE_LKGS)) {
native_lkgs(selector);
} else {
unsigned long flags;
local_irq_save(flags);
asm_load_gs_index(selector);
local_irq_restore(flags);
}
}
#endif /* CONFIG_X86_64 */
static inline void __init lkgs_init(void)
{
#ifdef CONFIG_PARAVIRT_XXL
#ifdef CONFIG_X86_64
if (cpu_feature_enabled(X86_FEATURE_LKGS))
pv_ops.cpu.load_gs_index = native_lkgs;
#endif
#endif
}
#ifndef CONFIG_PARAVIRT_XXL
static inline void load_gs_index(unsigned int selector)
{
#ifdef CONFIG_X86_64
native_load_gs_index(selector);
#else
loadsegment(gs, selector);
#endif
}
#endif /* CONFIG_PARAVIRT_XXL */
#endif /* _ASM_X86_GSSEG_H */
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