diff options
Diffstat (limited to 'arch/x86/include/asm/gsseg.h')
| -rw-r--r-- | arch/x86/include/asm/gsseg.h | 66 |
1 files changed, 66 insertions, 0 deletions
diff --git a/arch/x86/include/asm/gsseg.h b/arch/x86/include/asm/gsseg.h new file mode 100644 index 0000000000..ab6a595cea --- /dev/null +++ b/arch/x86/include/asm/gsseg.h @@ -0,0 +1,66 @@ +/* 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 */ |