1 | /* SPDX-License-Identifier: GPL-2.0-only */ |
---|---|
2 | #ifndef _ASM_X86_GSSEG_H |
3 | #define _ASM_X86_GSSEG_H |
4 | |
5 | #include <linux/types.h> |
6 | |
7 | #include <asm/asm.h> |
8 | #include <asm/cpufeature.h> |
9 | #include <asm/alternative.h> |
10 | #include <asm/processor.h> |
11 | #include <asm/nops.h> |
12 | |
13 | #ifdef CONFIG_X86_64 |
14 | |
15 | extern asmlinkage void asm_load_gs_index(u16 selector); |
16 | |
17 | /* Replace with "lkgs %di" once binutils support LKGS instruction */ |
18 | #define LKGS_DI _ASM_BYTES(0xf2,0x0f,0x00,0xf7) |
19 | |
20 | static inline void native_lkgs(unsigned int selector) |
21 | { |
22 | u16 sel = selector; |
23 | asm_inline volatile("1: "LKGS_DI |
24 | _ASM_EXTABLE_TYPE_REG(1b, 1b, EX_TYPE_ZERO_REG, %k[sel]) |
25 | : [sel] "+D"(sel)); |
26 | } |
27 | |
28 | static inline void native_load_gs_index(unsigned int selector) |
29 | { |
30 | if (cpu_feature_enabled(X86_FEATURE_LKGS)) { |
31 | native_lkgs(selector); |
32 | } else { |
33 | unsigned long flags; |
34 | |
35 | local_irq_save(flags); |
36 | asm_load_gs_index(selector); |
37 | local_irq_restore(flags); |
38 | } |
39 | } |
40 | |
41 | #endif /* CONFIG_X86_64 */ |
42 | |
43 | static inline void __init lkgs_init(void) |
44 | { |
45 | #ifdef CONFIG_PARAVIRT_XXL |
46 | #ifdef CONFIG_X86_64 |
47 | if (cpu_feature_enabled(X86_FEATURE_LKGS)) |
48 | pv_ops.cpu.load_gs_index = native_lkgs; |
49 | #endif |
50 | #endif |
51 | } |
52 | |
53 | #ifndef CONFIG_PARAVIRT_XXL |
54 | |
55 | static inline void load_gs_index(unsigned int selector) |
56 | { |
57 | #ifdef CONFIG_X86_64 |
58 | native_load_gs_index(selector); |
59 | #else |
60 | loadsegment(gs, selector); |
61 | #endif |
62 | } |
63 | |
64 | #endif /* CONFIG_PARAVIRT_XXL */ |
65 | |
66 | #endif /* _ASM_X86_GSSEG_H */ |
67 |