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gerrit-public.fairphone.software / kernel / msm-5.4 / 3cedbec301015d8fb914e7e3af0fc0e034b87d34 / . / arch / x86 / include / asm / jump_label.h
blob: adc54c12cbd15650fee002cff6d773de7f15429e [file] [log] [blame]
Jason Barond9f5ab72010-09-17 11:09:22 -0400[diff] [blame]1#ifndef _ASM_X86_JUMP_LABEL_H
2#define _ASM_X86_JUMP_LABEL_H
3
Andy Lutomirskic2845432015-11-12 12:59:02 -0800[diff] [blame]4#ifndef HAVE_JUMP_LABEL
5/*
6 * For better or for worse, if jump labels (the gcc extension) are missing,
7 * then the entire static branch patching infrastructure is compiled out.
8 * If that happens, the code in here will malfunction. Raise a compiler
9 * error instead.
10 *
11 * In theory, jump labels and the static branch patching infrastructure
12 * could be decoupled to fix this.
13 */
14#error asm/jump_label.h included on a non-jump-label kernel
15#endif
16
Jason Barond9f5ab72010-09-17 11:09:22 -0400[diff] [blame]17#define JUMP_LABEL_NOP_SIZE 5
18
Steven Rostedtc3c7f142012-01-26 18:06:45 -0500[diff] [blame]19#ifdef CONFIG_X86_64
20# define STATIC_KEY_INIT_NOP P6_NOP5_ATOMIC
21#else
22# define STATIC_KEY_INIT_NOP GENERIC_NOP5_ATOMIC
23#endif
Jason Barond9f5ab72010-09-17 11:09:22 -0400[diff] [blame]24
Andy Lutomirski2671c3e42015-11-12 12:59:03 -0800[diff] [blame]25#include <asm/asm.h>
26#include <asm/nops.h>
27
28#ifndef __ASSEMBLY__
29
30#include <linux/stringify.h>
31#include <linux/types.h>
32
Peter Zijlstra11276d52015-07-24 15:09:55 +0200[diff] [blame]33static __always_inline bool arch_static_branch(struct static_key *key, bool branch)
Jason Barond430d3d2011-03-16 17:29:47 -0400[diff] [blame]34{
Ingo Molnar3f0116c2013-10-10 10:16:30 +0200[diff] [blame]35 asm_volatile_goto("1:"
Steven Rostedtc3c7f142012-01-26 18:06:45 -0500[diff] [blame]36 ".byte " __stringify(STATIC_KEY_INIT_NOP) "\n\t"
Jason Barond430d3d2011-03-16 17:29:47 -0400[diff] [blame]37 ".pushsection __jump_table, \"aw\" \n\t"
Jason Baronef647892011-03-16 15:58:27 -0400[diff] [blame]38 _ASM_ALIGN "\n\t"
Peter Zijlstrad420acd2015-08-12 21:04:22 +0200[diff] [blame]39 _ASM_PTR "1b, %l[l_yes], %c0 + %c1 \n\t"
Jason Barond430d3d2011-03-16 17:29:47 -0400[diff] [blame]40 ".popsection \n\t"
Peter Zijlstrad420acd2015-08-12 21:04:22 +0200[diff] [blame]41 : : "i" (key), "i" (branch) : : l_yes);
Peter Zijlstra11276d52015-07-24 15:09:55 +0200[diff] [blame]42
43 return false;
44l_yes:
45 return true;
46}
47
48static __always_inline bool arch_static_branch_jump(struct static_key *key, bool branch)
49{
50 asm_volatile_goto("1:"
51 ".byte 0xe9\n\t .long %l[l_yes] - 2f\n\t"
52 "2:\n\t"
53 ".pushsection __jump_table, \"aw\" \n\t"
54 _ASM_ALIGN "\n\t"
Peter Zijlstrad420acd2015-08-12 21:04:22 +0200[diff] [blame]55 _ASM_PTR "1b, %l[l_yes], %c0 + %c1 \n\t"
Peter Zijlstra11276d52015-07-24 15:09:55 +0200[diff] [blame]56 ".popsection \n\t"
Peter Zijlstrad420acd2015-08-12 21:04:22 +0200[diff] [blame]57 : : "i" (key), "i" (branch) : : l_yes);
Peter Zijlstra11276d52015-07-24 15:09:55 +0200[diff] [blame]58
Jason Barond430d3d2011-03-16 17:29:47 -0400[diff] [blame]59 return false;
60l_yes:
61 return true;
62}
Jason Barond9f5ab72010-09-17 11:09:22 -0400[diff] [blame]63
Jason Barond9f5ab72010-09-17 11:09:22 -0400[diff] [blame]64#ifdef CONFIG_X86_64
Jason Barond9f5ab72010-09-17 11:09:22 -0400[diff] [blame]65typedef u64 jump_label_t;
Jason Barond9f5ab72010-09-17 11:09:22 -0400[diff] [blame]66#else
Jason Barond9f5ab72010-09-17 11:09:22 -0400[diff] [blame]67typedef u32 jump_label_t;
Steven Rostedt95fccd42010-09-22 17:37:43 -0400[diff] [blame]68#endif
Jason Barond9f5ab72010-09-17 11:09:22 -0400[diff] [blame]69
70struct jump_entry {
71 jump_label_t code;
72 jump_label_t target;
73 jump_label_t key;
74};
75
Andy Lutomirski2671c3e42015-11-12 12:59:03 -0800[diff] [blame]76#else /* __ASSEMBLY__ */
77
78.macro STATIC_JUMP_IF_TRUE target, key, def
79.Lstatic_jump_\@:
80 .if \def
81 /* Equivalent to "jmp.d32 \target" */
82 .byte 0xe9
83 .long \target - .Lstatic_jump_after_\@
84.Lstatic_jump_after_\@:
85 .else
86 .byte STATIC_KEY_INIT_NOP
87 .endif
88 .pushsection __jump_table, "aw"
89 _ASM_ALIGN
90 _ASM_PTR .Lstatic_jump_\@, \target, \key
91 .popsection
92.endm
93
94.macro STATIC_JUMP_IF_FALSE target, key, def
95.Lstatic_jump_\@:
96 .if \def
97 .byte STATIC_KEY_INIT_NOP
98 .else
99 /* Equivalent to "jmp.d32 \target" */
100 .byte 0xe9
101 .long \target - .Lstatic_jump_after_\@
102.Lstatic_jump_after_\@:
103 .endif
104 .pushsection __jump_table, "aw"
105 _ASM_ALIGN
106 _ASM_PTR .Lstatic_jump_\@, \target, \key + 1
107 .popsection
108.endm
109
110#endif /* __ASSEMBLY__ */
111
Jason Barond9f5ab72010-09-17 11:09:22 -0400[diff] [blame]112#endif