blob: 46c8596259d2d921fc0395a9eaf8dd444032029c (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
|
/* SPDX-License-Identifier: GPL-2.0 */
/* Copyright (C) 2018 Cadence Design Systems Inc. */
#ifndef _ASM_XTENSA_JUMP_LABEL_H
#define _ASM_XTENSA_JUMP_LABEL_H
#ifndef __ASSEMBLY__
#include <linux/types.h>
#define JUMP_LABEL_NOP_SIZE 3
static __always_inline bool arch_static_branch(struct static_key *key,
bool branch)
{
asm goto("1:\n\t"
"_nop\n\t"
".pushsection __jump_table, \"aw\"\n\t"
".word 1b, %l[l_yes], %c0\n\t"
".popsection\n\t"
: : "i" (&((char *)key)[branch]) : : l_yes);
return false;
l_yes:
return true;
}
static __always_inline bool arch_static_branch_jump(struct static_key *key,
bool branch)
{
/*
* Xtensa assembler will mark certain points in the code
* as unreachable, so that later assembler or linker relaxation
* passes could use them. A spot right after the J instruction
* is one such point. Assembler and/or linker may insert padding
* or literals here, breaking code flow in case the J instruction
* is later replaced with NOP. Put a label right after the J to
* make it reachable and wrap both into a no-transform block
* to avoid any assembler interference with this.
*/
asm goto("1:\n\t"
".begin no-transform\n\t"
"_j %l[l_yes]\n\t"
"2:\n\t"
".end no-transform\n\t"
".pushsection __jump_table, \"aw\"\n\t"
".word 1b, %l[l_yes], %c0\n\t"
".popsection\n\t"
: : "i" (&((char *)key)[branch]) : : l_yes);
return false;
l_yes:
return true;
}
typedef u32 jump_label_t;
struct jump_entry {
jump_label_t code;
jump_label_t target;
jump_label_t key;
};
#endif /* __ASSEMBLY__ */
#endif
|
