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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
5373db88 JG |
2 | /* |
3 | * Jump label s390 support | |
4 | * | |
5 | * Copyright IBM Corp. 2011 | |
6 | * Author(s): Jan Glauber <jang@linux.vnet.ibm.com> | |
7 | */ | |
5373db88 JG |
8 | #include <linux/uaccess.h> |
9 | #include <linux/stop_machine.h> | |
10 | #include <linux/jump_label.h> | |
11 | #include <asm/ipl.h> | |
12 | ||
5373db88 JG |
13 | struct insn { |
14 | u16 opcode; | |
15 | s32 offset; | |
16 | } __packed; | |
17 | ||
18 | struct insn_args { | |
61f42183 JF |
19 | struct jump_entry *entry; |
20 | enum jump_label_type type; | |
5373db88 JG |
21 | }; |
22 | ||
5c6497c5 HC |
23 | static void jump_label_make_nop(struct jump_entry *entry, struct insn *insn) |
24 | { | |
25 | /* brcl 0,0 */ | |
26 | insn->opcode = 0xc004; | |
27 | insn->offset = 0; | |
28 | } | |
29 | ||
30 | static void jump_label_make_branch(struct jump_entry *entry, struct insn *insn) | |
31 | { | |
32 | /* brcl 15,offset */ | |
33 | insn->opcode = 0xc0f4; | |
13ddb52c | 34 | insn->offset = (jump_entry_target(entry) - jump_entry_code(entry)) >> 1; |
5c6497c5 HC |
35 | } |
36 | ||
72dace96 HC |
37 | static void jump_label_bug(struct jump_entry *entry, struct insn *expected, |
38 | struct insn *new) | |
5c6497c5 | 39 | { |
13ddb52c | 40 | unsigned char *ipc = (unsigned char *)jump_entry_code(entry); |
72dace96 HC |
41 | unsigned char *ipe = (unsigned char *)expected; |
42 | unsigned char *ipn = (unsigned char *)new; | |
5c6497c5 HC |
43 | |
44 | pr_emerg("Jump label code mismatch at %pS [%p]\n", ipc, ipc); | |
e4ec7351 AK |
45 | pr_emerg("Found: %6ph\n", ipc); |
46 | pr_emerg("Expected: %6ph\n", ipe); | |
47 | pr_emerg("New: %6ph\n", ipn); | |
5c6497c5 HC |
48 | panic("Corrupted kernel text"); |
49 | } | |
50 | ||
d5caa4db HC |
51 | static struct insn orignop = { |
52 | .opcode = 0xc004, | |
53 | .offset = JUMP_LABEL_NOP_OFFSET >> 1, | |
54 | }; | |
55 | ||
61f42183 | 56 | static void __jump_label_transform(struct jump_entry *entry, |
5c6497c5 HC |
57 | enum jump_label_type type, |
58 | int init) | |
5373db88 | 59 | { |
13ddb52c | 60 | void *code = (void *)jump_entry_code(entry); |
5c6497c5 | 61 | struct insn old, new; |
5373db88 | 62 | |
76b235c6 | 63 | if (type == JUMP_LABEL_JMP) { |
5c6497c5 HC |
64 | jump_label_make_nop(entry, &old); |
65 | jump_label_make_branch(entry, &new); | |
5373db88 | 66 | } else { |
d5caa4db | 67 | jump_label_make_branch(entry, &old); |
5c6497c5 | 68 | jump_label_make_nop(entry, &new); |
5373db88 | 69 | } |
d5caa4db | 70 | if (init) { |
13ddb52c | 71 | if (memcmp(code, &orignop, sizeof(orignop))) |
72dace96 | 72 | jump_label_bug(entry, &orignop, &new); |
d5caa4db | 73 | } else { |
13ddb52c | 74 | if (memcmp(code, &old, sizeof(old))) |
72dace96 | 75 | jump_label_bug(entry, &old, &new); |
d5caa4db | 76 | } |
13ddb52c | 77 | s390_kernel_write(code, &new, sizeof(new)); |
61f42183 | 78 | } |
5373db88 | 79 | |
61f42183 JF |
80 | static int __sm_arch_jump_label_transform(void *data) |
81 | { | |
82 | struct insn_args *args = data; | |
83 | ||
5c6497c5 | 84 | __jump_label_transform(args->entry, args->type, 0); |
61f42183 JF |
85 | return 0; |
86 | } | |
87 | ||
88 | void arch_jump_label_transform(struct jump_entry *entry, | |
89 | enum jump_label_type type) | |
90 | { | |
91 | struct insn_args args; | |
92 | ||
93 | args.entry = entry; | |
94 | args.type = type; | |
95 | ||
5d5dbc4e | 96 | stop_machine_cpuslocked(__sm_arch_jump_label_transform, &args, NULL); |
61f42183 JF |
97 | } |
98 | ||
99 | void arch_jump_label_transform_static(struct jump_entry *entry, | |
100 | enum jump_label_type type) | |
101 | { | |
5c6497c5 | 102 | __jump_label_transform(entry, type, 1); |
5373db88 | 103 | } |