Commit | Line | Data |
---|---|---|
5373db88 JG |
1 | /* |
2 | * Jump label s390 support | |
3 | * | |
4 | * Copyright IBM Corp. 2011 | |
5 | * Author(s): Jan Glauber <jang@linux.vnet.ibm.com> | |
6 | */ | |
7 | #include <linux/module.h> | |
8 | #include <linux/uaccess.h> | |
9 | #include <linux/stop_machine.h> | |
10 | #include <linux/jump_label.h> | |
11 | #include <asm/ipl.h> | |
12 | ||
13 | #ifdef HAVE_JUMP_LABEL | |
14 | ||
15 | struct insn { | |
16 | u16 opcode; | |
17 | s32 offset; | |
18 | } __packed; | |
19 | ||
20 | struct insn_args { | |
61f42183 JF |
21 | struct jump_entry *entry; |
22 | enum jump_label_type type; | |
5373db88 JG |
23 | }; |
24 | ||
5c6497c5 HC |
25 | static void jump_label_make_nop(struct jump_entry *entry, struct insn *insn) |
26 | { | |
27 | /* brcl 0,0 */ | |
28 | insn->opcode = 0xc004; | |
29 | insn->offset = 0; | |
30 | } | |
31 | ||
32 | static void jump_label_make_branch(struct jump_entry *entry, struct insn *insn) | |
33 | { | |
34 | /* brcl 15,offset */ | |
35 | insn->opcode = 0xc0f4; | |
36 | insn->offset = (entry->target - entry->code) >> 1; | |
37 | } | |
38 | ||
72dace96 HC |
39 | static void jump_label_bug(struct jump_entry *entry, struct insn *expected, |
40 | struct insn *new) | |
5c6497c5 HC |
41 | { |
42 | unsigned char *ipc = (unsigned char *)entry->code; | |
72dace96 HC |
43 | unsigned char *ipe = (unsigned char *)expected; |
44 | unsigned char *ipn = (unsigned char *)new; | |
5c6497c5 HC |
45 | |
46 | pr_emerg("Jump label code mismatch at %pS [%p]\n", ipc, ipc); | |
e4ec7351 AK |
47 | pr_emerg("Found: %6ph\n", ipc); |
48 | pr_emerg("Expected: %6ph\n", ipe); | |
49 | pr_emerg("New: %6ph\n", ipn); | |
5c6497c5 HC |
50 | panic("Corrupted kernel text"); |
51 | } | |
52 | ||
d5caa4db HC |
53 | static struct insn orignop = { |
54 | .opcode = 0xc004, | |
55 | .offset = JUMP_LABEL_NOP_OFFSET >> 1, | |
56 | }; | |
57 | ||
61f42183 | 58 | static void __jump_label_transform(struct jump_entry *entry, |
5c6497c5 HC |
59 | enum jump_label_type type, |
60 | int init) | |
5373db88 | 61 | { |
5c6497c5 | 62 | struct insn old, new; |
5373db88 | 63 | |
76b235c6 | 64 | if (type == JUMP_LABEL_JMP) { |
5c6497c5 HC |
65 | jump_label_make_nop(entry, &old); |
66 | jump_label_make_branch(entry, &new); | |
5373db88 | 67 | } else { |
d5caa4db | 68 | jump_label_make_branch(entry, &old); |
5c6497c5 | 69 | jump_label_make_nop(entry, &new); |
5373db88 | 70 | } |
d5caa4db HC |
71 | if (init) { |
72 | if (memcmp((void *)entry->code, &orignop, sizeof(orignop))) | |
72dace96 | 73 | jump_label_bug(entry, &orignop, &new); |
d5caa4db HC |
74 | } else { |
75 | if (memcmp((void *)entry->code, &old, sizeof(old))) | |
72dace96 | 76 | jump_label_bug(entry, &old, &new); |
d5caa4db | 77 | } |
8a5d8473 | 78 | s390_kernel_write((void *)entry->code, &new, sizeof(new)); |
61f42183 | 79 | } |
5373db88 | 80 | |
61f42183 JF |
81 | static int __sm_arch_jump_label_transform(void *data) |
82 | { | |
83 | struct insn_args *args = data; | |
84 | ||
5c6497c5 | 85 | __jump_label_transform(args->entry, args->type, 0); |
61f42183 JF |
86 | return 0; |
87 | } | |
88 | ||
89 | void arch_jump_label_transform(struct jump_entry *entry, | |
90 | enum jump_label_type type) | |
91 | { | |
92 | struct insn_args args; | |
93 | ||
94 | args.entry = entry; | |
95 | args.type = type; | |
96 | ||
97 | stop_machine(__sm_arch_jump_label_transform, &args, NULL); | |
98 | } | |
99 | ||
100 | void arch_jump_label_transform_static(struct jump_entry *entry, | |
101 | enum jump_label_type type) | |
102 | { | |
5c6497c5 | 103 | __jump_label_transform(entry, type, 1); |
5373db88 JG |
104 | } |
105 | ||
106 | #endif |