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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 | ||
5c6497c5 HC |
18 | static void jump_label_make_nop(struct jump_entry *entry, struct insn *insn) |
19 | { | |
a646ef39 | 20 | /* brcl 0,offset */ |
5c6497c5 | 21 | insn->opcode = 0xc004; |
a646ef39 | 22 | insn->offset = (jump_entry_target(entry) - jump_entry_code(entry)) >> 1; |
5c6497c5 HC |
23 | } |
24 | ||
25 | static void jump_label_make_branch(struct jump_entry *entry, struct insn *insn) | |
26 | { | |
27 | /* brcl 15,offset */ | |
28 | insn->opcode = 0xc0f4; | |
13ddb52c | 29 | insn->offset = (jump_entry_target(entry) - jump_entry_code(entry)) >> 1; |
5c6497c5 HC |
30 | } |
31 | ||
72dace96 HC |
32 | static void jump_label_bug(struct jump_entry *entry, struct insn *expected, |
33 | struct insn *new) | |
5c6497c5 | 34 | { |
13ddb52c | 35 | unsigned char *ipc = (unsigned char *)jump_entry_code(entry); |
72dace96 HC |
36 | unsigned char *ipe = (unsigned char *)expected; |
37 | unsigned char *ipn = (unsigned char *)new; | |
5c6497c5 HC |
38 | |
39 | pr_emerg("Jump label code mismatch at %pS [%p]\n", ipc, ipc); | |
e4ec7351 AK |
40 | pr_emerg("Found: %6ph\n", ipc); |
41 | pr_emerg("Expected: %6ph\n", ipe); | |
42 | pr_emerg("New: %6ph\n", ipn); | |
5c6497c5 HC |
43 | panic("Corrupted kernel text"); |
44 | } | |
45 | ||
d5caa4db HC |
46 | static struct insn orignop = { |
47 | .opcode = 0xc004, | |
48 | .offset = JUMP_LABEL_NOP_OFFSET >> 1, | |
49 | }; | |
50 | ||
61f42183 | 51 | static void __jump_label_transform(struct jump_entry *entry, |
5c6497c5 HC |
52 | enum jump_label_type type, |
53 | int init) | |
5373db88 | 54 | { |
13ddb52c | 55 | void *code = (void *)jump_entry_code(entry); |
5c6497c5 | 56 | struct insn old, new; |
5373db88 | 57 | |
76b235c6 | 58 | if (type == JUMP_LABEL_JMP) { |
5c6497c5 HC |
59 | jump_label_make_nop(entry, &old); |
60 | jump_label_make_branch(entry, &new); | |
5373db88 | 61 | } else { |
d5caa4db | 62 | jump_label_make_branch(entry, &old); |
5c6497c5 | 63 | jump_label_make_nop(entry, &new); |
5373db88 | 64 | } |
d5caa4db | 65 | if (init) { |
13ddb52c | 66 | if (memcmp(code, &orignop, sizeof(orignop))) |
72dace96 | 67 | jump_label_bug(entry, &orignop, &new); |
d5caa4db | 68 | } else { |
13ddb52c | 69 | if (memcmp(code, &old, sizeof(old))) |
72dace96 | 70 | jump_label_bug(entry, &old, &new); |
d5caa4db | 71 | } |
13ddb52c | 72 | s390_kernel_write(code, &new, sizeof(new)); |
61f42183 | 73 | } |
5373db88 | 74 | |
a646ef39 | 75 | static void __jump_label_sync(void *dummy) |
61f42183 | 76 | { |
61f42183 JF |
77 | } |
78 | ||
79 | void arch_jump_label_transform(struct jump_entry *entry, | |
80 | enum jump_label_type type) | |
81 | { | |
a646ef39 MS |
82 | __jump_label_transform(entry, type, 0); |
83 | smp_call_function(__jump_label_sync, NULL, 1); | |
61f42183 JF |
84 | } |
85 | ||
86 | void arch_jump_label_transform_static(struct jump_entry *entry, | |
87 | enum jump_label_type type) | |
88 | { | |
5c6497c5 | 89 | __jump_label_transform(entry, type, 1); |
5373db88 | 90 | } |