Jan Glauber | 5373db8 | 2011-03-16 15:58:30 -0400 | [diff] [blame] | 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 { |
Jeremy Fitzhardinge | 61f4218 | 2011-09-29 10:58:46 -0700 | [diff] [blame] | 21 | struct jump_entry *entry; |
| 22 | enum jump_label_type type; |
Jan Glauber | 5373db8 | 2011-03-16 15:58:30 -0400 | [diff] [blame] | 23 | }; |
| 24 | |
Heiko Carstens | 5c6497c | 2015-01-29 13:45:35 +0100 | [diff] [blame] | 25 | static void jump_label_make_nop(struct jump_entry *entry, struct insn *insn) |
Jan Glauber | 5373db8 | 2011-03-16 15:58:30 -0400 | [diff] [blame] | 26 | { |
Heiko Carstens | 5c6497c | 2015-01-29 13:45:35 +0100 | [diff] [blame] | 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 | |
Heiko Carstens | 72dace9 | 2015-02-20 08:33:31 +0100 | [diff] [blame] | 39 | static void jump_label_bug(struct jump_entry *entry, struct insn *expected, |
| 40 | struct insn *new) |
Heiko Carstens | 5c6497c | 2015-01-29 13:45:35 +0100 | [diff] [blame] | 41 | { |
| 42 | unsigned char *ipc = (unsigned char *)entry->code; |
Heiko Carstens | 72dace9 | 2015-02-20 08:33:31 +0100 | [diff] [blame] | 43 | unsigned char *ipe = (unsigned char *)expected; |
| 44 | unsigned char *ipn = (unsigned char *)new; |
Heiko Carstens | 5c6497c | 2015-01-29 13:45:35 +0100 | [diff] [blame] | 45 | |
| 46 | pr_emerg("Jump label code mismatch at %pS [%p]\n", ipc, ipc); |
Alexander Kuleshov | e4ec735 | 2015-08-27 01:17:46 +0600 | [diff] [blame] | 47 | pr_emerg("Found: %6ph\n", ipc); |
| 48 | pr_emerg("Expected: %6ph\n", ipe); |
| 49 | pr_emerg("New: %6ph\n", ipn); |
Heiko Carstens | 5c6497c | 2015-01-29 13:45:35 +0100 | [diff] [blame] | 50 | panic("Corrupted kernel text"); |
| 51 | } |
| 52 | |
Heiko Carstens | d5caa4d | 2015-01-29 14:10:22 +0100 | [diff] [blame] | 53 | static struct insn orignop = { |
| 54 | .opcode = 0xc004, |
| 55 | .offset = JUMP_LABEL_NOP_OFFSET >> 1, |
| 56 | }; |
| 57 | |
Heiko Carstens | 5c6497c | 2015-01-29 13:45:35 +0100 | [diff] [blame] | 58 | static void __jump_label_transform(struct jump_entry *entry, |
| 59 | enum jump_label_type type, |
| 60 | int init) |
| 61 | { |
| 62 | struct insn old, new; |
Jan Glauber | 5373db8 | 2011-03-16 15:58:30 -0400 | [diff] [blame] | 63 | |
Peter Zijlstra | 76b235c | 2015-07-24 14:45:44 +0200 | [diff] [blame] | 64 | if (type == JUMP_LABEL_JMP) { |
Heiko Carstens | 5c6497c | 2015-01-29 13:45:35 +0100 | [diff] [blame] | 65 | jump_label_make_nop(entry, &old); |
| 66 | jump_label_make_branch(entry, &new); |
Jan Glauber | 5373db8 | 2011-03-16 15:58:30 -0400 | [diff] [blame] | 67 | } else { |
Heiko Carstens | d5caa4d | 2015-01-29 14:10:22 +0100 | [diff] [blame] | 68 | jump_label_make_branch(entry, &old); |
Heiko Carstens | 5c6497c | 2015-01-29 13:45:35 +0100 | [diff] [blame] | 69 | jump_label_make_nop(entry, &new); |
Jan Glauber | 5373db8 | 2011-03-16 15:58:30 -0400 | [diff] [blame] | 70 | } |
Heiko Carstens | d5caa4d | 2015-01-29 14:10:22 +0100 | [diff] [blame] | 71 | if (init) { |
| 72 | if (memcmp((void *)entry->code, &orignop, sizeof(orignop))) |
Heiko Carstens | 72dace9 | 2015-02-20 08:33:31 +0100 | [diff] [blame] | 73 | jump_label_bug(entry, &orignop, &new); |
Heiko Carstens | d5caa4d | 2015-01-29 14:10:22 +0100 | [diff] [blame] | 74 | } else { |
| 75 | if (memcmp((void *)entry->code, &old, sizeof(old))) |
Heiko Carstens | 72dace9 | 2015-02-20 08:33:31 +0100 | [diff] [blame] | 76 | jump_label_bug(entry, &old, &new); |
Heiko Carstens | d5caa4d | 2015-01-29 14:10:22 +0100 | [diff] [blame] | 77 | } |
Heiko Carstens | 8a5d847 | 2015-03-13 12:55:56 +0100 | [diff] [blame] | 78 | s390_kernel_write((void *)entry->code, &new, sizeof(new)); |
Jeremy Fitzhardinge | 61f4218 | 2011-09-29 10:58:46 -0700 | [diff] [blame] | 79 | } |
Jan Glauber | 5373db8 | 2011-03-16 15:58:30 -0400 | [diff] [blame] | 80 | |
Jeremy Fitzhardinge | 61f4218 | 2011-09-29 10:58:46 -0700 | [diff] [blame] | 81 | static int __sm_arch_jump_label_transform(void *data) |
| 82 | { |
| 83 | struct insn_args *args = data; |
| 84 | |
Heiko Carstens | 5c6497c | 2015-01-29 13:45:35 +0100 | [diff] [blame] | 85 | __jump_label_transform(args->entry, args->type, 0); |
Jeremy Fitzhardinge | 61f4218 | 2011-09-29 10:58:46 -0700 | [diff] [blame] | 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 | { |
Heiko Carstens | 5c6497c | 2015-01-29 13:45:35 +0100 | [diff] [blame] | 103 | __jump_label_transform(entry, type, 1); |
Jan Glauber | 5373db8 | 2011-03-16 15:58:30 -0400 | [diff] [blame] | 104 | } |
| 105 | |
| 106 | #endif |