1 // SPDX-License-Identifier: GPL-2.0
3 * Jump label s390 support
5 * Copyright IBM Corp. 2011
6 * Author(s): Jan Glauber <jang@linux.vnet.ibm.com>
8 #include <linux/uaccess.h>
9 #include <linux/jump_label.h>
10 #include <linux/module.h>
11 #include <asm/text-patching.h>
19 static void jump_label_make_nop(struct jump_entry *entry, struct insn *insn)
22 insn->opcode = 0xc004;
23 insn->offset = (jump_entry_target(entry) - jump_entry_code(entry)) >> 1;
26 static void jump_label_make_branch(struct jump_entry *entry, struct insn *insn)
29 insn->opcode = 0xc0f4;
30 insn->offset = (jump_entry_target(entry) - jump_entry_code(entry)) >> 1;
33 static void jump_label_bug(struct jump_entry *entry, struct insn *expected,
36 unsigned char *ipc = (unsigned char *)jump_entry_code(entry);
37 unsigned char *ipe = (unsigned char *)expected;
38 unsigned char *ipn = (unsigned char *)new;
40 pr_emerg("Jump label code mismatch at %pS [%px]\n", ipc, ipc);
41 pr_emerg("Found: %6ph\n", ipc);
42 pr_emerg("Expected: %6ph\n", ipe);
43 pr_emerg("New: %6ph\n", ipn);
44 panic("Corrupted kernel text");
47 static void jump_label_transform(struct jump_entry *entry,
48 enum jump_label_type type)
50 void *code = (void *)jump_entry_code(entry);
53 if (type == JUMP_LABEL_JMP) {
54 jump_label_make_nop(entry, &old);
55 jump_label_make_branch(entry, &new);
57 jump_label_make_branch(entry, &old);
58 jump_label_make_nop(entry, &new);
60 if (memcmp(code, &old, sizeof(old)))
61 jump_label_bug(entry, &old, &new);
62 s390_kernel_write(code, &new, sizeof(new));
65 void arch_jump_label_transform(struct jump_entry *entry,
66 enum jump_label_type type)
68 jump_label_transform(entry, type);
72 bool arch_jump_label_transform_queue(struct jump_entry *entry,
73 enum jump_label_type type)
75 jump_label_transform(entry, type);
79 void arch_jump_label_transform_apply(void)