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/stop_machine.h>
10 #include <linux/jump_label.h>
19 struct jump_entry *entry;
20 enum jump_label_type type;
23 static void jump_label_make_nop(struct jump_entry *entry, struct insn *insn)
26 insn->opcode = 0xc004;
30 static void jump_label_make_branch(struct jump_entry *entry, struct insn *insn)
33 insn->opcode = 0xc0f4;
34 insn->offset = (entry->target - entry->code) >> 1;
37 static void jump_label_bug(struct jump_entry *entry, struct insn *expected,
40 unsigned char *ipc = (unsigned char *)entry->code;
41 unsigned char *ipe = (unsigned char *)expected;
42 unsigned char *ipn = (unsigned char *)new;
44 pr_emerg("Jump label code mismatch at %pS [%px]\n", ipc, ipc);
45 pr_emerg("Found: %6ph\n", ipc);
46 pr_emerg("Expected: %6ph\n", ipe);
47 pr_emerg("New: %6ph\n", ipn);
48 panic("Corrupted kernel text");
51 static struct insn orignop = {
53 .offset = JUMP_LABEL_NOP_OFFSET >> 1,
56 static void __jump_label_transform(struct jump_entry *entry,
57 enum jump_label_type type,
62 if (type == JUMP_LABEL_JMP) {
63 jump_label_make_nop(entry, &old);
64 jump_label_make_branch(entry, &new);
66 jump_label_make_branch(entry, &old);
67 jump_label_make_nop(entry, &new);
70 if (memcmp((void *)entry->code, &orignop, sizeof(orignop)))
71 jump_label_bug(entry, &orignop, &new);
73 if (memcmp((void *)entry->code, &old, sizeof(old)))
74 jump_label_bug(entry, &old, &new);
76 s390_kernel_write((void *)entry->code, &new, sizeof(new));
79 static int __sm_arch_jump_label_transform(void *data)
81 struct insn_args *args = data;
83 __jump_label_transform(args->entry, args->type, 0);
87 void arch_jump_label_transform(struct jump_entry *entry,
88 enum jump_label_type type)
90 struct insn_args args;
95 stop_machine_cpuslocked(__sm_arch_jump_label_transform, &args, NULL);
98 void arch_jump_label_transform_static(struct jump_entry *entry,
99 enum jump_label_type type)
101 __jump_label_transform(entry, type, 1);