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Diffstat (limited to 'arch/s390/kernel/jump_label.c')
-rw-r--r--arch/s390/kernel/jump_label.c63
1 files changed, 49 insertions, 14 deletions
diff --git a/arch/s390/kernel/jump_label.c b/arch/s390/kernel/jump_label.c
index b987ab2c1541..cb2d51e779df 100644
--- a/arch/s390/kernel/jump_label.c
+++ b/arch/s390/kernel/jump_label.c
@@ -22,31 +22,66 @@ struct insn_args {
enum jump_label_type type;
};
+static void jump_label_make_nop(struct jump_entry *entry, struct insn *insn)
+{
+ /* brcl 0,0 */
+ insn->opcode = 0xc004;
+ insn->offset = 0;
+}
+
+static void jump_label_make_branch(struct jump_entry *entry, struct insn *insn)
+{
+ /* brcl 15,offset */
+ insn->opcode = 0xc0f4;
+ insn->offset = (entry->target - entry->code) >> 1;
+}
+
+static void jump_label_bug(struct jump_entry *entry, struct insn *insn)
+{
+ unsigned char *ipc = (unsigned char *)entry->code;
+ unsigned char *ipe = (unsigned char *)insn;
+
+ pr_emerg("Jump label code mismatch at %pS [%p]\n", ipc, ipc);
+ pr_emerg("Found: %02x %02x %02x %02x %02x %02x\n",
+ ipc[0], ipc[1], ipc[2], ipc[3], ipc[4], ipc[5]);
+ pr_emerg("Expected: %02x %02x %02x %02x %02x %02x\n",
+ ipe[0], ipe[1], ipe[2], ipe[3], ipe[4], ipe[5]);
+ panic("Corrupted kernel text");
+}
+
+static struct insn orignop = {
+ .opcode = 0xc004,
+ .offset = JUMP_LABEL_NOP_OFFSET >> 1,
+};
+
static void __jump_label_transform(struct jump_entry *entry,
- enum jump_label_type type)
+ enum jump_label_type type,
+ int init)
{
- struct insn insn;
- int rc;
+ struct insn old, new;
if (type == JUMP_LABEL_ENABLE) {
- /* brcl 15,offset */
- insn.opcode = 0xc0f4;
- insn.offset = (entry->target - entry->code) >> 1;
+ jump_label_make_nop(entry, &old);
+ jump_label_make_branch(entry, &new);
} else {
- /* brcl 0,0 */
- insn.opcode = 0xc004;
- insn.offset = 0;
+ jump_label_make_branch(entry, &old);
+ jump_label_make_nop(entry, &new);
}
-
- rc = probe_kernel_write((void *)entry->code, &insn, JUMP_LABEL_NOP_SIZE);
- WARN_ON_ONCE(rc < 0);
+ if (init) {
+ if (memcmp((void *)entry->code, &orignop, sizeof(orignop)))
+ jump_label_bug(entry, &old);
+ } else {
+ if (memcmp((void *)entry->code, &old, sizeof(old)))
+ jump_label_bug(entry, &old);
+ }
+ probe_kernel_write((void *)entry->code, &new, sizeof(new));
}
static int __sm_arch_jump_label_transform(void *data)
{
struct insn_args *args = data;
- __jump_label_transform(args->entry, args->type);
+ __jump_label_transform(args->entry, args->type, 0);
return 0;
}
@@ -64,7 +99,7 @@ void arch_jump_label_transform(struct jump_entry *entry,
void arch_jump_label_transform_static(struct jump_entry *entry,
enum jump_label_type type)
{
- __jump_label_transform(entry, type);
+ __jump_label_transform(entry, type, 1);
}
#endif