diff options
| author |   Ard Biesheuvel <ardb@kernel.org> | 2022-06-15 17:41:40 +0200 |
|---|---|---|
| committer |   Peter Zijlstra <peterz@infradead.org> | 2022-06-24 09:48:54 +0200 |
| commit | 0c3b61e00a0d0872c521586494ec23f6016c317a (patch) | |
| tree | 615555f1d725b28b547d7c60c9d9d7f45371b76c /arch/s390/kernel | |
| parent | Linux 5.19-rc3 (diff) | |
| download | linux-dev-0c3b61e00a0d0872c521586494ec23f6016c317a.tar.xz linux-dev-0c3b61e00a0d0872c521586494ec23f6016c317a.zip | |
jump_label: s390: avoid pointless initial NOP patching
Patching NOPs into other NOPs at boot time serves no purpose, so let's
use the same NOP encodings at compile time and runtime.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220615154142.1574619-2-ardb@kernel.org
Diffstat (limited to 'arch/s390/kernel')
| -rw-r--r-- | arch/s390/kernel/jump_label.c | 23 |
1 files changed, 5 insertions, 18 deletions
diff --git a/arch/s390/kernel/jump_label.c b/arch/s390/kernel/jump_label.c index 6bec000c6c1c..d764f0d229ab 100644 --- a/arch/s390/kernel/jump_label.c +++ b/arch/s390/kernel/jump_label.c @@ -44,14 +44,8 @@ static void jump_label_bug(struct jump_entry *entry, struct insn *expected, 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, - int init) + enum jump_label_type type) { void *code = (void *)jump_entry_code(entry); struct insn old, new; @@ -63,27 +57,22 @@ static void jump_label_transform(struct jump_entry *entry, jump_label_make_branch(entry, &old); jump_label_make_nop(entry, &new); } - if (init) { - if (memcmp(code, &orignop, sizeof(orignop))) - jump_label_bug(entry, &orignop, &new); - } else { - if (memcmp(code, &old, sizeof(old))) - jump_label_bug(entry, &old, &new); - } + if (memcmp(code, &old, sizeof(old))) + jump_label_bug(entry, &old, &new); s390_kernel_write(code, &new, sizeof(new)); } void arch_jump_label_transform(struct jump_entry *entry, enum jump_label_type type) { - jump_label_transform(entry, type, 0); + jump_label_transform(entry, type); text_poke_sync(); } bool arch_jump_label_transform_queue(struct jump_entry *entry, enum jump_label_type type) { - jump_label_transform(entry, type, 0); + jump_label_transform(entry, type); return true; } @@ -95,6 +84,4 @@ void arch_jump_label_transform_apply(void) void __init_or_module arch_jump_label_transform_static(struct jump_entry *entry, enum jump_label_type type) { - jump_label_transform(entry, type, 1); - text_poke_sync(); } |