From: Peter Zijlstra peterz@infradead.org
stable inclusion from stable-v5.10.133 commit 38a80a3ca2cb069dd5608703b015a206a672aae5 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I5YVKO
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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commit d4b5a5c993009ffeb5febe3b701da3faab6adb96 upstream.
Make sure we can see the text changes when booting with 'debug-alternative'.
Example output:
[ ] SMP alternatives: retpoline at: __traceiter_initcall_level+0x1f/0x30 (ffffffff8100066f) len: 5 to: __x86_indirect_thunk_rax+0x0/0x20 [ ] SMP alternatives: ffffffff82603e58: [2:5) optimized NOPs: ff d0 0f 1f 00 [ ] SMP alternatives: ffffffff8100066f: orig: e8 cc 30 00 01 [ ] SMP alternatives: ffffffff8100066f: repl: ff d0 0f 1f 00
Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Reviewed-by: Borislav Petkov bp@suse.de Acked-by: Josh Poimboeuf jpoimboe@redhat.com Tested-by: Alexei Starovoitov ast@kernel.org Link: https://lore.kernel.org/r/20211026120310.422273830@infradead.org Signed-off-by: Thadeu Lima de Souza Cascardo cascardo@canonical.com Signed-off-by: Ben Hutchings ben@decadent.org.uk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com Acked-by: Xie XiuQi xiexiuqi@huawei.com --- arch/x86/kernel/alternative.c | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c index 487ade1768b1..fa79a46fa5d2 100644 --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -648,9 +648,15 @@ void __init_or_module noinline apply_retpolines(s32 *start, s32 *end) continue; }
+ DPRINTK("retpoline at: %pS (%px) len: %d to: %pS", + addr, addr, insn.length, + addr + insn.length + insn.immediate.value); + len = patch_retpoline(addr, &insn, bytes); if (len == insn.length) { optimize_nops(bytes, len); + DUMP_BYTES(((u8*)addr), len, "%px: orig: ", addr); + DUMP_BYTES(((u8*)bytes), len, "%px: repl: ", addr); text_poke_early(addr, bytes, len); } }