From f66c05d6baf36069c01a02f869bebb75586f2318 Mon Sep 17 00:00:00 2001
From: Vasily Gorbik <gor@linux.ibm.com>
Date: Wed, 12 May 2021 19:42:13 +0200
Subject: [PATCH] objtool/x86: Fix elf_add_alternative() endianness
Currently x86 kernel cross-compiled on big endian system fails at boot with:
kernel BUG at arch/x86/kernel/alternative.c:258!
Corresponding bug condition look like the following:
BUG_ON(feature >= (NCAPINTS + NBUGINTS) * 32);
Fix that by converting alternative feature/cpuid to target endianness.
Fixes: 9bc0bb50727c ("objtool/x86: Rewrite retpoline thunk calls")
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: https://lore.kernel.org/r/patch-2.thread-6c9df9.git-6c9df9a8098d.your-ad-here.call-01620841104-ext-2554@work.hours
---
tools/objtool/arch/x86/decode.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/tools/objtool/arch/x86/decode.c b/tools/objtool/arch/x86/decode.c
index cedf3ede75455..24295d39713b2 100644
--- a/tools/objtool/arch/x86/decode.c
+++ b/tools/objtool/arch/x86/decode.c
@@ -19,6 +19,7 @@
#include <objtool/elf.h>
#include <objtool/arch.h>
#include <objtool/warn.h>
+#include <objtool/endianness.h>
#include <arch/elf.h>
static int is_x86_64(const struct elf *elf)
@@ -725,7 +726,7 @@ static int elf_add_alternative(struct elf *elf,
return -1;
}
- alt->cpuid = cpuid;
+ alt->cpuid = bswap_if_needed(cpuid);
alt->instrlen = orig_len;
alt->replacementlen = repl_len;
--
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