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| author |   Peter Zijlstra <peterz@infradead.org> | 2022-03-28 13:13:41 +0200 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2022-04-07 11:27:02 +0200 |
| commit | be8a096521ca1a252bf078b347f96ce94582612e (patch) | |
| tree | c2b291f421ed2f0186eace3a065df45b95acd18f /arch/x86 | |
| parent | objtool: Fix SLS validation for kcov tail-call replacement (diff) | |
| download | linux-dev-be8a096521ca1a252bf078b347f96ce94582612e.tar.xz linux-dev-be8a096521ca1a252bf078b347f96ce94582612e.zip | |
x86,bpf: Avoid IBT objtool warning
Clang can inline emit_indirect_jump() and then folds constants, which
results in:
| vmlinux.o: warning: objtool: emit_bpf_dispatcher()+0x6a4: relocation to !ENDBR: .text.__x86.indirect_thunk+0x40
| vmlinux.o: warning: objtool: emit_bpf_dispatcher()+0x67d: relocation to !ENDBR: .text.__x86.indirect_thunk+0x40
| vmlinux.o: warning: objtool: emit_bpf_tail_call_indirect()+0x386: relocation to !ENDBR: .text.__x86.indirect_thunk+0x20
| vmlinux.o: warning: objtool: emit_bpf_tail_call_indirect()+0x35d: relocation to !ENDBR: .text.__x86.indirect_thunk+0x20
Suppress the optimization such that it must emit a code reference to
the __x86_indirect_thunk_array[] base.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lkml.kernel.org/r/20220405075531.GB30877@worktop.programming.kicks-ass.net
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/net/bpf_jit_comp.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index 8fe35ed11fd6..16b6efacf7c6 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -412,6 +412,7 @@ static void emit_indirect_jump(u8 **pprog, int reg, u8 *ip) EMIT_LFENCE(); EMIT2(0xFF, 0xE0 + reg); } else if (cpu_feature_enabled(X86_FEATURE_RETPOLINE)) { + OPTIMIZER_HIDE_VAR(reg); emit_jump(&prog, &__x86_indirect_thunk_array[reg], ip); } else #endif |