From f56dae88a81fded66adf2bea9922d1d98d1da14f Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 24 Jun 2021 11:41:02 +0200 Subject: objtool: Handle __sanitize_cov*() tail calls Turns out the compilers also generate tail calls to __sanitize_cov*(), make sure to also patch those out in noinstr code. Fixes: 0f1441b44e82 ("objtool: Fix noinstr vs KCOV") Signed-off-by: Peter Zijlstra (Intel) Acked-by: Marco Elver Link: https://lore.kernel.org/r/20210624095147.818783799@infradead.org --- tools/objtool/arch/x86/decode.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) (limited to 'tools/objtool/arch') diff --git a/tools/objtool/arch/x86/decode.c b/tools/objtool/arch/x86/decode.c index 3435a32afbd1..340a3dce94a0 100644 --- a/tools/objtool/arch/x86/decode.c +++ b/tools/objtool/arch/x86/decode.c @@ -659,6 +659,26 @@ const char *arch_nop_insn(int len) return nops[len-1]; } +#define BYTE_RET 0xC3 + +const char *arch_ret_insn(int len) +{ + static const char ret[5][5] = { + { BYTE_RET }, + { BYTE_RET, BYTES_NOP1 }, + { BYTE_RET, BYTES_NOP2 }, + { BYTE_RET, BYTES_NOP3 }, + { BYTE_RET, BYTES_NOP4 }, + }; + + if (len < 1 || len > 5) { + WARN("invalid RET size: %d\n", len); + return NULL; + } + + return ret[len-1]; +} + /* asm/alternative.h ? */ #define ALTINSTR_FLAG_INV (1 << 15) -- cgit v1.2.3