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| author | Miroslav Benes <mbenes@suse.cz> | 2020-04-24 16:30:42 +0200 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2020-04-30 20:14:33 +0200 |
| commit | b490f45362002fef57996388e395efc974b013f4 (patch) | |
| tree | 2c436e0e83e3c8af5ebaac541352fd0b8ed494db /tools/objtool/arch/x86 | |
| parent | b09fb65e863733e192d4825a285b4b4998969ce0 (diff) | |
| download | linux-b490f45362002fef57996388e395efc974b013f4.tar.gz linux-b490f45362002fef57996388e395efc974b013f4.tar.bz2 linux-b490f45362002fef57996388e395efc974b013f4.zip | |
objtool: Move the IRET hack into the arch decoder
Quoting Julien:
"And the other suggestion is my other email was that you don't even
need to add INSN_EXCEPTION_RETURN. You can keep IRET as
INSN_CONTEXT_SWITCH by default and x86 decoder lookups the symbol
conaining an iret. If it's a function symbol, it can just set the type
to INSN_OTHER so that it caries on to the next instruction after
having handled the stack_op."
Suggested-by: Julien Thierry <jthierry@redhat.com>
Signed-off-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lkml.kernel.org/r/20200428191659.913283807@infradead.org
Diffstat (limited to 'tools/objtool/arch/x86')
| -rw-r--r-- | tools/objtool/arch/x86/decode.c | 28 |
1 files changed, 18 insertions, 10 deletions
diff --git a/tools/objtool/arch/x86/decode.c b/tools/objtool/arch/x86/decode.c index e26bedbfff95..d7b5d1096913 100644 --- a/tools/objtool/arch/x86/decode.c +++ b/tools/objtool/arch/x86/decode.c @@ -94,6 +94,7 @@ int arch_decode_instruction(const struct elf *elf, const struct section *sec, rex_x = 0, modrm = 0, modrm_mod = 0, modrm_rm = 0, modrm_reg = 0, sib = 0; struct stack_op *op = NULL; + struct symbol *sym; x86_64 = is_x86_64(elf); if (x86_64 == -1) @@ -469,17 +470,24 @@ int arch_decode_instruction(const struct elf *elf, const struct section *sec, break; case 0xcf: /* iret */ - *type = INSN_EXCEPTION_RETURN; - - ADD_OP(op) { - /* add $40, %rsp */ - op->src.type = OP_SRC_ADD; - op->src.reg = CFI_SP; - op->src.offset = 5*8; - op->dest.type = OP_DEST_REG; - op->dest.reg = CFI_SP; + /* + * Handle sync_core(), which has an IRET to self. + * All other IRET are in STT_NONE entry code. + */ + sym = find_symbol_containing(sec, offset); + if (sym && sym->type == STT_FUNC) { + ADD_OP(op) { + /* add $40, %rsp */ + op->src.type = OP_SRC_ADD; + op->src.reg = CFI_SP; + op->src.offset = 5*8; + op->dest.type = OP_DEST_REG; + op->dest.reg = CFI_SP; + } + break; } - break; + + /* fallthrough */ case 0xca: /* retf */ case 0xcb: /* retf */ |