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b68b990706
A Clang-built kernel is showing the following warning:
arch/x86/kernel/platform-quirks.o: warning: objtool: x86_early_init_platform_quirks()+0x84: unreachable instruction
That corresponds to this code:
7e: 0f 85 00 00 00 00 jne 84 <x86_early_init_platform_quirks+0x84>
80: R_X86_64_PC32 __x86_indirect_thunk_r11-0x4
84: c3 retq
This is a conditional retpoline sibling call, which is now possible
thanks to retpolines. Objtool hasn't seen that before. It's
incorrectly interpreting the conditional jump as an unconditional
dynamic jump.
Reported-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/30d4c758b267ef487fb97e6ecb2f148ad007b554.1563413318.git.jpoimboe@redhat.com
79 lines
1.3 KiB
C
79 lines
1.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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* Copyright (C) 2015 Josh Poimboeuf <jpoimboe@redhat.com>
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*/
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#ifndef _ARCH_H
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#define _ARCH_H
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#include <stdbool.h>
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#include <linux/list.h>
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#include "elf.h"
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#include "cfi.h"
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enum insn_type {
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INSN_JUMP_CONDITIONAL,
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INSN_JUMP_UNCONDITIONAL,
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INSN_JUMP_DYNAMIC,
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INSN_JUMP_DYNAMIC_CONDITIONAL,
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INSN_CALL,
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INSN_CALL_DYNAMIC,
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INSN_RETURN,
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INSN_CONTEXT_SWITCH,
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INSN_STACK,
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INSN_BUG,
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INSN_NOP,
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INSN_STAC,
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INSN_CLAC,
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INSN_STD,
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INSN_CLD,
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INSN_OTHER,
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};
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enum op_dest_type {
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OP_DEST_REG,
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OP_DEST_REG_INDIRECT,
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OP_DEST_MEM,
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OP_DEST_PUSH,
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OP_DEST_PUSHF,
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OP_DEST_LEAVE,
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};
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struct op_dest {
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enum op_dest_type type;
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unsigned char reg;
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int offset;
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};
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enum op_src_type {
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OP_SRC_REG,
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OP_SRC_REG_INDIRECT,
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OP_SRC_CONST,
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OP_SRC_POP,
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OP_SRC_POPF,
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OP_SRC_ADD,
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OP_SRC_AND,
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};
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struct op_src {
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enum op_src_type type;
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unsigned char reg;
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int offset;
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};
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struct stack_op {
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struct op_dest dest;
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struct op_src src;
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};
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void arch_initial_func_cfi_state(struct cfi_state *state);
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int arch_decode_instruction(struct elf *elf, struct section *sec,
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unsigned long offset, unsigned int maxlen,
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unsigned int *len, enum insn_type *type,
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unsigned long *immediate, struct stack_op *op);
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bool arch_callee_saved_reg(unsigned char reg);
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#endif /* _ARCH_H */
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