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db2b0c5d7b
Normally objtool will now follow indirect calls; there is no need.
However, this becomes a problem with noinstr validation; if there's an
indirect call from noinstr code, we very much need to know it is to
another noinstr function. Luckily there aren't many indirect calls in
entry code with the obvious exception of paravirt. As such, noinstr
validation didn't work with paravirt kernels.
In order to track pv_ops[] call targets, objtool reads the static
pv_ops[] tables as well as direct assignments to the pv_ops[] array,
provided the compiler makes them a single instruction like:
bf87: 48 c7 05 00 00 00 00 00 00 00 00 movq $0x0,0x0(%rip)
bf92 <xen_init_spinlocks+0x5f>
bf8a: R_X86_64_PC32 pv_ops+0x268
There are, as of yet, no warnings for when this goes wrong :/
Using the functions found with the above means, all pv_ops[] calls are
now subject to noinstr validation.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210624095149.118815755@infradead.org
94 lines
1.7 KiB
C
94 lines
1.7 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 <objtool/objtool.h>
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#include <objtool/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_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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};
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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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struct list_head list;
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};
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struct instruction;
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void arch_initial_func_cfi_state(struct cfi_init_state *state);
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int arch_decode_instruction(struct objtool_file *file, const 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,
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struct list_head *ops_list);
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bool arch_callee_saved_reg(unsigned char reg);
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unsigned long arch_jump_destination(struct instruction *insn);
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unsigned long arch_dest_reloc_offset(int addend);
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const char *arch_nop_insn(int len);
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const char *arch_ret_insn(int len);
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int arch_decode_hint_reg(u8 sp_reg, int *base);
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bool arch_is_retpoline(struct symbol *sym);
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int arch_rewrite_retpolines(struct objtool_file *file);
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#endif /* _ARCH_H */
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