The following commit has been merged into the objtool/core branch of tip: Commit-ID: dd4d6c5599065055dd89e5d7773c267cf86431e2 Gitweb: https://git.kernel.org/tip/dd4d6c5599065055dd89e5d7773c267cf86431e2 Author: Julien Thierry <jthierry@xxxxxxxxxx> AuthorDate: Fri, 27 Mar 2020 15:28:47 Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx> CommitterDate: Wed, 22 Apr 2020 23:10:05 +02:00 objtool: Support multiple stack_op per instruction Instruction sets can include more or less complex operations which might not fit the currently defined set of stack_ops. Combining more than one stack_op provides more flexibility to describe the behaviour of an instruction. This also reduces the need to define new stack_ops specific to a single instruction set. Allow instruction decoders to generate multiple stack_op per instruction. Signed-off-by: Julien Thierry <jthierry@xxxxxxxxxx> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Reviewed-by: Miroslav Benes <mbenes@xxxxxxx> Reviewed-by: Alexandre Chartre <alexandre.chartre@xxxxxxxxxx> Acked-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx> Link: https://lkml.kernel.org/r/20200327152847.15294-11-jthierry@xxxxxxxxxx --- tools/objtool/arch.h | 4 +- tools/objtool/arch/x86/decode.c | 13 +++++- tools/objtool/check.c | 74 +++++++++++++++++++------------- tools/objtool/check.h | 2 +- 4 files changed, 62 insertions(+), 31 deletions(-) diff --git a/tools/objtool/arch.h b/tools/objtool/arch.h index a9a50a2..f9883c4 100644 --- a/tools/objtool/arch.h +++ b/tools/objtool/arch.h @@ -64,6 +64,7 @@ struct op_src { struct stack_op { struct op_dest dest; struct op_src src; + struct list_head list; }; struct instruction; @@ -73,7 +74,8 @@ void arch_initial_func_cfi_state(struct cfi_state *state); int arch_decode_instruction(struct elf *elf, struct section *sec, unsigned long offset, unsigned int maxlen, unsigned int *len, enum insn_type *type, - unsigned long *immediate, struct stack_op *op); + unsigned long *immediate, + struct list_head *ops_list); bool arch_callee_saved_reg(unsigned char reg); diff --git a/tools/objtool/arch/x86/decode.c b/tools/objtool/arch/x86/decode.c index 7ce8650..199b408 100644 --- a/tools/objtool/arch/x86/decode.c +++ b/tools/objtool/arch/x86/decode.c @@ -80,13 +80,15 @@ unsigned long arch_jump_destination(struct instruction *insn) int arch_decode_instruction(struct elf *elf, struct section *sec, unsigned long offset, unsigned int maxlen, unsigned int *len, enum insn_type *type, - unsigned long *immediate, struct stack_op *op) + unsigned long *immediate, + struct list_head *ops_list) { struct insn insn; int x86_64, sign; unsigned char op1, op2, rex = 0, rex_b = 0, rex_r = 0, rex_w = 0, rex_x = 0, modrm = 0, modrm_mod = 0, modrm_rm = 0, modrm_reg = 0, sib = 0; + struct stack_op *op; x86_64 = is_x86_64(elf); if (x86_64 == -1) @@ -127,6 +129,10 @@ int arch_decode_instruction(struct elf *elf, struct section *sec, if (insn.sib.nbytes) sib = insn.sib.bytes[0]; + op = calloc(1, sizeof(*op)); + if (!op) + return -1; + switch (op1) { case 0x1: @@ -488,6 +494,11 @@ int arch_decode_instruction(struct elf *elf, struct section *sec, *immediate = insn.immediate.nbytes ? insn.immediate.value : 0; + if (*type == INSN_STACK) + list_add_tail(&op->list, ops_list); + else + free(op); + return 0; } diff --git a/tools/objtool/check.c b/tools/objtool/check.c index f4254d4..819de0d 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -260,6 +260,7 @@ static int decode_instructions(struct objtool_file *file) } memset(insn, 0, sizeof(*insn)); INIT_LIST_HEAD(&insn->alts); + INIT_LIST_HEAD(&insn->stack_ops); clear_insn_state(&insn->state); insn->sec = sec; @@ -269,7 +270,7 @@ static int decode_instructions(struct objtool_file *file) sec->len - offset, &insn->len, &insn->type, &insn->immediate, - &insn->stack_op); + &insn->stack_ops); if (ret) goto err; @@ -770,6 +771,7 @@ static int handle_group_alt(struct objtool_file *file, } memset(fake_jump, 0, sizeof(*fake_jump)); INIT_LIST_HEAD(&fake_jump->alts); + INIT_LIST_HEAD(&fake_jump->stack_ops); clear_insn_state(&fake_jump->state); fake_jump->sec = special_alt->new_sec; @@ -1468,10 +1470,11 @@ static bool has_valid_stack_frame(struct insn_state *state) return false; } -static int update_insn_state_regs(struct instruction *insn, struct insn_state *state) +static int update_insn_state_regs(struct instruction *insn, + struct insn_state *state, + struct stack_op *op) { struct cfi_reg *cfa = &state->cfa; - struct stack_op *op = &insn->stack_op; if (cfa->base != CFI_SP) return 0; @@ -1561,9 +1564,9 @@ static void restore_reg(struct insn_state *state, unsigned char reg) * 41 5d pop %r13 * c3 retq */ -static int update_insn_state(struct instruction *insn, struct insn_state *state) +static int update_insn_state(struct instruction *insn, struct insn_state *state, + struct stack_op *op) { - struct stack_op *op = &insn->stack_op; struct cfi_reg *cfa = &state->cfa; struct cfi_reg *regs = state->regs; @@ -1577,7 +1580,7 @@ static int update_insn_state(struct instruction *insn, struct insn_state *state) } if (state->type == ORC_TYPE_REGS || state->type == ORC_TYPE_REGS_IRET) - return update_insn_state_regs(insn, state); + return update_insn_state_regs(insn, state, op); switch (op->dest.type) { @@ -1914,6 +1917,42 @@ static int update_insn_state(struct instruction *insn, struct insn_state *state) return 0; } +static int handle_insn_ops(struct instruction *insn, struct insn_state *state) +{ + struct stack_op *op; + + list_for_each_entry(op, &insn->stack_ops, list) { + int res; + + res = update_insn_state(insn, state, op); + if (res) + return res; + + if (op->dest.type == OP_DEST_PUSHF) { + if (!state->uaccess_stack) { + state->uaccess_stack = 1; + } else if (state->uaccess_stack >> 31) { + WARN_FUNC("PUSHF stack exhausted", + insn->sec, insn->offset); + return 1; + } + state->uaccess_stack <<= 1; + state->uaccess_stack |= state->uaccess; + } + + if (op->src.type == OP_SRC_POPF) { + if (state->uaccess_stack) { + state->uaccess = state->uaccess_stack & 1; + state->uaccess_stack >>= 1; + if (state->uaccess_stack == 1) + state->uaccess_stack = 0; + } + } + } + + return 0; +} + static bool insn_state_match(struct instruction *insn, struct insn_state *state) { struct insn_state *state1 = &insn->state, *state2 = state; @@ -2214,29 +2253,8 @@ static int validate_branch(struct objtool_file *file, struct symbol *func, return 0; case INSN_STACK: - if (update_insn_state(insn, &state)) + if (handle_insn_ops(insn, &state)) return 1; - - if (insn->stack_op.dest.type == OP_DEST_PUSHF) { - if (!state.uaccess_stack) { - state.uaccess_stack = 1; - } else if (state.uaccess_stack >> 31) { - WARN_FUNC("PUSHF stack exhausted", sec, insn->offset); - return 1; - } - state.uaccess_stack <<= 1; - state.uaccess_stack |= state.uaccess; - } - - if (insn->stack_op.src.type == OP_SRC_POPF) { - if (state.uaccess_stack) { - state.uaccess = state.uaccess_stack & 1; - state.uaccess_stack >>= 1; - if (state.uaccess_stack == 1) - state.uaccess_stack = 0; - } - } - break; case INSN_STAC: diff --git a/tools/objtool/check.h b/tools/objtool/check.h index f0ce8ff..2c55f75 100644 --- a/tools/objtool/check.h +++ b/tools/objtool/check.h @@ -42,7 +42,7 @@ struct instruction { struct rela *jump_table; struct list_head alts; struct symbol *func; - struct stack_op stack_op; + struct list_head stack_ops; struct insn_state state; struct orc_entry orc; };
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