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@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lkml.kernel.org/r/20200327152847.15294-11-jthierry@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index e06a891..9e854fd1 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;
@@ -754,6 +755,7 @@ 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;
@@ -1452,10 +1454,11 @@ 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;
@@ -1545,9 +1548,9 @@ 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;
@@ -1561,7 +1564,7 @@ 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) {
@@ -1898,6 +1901,42 @@ 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;
@@ -2198,29 +2237,8 @@ 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: