[tip: objtool/core] objtool: Add STT_NOTYPE noinstr validation

From: tip-bot2 for Peter Zijlstra
Date: Thu Apr 23 2020 - 03:49:47 EST


The following commit has been merged into the objtool/core branch of tip:

Commit-ID: 932f8e987bfdcfc2365177978a30fdc0d6f6bd60
Gitweb: https://git.kernel.org/tip/932f8e987bfdcfc2365177978a30fdc0d6f6bd60
Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate: Mon, 23 Mar 2020 18:26:03 +01:00
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Wed, 22 Apr 2020 10:53:51 +02:00

objtool: Add STT_NOTYPE noinstr validation

Make sure to also check STT_NOTYPE symbols for noinstr violations.

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/20200416115119.465335884@xxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
tools/objtool/check.c | 46 +++++++++++++++++++++++++++---------------
1 file changed, 30 insertions(+), 16 deletions(-)

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index f49bf83..0d9f9cf 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -229,10 +229,18 @@ static void init_cfi_state(struct cfi_state *cfi)
cfi->drap_offset = -1;
}

-static void clear_insn_state(struct insn_state *state)
+static void init_insn_state(struct insn_state *state, struct section *sec)
{
memset(state, 0, sizeof(*state));
init_cfi_state(&state->cfi);
+
+ /*
+ * We need the full vmlinux for noinstr validation, otherwise we can
+ * not correctly determine insn->call_dest->sec (external symbols do
+ * not have a section).
+ */
+ if (vmlinux && sec)
+ state->noinstr = sec->noinstr;
}

/*
@@ -2354,24 +2362,34 @@ static int validate_branch(struct objtool_file *file, struct symbol *func,
return 0;
}

-static int validate_unwind_hints(struct objtool_file *file)
+static int validate_unwind_hints(struct objtool_file *file, struct section *sec)
{
struct instruction *insn;
- int ret, warnings = 0;
struct insn_state state;
+ int ret, warnings = 0;

if (!file->hints)
return 0;

- clear_insn_state(&state);
+ init_insn_state(&state, sec);

- for_each_insn(file, insn) {
+ if (sec) {
+ insn = find_insn(file, sec, 0);
+ if (!insn)
+ return 0;
+ } else {
+ insn = list_first_entry(&file->insn_list, typeof(*insn), list);
+ }
+
+ while (&insn->list != &file->insn_list && (!sec || insn->sec == sec)) {
if (insn->hint && !insn->visited) {
ret = validate_branch(file, insn->func, insn, state);
if (ret && backtrace)
BT_FUNC("<=== (hint)", insn);
warnings += ret;
}
+
+ insn = list_next_entry(insn, list);
}

return warnings;
@@ -2518,19 +2536,11 @@ static int validate_section(struct objtool_file *file, struct section *sec)
struct symbol *func;
int warnings = 0;

- /*
- * We need the full vmlinux for noinstr validation, otherwise we can
- * not correctly determine insn->call_dest->sec (external symbols do
- * not have a section).
- */
- if (vmlinux)
- state.noinstr = sec->noinstr;
-
list_for_each_entry(func, &sec->symbol_list, list) {
if (func->type != STT_FUNC)
continue;

- clear_insn_state(&state);
+ init_insn_state(&state, sec);
state.cfi.cfa = initial_func_cfi.cfa;
memcpy(&state.cfi.regs, &initial_func_cfi.regs,
CFI_NUM_REGS * sizeof(struct cfi_reg));
@@ -2545,12 +2555,16 @@ static int validate_section(struct objtool_file *file, struct section *sec)
static int validate_vmlinux_functions(struct objtool_file *file)
{
struct section *sec;
+ int warnings = 0;

sec = find_section_by_name(file->elf, ".noinstr.text");
if (!sec)
return 0;

- return validate_section(file, sec);
+ warnings += validate_section(file, sec);
+ warnings += validate_unwind_hints(file, sec);
+
+ return warnings;
}

static int validate_functions(struct objtool_file *file)
@@ -2635,7 +2649,7 @@ int check(const char *_objname, bool orc)
goto out;
warnings += ret;

- ret = validate_unwind_hints(&file);
+ ret = validate_unwind_hints(&file, NULL);
if (ret < 0)
goto out;
warnings += ret;