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authorJosh Poimboeuf <jpoimboe@kernel.org>2022-06-24 13:52:40 +0300
committerBorislav Petkov <bp@suse.de>2022-06-27 11:34:00 +0300
commit8faea26e611189e933ea2281975ff4dc7c1106b6 (patch)
treebf9fe4d4748f6ae1dff2f015f9507bc04d17dfe0 /tools
parentacac5e98ef8d638a411cfa2ee676c87e1973f126 (diff)
downloadlinux-8faea26e611189e933ea2281975ff4dc7c1106b6.tar.xz
objtool: Re-add UNWIND_HINT_{SAVE_RESTORE}
Commit c536ed2fffd5 ("objtool: Remove SAVE/RESTORE hints") removed the save/restore unwind hints because they were no longer needed. Now they're going to be needed again so re-add them. Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de>
Diffstat (limited to 'tools')
-rw-r--r--tools/include/linux/objtool.h6
-rw-r--r--tools/objtool/check.c40
-rw-r--r--tools/objtool/include/objtool/check.h19
3 files changed, 54 insertions, 11 deletions
diff --git a/tools/include/linux/objtool.h b/tools/include/linux/objtool.h
index b026f1ae39c6..10bc88cc3bf6 100644
--- a/tools/include/linux/objtool.h
+++ b/tools/include/linux/objtool.h
@@ -40,6 +40,8 @@ struct unwind_hint {
#define UNWIND_HINT_TYPE_REGS_PARTIAL 2
#define UNWIND_HINT_TYPE_FUNC 3
#define UNWIND_HINT_TYPE_ENTRY 4
+#define UNWIND_HINT_TYPE_SAVE 5
+#define UNWIND_HINT_TYPE_RESTORE 6
#ifdef CONFIG_OBJTOOL
@@ -127,7 +129,7 @@ struct unwind_hint {
* the debuginfo as necessary. It will also warn if it sees any
* inconsistencies.
*/
-.macro UNWIND_HINT sp_reg:req sp_offset=0 type:req end=0
+.macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 end=0
.Lunwind_hint_ip_\@:
.pushsection .discard.unwind_hints
/* struct unwind_hint */
@@ -180,7 +182,7 @@ struct unwind_hint {
#define ASM_REACHABLE
#else
#define ANNOTATE_INTRA_FUNCTION_CALL
-.macro UNWIND_HINT sp_reg:req sp_offset=0 type:req end=0
+.macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 end=0
.endm
.macro STACK_FRAME_NON_STANDARD func:req
.endm
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 822a490e6d87..ddfdd138cc2a 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -2032,6 +2032,17 @@ static int read_unwind_hints(struct objtool_file *file)
insn->hint = true;
+ if (hint->type == UNWIND_HINT_TYPE_SAVE) {
+ insn->hint = false;
+ insn->save = true;
+ continue;
+ }
+
+ if (hint->type == UNWIND_HINT_TYPE_RESTORE) {
+ insn->restore = true;
+ continue;
+ }
+
if (hint->type == UNWIND_HINT_TYPE_REGS_PARTIAL) {
struct symbol *sym = find_symbol_by_offset(insn->sec, insn->offset);
@@ -3329,6 +3340,35 @@ static int validate_branch(struct objtool_file *file, struct symbol *func,
state.instr += insn->instr;
if (insn->hint) {
+ if (insn->restore) {
+ struct instruction *save_insn, *i;
+
+ i = insn;
+ save_insn = NULL;
+
+ sym_for_each_insn_continue_reverse(file, func, i) {
+ if (i->save) {
+ save_insn = i;
+ break;
+ }
+ }
+
+ if (!save_insn) {
+ WARN_FUNC("no corresponding CFI save for CFI restore",
+ sec, insn->offset);
+ return 1;
+ }
+
+ if (!save_insn->visited) {
+ WARN_FUNC("objtool isn't smart enough to handle this CFI save/restore combo",
+ sec, insn->offset);
+ return 1;
+ }
+
+ insn->cfi = save_insn->cfi;
+ nr_cfi_reused++;
+ }
+
state.cfi = *insn->cfi;
} else {
/* XXX track if we actually changed state.cfi */
diff --git a/tools/objtool/include/objtool/check.h b/tools/objtool/include/objtool/check.h
index 0eeedeacbefb..036129cebeee 100644
--- a/tools/objtool/include/objtool/check.h
+++ b/tools/objtool/include/objtool/check.h
@@ -46,18 +46,19 @@ struct instruction {
enum insn_type type;
unsigned long immediate;
- u8 dead_end : 1,
- ignore : 1,
- ignore_alts : 1,
- hint : 1,
- retpoline_safe : 1,
- noendbr : 1,
- entry : 1;
- /* 1 bit hole */
+ u16 dead_end : 1,
+ ignore : 1,
+ ignore_alts : 1,
+ hint : 1,
+ save : 1,
+ restore : 1,
+ retpoline_safe : 1,
+ noendbr : 1,
+ entry : 1;
+ /* 7 bit hole */
s8 instr;
u8 visited;
- /* u8 hole */
struct alt_group *alt_group;
struct symbol *call_dest;