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Date: Tue, 12 Jul 2022 20:39:34 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org, Josh Poimboeuf <jpoimboe@...nel.org>,
"Peter Zijlstra (Intel)" <peterz@...radead.org>,
Borislav Petkov <bp@...e.de>,
Thadeu Lima de Souza Cascardo <cascardo@...onical.com>
Subject: [PATCH 5.15 64/78] objtool: Re-add UNWIND_HINT_{SAVE_RESTORE}
From: Josh Poimboeuf <jpoimboe@...nel.org>
commit 8faea26e611189e933ea2281975ff4dc7c1106b6 upstream.
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@...nel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Signed-off-by: Borislav Petkov <bp@...e.de>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@...onical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
arch/x86/include/asm/unwind_hints.h | 12 ++++++++--
include/linux/objtool.h | 6 +++--
tools/include/linux/objtool.h | 6 +++--
tools/objtool/check.c | 40 ++++++++++++++++++++++++++++++++++
tools/objtool/include/objtool/check.h | 1
5 files changed, 59 insertions(+), 6 deletions(-)
--- a/arch/x86/include/asm/unwind_hints.h
+++ b/arch/x86/include/asm/unwind_hints.h
@@ -8,11 +8,11 @@
#ifdef __ASSEMBLY__
.macro UNWIND_HINT_EMPTY
- UNWIND_HINT sp_reg=ORC_REG_UNDEFINED type=UNWIND_HINT_TYPE_CALL end=1
+ UNWIND_HINT type=UNWIND_HINT_TYPE_CALL end=1
.endm
.macro UNWIND_HINT_ENTRY
- UNWIND_HINT sp_reg=ORC_REG_UNDEFINED type=UNWIND_HINT_TYPE_ENTRY end=1
+ UNWIND_HINT type=UNWIND_HINT_TYPE_ENTRY end=1
.endm
.macro UNWIND_HINT_REGS base=%rsp offset=0 indirect=0 extra=1 partial=0
@@ -56,6 +56,14 @@
UNWIND_HINT sp_reg=ORC_REG_SP sp_offset=8 type=UNWIND_HINT_TYPE_FUNC
.endm
+.macro UNWIND_HINT_SAVE
+ UNWIND_HINT type=UNWIND_HINT_TYPE_SAVE
+.endm
+
+.macro UNWIND_HINT_RESTORE
+ UNWIND_HINT type=UNWIND_HINT_TYPE_RESTORE
+.endm
+
#endif /* __ASSEMBLY__ */
#endif /* _ASM_X86_UNWIND_HINTS_H */
--- a/include/linux/objtool.h
+++ b/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_STACK_VALIDATION
@@ -102,7 +104,7 @@ 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 */
@@ -132,7 +134,7 @@ struct unwind_hint {
#define STACK_FRAME_NON_STANDARD(func)
#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
--- 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_STACK_VALIDATION
@@ -102,7 +104,7 @@ 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 */
@@ -132,7 +134,7 @@ struct unwind_hint {
#define STACK_FRAME_NON_STANDARD(func)
#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
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -1847,6 +1847,17 @@ static int read_unwind_hints(struct objt
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);
@@ -3025,6 +3036,35 @@ static int validate_branch(struct objtoo
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 */
--- a/tools/objtool/include/objtool/check.h
+++ b/tools/objtool/include/objtool/check.h
@@ -47,6 +47,7 @@ struct instruction {
unsigned long immediate;
bool dead_end, ignore, ignore_alts;
bool hint;
+ bool save, restore;
bool retpoline_safe;
bool entry;
s8 instr;
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