Commit 8faea26e authored by Josh Poimboeuf's avatar Josh Poimboeuf Committed by Borislav Petkov
Browse files

objtool: Re-add UNWIND_HINT_{SAVE_RESTORE} 



Commit

  c536ed2f ("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: default avatarJosh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
parent acac5e98

arch/x86/include/asm/unwind_hints.h

+10 −2
Original line number Diff line number Diff line
@@ -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



#else



#define UNWIND_HINT_FUNC \

include/linux/objtool.h

+4 −2
Original line number Diff line number Diff line
@@ -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

tools/include/linux/objtool.h

+4 −2
Original line number Diff line number Diff line
@@ -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

tools/objtool/check.c

+40 −0
Original line number Diff line number Diff line
@@ -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 */

tools/objtool/include/objtool/check.h

+10 −9
Original line number Diff line number Diff line
@@ -46,18 +46,19 @@ struct instruction { 
	enum insn_type type;

	unsigned long immediate;



	u8 dead_end	: 1,

	u16 dead_end		: 1,

	   ignore		: 1,

	   ignore_alts		: 1,

	   hint			: 1,

	   save			: 1,

	   restore		: 1,

	   retpoline_safe	: 1,

	   noendbr		: 1,

	   entry		: 1;

		/* 1 bit hole */

		/* 7 bit hole */



	s8 instr;

	u8 visited;

	/* u8 hole */



	struct alt_group *alt_group;

	struct symbol *call_dest;