[PATCH v2 20/20] x86/power: Support objtool validation in hibernate_asm_64.S

From: Josh Poimboeuf
Date: Thu Jan 21 2021 - 16:40:05 EST


The OBJECT_FILES_NON_STANDARD annotation is used to tell objtool to
ignore a file. File-level ignores won't work when validating vmlinux.o.

Instead, convert restore_image() and core_restore_code() to be ELF
functions. Their code is conventional enough for objtool to be able to
understand them.

Cc: "Rafael J. Wysocki" <rjw@xxxxxxxxxxxxx>
Cc: Pavel Machek <pavel@xxxxxx>
Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
---
arch/x86/power/Makefile | 1 -
arch/x86/power/hibernate_asm_64.S | 8 ++++----
2 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/arch/x86/power/Makefile b/arch/x86/power/Makefile
index 6907b523e856..3ff80156f21a 100644
--- a/arch/x86/power/Makefile
+++ b/arch/x86/power/Makefile
@@ -1,5 +1,4 @@
# SPDX-License-Identifier: GPL-2.0
-OBJECT_FILES_NON_STANDARD_hibernate_asm_$(BITS).o := y

# __restore_processor_state() restores %gs after S3 resume and so should not
# itself be stack-protected
diff --git a/arch/x86/power/hibernate_asm_64.S b/arch/x86/power/hibernate_asm_64.S
index 91c4602d2b5d..d9bed596d849 100644
--- a/arch/x86/power/hibernate_asm_64.S
+++ b/arch/x86/power/hibernate_asm_64.S
@@ -99,7 +99,7 @@ SYM_FUNC_START(swsusp_arch_suspend)
ret
SYM_FUNC_END(swsusp_arch_suspend)

-SYM_CODE_START(restore_image)
+SYM_FUNC_START(restore_image)
/* prepare to jump to the image kernel */
movq restore_jump_address(%rip), %r8
movq restore_cr3(%rip), %r9
@@ -115,10 +115,10 @@ SYM_CODE_START(restore_image)
movq relocated_restore_code(%rip), %rcx
ANNOTATE_RETPOLINE_SAFE
jmpq *%rcx
-SYM_CODE_END(restore_image)
+SYM_FUNC_END(restore_image)

/* code below has been relocated to a safe page */
-SYM_CODE_START(core_restore_code)
+SYM_FUNC_START(core_restore_code)
/* switch to temporary page tables */
movq %rax, %cr3
/* flush TLB */
@@ -147,4 +147,4 @@ SYM_CODE_START(core_restore_code)
/* jump to the restore_registers address from the image header */
ANNOTATE_RETPOLINE_SAFE
jmpq *%r8
-SYM_CODE_END(core_restore_code)
+SYM_FUNC_END(core_restore_code)
--
2.29.2