[PATCH v6 22/25] x86/asm: annotate indirect jumps

Sami Tolvanen
2020-10-13T02:42:12Z

Running objtool --vmlinux --duplicate on vmlinux.o produces a few
warnings about indirect jumps with retpoline:

vmlinux.o: warning: objtool: wakeup_long64()+0x61: indirect jump
found in RETPOLINE build
...

This change adds ANNOTATE_RETPOLINE_SAFE annotations to the jumps
in assembly code to stop the warnings.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
---
arch/x86/kernel/acpi/wakeup_64.S | 2 ++
arch/x86/platform/pvh/head.S | 2 ++
arch/x86/power/hibernate_asm_64.S | 3 +++
3 files changed, 7 insertions(+)

diff --git a/arch/x86/kernel/acpi/wakeup_64.S b/arch/x86/kernel/acpi/wakeup_64.S
index c8daa92f38dc..041e79c4e195 100644
--- a/arch/x86/kernel/acpi/wakeup_64.S
+++ b/arch/x86/kernel/acpi/wakeup_64.S
@@ -7,6 +7,7 @@
#include <asm/msr.h>
#include <asm/asm-offsets.h>
#include <asm/frame.h>
+#include <asm/nospec-branch.h>

# Copyright 2003 Pavel Machek <pavel@suse.cz

@@ -39,6 +40,7 @@ SYM_FUNC_START(wakeup_long64)
movq saved_rbp, %rbp

movq saved_rip, %rax
+ ANNOTATE_RETPOLINE_SAFE
jmp *%rax
SYM_FUNC_END(wakeup_long64)

diff --git a/arch/x86/platform/pvh/head.S b/arch/x86/platform/pvh/head.S
index 43b4d864817e..640b79cc64b8 100644
--- a/arch/x86/platform/pvh/head.S
+++ b/arch/x86/platform/pvh/head.S
@@ -15,6 +15,7 @@
#include <asm/asm.h>
#include <asm/boot.h>
#include <asm/processor-flags.h>
+#include <asm/nospec-branch.h>
#include <asm/msr.h>
#include <xen/interface/elfnote.h>

@@ -105,6 +106,7 @@ SYM_CODE_START_LOCAL(pvh_start_xen)
/* startup_64 expects boot_params in %rsi. */
mov $_pa(pvh_bootparams), %rsi
mov $_pa(startup_64), %rax
+ ANNOTATE_RETPOLINE_SAFE
jmp *%rax

#else /* CONFIG_X86_64 */
diff --git a/arch/x86/power/hibernate_asm_64.S b/arch/x86/power/hibernate_asm_64.S
index 7918b8415f13..715509d94fa3 100644
--- a/arch/x86/power/hibernate_asm_64.S
+++ b/arch/x86/power/hibernate_asm_64.S
@@ -21,6 +21,7 @@
#include <asm/asm-offsets.h>
#include <asm/processor-flags.h>
#include <asm/frame.h>
+#include <asm/nospec-branch.h>

SYM_FUNC_START(swsusp_arch_suspend)
movq $saved_context, %rax
@@ -66,6 +67,7 @@ SYM_CODE_START(restore_image)

/* jump to relocated restore code */
movq relocated_restore_code(%rip), %rcx
+ ANNOTATE_RETPOLINE_SAFE
jmpq *%rcx
SYM_CODE_END(restore_image)

@@ -97,6 +99,7 @@ SYM_CODE_START(core_restore_code)

.Ldone:
/* jump to the restore_registers address from the image header */
+ ANNOTATE_RETPOLINE_SAFE
jmpq *%r8
SYM_CODE_END(core_restore_code)

--
2.28.0.1011.ga647a8990f-goog