[PATCH v5 07/10] x86/asm/acpi: Fix asmvalidate warnings for wakeup_64.S

Josh Poimboeuf
2015-06-10T12:09:15Z

Fix the following asmvalidate warnings:

asmvalidate: arch/x86/kernel/acpi/wakeup_64.o: wakeup_long64()+0x15: unsupported jump to outside of function
asmvalidate: arch/x86/kernel/acpi/wakeup_64.o: wakeup_long64()+0x55: unsupported jump to outside of function
asmvalidate: arch/x86/kernel/acpi/wakeup_64.o: wakeup_long64(): unsupported fallthrough at end of function
asmvalidate: arch/x86/kernel/acpi/wakeup_64.o: do_suspend_lowlevel()+0x9a: unsupported jump to outside of function
asmvalidate: arch/x86/kernel/acpi/wakeup_64.o: do_suspend_lowlevel()+0x116: unsupported jump to outside of function
asmvalidate: arch/x86/kernel/acpi/wakeup_64.o: do_suspend_lowlevel(): unsupported fallthrough at end of function
asmvalidate: arch/x86/kernel/acpi/wakeup_64.o: do_suspend_lowlevel(): missing FP_SAVE/RESTORE macros

1. wakeup_long64() isn't a function that can be called. It's actually
redirected to via a return instruction in the entry code. It
shouldn't be annotated as a callable function. Change ENDPROC ->
PROC accordingly.

2. do_suspend_lowlevel() is a non-leaf callable function, so
save/restore the frame pointer with FP_SAVE/RESTORE.

3. Remove the unnecessary jump to .Lresume_point, as it just results in
jumping to the next instruction (which is a nop because of the
align). Otherwise asmvalidate gets confused by the jump.

4. Change the "jmp restore_processor_state" to a call instruction,
because jumping outside the function's boundaries isn't allowed. Now
restore_processor_state() will return back to do_suspend_lowlevel()
instead of do_suspend_lowlevel()'s caller.

5. Remove superfluous rsp changes.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Len Brown <len.brown@intel.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: linux-pm@vger.kernel.org
---
arch/x86/kernel/acpi/wakeup_64.S | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kernel/acpi/wakeup_64.S b/arch/x86/kernel/acpi/wakeup_64.S
index 8c35df4..7e442be 100644
--- a/arch/x86/kernel/acpi/wakeup_64.S
+++ b/arch/x86/kernel/acpi/wakeup_64.S
@@ -5,6 +5,7 @@
#include <asm/page_types.h>
#include <asm/msr.h>
#include <asm/asm-offsets.h>
+#include <asm/func.h>

# Copyright 2003 Pavel Machek <pavel@suse.cz>, distribute under GPLv2

@@ -33,13 +34,13 @@ ENTRY(wakeup_long64)

movq saved_rip, %rax
jmp *%rax
-ENDPROC(wakeup_long64)
+END(wakeup_long64)

bogus_64_magic:
jmp bogus_64_magic

ENTRY(do_suspend_lowlevel)
- subq $8, %rsp
+ FP_SAVE
xorl %eax, %eax
call save_processor_state

@@ -70,12 +71,11 @@ ENTRY(do_suspend_lowlevel)
movq %rdi, saved_rdi
movq %rsi, saved_rsi

- addq $8, %rsp
movl $3, %edi
xorl %eax, %eax
call x86_acpi_enter_sleep_state
+
/* in case something went wrong, restore the machine status and go on */
- jmp .Lresume_point

.align 4
.Lresume_point:
@@ -108,8 +108,9 @@ ENTRY(do_suspend_lowlevel)
movq pt_regs_r15(%rax), %r15

xorl %eax, %eax
- addq $8, %rsp
- jmp restore_processor_state
+ call restore_processor_state
+ FP_RESTORE
+ ret
ENDPROC(do_suspend_lowlevel)

.data
--
2.1.0