[PATCH 2/2] x86/acpi: Call acpi_enter_sleep_state via an asmlinkage C function from assembler.

From: Konrad Rzeszutek Wilk
Date: Wed Apr 18 2012 - 13:23:50 EST

With commit a2ef5c4fd44ce3922435139393b89f2cce47f576
"ACPI: Move module parameter gts and bfs to sleep.c" the
wake_sleep_flags is required when calling acpi_enter_sleep_state.

The assembler code in wakeup_*.S did not do that. One solution
is to call it from assembler and stick the wake_sleep_flags on
the stack (for 32-bit) or in %esi (for 64-bit). hpa and rafael
both suggested however to create a wrapper function to call
acpi_enter_sleep_state and call said wrapper function
("acpi_enter_s3") from assembler.

For 32-bit, the acpi_enter_s3 ends up looking as so:

push %ebp
mov %esp,%ebp
sub $0x8,%esp
movzbl 0xc1809314,%eax [wake_sleep_flags]
movl $0x3,(%esp)
mov %eax,0x4(%esp)
call 0xc12d1fa0 <acpi_enter_sleep_state>

And 64-bit:

movzbl 0x9afde1(%rip),%esi [wake_sleep_flags]
push %rbp
mov $0x3,%edi
mov %rsp,%rbp
callq 0xffffffff812e9800 <acpi_enter_sleep_state>

Suggested-by: H. Peter Anvin <hpa@xxxxxxxxx>
[v2: Remove extra assembler operations, per hpa review]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
arch/x86/kernel/acpi/sleep.c | 4 ++++
arch/x86/kernel/acpi/sleep.h | 2 ++
arch/x86/kernel/acpi/wakeup_32.S | 4 +---
arch/x86/kernel/acpi/wakeup_64.S | 4 +---
4 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kernel/acpi/sleep.c b/arch/x86/kernel/acpi/sleep.c
index 103b6ab..146a49c 100644
--- a/arch/x86/kernel/acpi/sleep.c
+++ b/arch/x86/kernel/acpi/sleep.c
@@ -24,6 +24,10 @@ unsigned long acpi_realmode_flags;
static char temp_stack[4096];

+asmlinkage void acpi_enter_s3(void)
+ acpi_enter_sleep_state(3, wake_sleep_flags);
* acpi_suspend_lowlevel - save kernel state
diff --git a/arch/x86/kernel/acpi/sleep.h b/arch/x86/kernel/acpi/sleep.h
index fe5fdda..d68677a 100644
--- a/arch/x86/kernel/acpi/sleep.h
+++ b/arch/x86/kernel/acpi/sleep.h
@@ -3,6 +3,7 @@

#include <asm/trampoline.h>
+#include <linux/linkage.h>

extern unsigned long saved_video_mode;
extern long saved_magic;
@@ -10,6 +11,7 @@ extern long saved_magic;
extern int wakeup_pmode_return;

extern u8 wake_sleep_flags;
+extern asmlinkage void acpi_enter_s3(void);

extern unsigned long acpi_copy_wakeup_routine(unsigned long);
extern void wakeup_long64(void);
diff --git a/arch/x86/kernel/acpi/wakeup_32.S b/arch/x86/kernel/acpi/wakeup_32.S
index 13ab720..7261083 100644
--- a/arch/x86/kernel/acpi/wakeup_32.S
+++ b/arch/x86/kernel/acpi/wakeup_32.S
@@ -74,9 +74,7 @@ restore_registers:
call save_processor_state
call save_registers
- pushl $3
- call acpi_enter_sleep_state
- addl $4, %esp
+ call acpi_enter_s3

# In case of S3 failure, we'll emerge here. Jump
# to ret_point to recover
diff --git a/arch/x86/kernel/acpi/wakeup_64.S b/arch/x86/kernel/acpi/wakeup_64.S
index 8ea5164..014d1d2 100644
--- a/arch/x86/kernel/acpi/wakeup_64.S
+++ b/arch/x86/kernel/acpi/wakeup_64.S
@@ -71,9 +71,7 @@ ENTRY(do_suspend_lowlevel)
movq %rsi, saved_rsi

addq $8, %rsp
- movl $3, %edi
- xorl %eax, %eax
- call acpi_enter_sleep_state
+ call acpi_enter_s3
/* in case something went wrong, restore the machine status and go on */
jmp resume_point


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