[PATCH] gts and bfs fixes (v3).

[PATCH] gts and bfs fixes (v3).

[Konrad Rzeszutek Wilk]

Since v2 [https://lkml.org/lkml/2012/4/9/474]
 - ditched the assembler version and used a C wrapper

With git commit a2ef5c4fd44ce3922435139393b89f2cce47f576
"ACPI: Move module parameter gts and bfs to sleep.c" the
sampling of gts/bfs module parameters flag by acpi_enter_sleep_state
has been moved. It has been moved out of the inner ACPI code and
out in the more x86 specific. This means that any caller of
the exported acpi_enter_sleep_state function needs to provide
two parameters now: sleep state and the bit flag whether to us _GTS|_BFS.

All of the callers of acpi_enter_sleep_state did that, with
the exception of the assembler version and as well any
third-party callers of acpi_enter_sleep_state.

These two patches expose 'wake_sleep_flags' as the product
of the gts/bfs module parameter invocation. And also use said
flag in the assembler 'do_suspend_lowlevel()' function.

Konrad Rzeszutek Wilk (2):
      ACPI: Convert wake_sleep_flags to a value instead of function (v4)
      x86/acpi: Call acpi_enter_sleep_state via an asmlinkage C function from assembler.

 arch/x86/kernel/acpi/sleep.c     |    4 +++
 arch/x86/kernel/acpi/sleep.h     |    4 +++
 arch/x86/kernel/acpi/wakeup_32.S |    3 +-
 arch/x86/kernel/acpi/wakeup_64.S |    3 +-
 drivers/acpi/sleep.c             |   52 ++++++++++++++++++++-----------------
 5 files changed, 38 insertions(+), 28 deletions(-)

[PATCH 1/2] ACPI: Convert wake_sleep_flags to a value instead of function (v4)

[Konrad Rzeszutek Wilk]

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,
which means that if there are functions outside the sleep.c code
they can't get get the wake_sleep_flags values.

This converts the function in to a exported value and converts
the module config operands to a function.

Acked-by: Lin Ming <ming.m.lin@intel.com>
[v2: Parameters can be turned on/off dynamically]
[v3: unsigned char -> u8]
[v4: val -> kp->arg]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 arch/x86/kernel/acpi/sleep.h |    2 +
 drivers/acpi/sleep.c         |   52 ++++++++++++++++++++++-------------------
 2 files changed, 30 insertions(+), 24 deletions(-)

diff --git a/arch/x86/kernel/acpi/sleep.h b/arch/x86/kernel/acpi/sleep.h
index 416d4be..fe5fdda 100644
--- a/arch/x86/kernel/acpi/sleep.h
+++ b/arch/x86/kernel/acpi/sleep.h
@@ -9,6 +9,8 @@ extern long saved_magic;
 
 extern int wakeup_pmode_return;
 
+extern u8 wake_sleep_flags;
+
 extern unsigned long acpi_copy_wakeup_routine(unsigned long);
 extern void wakeup_long64(void);
 
diff --git a/drivers/acpi/sleep.c b/drivers/acpi/sleep.c
index 1d661b5..eb6fd23 100644
--- a/drivers/acpi/sleep.c
+++ b/drivers/acpi/sleep.c
@@ -28,23 +28,33 @@
 #include "internal.h"
 #include "sleep.h"
 
+u8 wake_sleep_flags = ACPI_NO_OPTIONAL_METHODS;
 static unsigned int gts, bfs;
-module_param(gts, uint, 0644);
-module_param(bfs, uint, 0644);
-MODULE_PARM_DESC(gts, "Enable evaluation of _GTS on suspend.");
-MODULE_PARM_DESC(bfs, "Enable evaluation of _BFS on resume".);
-
-static u8 wake_sleep_flags(void)
+static int set_param_wake_flag(const char *val, struct kernel_param *kp)
 {
-	u8 flags = ACPI_NO_OPTIONAL_METHODS;
+	int ret = param_set_int(val, kp);
 
-	if (gts)
-		flags |= ACPI_EXECUTE_GTS;
-	if (bfs)
-		flags |= ACPI_EXECUTE_BFS;
+	if (ret)
+		return ret;
 
-	return flags;
+	if (kp->arg == (const char *)&gts) {
+		if (gts)
+			wake_sleep_flags |= ACPI_EXECUTE_GTS;
+		else
+			wake_sleep_flags &= ~ACPI_EXECUTE_GTS;
+	}
+	if (kp->arg == (const char *)&bfs) {
+		if (bfs)
+			wake_sleep_flags |= ACPI_EXECUTE_BFS;
+		else
+			wake_sleep_flags &= ~ACPI_EXECUTE_BFS;
+	}
+	return ret;
 }
+module_param_call(gts, set_param_wake_flag, param_get_int, &gts, 0644);
+module_param_call(bfs, set_param_wake_flag, param_get_int, &bfs, 0644);
+MODULE_PARM_DESC(gts, "Enable evaluation of _GTS on suspend.");
+MODULE_PARM_DESC(bfs, "Enable evaluation of _BFS on resume".);
 
 static u8 sleep_states[ACPI_S_STATE_COUNT];
 
@@ -263,7 +273,6 @@ static int acpi_suspend_enter(suspend_state_t pm_state)
 {
 	acpi_status status = AE_OK;
 	u32 acpi_state = acpi_target_sleep_state;
-	u8 flags = wake_sleep_flags();
 	int error;
 
 	ACPI_FLUSH_CPU_CACHE();
@@ -271,7 +280,7 @@ static int acpi_suspend_enter(suspend_state_t pm_state)
 	switch (acpi_state) {
 	case ACPI_STATE_S1:
 		barrier();
-		status = acpi_enter_sleep_state(acpi_state, flags);
+		status = acpi_enter_sleep_state(acpi_state, wake_sleep_flags);
 		break;
 
 	case ACPI_STATE_S3:
@@ -286,7 +295,7 @@ static int acpi_suspend_enter(suspend_state_t pm_state)
 	acpi_write_bit_register(ACPI_BITREG_SCI_ENABLE, 1);
 
 	/* Reprogram control registers and execute _BFS */
-	acpi_leave_sleep_state_prep(acpi_state, flags);
+	acpi_leave_sleep_state_prep(acpi_state, wake_sleep_flags);
 
 	/* ACPI 3.0 specs (P62) says that it's the responsibility
 	 * of the OSPM to clear the status bit [ implying that the
@@ -550,30 +559,27 @@ static int acpi_hibernation_begin(void)
 
 static int acpi_hibernation_enter(void)
 {
-	u8 flags = wake_sleep_flags();
 	acpi_status status = AE_OK;
 
 	ACPI_FLUSH_CPU_CACHE();
 
 	/* This shouldn't return.  If it returns, we have a problem */
-	status = acpi_enter_sleep_state(ACPI_STATE_S4, flags);
+	status = acpi_enter_sleep_state(ACPI_STATE_S4, wake_sleep_flags);
 	/* Reprogram control registers and execute _BFS */
-	acpi_leave_sleep_state_prep(ACPI_STATE_S4, flags);
+	acpi_leave_sleep_state_prep(ACPI_STATE_S4, wake_sleep_flags);
 
 	return ACPI_SUCCESS(status) ? 0 : -EFAULT;
 }
 
 static void acpi_hibernation_leave(void)
 {
-	u8 flags = wake_sleep_flags();
-
 	/*
 	 * If ACPI is not enabled by the BIOS and the boot kernel, we need to
 	 * enable it here.
 	 */
 	acpi_enable();
 	/* Reprogram control registers and execute _BFS */
-	acpi_leave_sleep_state_prep(ACPI_STATE_S4, flags);
+	acpi_leave_sleep_state_prep(ACPI_STATE_S4, wake_sleep_flags);
 	/* Check the hardware signature */
 	if (facs && s4_hardware_signature != facs->hardware_signature) {
 		printk(KERN_EMERG "ACPI: Hardware changed while hibernated, "
@@ -828,12 +834,10 @@ static void acpi_power_off_prepare(void)
 
 static void acpi_power_off(void)
 {
-	u8 flags = wake_sleep_flags();
-
 	/* acpi_sleep_prepare(ACPI_STATE_S5) should have already been called */
 	printk(KERN_DEBUG "%s called\n", __func__);
 	local_irq_disable();
-	acpi_enter_sleep_state(ACPI_STATE_S5, flags);
+	acpi_enter_sleep_state(ACPI_STATE_S5, wake_sleep_flags);
 }
 
 /*
-- 
1.7.7.5

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

[Konrad Rzeszutek Wilk]

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>
  leave
  ret

And 64-bit:

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

Suggested-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 arch/x86/kernel/acpi/sleep.c     |    4 ++++
 arch/x86/kernel/acpi/sleep.h     |    2 ++
 arch/x86/kernel/acpi/wakeup_32.S |    3 +--
 arch/x86/kernel/acpi/wakeup_64.S |    3 +--
 4 files changed, 8 insertions(+), 4 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];
 #endif
 
+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..d3a18a4 100644
--- a/arch/x86/kernel/acpi/wakeup_32.S
+++ b/arch/x86/kernel/acpi/wakeup_32.S
@@ -74,8 +74,7 @@ restore_registers:
 ENTRY(do_suspend_lowlevel)
 	call	save_processor_state
 	call	save_registers
-	pushl	$3
-	call	acpi_enter_sleep_state
+	call	acpi_enter_s3
 	addl	$4, %esp
 
 #	In case of S3 failure, we'll emerge here.  Jump
diff --git a/arch/x86/kernel/acpi/wakeup_64.S b/arch/x86/kernel/acpi/wakeup_64.S
index 8ea5164..fea733d 100644
--- a/arch/x86/kernel/acpi/wakeup_64.S
+++ b/arch/x86/kernel/acpi/wakeup_64.S
@@ -71,9 +71,8 @@ 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
 
-- 
1.7.7.5

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

[H. Peter Anvin]

On 04/17/2012 11:29 AM, Konrad Rzeszutek Wilk wrote:
> diff --git a/arch/x86/kernel/acpi/wakeup_32.S b/arch/x86/kernel/acpi/wakeup_32.S
> index 13ab720..d3a18a4 100644
> --- a/arch/x86/kernel/acpi/wakeup_32.S
> +++ b/arch/x86/kernel/acpi/wakeup_32.S
> @@ -74,8 +74,7 @@ restore_registers:
>  ENTRY(do_suspend_lowlevel)
>  	call	save_processor_state
>  	call	save_registers
> -	pushl	$3
> -	call	acpi_enter_sleep_state
> +	call	acpi_enter_s3
>  	addl	$4, %esp
>  

You need to drop the %esp adjustment here.

>  #	In case of S3 failure, we'll emerge here.  Jump
> diff --git a/arch/x86/kernel/acpi/wakeup_64.S b/arch/x86/kernel/acpi/wakeup_64.S
> index 8ea5164..fea733d 100644
> --- a/arch/x86/kernel/acpi/wakeup_64.S
> +++ b/arch/x86/kernel/acpi/wakeup_64.S
> @@ -71,9 +71,8 @@ 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 */

You can presumably remove the xorl here ... setting %eax to zero
immediately before calling a non-varadic C function is meaningless.

	-hpa

Re: [PATCH] gts and bfs fixes (v3).

[Len Brown]

Ugh.

I think instead we should go the other way
and simply delete the code
for _GTS and _BFS support.

The evidence is that while it is documented in the ACPI spec,
no OS implements it -- for when we tried it, we found some
systems that shipped AML that doesn't work.

-Len

ps. yes, we should also petition the ACPI authors
to remove _GTS and _BFS from an upcoming revision.

Re: [PATCH] gts and bfs fixes (v3).

[Rafael J. Wysocki]

On Tuesday, May 08, 2012, Len Brown wrote:
> Ugh.
> 
> I think instead we should go the other way
> and simply delete the code
> for _GTS and _BFS support.
> 
> The evidence is that while it is documented in the ACPI spec,
> no OS implements it -- for when we tried it, we found some
> systems that shipped AML that doesn't work.

Well, we can still remove it ...
 
> ps. yes, we should also petition the ACPI authors
> to remove _GTS and _BFS from an upcoming revision.

Oh, yes, I totally agree. :-)

Thanks,
Rafael

RE: [PATCH] gts and bfs fixes (v3).

[Moore, Robert]

I opened a problem report against the spec about a month ago on this subject -- to remove _GTS and _BFS from the ACPI spec.

bob

> -----Original Message-----
> From: linux-acpi-owner@vger.kernel.org [mailto:linux-acpi-
> owner@vger.kernel.org] On Behalf Of Rafael J. Wysocki
> Sent: Tuesday, May 08, 2012 2:39 PM
> To: Len Brown
> Cc: Konrad Rzeszutek Wilk; linux-kernel@vger.kernel.org; linux-
> acpi@vger.kernel.org; Lin, Ming M; hpa@zytor.com; x86@kernel.org
> Subject: Re: [PATCH] gts and bfs fixes (v3).
> 
> On Tuesday, May 08, 2012, Len Brown wrote:
> > Ugh.
> >
> > I think instead we should go the other way and simply delete the code
> > for _GTS and _BFS support.
> >
> > The evidence is that while it is documented in the ACPI spec, no OS
> > implements it -- for when we tried it, we found some systems that
> > shipped AML that doesn't work.
> 
> Well, we can still remove it ...
> 
> > ps. yes, we should also petition the ACPI authors to remove _GTS and
> > _BFS from an upcoming revision.
> 
> Oh, yes, I totally agree. :-)
> 
> Thanks,
> Rafael
> --
> To unsubscribe from this list: send the line "unsubscribe linux-acpi"
> in the body of a message to majordomo@vger.kernel.org More majordomo
> info at  http://vger.kernel.org/majordomo-info.html

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

[Len Brown]

On 04/18/2012 05:02 PM, Rafael J. Wysocki wrote:

> On Wednesday, April 18, 2012, H. Peter Anvin wrote:
>> On 04/18/2012 10:18 AM, Konrad Rzeszutek Wilk wrote:
>>>
>>> Suggested-by: H. Peter Anvin <hpa@zytor.com>
>>> [v2: Remove extra assembler operations, per hpa review]
>>> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
>>
>> Reviewed-by: H. Peter Anvin <hpa@zytor.com>
>>
>> Len, your tree or mine?


I think it was a mistake to apply this.
Instead we should have removed the code that it fixed.

-Len

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

[Rafael J. Wysocki]

On Wednesday, April 18, 2012, H. Peter Anvin wrote:
> On 04/18/2012 10:18 AM, Konrad Rzeszutek Wilk wrote:
> > 
> > Suggested-by: H. Peter Anvin <hpa@zytor.com>
> > [v2: Remove extra assembler operations, per hpa review]
> > Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> 
> Reviewed-by: H. Peter Anvin <hpa@zytor.com>
> 
> Len, your tree or mine?

Well, I think you can take both, if that's not a problem. :-)

Rafael

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

[H. Peter Anvin]

On 04/18/2012 10:18 AM, Konrad Rzeszutek Wilk wrote:
> 
> Suggested-by: H. Peter Anvin <hpa@zytor.com>
> [v2: Remove extra assembler operations, per hpa review]
> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Reviewed-by: H. Peter Anvin <hpa@zytor.com>

Len, your tree or mine?

	-hpa

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

[Rafael J. Wysocki]

On Wednesday, April 18, 2012, Konrad Rzeszutek Wilk wrote:
> 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>
>   leave
>   ret
> 
> And 64-bit:
> 
>   movzbl 0x9afde1(%rip),%esi        [wake_sleep_flags]
>   push   %rbp
>   mov    $0x3,%edi
>   mov    %rsp,%rbp
>   callq  0xffffffff812e9800 <acpi_enter_sleep_state>
>   leaveq
>   retq
> 
> Suggested-by: H. Peter Anvin <hpa@zytor.com>
> [v2: Remove extra assembler operations, per hpa review]
> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Acked-by: Rafael J. Wysocki <rjw@sisk.pl>

> ---
>  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];
>  #endif
>  
> +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:
>  ENTRY(do_suspend_lowlevel)
>  	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
>  
> 

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

[Konrad Rzeszutek Wilk]

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>
  leave
  ret

And 64-bit:

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

Suggested-by: H. Peter Anvin <hpa@zytor.com>
[v2: Remove extra assembler operations, per hpa review]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 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];
 #endif
 
+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:
 ENTRY(do_suspend_lowlevel)
 	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
 
-- 
1.7.7.5