Re: [PATCH 2/7] tboot: Add return values for tboot_sleep

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

On Thu, Jan 26, 2012 at 12:16:39AM +0000, Cihula, Joseph wrote:
> > From: Konrad Rzeszutek Wilk [mailto:konrad.wilk@oracle.com]
> > Sent: Thursday, January 12, 2012 12:23 PM
> eturn values for tboot_sleep
> > 
> > On Thu, Jan 12, 2012 at 09:49:58AM -0800, Konrad Rzeszutek Wilk wrote:
> > > On Tue, Jan 10, 2012 at 08:10:53PM +0000, Cihula, Joseph wrote:
> > > > ACK, but tboot_sleep() calls tboot_shutdown() and there are error conditions in that which you
> > are not reflecting upward--i.e. you should make tboot_shutdown() return an 'int' and propagate its
> > errors through tboot_sleep().
> > >
> > > Hey Joe,
> > >
> > > Thanks for looking at the patches.
> > >
> > > Right now [with this patch applied] the code looks as so:
> > >
> > > 297
> > > 298         tboot_shutdown(acpi_shutdown_map[sleep_state]);
> > > 299         return 0;
> > > 300 }
> > >
> > >
> > > If we do make tboot_shutdown() return an int, there will be a need to
> > > modify other callers: native_machine_emergency_restart,
> > > native_machine_halt, native_machine_power_off, and native_play_dead as well.
> > >
> > > Perhaps that could be done in another patch and leave this one as is
> > > where the 'tboot_sleep' would just return 0 instead of 'return
> > > tboot_shutdown(...)' ?
> > >
> > > Perhaps another way to do this is to extract the common code of
> > > tboot_sleep and tboot_shutdown?
> 
> I'd be happier to see the callers above changed to handle a tboot_shutdown() that returned an error than splitting this up and only checking the error in one path.

OK, so something like this then:

>From da60a441fd62aee83763758455c08c281893ae93 Mon Sep 17 00:00:00 2001
From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Date: Thu, 8 Dec 2011 17:14:08 +0800
Subject: [PATCH] tboot: Add return values for tboot_sleep and consequently
 tboot_shutdown

.. as appropiately. As tboot_sleep now returns values.
remove tboot_sleep_wrapper.

Suggested-by: "Rafael J. Wysocki" <rjw@sisk.pl>
Acked-by: Joseph Cihula <joseph.cihula@intel.com>
[v1: Return -1/0/+1 instead of ACPI_xx values]
[v2: Also make tboot_shutdown return error code]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 arch/x86/kernel/reboot.c  |    6 +++---
 arch/x86/kernel/smpboot.c |    2 +-
 arch/x86/kernel/tboot.c   |   33 +++++++++++++++------------------
 include/linux/tboot.h     |    4 ++--
 4 files changed, 21 insertions(+), 24 deletions(-)

diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c
index 37a458b..b29326a 100644
--- a/arch/x86/kernel/reboot.c
+++ b/arch/x86/kernel/reboot.c
@@ -549,7 +549,7 @@ static void native_machine_emergency_restart(void)
 	if (reboot_emergency)
 		emergency_vmx_disable_all();
 
-	tboot_shutdown(TB_SHUTDOWN_REBOOT);
+	WARN_ON(tboot_shutdown(TB_SHUTDOWN_REBOOT));
 
 	/* Tell the BIOS if we want cold or warm reboot */
 	*((unsigned short *)__va(0x472)) = reboot_mode;
@@ -684,7 +684,7 @@ static void native_machine_halt(void)
 	/* stop other cpus and apics */
 	machine_shutdown();
 
-	tboot_shutdown(TB_SHUTDOWN_HALT);
+	WARN_ON(tboot_shutdown(TB_SHUTDOWN_HALT));
 
 	/* stop this cpu */
 	stop_this_cpu(NULL);
@@ -698,7 +698,7 @@ static void native_machine_power_off(void)
 		pm_power_off();
 	}
 	/* a fallback in case there is no PM info available */
-	tboot_shutdown(TB_SHUTDOWN_HALT);
+	WARN_ON(tboot_shutdown(TB_SHUTDOWN_HALT));
 }
 
 struct machine_ops machine_ops = {
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 66d250c..9aa903a 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -1419,7 +1419,7 @@ static inline void hlt_play_dead(void)
 void native_play_dead(void)
 {
 	play_dead_common();
-	tboot_shutdown(TB_SHUTDOWN_WFS);
+	WARN_ON(tboot_shutdown(TB_SHUTDOWN_WFS));
 
 	mwait_play_dead();	/* Only returns on failure */
 	hlt_play_dead();
diff --git a/arch/x86/kernel/tboot.c b/arch/x86/kernel/tboot.c
index 1a4ab7d..9504a7a 100644
--- a/arch/x86/kernel/tboot.c
+++ b/arch/x86/kernel/tboot.c
@@ -217,12 +217,12 @@ static int tboot_setup_sleep(void)
 
 #endif
 
-void tboot_shutdown(u32 shutdown_type)
+int tboot_shutdown(u32 shutdown_type)
 {
 	void (*shutdown)(void);
 
 	if (!tboot_enabled())
-		return;
+		return 0;
 
 	/*
 	 * if we're being called before the 1:1 mapping is set up then just
@@ -230,13 +230,14 @@ void tboot_shutdown(u32 shutdown_type)
 	 * due to very early panic()
 	 */
 	if (!tboot_pg_dir)
-		return;
+		return 0;
 
 	/* if this is S3 then set regions to MAC */
-	if (shutdown_type == TB_SHUTDOWN_S3)
-		if (tboot_setup_sleep())
-			return;
-
+	if (shutdown_type == TB_SHUTDOWN_S3) {
+		int rc = tboot_setup_sleep();
+		if (rc)
+			return rc;
+	}
 	tboot->shutdown_type = shutdown_type;
 
 	switch_to_tboot_pt();
@@ -247,6 +248,8 @@ void tboot_shutdown(u32 shutdown_type)
 	/* should not reach here */
 	while (1)
 		halt();
+
+	return 0;
 }
 
 static void tboot_copy_fadt(const struct acpi_table_fadt *fadt)
@@ -272,7 +275,7 @@ static void tboot_copy_fadt(const struct acpi_table_fadt *fadt)
 		offsetof(struct acpi_table_facs, firmware_waking_vector);
 }
 
-void tboot_sleep(u8 sleep_state, u32 pm1a_control, u32 pm1b_control)
+static int tboot_sleep(u8 sleep_state, u32 pm1a_control, u32 pm1b_control)
 {
 	static u32 acpi_shutdown_map[ACPI_S_STATE_COUNT] = {
 		/* S0,1,2: */ -1, -1, -1,
@@ -281,7 +284,7 @@ void tboot_sleep(u8 sleep_state, u32 pm1a_control, u32 pm1b_control)
 		/* S5: */ TB_SHUTDOWN_S5 };
 
 	if (!tboot_enabled())
-		return;
+		return 0;
 
 	tboot_copy_fadt(&acpi_gbl_FADT);
 	tboot->acpi_sinfo.pm1a_cnt_val = pm1a_control;
@@ -292,16 +295,10 @@ void tboot_sleep(u8 sleep_state, u32 pm1a_control, u32 pm1b_control)
 	if (sleep_state >= ACPI_S_STATE_COUNT ||
 	    acpi_shutdown_map[sleep_state] == -1) {
 		pr_warning("unsupported sleep state 0x%x\n", sleep_state);
-		return;
+		return -1;
 	}
 
-	tboot_shutdown(acpi_shutdown_map[sleep_state]);
-}
-static int tboot_sleep_wrapper(u8 sleep_state, u32 pm1a_control,
-			       u32 pm1b_control)
-{
-	tboot_sleep(sleep_state, pm1a_control, pm1b_control);
-	return 0;
+	return tboot_shutdown(acpi_shutdown_map[sleep_state]);
 }
 
 static atomic_t ap_wfs_count;
@@ -352,7 +349,7 @@ static __init int tboot_late_init(void)
 	atomic_set(&ap_wfs_count, 0);
 	register_hotcpu_notifier(&tboot_cpu_notifier);
 
-	acpi_os_set_prepare_sleep(&tboot_sleep_wrapper);
+	acpi_os_set_prepare_sleep(&tboot_sleep);
 	return 0;
 }
 
diff --git a/include/linux/tboot.h b/include/linux/tboot.h
index c75128b..8f14fe0 100644
--- a/include/linux/tboot.h
+++ b/include/linux/tboot.h
@@ -142,7 +142,7 @@ static inline int tboot_enabled(void)
 }
 
 extern void tboot_probe(void);
-extern void tboot_shutdown(u32 shutdown_type);
+extern int tboot_shutdown(u32 shutdown_type);
 extern struct acpi_table_header *tboot_get_dmar_table(
 				      struct acpi_table_header *dmar_tbl);
 extern int tboot_force_iommu(void);
@@ -151,7 +151,7 @@ extern int tboot_force_iommu(void);
 
 #define tboot_enabled()			0
 #define tboot_probe()			do { } while (0)
-#define tboot_shutdown(shutdown_type)	do { } while (0)
+#define tboot_shutdown(shutdown_type)	0
 #define tboot_sleep(sleep_state, pm1a_control, pm1b_control)	\
 					do { } while (0)
 #define tboot_get_dmar_table(dmar_tbl)	(dmar_tbl)
-- 
1.7.7.5