Patches adding support for hibernation on ARM
- ARM hibernation / suspend-to-disk
- Fix hang in freeze_processes during hibernation
- add an irq disabled version of soft_restart
Patches based on v3.13 tag, verified hibernation on beaglebone black on a branch
based on 3.13 merged with initial omap support from Russ Dill which be found here:
http://git.linaro.org/git-ro/people/sebastian.capella/linux.git hibernation_3.13_russMerge
(includes v1 patchset)
[PATCH v2 1/3] ARM: Add irq disabled version of soft_restart.
arch/arm/include/asm/system_misc.h | 1 +
arch/arm/kernel/process.c | 15 ++++++++++-----
2 files changed, 11 insertions(+), 5 deletions(-)
Adds the ability to run soft restart with local_irq/fiq_disable
Useful in hibernation code paths (unchanged from v1)
[PATCH v2 2/3] Fix hibernation restore hang in freeze_processes
drivers/base/firmware_class.c | 1 +
1 file changed, 1 insertion(+)
Add handling for PM_RESTORE_PREPARE notifier (unchanged from v1)
[PATCH v2 3/3] ARM hibernation / suspend-to-disk
arch/arm/include/asm/memory.h | 1 +
arch/arm/kernel/Makefile | 1 +
arch/arm/kernel/hibernate.c | 104 +++++++++++++++++++++++++++++++++++++++++
arch/arm/mm/Kconfig | 5 ++
include/linux/suspend.h | 2 +
5 files changed, 113 insertions(+)
Adds support for ARM based hibernation
Additional notes:
-----------------
There are two checkpatch warnings added by this patch. These follow
behavior in existing hibernation implementations on other platforms.
WARNING: externs should be avoided in .c files
#116: FILE: arch/arm/kernel/hibernate.c:26:
+extern const void __nosave_begin, __nosave_end;
This extern is picking up the linker nosave region definitions, only
used in hibernate. Follows same extern line used mips, powerpc, s390,
sh, sparc, x86 & unicore32
WARNING: externs should be avoided in .c files
#191: FILE: arch/arm/kernel/hibernate.c:101:
+extern void call_with_stack(void (*fn)(void *), void *arg, void *sp);
This extern is used in the arch/arm/ in hibernate, process and bL_switcher
Changes in v2:
--------------
* Removed unneeded flush_thread, use of __naked and cpu_init.
* dropped Cyril Chemparathy <[email protected]> from Cc: list as
emails are bouncing.
From: Russ Dill <[email protected]>
Enable hibernation for ARM architectures and provide ARM
architecture specific calls used during hibernation.
The swsusp hibernation framework depends on the
platform first having functional suspend/resume.
Then, in order to enable hibernation on a given platform, a
platform_hibernation_ops structure may need to be registered with
the system in order to save/restore any SoC-specific / cpu specific
state needing (re)init over a suspend-to-disk/resume-from-disk cycle.
For example:
- "secure" SoCs that have different sets of control registers
and/or different CR reg access patterns.
- SoCs with L2 caches as the activation sequence there is
SoC-dependent; a full off-on cycle for L2 is not done
by the hibernation support code.
- SoCs requiring steps on wakeup _before_ the "generic" parts
done by cpu_suspend / cpu_resume can work correctly.
- SoCs having persistent state which is maintained during suspend
and resume, but will be lost during the power off cycle after
suspend-to-disk.
This is a rebase/rework of Frank Hofmann's v5 hibernation patchset.
Cc: Russ Dill <[email protected]>
Cc: "Rafael J. Wysocki" <[email protected]>
Signed-off-by: Sebastian Capella <[email protected]>
Cc: Russell King <[email protected]>
Cc: Len Brown <[email protected]>
Cc: Pavel Machek <[email protected]>
Cc: Nicolas Pitre <[email protected]>
Cc: Santosh Shilimkar <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Jonathan Austin <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: "Uwe Kleine-König" <[email protected]>
Cc: Stephen Boyd <[email protected]>
---
arch/arm/include/asm/memory.h | 1 +
arch/arm/kernel/Makefile | 1 +
arch/arm/kernel/hibernate.c | 104 +++++++++++++++++++++++++++++++++++++++++
arch/arm/mm/Kconfig | 5 ++
include/linux/suspend.h | 2 +
5 files changed, 113 insertions(+)
create mode 100644 arch/arm/kernel/hibernate.c
diff --git a/arch/arm/include/asm/memory.h b/arch/arm/include/asm/memory.h
index 8756e4b..1079ea8 100644
--- a/arch/arm/include/asm/memory.h
+++ b/arch/arm/include/asm/memory.h
@@ -291,6 +291,7 @@ static inline void *phys_to_virt(phys_addr_t x)
*/
#define __pa(x) __virt_to_phys((unsigned long)(x))
#define __va(x) ((void *)__phys_to_virt((phys_addr_t)(x)))
+#define __pa_symbol(x) __pa(RELOC_HIDE((unsigned long)(x), 0))
#define pfn_to_kaddr(pfn) __va((pfn) << PAGE_SHIFT)
extern phys_addr_t (*arch_virt_to_idmap)(unsigned long x);
diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile
index a30fc9b..8afa848 100644
--- a/arch/arm/kernel/Makefile
+++ b/arch/arm/kernel/Makefile
@@ -39,6 +39,7 @@ obj-$(CONFIG_ARTHUR) += arthur.o
obj-$(CONFIG_ISA_DMA) += dma-isa.o
obj-$(CONFIG_PCI) += bios32.o isa.o
obj-$(CONFIG_ARM_CPU_SUSPEND) += sleep.o suspend.o
+obj-$(CONFIG_HIBERNATION) += hibernate.o
obj-$(CONFIG_SMP) += smp.o
ifdef CONFIG_MMU
obj-$(CONFIG_SMP) += smp_tlb.o
diff --git a/arch/arm/kernel/hibernate.c b/arch/arm/kernel/hibernate.c
new file mode 100644
index 0000000..74bfa8b
--- /dev/null
+++ b/arch/arm/kernel/hibernate.c
@@ -0,0 +1,104 @@
+/*
+ * Hibernation support specific for ARM
+ *
+ * Derived from work on ARM hibernation support by:
+ *
+ * Ubuntu project, hibernation support for mach-dove
+ * Copyright (C) 2010 Nokia Corporation (Hiroshi Doyu)
+ * Copyright (C) 2010 Texas Instruments, Inc. (Teerth Reddy et al.)
+ * https://lkml.org/lkml/2010/6/18/4
+ * https://lists.linux-foundation.org/pipermail/linux-pm/2010-June/027422.html
+ * https://patchwork.kernel.org/patch/96442/
+ *
+ * Copyright (C) 2006 Rafael J. Wysocki <[email protected]>
+ *
+ * License terms: GNU General Public License (GPL) version 2
+ */
+
+#include <linux/mm.h>
+#include <linux/suspend.h>
+#include <asm/tlbflush.h>
+#include <asm/cacheflush.h>
+#include <asm/system_misc.h>
+#include <asm/idmap.h>
+#include <asm/suspend.h>
+
+extern const void __nosave_begin, __nosave_end;
+
+int pfn_is_nosave(unsigned long pfn)
+{
+ unsigned long nosave_begin_pfn =
+ __pa_symbol(&__nosave_begin) >> PAGE_SHIFT;
+ unsigned long nosave_end_pfn =
+ PAGE_ALIGN(__pa_symbol(&__nosave_end)) >> PAGE_SHIFT;
+
+ return (pfn >= nosave_begin_pfn) && (pfn < nosave_end_pfn);
+}
+
+void notrace save_processor_state(void)
+{
+ WARN_ON(num_online_cpus() != 1);
+ local_fiq_disable();
+}
+
+void notrace restore_processor_state(void)
+{
+ local_fiq_enable();
+}
+
+/*
+ * Snapshot kernel memory and reset the system.
+ * After resume, the hibernation snapshot is written out.
+ */
+static int notrace __swsusp_arch_save_image(unsigned long unused)
+{
+ int ret;
+
+ ret = swsusp_save();
+ if (ret == 0)
+ soft_restart(virt_to_phys(cpu_resume));
+ return ret;
+}
+
+/*
+ * Save the current CPU state before suspend / poweroff.
+ */
+int notrace swsusp_arch_suspend(void)
+{
+ return cpu_suspend(0, __swsusp_arch_save_image);
+}
+
+/*
+ * The framework loads the hibernation image into a linked list anchored
+ * at restore_pblist, for swsusp_arch_resume() to copy back to the proper
+ * destinations.
+ *
+ * To make this work if resume is triggered from initramfs, the
+ * pagetables need to be switched to allow writes to kernel mem.
+ */
+static void notrace __swsusp_arch_restore_image(void *unused)
+{
+ struct pbe *pbe;
+
+ cpu_switch_mm(idmap_pgd, &init_mm);
+ for (pbe = restore_pblist; pbe; pbe = pbe->next)
+ copy_page(pbe->orig_address, pbe->address);
+
+ soft_restart_noirq(virt_to_phys(cpu_resume));
+}
+
+static u8 __swsusp_resume_stk[PAGE_SIZE/2] __nosavedata;
+
+/*
+ * Resume from the hibernation image.
+ * Due to the kernel heap / data restore, stack contents change underneath
+ * and that would make function calls impossible; switch to a temporary
+ * stack within the nosave region to avoid that problem.
+ */
+int swsusp_arch_resume(void)
+{
+ extern void call_with_stack(void (*fn)(void *), void *arg, void *sp);
+ call_with_stack(__swsusp_arch_restore_image, 0,
+ __swsusp_resume_stk + sizeof(__swsusp_resume_stk));
+ return 0;
+}
diff --git a/arch/arm/mm/Kconfig b/arch/arm/mm/Kconfig
index 1f8fed9..83707702 100644
--- a/arch/arm/mm/Kconfig
+++ b/arch/arm/mm/Kconfig
@@ -611,6 +611,11 @@ config CPU_USE_DOMAINS
config IO_36
bool
+config ARCH_HIBERNATION_POSSIBLE
+ bool
+ depends on MMU
+ default y if CPU_ARM920T || CPU_ARM926T || CPU_SA1100 || CPU_XSCALE || CPU_XSC3 || CPU_V6 || CPU_V6K || CPU_V7
+
comment "Processor Features"
config ARM_LPAE
diff --git a/include/linux/suspend.h b/include/linux/suspend.h
index f73cabf..38bbf95 100644
--- a/include/linux/suspend.h
+++ b/include/linux/suspend.h
@@ -320,6 +320,8 @@ extern unsigned long get_safe_page(gfp_t gfp_mask);
extern void hibernation_set_ops(const struct platform_hibernation_ops *ops);
extern int hibernate(void);
extern bool system_entering_hibernation(void);
+asmlinkage int swsusp_save(void);
+extern struct pbe *restore_pblist;
#else /* CONFIG_HIBERNATION */
static inline void register_nosave_region(unsigned long b, unsigned long e) {}
static inline void register_nosave_region_late(unsigned long b, unsigned long e) {}
--
1.7.9.5
During restore, pm_notifier chain are called with
PM_RESTORE_PREPARE. The firmware_class driver handler
fw_pm_notify does not have a handler for this. As a result,
it keeps a reader on the kmod.c umhelper_sem. During
freeze_processes, the call to __usermodehelper_disable tries to
take a write lock on this semaphore and hangs waiting.
Signed-off-by: Sebastian Capella <[email protected]>
Acked-by: Ming Lei <[email protected]>
Cc: Russ Dill <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
---
drivers/base/firmware_class.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c
index eb8fb94..e2b51f8 100644
--- a/drivers/base/firmware_class.c
+++ b/drivers/base/firmware_class.c
@@ -1541,6 +1541,7 @@ static int fw_pm_notify(struct notifier_block *notify_block,
switch (mode) {
case PM_HIBERNATION_PREPARE:
case PM_SUSPEND_PREPARE:
+ case PM_RESTORE_PREPARE:
kill_requests_without_uevent();
device_cache_fw_images();
break;
--
1.7.9.5
From: Russ Dill <[email protected]>
This adds the ability to run soft_restart with local_irq/fiq_disable
already called. This is helpful for the hibernation code paths.
Signed-off-by: Russ Dill <[email protected]>
Signed-off-by: Sebastian Capella <[email protected]>
Cc: Russell King <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Robin Holt <[email protected]>
---
arch/arm/include/asm/system_misc.h | 1 +
arch/arm/kernel/process.c | 15 ++++++++++-----
2 files changed, 11 insertions(+), 5 deletions(-)
diff --git a/arch/arm/include/asm/system_misc.h b/arch/arm/include/asm/system_misc.h
index a3d61ad..eca8dd4 100644
--- a/arch/arm/include/asm/system_misc.h
+++ b/arch/arm/include/asm/system_misc.h
@@ -10,6 +10,7 @@
extern void cpu_init(void);
+void soft_restart_noirq(unsigned long);
void soft_restart(unsigned long);
extern void (*arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd);
extern void (*arm_pm_idle)(void);
diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c
index 92f7b15..685bc4a 100644
--- a/arch/arm/kernel/process.c
+++ b/arch/arm/kernel/process.c
@@ -95,14 +95,10 @@ static void __soft_restart(void *addr)
BUG();
}
-void soft_restart(unsigned long addr)
+void soft_restart_noirq(unsigned long addr)
{
u64 *stack = soft_restart_stack + ARRAY_SIZE(soft_restart_stack);
- /* Disable interrupts first */
- local_irq_disable();
- local_fiq_disable();
-
/* Disable the L2 if we're the last man standing. */
if (num_online_cpus() == 1)
outer_disable();
@@ -114,6 +110,15 @@ void soft_restart(unsigned long addr)
BUG();
}
+void soft_restart(unsigned long addr)
+{
+ /* Disable interrupts first */
+ local_irq_disable();
+ local_fiq_disable();
+
+ soft_restart_noirq(addr);
+}
+
static void null_restart(enum reboot_mode reboot_mode, const char *cmd)
{
}
--
1.7.9.5