Re: [PATCH v4 2/2] ARM hibernation / suspend-to-disk

Accidentally missed a trailing space on a comment line.. will submit patch v5 to fix this.

Sebastian

On 26 February 2014 11:10, Sebastian Capella sebastian.capella@linaro.orgwrote:

From: Russ Dill Russ.Dill@ti.com

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 Russ.Dill@ti.com Cc: "Rafael J. Wysocki" rjw@rjwysocki.net Signed-off-by: Sebastian Capella sebastian.capella@linaro.org Cc: Russell King linux@arm.linux.org.uk Cc: Len Brown len.brown@intel.com Cc: Pavel Machek pavel@ucw.cz Cc: Nicolas Pitre nico@linaro.org Cc: Santosh Shilimkar santosh.shilimkar@ti.com Cc: Will Deacon will.deacon@arm.com Cc: Jonathan Austin jonathan.austin@arm.com Cc: Catalin Marinas catalin.marinas@arm.com Cc: "Uwe Kleine-König" u.kleine-koenig@pengutronix.de Cc: Stephen Boyd sboyd@codeaurora.org Cc: Lorenzo Pieralisi lorenzo.pieralisi@arm.com

---

arch/arm/include/asm/memory.h | 1 + arch/arm/kernel/Makefile | 1 + arch/arm/kernel/hibernate.c | 113 +++++++++++++++++++++++++++++++++++++++++ arch/arm/mm/Kconfig | 5 ++ include/linux/suspend.h | 2 + 5 files changed, 122 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..70e17d2 --- /dev/null +++ b/arch/arm/kernel/hibernate.c @@ -0,0 +1,113 @@ +/*

• • 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 rjw@sisk.pl
• • 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.
• • swsusp_save() is executed in the suspend finisher so that the CPU
• • context pointer and memory are part of the saved image, which is
• • required by the resume kernel image to restart execution from
• • swsusp_arch_suspend().
• • soft_restart is not technically needed, but is used to get success
• • returned from cpu_suspend.
• • When soft reboot completes, 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(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