On Thu, Feb 27, 2014 at 11:57:58PM +0000, Sebastian Capella wrote:
[...]
diff --git a/arch/arm/kernel/hibernate.c b/arch/arm/kernel/hibernate.c new file mode 100644 index 0000000..a41e0e3 --- /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.)
- 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>
You can drop tlbflush.h and cacheflush.h, they do not seem to be needed.
+#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 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, 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.
- */
Comment above needs updating. We are switching page tables to a set of page tables that are certain to live at the same location in the older kernel, that's the only reason, as we discussed. soft_restart will make sure (again) to switch to 1:1 page tables so that we can call cpu_resume with the MMU off.
+static void notrace 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 resume_stack[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(arch_restore_image, 0,
resume_stack + sizeof(resume_stack));
This does not guarantee your stack is 8-byte aligned, that's not AAPCS compliant and might buy you trouble.
Either you align the stack or you align the pointer you are passing.
Please have a look at kernel/process.c
Thanks, Lorenzo