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.) > + * 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> 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
