1 /* 2 * Hibernation support specific for ARM 3 * 4 * Derived from work on ARM hibernation support by: 5 * 6 * Ubuntu project, hibernation support for mach-dove 7 * Copyright (C) 2010 Nokia Corporation (Hiroshi Doyu) 8 * Copyright (C) 2010 Texas Instruments, Inc. (Teerth Reddy et al.) 9 * https://lkml.org/lkml/2010/6/18/4 10 * https://lists.linux-foundation.org/pipermail/linux-pm/2010-June/027422.html 11 * https://patchwork.kernel.org/patch/96442/ 12 * 13 * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl> 14 * 15 * License terms: GNU General Public License (GPL) version 2 16 */ 17 18 #include <linux/mm.h> 19 #include <linux/suspend.h> 20 #include <asm/system_misc.h> 21 #include <asm/idmap.h> 22 #include <asm/suspend.h> 23 #include <asm/memory.h> 24 25 extern const void __nosave_begin, __nosave_end; 26 27 int pfn_is_nosave(unsigned long pfn) 28 { 29 unsigned long nosave_begin_pfn = virt_to_pfn(&__nosave_begin); 30 unsigned long nosave_end_pfn = virt_to_pfn(&__nosave_end - 1); 31 32 return (pfn >= nosave_begin_pfn) && (pfn <= nosave_end_pfn); 33 } 34 35 void notrace save_processor_state(void) 36 { 37 WARN_ON(num_online_cpus() != 1); 38 local_fiq_disable(); 39 } 40 41 void notrace restore_processor_state(void) 42 { 43 local_fiq_enable(); 44 } 45 46 /* 47 * Snapshot kernel memory and reset the system. 48 * 49 * swsusp_save() is executed in the suspend finisher so that the CPU 50 * context pointer and memory are part of the saved image, which is 51 * required by the resume kernel image to restart execution from 52 * swsusp_arch_suspend(). 53 * 54 * soft_restart is not technically needed, but is used to get success 55 * returned from cpu_suspend. 56 * 57 * When soft reboot completes, the hibernation snapshot is written out. 58 */ 59 static int notrace arch_save_image(unsigned long unused) 60 { 61 int ret; 62 63 ret = swsusp_save(); 64 if (ret == 0) 65 soft_restart(virt_to_phys(cpu_resume)); 66 return ret; 67 } 68 69 /* 70 * Save the current CPU state before suspend / poweroff. 71 */ 72 int notrace swsusp_arch_suspend(void) 73 { 74 return cpu_suspend(0, arch_save_image); 75 } 76 77 /* 78 * Restore page contents for physical pages that were in use during loading 79 * hibernation image. Switch to idmap_pgd so the physical page tables 80 * are overwritten with the same contents. 81 */ 82 static void notrace arch_restore_image(void *unused) 83 { 84 struct pbe *pbe; 85 86 cpu_switch_mm(idmap_pgd, &init_mm); 87 for (pbe = restore_pblist; pbe; pbe = pbe->next) 88 copy_page(pbe->orig_address, pbe->address); 89 90 soft_restart(virt_to_phys(cpu_resume)); 91 } 92 93 static u64 resume_stack[PAGE_SIZE/2/sizeof(u64)] __nosavedata; 94 95 /* 96 * Resume from the hibernation image. 97 * Due to the kernel heap / data restore, stack contents change underneath 98 * and that would make function calls impossible; switch to a temporary 99 * stack within the nosave region to avoid that problem. 100 */ 101 int swsusp_arch_resume(void) 102 { 103 extern void call_with_stack(void (*fn)(void *), void *arg, void *sp); 104 call_with_stack(arch_restore_image, 0, 105 resume_stack + ARRAY_SIZE(resume_stack)); 106 return 0; 107 } 108