1 #include <linux/percpu.h> 2 #include <linux/slab.h> 3 #include <asm/cacheflush.h> 4 #include <asm/debug-monitors.h> 5 #include <asm/pgtable.h> 6 #include <asm/memory.h> 7 #include <asm/mmu_context.h> 8 #include <asm/smp_plat.h> 9 #include <asm/suspend.h> 10 #include <asm/tlbflush.h> 11 12 extern int __cpu_suspend_enter(unsigned long arg, int (*fn)(unsigned long)); 13 /* 14 * This is called by __cpu_suspend_enter() to save the state, and do whatever 15 * flushing is required to ensure that when the CPU goes to sleep we have 16 * the necessary data available when the caches are not searched. 17 * 18 * ptr: CPU context virtual address 19 * save_ptr: address of the location where the context physical address 20 * must be saved 21 */ 22 void notrace __cpu_suspend_save(struct cpu_suspend_ctx *ptr, 23 phys_addr_t *save_ptr) 24 { 25 *save_ptr = virt_to_phys(ptr); 26 27 cpu_do_suspend(ptr); 28 /* 29 * Only flush the context that must be retrieved with the MMU 30 * off. VA primitives ensure the flush is applied to all 31 * cache levels so context is pushed to DRAM. 32 */ 33 __flush_dcache_area(ptr, sizeof(*ptr)); 34 __flush_dcache_area(save_ptr, sizeof(*save_ptr)); 35 } 36 37 /* 38 * This hook is provided so that cpu_suspend code can restore HW 39 * breakpoints as early as possible in the resume path, before reenabling 40 * debug exceptions. Code cannot be run from a CPU PM notifier since by the 41 * time the notifier runs debug exceptions might have been enabled already, 42 * with HW breakpoints registers content still in an unknown state. 43 */ 44 void (*hw_breakpoint_restore)(void *); 45 void __init cpu_suspend_set_dbg_restorer(void (*hw_bp_restore)(void *)) 46 { 47 /* Prevent multiple restore hook initializations */ 48 if (WARN_ON(hw_breakpoint_restore)) 49 return; 50 hw_breakpoint_restore = hw_bp_restore; 51 } 52 53 /* 54 * cpu_suspend 55 * 56 * arg: argument to pass to the finisher function 57 * fn: finisher function pointer 58 * 59 */ 60 int cpu_suspend(unsigned long arg, int (*fn)(unsigned long)) 61 { 62 struct mm_struct *mm = current->active_mm; 63 int ret; 64 unsigned long flags; 65 66 /* 67 * From this point debug exceptions are disabled to prevent 68 * updates to mdscr register (saved and restored along with 69 * general purpose registers) from kernel debuggers. 70 */ 71 local_dbg_save(flags); 72 73 /* 74 * mm context saved on the stack, it will be restored when 75 * the cpu comes out of reset through the identity mapped 76 * page tables, so that the thread address space is properly 77 * set-up on function return. 78 */ 79 ret = __cpu_suspend_enter(arg, fn); 80 if (ret == 0) { 81 /* 82 * We are resuming from reset with TTBR0_EL1 set to the 83 * idmap to enable the MMU; restore the active_mm mappings in 84 * TTBR0_EL1 unless the active_mm == &init_mm, in which case 85 * the thread entered cpu_suspend with TTBR0_EL1 set to 86 * reserved TTBR0 page tables and should be restored as such. 87 */ 88 if (mm == &init_mm) 89 cpu_set_reserved_ttbr0(); 90 else 91 cpu_switch_mm(mm->pgd, mm); 92 93 flush_tlb_all(); 94 95 /* 96 * Restore per-cpu offset before any kernel 97 * subsystem relying on it has a chance to run. 98 */ 99 set_my_cpu_offset(per_cpu_offset(smp_processor_id())); 100 101 /* 102 * Restore HW breakpoint registers to sane values 103 * before debug exceptions are possibly reenabled 104 * through local_dbg_restore. 105 */ 106 if (hw_breakpoint_restore) 107 hw_breakpoint_restore(NULL); 108 } 109 110 /* 111 * Restore pstate flags. OS lock and mdscr have been already 112 * restored, so from this point onwards, debugging is fully 113 * renabled if it was enabled when core started shutdown. 114 */ 115 local_dbg_restore(flags); 116 117 return ret; 118 } 119 120 struct sleep_save_sp sleep_save_sp; 121 122 static int __init cpu_suspend_init(void) 123 { 124 void *ctx_ptr; 125 126 /* ctx_ptr is an array of physical addresses */ 127 ctx_ptr = kcalloc(mpidr_hash_size(), sizeof(phys_addr_t), GFP_KERNEL); 128 129 if (WARN_ON(!ctx_ptr)) 130 return -ENOMEM; 131 132 sleep_save_sp.save_ptr_stash = ctx_ptr; 133 sleep_save_sp.save_ptr_stash_phys = virt_to_phys(ctx_ptr); 134 __flush_dcache_area(&sleep_save_sp, sizeof(struct sleep_save_sp)); 135 136 return 0; 137 } 138 early_initcall(cpu_suspend_init); 139