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 static 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; set the TTBR0 to the reserved 84 * page tables to prevent speculative TLB allocations, flush 85 * the local tlb and set the default tcr_el1.t0sz so that 86 * the TTBR0 address space set-up is properly restored. 87 * If the current active_mm != &init_mm we entered cpu_suspend 88 * with mappings in TTBR0 that must be restored, so we switch 89 * them back to complete the address space configuration 90 * restoration before returning. 91 */ 92 cpu_set_reserved_ttbr0(); 93 local_flush_tlb_all(); 94 cpu_set_default_tcr_t0sz(); 95 96 if (mm != &init_mm) 97 cpu_switch_mm(mm->pgd, mm); 98 99 /* 100 * Restore per-cpu offset before any kernel 101 * subsystem relying on it has a chance to run. 102 */ 103 set_my_cpu_offset(per_cpu_offset(smp_processor_id())); 104 105 /* 106 * Restore HW breakpoint registers to sane values 107 * before debug exceptions are possibly reenabled 108 * through local_dbg_restore. 109 */ 110 if (hw_breakpoint_restore) 111 hw_breakpoint_restore(NULL); 112 } 113 114 /* 115 * Restore pstate flags. OS lock and mdscr have been already 116 * restored, so from this point onwards, debugging is fully 117 * renabled if it was enabled when core started shutdown. 118 */ 119 local_dbg_restore(flags); 120 121 return ret; 122 } 123 124 struct sleep_save_sp sleep_save_sp; 125 126 static int __init cpu_suspend_init(void) 127 { 128 void *ctx_ptr; 129 130 /* ctx_ptr is an array of physical addresses */ 131 ctx_ptr = kcalloc(mpidr_hash_size(), sizeof(phys_addr_t), GFP_KERNEL); 132 133 if (WARN_ON(!ctx_ptr)) 134 return -ENOMEM; 135 136 sleep_save_sp.save_ptr_stash = ctx_ptr; 137 sleep_save_sp.save_ptr_stash_phys = virt_to_phys(ctx_ptr); 138 __flush_dcache_area(&sleep_save_sp, sizeof(struct sleep_save_sp)); 139 140 return 0; 141 } 142 early_initcall(cpu_suspend_init); 143