1 // SPDX-License-Identifier: GPL-2.0 2 #include <linux/ftrace.h> 3 #include <linux/init.h> 4 #include <linux/slab.h> 5 #include <linux/mm_types.h> 6 #include <linux/pgtable.h> 7 8 #include <asm/bugs.h> 9 #include <asm/cacheflush.h> 10 #include <asm/idmap.h> 11 #include <asm/page.h> 12 #include <asm/smp_plat.h> 13 #include <asm/suspend.h> 14 #include <asm/tlbflush.h> 15 #include <asm/uaccess.h> 16 17 extern int __cpu_suspend(unsigned long, int (*)(unsigned long), u32 cpuid); 18 extern void cpu_resume_mmu(void); 19 20 #ifdef CONFIG_MMU 21 int cpu_suspend(unsigned long arg, int (*fn)(unsigned long)) 22 { 23 struct mm_struct *mm = current->active_mm; 24 u32 __mpidr = cpu_logical_map(smp_processor_id()); 25 int ret; 26 27 if (!idmap_pgd) 28 return -EINVAL; 29 30 /* 31 * Needed for the MMU disabling/enabing code to be able to run from 32 * TTBR0 addresses. 33 */ 34 if (IS_ENABLED(CONFIG_CPU_TTBR0_PAN)) 35 uaccess_save_and_enable(); 36 37 /* 38 * Function graph tracer state gets incosistent when the kernel 39 * calls functions that never return (aka suspend finishers) hence 40 * disable graph tracing during their execution. 41 */ 42 pause_graph_tracing(); 43 44 /* 45 * Provide a temporary page table with an identity mapping for 46 * the MMU-enable code, required for resuming. On successful 47 * resume (indicated by a zero return code), we need to switch 48 * back to the correct page tables. 49 */ 50 ret = __cpu_suspend(arg, fn, __mpidr); 51 52 unpause_graph_tracing(); 53 54 if (ret == 0) { 55 cpu_switch_mm(mm->pgd, mm); 56 local_flush_bp_all(); 57 local_flush_tlb_all(); 58 check_other_bugs(); 59 } 60 61 return ret; 62 } 63 #else 64 int cpu_suspend(unsigned long arg, int (*fn)(unsigned long)) 65 { 66 u32 __mpidr = cpu_logical_map(smp_processor_id()); 67 int ret; 68 69 pause_graph_tracing(); 70 ret = __cpu_suspend(arg, fn, __mpidr); 71 unpause_graph_tracing(); 72 73 return ret; 74 } 75 #define idmap_pgd NULL 76 #endif 77 78 /* 79 * This is called by __cpu_suspend() to save the state, and do whatever 80 * flushing is required to ensure that when the CPU goes to sleep we have 81 * the necessary data available when the caches are not searched. 82 */ 83 void __cpu_suspend_save(u32 *ptr, u32 ptrsz, u32 sp, u32 *save_ptr) 84 { 85 u32 *ctx = ptr; 86 87 *save_ptr = virt_to_phys(ptr); 88 89 /* This must correspond to the LDM in cpu_resume() assembly */ 90 *ptr++ = virt_to_phys(idmap_pgd); 91 *ptr++ = sp; 92 *ptr++ = virt_to_phys(cpu_do_resume); 93 94 cpu_do_suspend(ptr); 95 96 flush_cache_louis(); 97 98 /* 99 * flush_cache_louis does not guarantee that 100 * save_ptr and ptr are cleaned to main memory, 101 * just up to the Level of Unification Inner Shareable. 102 * Since the context pointer and context itself 103 * are to be retrieved with the MMU off that 104 * data must be cleaned from all cache levels 105 * to main memory using "area" cache primitives. 106 */ 107 __cpuc_flush_dcache_area(ctx, ptrsz); 108 __cpuc_flush_dcache_area(save_ptr, sizeof(*save_ptr)); 109 110 outer_clean_range(*save_ptr, *save_ptr + ptrsz); 111 outer_clean_range(virt_to_phys(save_ptr), 112 virt_to_phys(save_ptr) + sizeof(*save_ptr)); 113 } 114 115 extern struct sleep_save_sp sleep_save_sp; 116 117 static int cpu_suspend_alloc_sp(void) 118 { 119 void *ctx_ptr; 120 /* ctx_ptr is an array of physical addresses */ 121 ctx_ptr = kcalloc(mpidr_hash_size(), sizeof(u32), GFP_KERNEL); 122 123 if (WARN_ON(!ctx_ptr)) 124 return -ENOMEM; 125 sleep_save_sp.save_ptr_stash = ctx_ptr; 126 sleep_save_sp.save_ptr_stash_phys = virt_to_phys(ctx_ptr); 127 sync_cache_w(&sleep_save_sp); 128 return 0; 129 } 130 early_initcall(cpu_suspend_alloc_sp); 131