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