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
17extern int __cpu_suspend(unsigned long, int (*)(unsigned long), u32 cpuid);
18extern void cpu_resume_mmu(void);
19
20#ifdef CONFIG_MMU
21int 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, cpuid: __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
64int 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 */
83void __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
115extern struct sleep_save_sp sleep_save_sp;
116
117static 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}
130early_initcall(cpu_suspend_alloc_sp);
131

source code of linux/arch/arm/kernel/suspend.c