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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
de818bd4 | 2 | #include <linux/ftrace.h> |
fb4a9602 | 3 | #include <linux/percpu.h> |
95322526 | 4 | #include <linux/slab.h> |
d0854412 | 5 | #include <asm/alternative.h> |
95322526 | 6 | #include <asm/cacheflush.h> |
d0854412 | 7 | #include <asm/cpufeature.h> |
95322526 | 8 | #include <asm/debug-monitors.h> |
d0854412 | 9 | #include <asm/exec.h> |
95322526 LP |
10 | #include <asm/pgtable.h> |
11 | #include <asm/memory.h> | |
f43c2718 | 12 | #include <asm/mmu_context.h> |
95322526 LP |
13 | #include <asm/smp_plat.h> |
14 | #include <asm/suspend.h> | |
15 | #include <asm/tlbflush.h> | |
16 | ||
95322526 | 17 | /* |
cabe1c81 JM |
18 | * This is allocated by cpu_suspend_init(), and used to store a pointer to |
19 | * the 'struct sleep_stack_data' the contains a particular CPUs state. | |
95322526 | 20 | */ |
cabe1c81 | 21 | unsigned long *sleep_save_stash; |
95322526 | 22 | |
65c021bb LP |
23 | /* |
24 | * This hook is provided so that cpu_suspend code can restore HW | |
25 | * breakpoints as early as possible in the resume path, before reenabling | |
26 | * debug exceptions. Code cannot be run from a CPU PM notifier since by the | |
27 | * time the notifier runs debug exceptions might have been enabled already, | |
28 | * with HW breakpoints registers content still in an unknown state. | |
29 | */ | |
d7a83d12 WD |
30 | static int (*hw_breakpoint_restore)(unsigned int); |
31 | void __init cpu_suspend_set_dbg_restorer(int (*hw_bp_restore)(unsigned int)) | |
65c021bb LP |
32 | { |
33 | /* Prevent multiple restore hook initializations */ | |
34 | if (WARN_ON(hw_breakpoint_restore)) | |
35 | return; | |
36 | hw_breakpoint_restore = hw_bp_restore; | |
37 | } | |
38 | ||
adc9b2df JM |
39 | void notrace __cpu_suspend_exit(void) |
40 | { | |
d7a83d12 WD |
41 | unsigned int cpu = smp_processor_id(); |
42 | ||
adc9b2df JM |
43 | /* |
44 | * We are resuming from reset with the idmap active in TTBR0_EL1. | |
45 | * We must uninstall the idmap and restore the expected MMU | |
46 | * state before we can possibly return to userspace. | |
47 | */ | |
48 | cpu_uninstall_idmap(); | |
49 | ||
d0854412 JM |
50 | /* |
51 | * PSTATE was not saved over suspend/resume, re-enable any detected | |
52 | * features that might not have been set correctly. | |
53 | */ | |
54 | asm(ALTERNATIVE("nop", SET_PSTATE_PAN(1), ARM64_HAS_PAN, | |
55 | CONFIG_ARM64_PAN)); | |
56 | uao_thread_switch(current); | |
57 | ||
adc9b2df JM |
58 | /* |
59 | * Restore HW breakpoint registers to sane values | |
60 | * before debug exceptions are possibly reenabled | |
61 | * through local_dbg_restore. | |
62 | */ | |
63 | if (hw_breakpoint_restore) | |
d7a83d12 | 64 | hw_breakpoint_restore(cpu); |
adc9b2df JM |
65 | } |
66 | ||
714f5992 | 67 | /* |
af391b15 | 68 | * cpu_suspend |
714f5992 LP |
69 | * |
70 | * arg: argument to pass to the finisher function | |
71 | * fn: finisher function pointer | |
72 | * | |
73 | */ | |
af391b15 | 74 | int cpu_suspend(unsigned long arg, int (*fn)(unsigned long)) |
714f5992 | 75 | { |
adc9b2df | 76 | int ret = 0; |
714f5992 | 77 | unsigned long flags; |
adc9b2df | 78 | struct sleep_stack_data state; |
95322526 LP |
79 | |
80 | /* | |
81 | * From this point debug exceptions are disabled to prevent | |
82 | * updates to mdscr register (saved and restored along with | |
83 | * general purpose registers) from kernel debuggers. | |
84 | */ | |
85 | local_dbg_save(flags); | |
86 | ||
de818bd4 LP |
87 | /* |
88 | * Function graph tracer state gets incosistent when the kernel | |
89 | * calls functions that never return (aka suspend finishers) hence | |
90 | * disable graph tracing during their execution. | |
91 | */ | |
92 | pause_graph_tracing(); | |
93 | ||
adc9b2df JM |
94 | if (__cpu_suspend_enter(&state)) { |
95 | /* Call the suspend finisher */ | |
96 | ret = fn(arg); | |
fb4a9602 | 97 | |
65c021bb | 98 | /* |
adc9b2df JM |
99 | * Never gets here, unless the suspend finisher fails. |
100 | * Successful cpu_suspend() should return from cpu_resume(), | |
101 | * returning through this code path is considered an error | |
102 | * If the return value is set to 0 force ret = -EOPNOTSUPP | |
103 | * to make sure a proper error condition is propagated | |
65c021bb | 104 | */ |
adc9b2df JM |
105 | if (!ret) |
106 | ret = -EOPNOTSUPP; | |
107 | } else { | |
108 | __cpu_suspend_exit(); | |
95322526 LP |
109 | } |
110 | ||
de818bd4 LP |
111 | unpause_graph_tracing(); |
112 | ||
95322526 LP |
113 | /* |
114 | * Restore pstate flags. OS lock and mdscr have been already | |
115 | * restored, so from this point onwards, debugging is fully | |
116 | * renabled if it was enabled when core started shutdown. | |
117 | */ | |
118 | local_dbg_restore(flags); | |
119 | ||
120 | return ret; | |
121 | } | |
122 | ||
18ab7db6 | 123 | static int __init cpu_suspend_init(void) |
95322526 | 124 | { |
95322526 | 125 | /* ctx_ptr is an array of physical addresses */ |
cabe1c81 JM |
126 | sleep_save_stash = kcalloc(mpidr_hash_size(), sizeof(*sleep_save_stash), |
127 | GFP_KERNEL); | |
95322526 | 128 | |
cabe1c81 | 129 | if (WARN_ON(!sleep_save_stash)) |
95322526 LP |
130 | return -ENOMEM; |
131 | ||
95322526 LP |
132 | return 0; |
133 | } | |
134 | early_initcall(cpu_suspend_init); |