1 /* SPDX-License-Identifier: GPL-2.0 */ 1
2 #ifndef __ASM_PREEMPT_H
3 #define __ASM_PREEMPT_H
4
5 #include <asm/rmwcc.h>
6 #include <asm/percpu.h>
7 #include <asm/current.h>
8
9 #include <linux/static_call_types.h>
10
11 /* We use the MSB mostly because its available
12 #define PREEMPT_NEED_RESCHED 0x80000000
13
14 /*
15 * We use the PREEMPT_NEED_RESCHED bit as an i
16 * that a decrement hitting 0 means we can and
17 */
18 #define PREEMPT_ENABLED (0 + PREEMPT_NEED_RESC
19
20 /*
21 * We mask the PREEMPT_NEED_RESCHED bit so as
22 * that think a non-zero value indicates we ca
23 */
24 static __always_inline int preempt_count(void)
25 {
26 return raw_cpu_read_4(pcpu_hot.preempt
27 }
28
29 static __always_inline void preempt_count_set(
30 {
31 int old, new;
32
33 old = raw_cpu_read_4(pcpu_hot.preempt_
34 do {
35 new = (old & PREEMPT_NEED_RESC
36 (pc & ~PREEMPT_NEED_RE
37 } while (!raw_cpu_try_cmpxchg_4(pcpu_h
38 }
39
40 /*
41 * must be macros to avoid header recursion he
42 */
43 #define init_task_preempt_count(p) do { } whil
44
45 #define init_idle_preempt_count(p, cpu) do { \
46 per_cpu(pcpu_hot.preempt_count, (cpu))
47 } while (0)
48
49 /*
50 * We fold the NEED_RESCHED bit into the preem
51 * preempt_enable() can decrement and test for
52 * single instruction.
53 *
54 * We invert the actual bit, so that when the
55 * need to resched (the bit is cleared) and ca
56 */
57
58 static __always_inline void set_preempt_need_r
59 {
60 raw_cpu_and_4(pcpu_hot.preempt_count,
61 }
62
63 static __always_inline void clear_preempt_need
64 {
65 raw_cpu_or_4(pcpu_hot.preempt_count, P
66 }
67
68 static __always_inline bool test_preempt_need_
69 {
70 return !(raw_cpu_read_4(pcpu_hot.preem
71 }
72
73 /*
74 * The various preempt_count add/sub methods
75 */
76
77 static __always_inline void __preempt_count_ad
78 {
79 raw_cpu_add_4(pcpu_hot.preempt_count,
80 }
81
82 static __always_inline void __preempt_count_su
83 {
84 raw_cpu_add_4(pcpu_hot.preempt_count,
85 }
86
87 /*
88 * Because we keep PREEMPT_NEED_RESCHED set wh
89 * a decrement which hits zero means we have n
90 * reschedule.
91 */
92 static __always_inline bool __preempt_count_de
93 {
94 return GEN_UNARY_RMWcc("decl", __my_cp
95 __percpu_arg([v
96 }
97
98 /*
99 * Returns true when we need to resched and ca
100 */
101 static __always_inline bool should_resched(int
102 {
103 return unlikely(raw_cpu_read_4(pcpu_ho
104 }
105
106 #ifdef CONFIG_PREEMPTION
107
108 extern asmlinkage void preempt_schedule(void);
109 extern asmlinkage void preempt_schedule_thunk(
110
111 #define preempt_schedule_dynamic_enabled
112 #define preempt_schedule_dynamic_disabled
113
114 extern asmlinkage void preempt_schedule_notrac
115 extern asmlinkage void preempt_schedule_notrac
116
117 #define preempt_schedule_notrace_dynamic_enabl
118 #define preempt_schedule_notrace_dynamic_disab
119
120 #ifdef CONFIG_PREEMPT_DYNAMIC
121
122 DECLARE_STATIC_CALL(preempt_schedule, preempt_
123
124 #define __preempt_schedule() \
125 do { \
126 __STATIC_CALL_MOD_ADDRESSABLE(preempt_
127 asm volatile ("call " STATIC_CALL_TRAM
128 } while (0)
129
130 DECLARE_STATIC_CALL(preempt_schedule_notrace,
131
132 #define __preempt_schedule_notrace() \
133 do { \
134 __STATIC_CALL_MOD_ADDRESSABLE(preempt_
135 asm volatile ("call " STATIC_CALL_TRAM
136 } while (0)
137
138 #else /* PREEMPT_DYNAMIC */
139
140 #define __preempt_schedule() \
141 asm volatile ("call preempt_schedule_t
142
143 #define __preempt_schedule_notrace() \
144 asm volatile ("call preempt_schedule_n
145
146 #endif /* PREEMPT_DYNAMIC */
147
148 #endif /* PREEMPTION */
149
150 #endif /* __ASM_PREEMPT_H */
151
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