1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * Author: Qi Hu <huqi@loongson.cn>
4 * Huacai Chen <chenhuacai@loongson.cn>
5 * Copyright (C) 2020-2023 Loongson Technology Corporation Limited
6 */
7 #ifndef _ASM_LBT_H
8 #define _ASM_LBT_H
9
10 #include <asm/cpu.h>
11 #include <asm/current.h>
12 #include <asm/loongarch.h>
13 #include <asm/processor.h>
14
15 extern void _init_lbt(void);
16 extern void _save_lbt(struct loongarch_lbt *);
17 extern void _restore_lbt(struct loongarch_lbt *);
18
19 static inline int is_lbt_enabled(void)
20 {
21 if (!cpu_has_lbt)
22 return 0;
23
24 return (csr_read32(LOONGARCH_CSR_EUEN) & CSR_EUEN_LBTEN) ?
25 1 : 0;
26 }
27
28 static inline int is_lbt_owner(void)
29 {
30 return test_thread_flag(TIF_USEDLBT);
31 }
32
33 #ifdef CONFIG_CPU_HAS_LBT
34
35 static inline void enable_lbt(void)
36 {
37 if (cpu_has_lbt)
38 csr_xchg32(CSR_EUEN_LBTEN, CSR_EUEN_LBTEN, LOONGARCH_CSR_EUEN);
39 }
40
41 static inline void disable_lbt(void)
42 {
43 if (cpu_has_lbt)
44 csr_xchg32(0, CSR_EUEN_LBTEN, LOONGARCH_CSR_EUEN);
45 }
46
47 static inline void __own_lbt(void)
48 {
49 enable_lbt();
50 set_thread_flag(TIF_USEDLBT);
51 KSTK_EUEN(current) |= CSR_EUEN_LBTEN;
52 }
53
54 static inline void own_lbt_inatomic(int restore)
55 {
56 if (cpu_has_lbt && !is_lbt_owner()) {
57 __own_lbt();
58 if (restore)
59 _restore_lbt(¤t->thread.lbt);
60 }
61 }
62
63 static inline void own_lbt(int restore)
64 {
65 preempt_disable();
66 own_lbt_inatomic(restore);
67 preempt_enable();
68 }
69
70 static inline void lose_lbt_inatomic(int save, struct task_struct *tsk)
71 {
72 if (cpu_has_lbt && is_lbt_owner()) {
73 if (save)
74 _save_lbt(&tsk->thread.lbt);
75
76 disable_lbt();
77 clear_tsk_thread_flag(tsk, TIF_USEDLBT);
78 }
79 KSTK_EUEN(tsk) &= ~(CSR_EUEN_LBTEN);
80 }
81
82 static inline void lose_lbt(int save)
83 {
84 preempt_disable();
85 lose_lbt_inatomic(save, current);
86 preempt_enable();
87 }
88
89 static inline void init_lbt(void)
90 {
91 __own_lbt();
92 _init_lbt();
93 }
94 #else
95 static inline void own_lbt_inatomic(int restore) {}
96 static inline void lose_lbt_inatomic(int save, struct task_struct *tsk) {}
97 static inline void init_lbt(void) {}
98 static inline void lose_lbt(int save) {}
99 #endif
100
101 static inline int thread_lbt_context_live(void)
102 {
103 if (!cpu_has_lbt)
104 return 0;
105
106 return test_thread_flag(TIF_LBT_CTX_LIVE);
107 }
108
109 #endif /* _ASM_LBT_H */
110
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