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 asmlinkage void _init_lbt(void);
16 asmlinkage void _save_lbt(struct loongarch_lbt *);
17 asmlinkage void _restore_lbt(struct loongarch_lbt *);
18 asmlinkage int _save_lbt_context(void __user *regs, void __user *eflags);
19 asmlinkage int _restore_lbt_context(void __user *regs, void __user *eflags);
20 asmlinkage int _save_ftop_context(void __user *ftop);
21 asmlinkage int _restore_ftop_context(void __user *ftop);
22
is_lbt_enabled(void)23 static inline int is_lbt_enabled(void)
24 {
25 if (!cpu_has_lbt)
26 return 0;
27
28 return (csr_read32(LOONGARCH_CSR_EUEN) & CSR_EUEN_LBTEN) ?
29 1 : 0;
30 }
31
is_lbt_owner(void)32 static inline int is_lbt_owner(void)
33 {
34 return test_thread_flag(TIF_USEDLBT);
35 }
36
37 #ifdef CONFIG_CPU_HAS_LBT
38
enable_lbt(void)39 static inline void enable_lbt(void)
40 {
41 if (cpu_has_lbt)
42 csr_xchg32(CSR_EUEN_LBTEN, CSR_EUEN_LBTEN, LOONGARCH_CSR_EUEN);
43 }
44
disable_lbt(void)45 static inline void disable_lbt(void)
46 {
47 if (cpu_has_lbt)
48 csr_xchg32(0, CSR_EUEN_LBTEN, LOONGARCH_CSR_EUEN);
49 }
50
__own_lbt(void)51 static inline void __own_lbt(void)
52 {
53 enable_lbt();
54 set_thread_flag(TIF_USEDLBT);
55 KSTK_EUEN(current) |= CSR_EUEN_LBTEN;
56 }
57
own_lbt_inatomic(int restore)58 static inline void own_lbt_inatomic(int restore)
59 {
60 if (cpu_has_lbt && !is_lbt_owner()) {
61 __own_lbt();
62 if (restore)
63 _restore_lbt(¤t->thread.lbt);
64 }
65 }
66
own_lbt(int restore)67 static inline void own_lbt(int restore)
68 {
69 preempt_disable();
70 own_lbt_inatomic(restore);
71 preempt_enable();
72 }
73
lose_lbt_inatomic(int save,struct task_struct * tsk)74 static inline void lose_lbt_inatomic(int save, struct task_struct *tsk)
75 {
76 if (cpu_has_lbt && is_lbt_owner()) {
77 if (save)
78 _save_lbt(&tsk->thread.lbt);
79
80 disable_lbt();
81 clear_tsk_thread_flag(tsk, TIF_USEDLBT);
82 }
83 KSTK_EUEN(tsk) &= ~(CSR_EUEN_LBTEN);
84 }
85
lose_lbt(int save)86 static inline void lose_lbt(int save)
87 {
88 preempt_disable();
89 lose_lbt_inatomic(save, current);
90 preempt_enable();
91 }
92
init_lbt(void)93 static inline void init_lbt(void)
94 {
95 __own_lbt();
96 _init_lbt();
97 }
98 #else
own_lbt_inatomic(int restore)99 static inline void own_lbt_inatomic(int restore) {}
lose_lbt_inatomic(int save,struct task_struct * tsk)100 static inline void lose_lbt_inatomic(int save, struct task_struct *tsk) {}
init_lbt(void)101 static inline void init_lbt(void) {}
lose_lbt(int save)102 static inline void lose_lbt(int save) {}
103 #endif
104
thread_lbt_context_live(void)105 static inline int thread_lbt_context_live(void)
106 {
107 if (!cpu_has_lbt)
108 return 0;
109
110 return test_thread_flag(TIF_LBT_CTX_LIVE);
111 }
112
113 #endif /* _ASM_LBT_H */
114