1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3 * Copyright (C) 2012 Regents of the University of California
4 */
5
6 #ifndef _ASM_RISCV_SWITCH_TO_H
7 #define _ASM_RISCV_SWITCH_TO_H
8
9 #include <linux/jump_label.h>
10 #include <linux/sched/task_stack.h>
11 #include <linux/mm_types.h>
12 #include <asm/vector.h>
13 #include <asm/cpufeature.h>
14 #include <asm/processor.h>
15 #include <asm/ptrace.h>
16 #include <asm/csr.h>
17 #include <asm/qos.h>
18
19 #ifdef CONFIG_FPU
20 extern void __fstate_save(struct task_struct *save_to);
21 extern void __fstate_restore(struct task_struct *restore_from);
22
__fstate_clean(struct pt_regs * regs)23 static inline void __fstate_clean(struct pt_regs *regs)
24 {
25 regs->status = (regs->status & ~SR_FS) | SR_FS_CLEAN;
26 }
27
fstate_off(struct task_struct * task,struct pt_regs * regs)28 static inline void fstate_off(struct task_struct *task,
29 struct pt_regs *regs)
30 {
31 regs->status = (regs->status & ~SR_FS) | SR_FS_OFF;
32 }
33
fstate_save(struct task_struct * task,struct pt_regs * regs)34 static inline void fstate_save(struct task_struct *task,
35 struct pt_regs *regs)
36 {
37 if ((regs->status & SR_FS) == SR_FS_DIRTY) {
38 __fstate_save(task);
39 __fstate_clean(regs);
40 }
41 }
42
fstate_restore(struct task_struct * task,struct pt_regs * regs)43 static inline void fstate_restore(struct task_struct *task,
44 struct pt_regs *regs)
45 {
46 if ((regs->status & SR_FS) != SR_FS_OFF) {
47 __fstate_restore(task);
48 __fstate_clean(regs);
49 }
50 }
51
__switch_to_fpu(struct task_struct * prev,struct task_struct * next)52 static inline void __switch_to_fpu(struct task_struct *prev,
53 struct task_struct *next)
54 {
55 struct pt_regs *regs;
56
57 regs = task_pt_regs(prev);
58 fstate_save(prev, regs);
59 fstate_restore(next, task_pt_regs(next));
60 }
61
has_fpu(void)62 static __always_inline bool has_fpu(void)
63 {
64 return riscv_has_extension_likely(RISCV_ISA_EXT_F) ||
65 riscv_has_extension_likely(RISCV_ISA_EXT_D);
66 }
67 #else
has_fpu(void)68 static __always_inline bool has_fpu(void) { return false; }
69 #define fstate_save(task, regs) do { } while (0)
70 #define fstate_restore(task, regs) do { } while (0)
71 #define __switch_to_fpu(__prev, __next) do { } while (0)
72 #endif
73
envcfg_update_bits(struct task_struct * task,unsigned long mask,unsigned long val)74 static inline void envcfg_update_bits(struct task_struct *task,
75 unsigned long mask, unsigned long val)
76 {
77 unsigned long envcfg;
78
79 envcfg = (task->thread.envcfg & ~mask) | val;
80 task->thread.envcfg = envcfg;
81 if (task == current)
82 csr_write(CSR_ENVCFG, envcfg);
83 }
84
__switch_to_envcfg(struct task_struct * next)85 static inline void __switch_to_envcfg(struct task_struct *next)
86 {
87 asm volatile (ALTERNATIVE("nop", "csrw " __stringify(CSR_ENVCFG) ", %0",
88 0, RISCV_ISA_EXT_XLINUXENVCFG, 1)
89 :: "r" (next->thread.envcfg) : "memory");
90 }
91
92 extern struct task_struct *__switch_to(struct task_struct *,
93 struct task_struct *);
94
switch_to_should_flush_icache(struct task_struct * task)95 static inline bool switch_to_should_flush_icache(struct task_struct *task)
96 {
97 #ifdef CONFIG_SMP
98 bool stale_mm = task->mm && task->mm->context.force_icache_flush;
99 bool stale_thread = task->thread.force_icache_flush;
100 bool thread_migrated = smp_processor_id() != task->thread.prev_cpu;
101
102 return thread_migrated && (stale_mm || stale_thread);
103 #else
104 return false;
105 #endif
106 }
107
108 #ifdef CONFIG_SMP
109 #define __set_prev_cpu(thread) ((thread).prev_cpu = smp_processor_id())
110 #else
111 #define __set_prev_cpu(thread)
112 #endif
113
114 #define switch_to(prev, next, last) \
115 do { \
116 struct task_struct *__prev = (prev); \
117 struct task_struct *__next = (next); \
118 __set_prev_cpu(__prev->thread); \
119 if (has_fpu()) \
120 __switch_to_fpu(__prev, __next); \
121 if (has_vector() || has_xtheadvector()) \
122 __switch_to_vector(__prev, __next); \
123 if (has_srmcfg()) \
124 __switch_to_srmcfg(__next); \
125 if (switch_to_should_flush_icache(__next)) \
126 local_flush_icache_all(); \
127 __switch_to_envcfg(__next); \
128 ((last) = __switch_to(__prev, __next)); \
129 } while (0)
130
131 #endif /* _ASM_RISCV_SWITCH_TO_H */
132