1 /*
2 * Copyright (C) 2012 Regents of the University of California
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation, version 2.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 */
13
14 #ifndef _ASM_RISCV_PROCESSOR_H
15 #define _ASM_RISCV_PROCESSOR_H
16
17 #include <linux/const.h>
18
19 #include <asm/ptrace.h>
20
21 /*
22 * This decides where the kernel will search for a free chunk of vm
23 * space during mmap's.
24 */
25 #define TASK_UNMAPPED_BASE PAGE_ALIGN(TASK_SIZE >> 1)
26
27 #define STACK_TOP TASK_SIZE
28 #define STACK_TOP_MAX STACK_TOP
29 #define STACK_ALIGN 16
30
31 #ifndef __ASSEMBLY__
32
33 struct task_struct;
34 struct pt_regs;
35
36 /*
37 * Default implementation of macro that returns current
38 * instruction pointer ("program counter").
39 */
40 #define current_text_addr() ({ __label__ _l; _l: &&_l; })
41
42 /* CPU-specific state of a task */
43 struct thread_struct {
44 /* Callee-saved registers */
45 unsigned long ra;
46 unsigned long sp; /* Kernel mode stack */
47 unsigned long s[12]; /* s[0]: frame pointer */
48 struct __riscv_d_ext_state fstate;
49 };
50
51 #define INIT_THREAD { \
52 .sp = sizeof(init_stack) + (long)&init_stack, \
53 }
54
55 #define task_pt_regs(tsk) \
56 ((struct pt_regs *)(task_stack_page(tsk) + THREAD_SIZE \
57 - ALIGN(sizeof(struct pt_regs), STACK_ALIGN)))
58
59 #define KSTK_EIP(tsk) (task_pt_regs(tsk)->sepc)
60 #define KSTK_ESP(tsk) (task_pt_regs(tsk)->sp)
61
62
63 /* Do necessary setup to start up a newly executed thread. */
64 extern void start_thread(struct pt_regs *regs,
65 unsigned long pc, unsigned long sp);
66
67 /* Free all resources held by a thread. */
68 static inline void release_thread(struct task_struct *dead_task)
69 {
70 }
71
72 extern unsigned long get_wchan(struct task_struct *p);
73
74
75 static inline void cpu_relax(void)
76 {
77 #ifdef __riscv_muldiv
78 int dummy;
79 /* In lieu of a halt instruction, induce a long-latency stall. */
80 __asm__ __volatile__ ("div %0, %0, zero" : "=r" (dummy));
81 #endif
82 barrier();
83 }
84
85 static inline void wait_for_interrupt(void)
86 {
87 __asm__ __volatile__ ("wfi");
88 }
89
90 struct device_node;
91 extern int riscv_of_processor_hart(struct device_node *node);
92
93 extern void riscv_fill_hwcap(void);
94
95 #endif /* __ASSEMBLY__ */
96
97 #endif /* _ASM_RISCV_PROCESSOR_H */
98
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