arch/riscv/include/asm/processor.h

   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 / 3)
  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 /* CPU-specific state of a task */
  37 struct thread_struct {
  38         /* Callee-saved registers */
  39         unsigned long ra;
  40         unsigned long sp;       /* Kernel mode stack */
  41         unsigned long s[12];    /* s[0]: frame pointer */
  42         struct __riscv_d_ext_state fstate;
  43 };
  44
  45 #define INIT_THREAD {                                   \
  46         .sp = sizeof(init_stack) + (long)&init_stack,   \
  47 }
  48
  49 #define task_pt_regs(tsk)                                               \
  50         ((struct pt_regs *)(task_stack_page(tsk) + THREAD_SIZE          \
  51                             - ALIGN(sizeof(struct pt_regs), STACK_ALIGN)))
  52
  53 #define KSTK_EIP(tsk)           (task_pt_regs(tsk)->sepc)
  54 #define KSTK_ESP(tsk)           (task_pt_regs(tsk)->sp)
  55
  56
  57 /* Do necessary setup to start up a newly executed thread. */
  58 extern void start_thread(struct pt_regs *regs,
  59                         unsigned long pc, unsigned long sp);
  60
  61 /* Free all resources held by a thread. */
  62 static inline void release_thread(struct task_struct *dead_task)
  63 {
  64 }
  65
  66 extern unsigned long get_wchan(struct task_struct *p);
  67
  68
  69 static inline void cpu_relax(void)
  70 {
  71 #ifdef __riscv_muldiv
  72         int dummy;
  73         /* In lieu of a halt instruction, induce a long-latency stall. */
  74         __asm__ __volatile__ ("div %0, %0, zero" : "=r" (dummy));
  75 #endif
  76         barrier();
  77 }
  78
  79 static inline void wait_for_interrupt(void)
  80 {
  81         __asm__ __volatile__ ("wfi");
  82 }
  83
  84 struct device_node;
  85 int riscv_of_processor_hartid(struct device_node *node);
  86
  87 extern void riscv_fill_hwcap(void);
  88
  89 #endif /* __ASSEMBLY__ */
  90
  91 #endif /* _ASM_RISCV_PROCESSOR_H */