LXR linux/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 >> 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
  33struct task_struct;
  34struct 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 */
  43struct 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. */
  64extern void start_thread(struct pt_regs *regs,
  65                        unsigned long pc, unsigned long sp);
  66
  67/* Free all resources held by a thread. */
  68static inline void release_thread(struct task_struct *dead_task)
  69{
  70}
  71
  72extern unsigned long get_wchan(struct task_struct *p);
  73
  74
  75static 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
  85static inline void wait_for_interrupt(void)
  86{
  87        __asm__ __volatile__ ("wfi");
  88}
  89
  90struct device_node;
  91extern int riscv_of_processor_hart(struct device_node *node);
  92
  93extern void riscv_fill_hwcap(void);
  94
  95#endif /* __ASSEMBLY__ */
  96
  97#endif /* _ASM_RISCV_PROCESSOR_H */
  98