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
  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 */