arch/riscv/include/asm/processor.h

   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_PROCESSOR_H
   7 #define _ASM_RISCV_PROCESSOR_H
   8
   9 #include <linux/const.h>
  10
  11 #include <asm/ptrace.h>
  12
  13 /*
  14  * This decides where the kernel will search for a free chunk of vm
  15  * space during mmap's.
  16  */
  17 #define TASK_UNMAPPED_BASE      PAGE_ALIGN(TASK_SIZE / 3)
  18
  19 #define STACK_TOP               TASK_SIZE
  20 #define STACK_TOP_MAX           STACK_TOP
  21 #define STACK_ALIGN             16
  22
  23 #ifndef __ASSEMBLY__
  24
  25 struct task_struct;
  26 struct pt_regs;
  27
  28 /* CPU-specific state of a task */
  29 struct thread_struct {
  30         /* Callee-saved registers */
  31         unsigned long ra;
  32         unsigned long sp;       /* Kernel mode stack */
  33         unsigned long s[12];    /* s[0]: frame pointer */
  34         struct __riscv_d_ext_state fstate;
  35 };
  36
  37 #define INIT_THREAD {                                   \
  38         .sp = sizeof(init_stack) + (long)&init_stack,   \
  39 }
  40
  41 #define task_pt_regs(tsk)                                               \
  42         ((struct pt_regs *)(task_stack_page(tsk) + THREAD_SIZE          \
  43                             - ALIGN(sizeof(struct pt_regs), STACK_ALIGN)))
  44
  45 #define KSTK_EIP(tsk)           (task_pt_regs(tsk)->epc)
  46 #define KSTK_ESP(tsk)           (task_pt_regs(tsk)->sp)
  47
  48
  49 /* Do necessary setup to start up a newly executed thread. */
  50 extern void start_thread(struct pt_regs *regs,
  51                         unsigned long pc, unsigned long sp);
  52
  53 /* Free all resources held by a thread. */
  54 static inline void release_thread(struct task_struct *dead_task)
  55 {
  56 }
  57
  58 extern unsigned long get_wchan(struct task_struct *p);
  59
  60
  61 static inline void cpu_relax(void)
  62 {
  63 #ifdef __riscv_muldiv
  64         int dummy;
  65         /* In lieu of a halt instruction, induce a long-latency stall. */
  66         __asm__ __volatile__ ("div %0, %0, zero" : "=r" (dummy));
  67 #endif
  68         barrier();
  69 }
  70
  71 static inline void wait_for_interrupt(void)
  72 {
  73         __asm__ __volatile__ ("wfi");
  74 }
  75
  76 struct device_node;
  77 int riscv_of_processor_hartid(struct device_node *node);
  78
  79 extern void riscv_fill_hwcap(void);
  80
  81 #endif /* __ASSEMBLY__ */
  82
  83 #endif /* _ASM_RISCV_PROCESSOR_H */