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