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)->sepc) 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 */ 84