linux_dsm_epyc7002/arch/riscv/include/asm/processor.h
Palmer Dabbelt 7db91e57a0 RISC-V: Task implementation
This patch contains the implementation of tasks on RISC-V, most of which
is involved in task switching.

Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com>
2017-09-26 15:26:46 -07:00

98 lines
2.4 KiB
C

/*
* Copyright (C) 2012 Regents of the University of California
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, version 2.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#ifndef _ASM_RISCV_PROCESSOR_H
#define _ASM_RISCV_PROCESSOR_H
#include <linux/const.h>
#include <asm/ptrace.h>
/*
* This decides where the kernel will search for a free chunk of vm
* space during mmap's.
*/
#define TASK_UNMAPPED_BASE PAGE_ALIGN(TASK_SIZE >> 1)
#define STACK_TOP TASK_SIZE
#define STACK_TOP_MAX STACK_TOP
#define STACK_ALIGN 16
#ifndef __ASSEMBLY__
struct task_struct;
struct pt_regs;
/*
* Default implementation of macro that returns current
* instruction pointer ("program counter").
*/
#define current_text_addr() ({ __label__ _l; _l: &&_l; })
/* CPU-specific state of a task */
struct thread_struct {
/* Callee-saved registers */
unsigned long ra;
unsigned long sp; /* Kernel mode stack */
unsigned long s[12]; /* s[0]: frame pointer */
struct __riscv_d_ext_state fstate;
};
#define INIT_THREAD { \
.sp = sizeof(init_stack) + (long)&init_stack, \
}
#define task_pt_regs(tsk) \
((struct pt_regs *)(task_stack_page(tsk) + THREAD_SIZE \
- ALIGN(sizeof(struct pt_regs), STACK_ALIGN)))
#define KSTK_EIP(tsk) (task_pt_regs(tsk)->sepc)
#define KSTK_ESP(tsk) (task_pt_regs(tsk)->sp)
/* Do necessary setup to start up a newly executed thread. */
extern void start_thread(struct pt_regs *regs,
unsigned long pc, unsigned long sp);
/* Free all resources held by a thread. */
static inline void release_thread(struct task_struct *dead_task)
{
}
extern unsigned long get_wchan(struct task_struct *p);
static inline void cpu_relax(void)
{
#ifdef __riscv_muldiv
int dummy;
/* In lieu of a halt instruction, induce a long-latency stall. */
__asm__ __volatile__ ("div %0, %0, zero" : "=r" (dummy));
#endif
barrier();
}
static inline void wait_for_interrupt(void)
{
__asm__ __volatile__ ("wfi");
}
struct device_node;
extern int riscv_of_processor_hart(struct device_node *node);
extern void riscv_fill_hwcap(void);
#endif /* __ASSEMBLY__ */
#endif /* _ASM_RISCV_PROCESSOR_H */