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