LXR linux/arch/riscv/kernel/process.c

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * Copyright (C) 2009 Sunplus Core Technology Co., Ltd.
   4 *  Chen Liqin <liqin.chen@sunplusct.com>
   5 *  Lennox Wu <lennox.wu@sunplusct.com>
   6 * Copyright (C) 2012 Regents of the University of California
   7 * Copyright (C) 2017 SiFive
   8 */
   9
  10#include <linux/cpu.h>
  11#include <linux/kernel.h>
  12#include <linux/sched.h>
  13#include <linux/sched/task_stack.h>
  14#include <linux/tick.h>
  15#include <linux/ptrace.h>
  16#include <linux/uaccess.h>
  17
  18#include <asm/unistd.h>
  19#include <asm/processor.h>
  20#include <asm/csr.h>
  21#include <asm/string.h>
  22#include <asm/switch_to.h>
  23#include <asm/thread_info.h>
  24
  25register unsigned long gp_in_global __asm__("gp");
  26
  27#ifdef CONFIG_STACKPROTECTOR
  28#include <linux/stackprotector.h>
  29unsigned long __stack_chk_guard __read_mostly;
  30EXPORT_SYMBOL(__stack_chk_guard);
  31#endif
  32
  33extern asmlinkage void ret_from_fork(void);
  34extern asmlinkage void ret_from_kernel_thread(void);
  35
  36void arch_cpu_idle(void)
  37{
  38        wait_for_interrupt();
  39        local_irq_enable();
  40}
  41
  42void show_regs(struct pt_regs *regs)
  43{
  44        show_regs_print_info(KERN_DEFAULT);
  45
  46        pr_cont("epc: " REG_FMT " ra : " REG_FMT " sp : " REG_FMT "\n",
  47                regs->epc, regs->ra, regs->sp);
  48        pr_cont(" gp : " REG_FMT " tp : " REG_FMT " t0 : " REG_FMT "\n",
  49                regs->gp, regs->tp, regs->t0);
  50        pr_cont(" t1 : " REG_FMT " t2 : " REG_FMT " s0 : " REG_FMT "\n",
  51                regs->t1, regs->t2, regs->s0);
  52        pr_cont(" s1 : " REG_FMT " a0 : " REG_FMT " a1 : " REG_FMT "\n",
  53                regs->s1, regs->a0, regs->a1);
  54        pr_cont(" a2 : " REG_FMT " a3 : " REG_FMT " a4 : " REG_FMT "\n",
  55                regs->a2, regs->a3, regs->a4);
  56        pr_cont(" a5 : " REG_FMT " a6 : " REG_FMT " a7 : " REG_FMT "\n",
  57                regs->a5, regs->a6, regs->a7);
  58        pr_cont(" s2 : " REG_FMT " s3 : " REG_FMT " s4 : " REG_FMT "\n",
  59                regs->s2, regs->s3, regs->s4);
  60        pr_cont(" s5 : " REG_FMT " s6 : " REG_FMT " s7 : " REG_FMT "\n",
  61                regs->s5, regs->s6, regs->s7);
  62        pr_cont(" s8 : " REG_FMT " s9 : " REG_FMT " s10: " REG_FMT "\n",
  63                regs->s8, regs->s9, regs->s10);
  64        pr_cont(" s11: " REG_FMT " t3 : " REG_FMT " t4 : " REG_FMT "\n",
  65                regs->s11, regs->t3, regs->t4);
  66        pr_cont(" t5 : " REG_FMT " t6 : " REG_FMT "\n",
  67                regs->t5, regs->t6);
  68
  69        pr_cont("status: " REG_FMT " badaddr: " REG_FMT " cause: " REG_FMT "\n",
  70                regs->status, regs->badaddr, regs->cause);
  71}
  72
  73void start_thread(struct pt_regs *regs, unsigned long pc,
  74        unsigned long sp)
  75{
  76        regs->status = SR_PIE;
  77        if (has_fpu) {
  78                regs->status |= SR_FS_INITIAL;
  79                /*
  80                 * Restore the initial value to the FP register
  81                 * before starting the user program.
  82                 */
  83                fstate_restore(current, regs);
  84        }
  85        regs->epc = pc;
  86        regs->sp = sp;
  87        set_fs(USER_DS);
  88}
  89
  90void flush_thread(void)
  91{
  92#ifdef CONFIG_FPU
  93        /*
  94         * Reset FPU state and context
  95         *      frm: round to nearest, ties to even (IEEE default)
  96         *      fflags: accrued exceptions cleared
  97         */
  98        fstate_off(current, task_pt_regs(current));
  99        memset(&current->thread.fstate, 0, sizeof(current->thread.fstate));
 100#endif
 101}
 102
 103int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
 104{
 105        fstate_save(src, task_pt_regs(src));
 106        *dst = *src;
 107        return 0;
 108}
 109
 110int copy_thread(unsigned long clone_flags, unsigned long usp, unsigned long arg,
 111                struct task_struct *p, unsigned long tls)
 112{
 113        struct pt_regs *childregs = task_pt_regs(p);
 114
 115        /* p->thread holds context to be restored by __switch_to() */
 116        if (unlikely(p->flags & PF_KTHREAD)) {
 117                /* Kernel thread */
 118                memset(childregs, 0, sizeof(struct pt_regs));
 119                childregs->gp = gp_in_global;
 120                /* Supervisor/Machine, irqs on: */
 121                childregs->status = SR_PP | SR_PIE;
 122
 123                p->thread.ra = (unsigned long)ret_from_kernel_thread;
 124                p->thread.s[0] = usp; /* fn */
 125                p->thread.s[1] = arg;
 126        } else {
 127                *childregs = *(current_pt_regs());
 128                if (usp) /* User fork */
 129                        childregs->sp = usp;
 130                if (clone_flags & CLONE_SETTLS)
 131                        childregs->tp = tls;
 132                childregs->a0 = 0; /* Return value of fork() */
 133                p->thread.ra = (unsigned long)ret_from_fork;
 134        }
 135        p->thread.sp = (unsigned long)childregs; /* kernel sp */
 136        return 0;
 137}
 138