1 /* 2 * Copyright (C) 2009 Sunplus Core Technology Co., Ltd. 3 * Chen Liqin <liqin.chen@sunplusct.com> 4 * Lennox Wu <lennox.wu@sunplusct.com> 5 * Copyright (C) 2012 Regents of the University of California 6 * Copyright (C) 2017 SiFive 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License as published by 10 * the Free Software Foundation; either version 2 of the License, or 11 * (at your option) any later version. 12 * 13 * This program is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 * GNU General Public License for more details. 17 * 18 * You should have received a copy of the GNU General Public License 19 * along with this program; if not, see the file COPYING, or write 20 * to the Free Software Foundation, Inc., 21 */ 22 23 #include <linux/kernel.h> 24 #include <linux/sched.h> 25 #include <linux/sched/task_stack.h> 26 #include <linux/tick.h> 27 #include <linux/ptrace.h> 28 #include <linux/uaccess.h> 29 30 #include <asm/unistd.h> 31 #include <asm/processor.h> 32 #include <asm/csr.h> 33 #include <asm/string.h> 34 #include <asm/switch_to.h> 35 36 extern asmlinkage void ret_from_fork(void); 37 extern asmlinkage void ret_from_kernel_thread(void); 38 39 void arch_cpu_idle(void) 40 { 41 wait_for_interrupt(); 42 local_irq_enable(); 43 } 44 45 void show_regs(struct pt_regs *regs) 46 { 47 show_regs_print_info(KERN_DEFAULT); 48 49 pr_cont("sepc: " REG_FMT " ra : " REG_FMT " sp : " REG_FMT "\n", 50 regs->sepc, regs->ra, regs->sp); 51 pr_cont(" gp : " REG_FMT " tp : " REG_FMT " t0 : " REG_FMT "\n", 52 regs->gp, regs->tp, regs->t0); 53 pr_cont(" t1 : " REG_FMT " t2 : " REG_FMT " s0 : " REG_FMT "\n", 54 regs->t1, regs->t2, regs->s0); 55 pr_cont(" s1 : " REG_FMT " a0 : " REG_FMT " a1 : " REG_FMT "\n", 56 regs->s1, regs->a0, regs->a1); 57 pr_cont(" a2 : " REG_FMT " a3 : " REG_FMT " a4 : " REG_FMT "\n", 58 regs->a2, regs->a3, regs->a4); 59 pr_cont(" a5 : " REG_FMT " a6 : " REG_FMT " a7 : " REG_FMT "\n", 60 regs->a5, regs->a6, regs->a7); 61 pr_cont(" s2 : " REG_FMT " s3 : " REG_FMT " s4 : " REG_FMT "\n", 62 regs->s2, regs->s3, regs->s4); 63 pr_cont(" s5 : " REG_FMT " s6 : " REG_FMT " s7 : " REG_FMT "\n", 64 regs->s5, regs->s6, regs->s7); 65 pr_cont(" s8 : " REG_FMT " s9 : " REG_FMT " s10: " REG_FMT "\n", 66 regs->s8, regs->s9, regs->s10); 67 pr_cont(" s11: " REG_FMT " t3 : " REG_FMT " t4 : " REG_FMT "\n", 68 regs->s11, regs->t3, regs->t4); 69 pr_cont(" t5 : " REG_FMT " t6 : " REG_FMT "\n", 70 regs->t5, regs->t6); 71 72 pr_cont("sstatus: " REG_FMT " sbadaddr: " REG_FMT " scause: " REG_FMT "\n", 73 regs->sstatus, regs->sbadaddr, regs->scause); 74 } 75 76 void start_thread(struct pt_regs *regs, unsigned long pc, 77 unsigned long sp) 78 { 79 regs->sstatus = SR_SPIE; 80 if (has_fpu) 81 regs->sstatus |= SR_FS_INITIAL; 82 regs->sepc = pc; 83 regs->sp = sp; 84 set_fs(USER_DS); 85 } 86 87 void flush_thread(void) 88 { 89 #ifdef CONFIG_FPU 90 /* 91 * Reset FPU context 92 * frm: round to nearest, ties to even (IEEE default) 93 * fflags: accrued exceptions cleared 94 */ 95 memset(¤t->thread.fstate, 0, sizeof(current->thread.fstate)); 96 #endif 97 } 98 99 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) 100 { 101 fstate_save(src, task_pt_regs(src)); 102 *dst = *src; 103 return 0; 104 } 105 106 int copy_thread(unsigned long clone_flags, unsigned long usp, 107 unsigned long arg, struct task_struct *p) 108 { 109 struct pt_regs *childregs = task_pt_regs(p); 110 111 /* p->thread holds context to be restored by __switch_to() */ 112 if (unlikely(p->flags & PF_KTHREAD)) { 113 /* Kernel thread */ 114 const register unsigned long gp __asm__ ("gp"); 115 memset(childregs, 0, sizeof(struct pt_regs)); 116 childregs->gp = gp; 117 childregs->sstatus = SR_SPP | SR_SPIE; /* Supervisor, irqs on */ 118 119 p->thread.ra = (unsigned long)ret_from_kernel_thread; 120 p->thread.s[0] = usp; /* fn */ 121 p->thread.s[1] = arg; 122 } else { 123 *childregs = *(current_pt_regs()); 124 if (usp) /* User fork */ 125 childregs->sp = usp; 126 if (clone_flags & CLONE_SETTLS) 127 childregs->tp = childregs->a5; 128 childregs->a0 = 0; /* Return value of fork() */ 129 p->thread.ra = (unsigned long)ret_from_fork; 130 } 131 p->thread.sp = (unsigned long)childregs; /* kernel sp */ 132 return 0; 133 } 134