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 25 extern asmlinkage void ret_from_fork(void); 26 extern asmlinkage void ret_from_kernel_thread(void); 27 28 void arch_cpu_idle(void) 29 { 30 wait_for_interrupt(); 31 local_irq_enable(); 32 } 33 34 void show_regs(struct pt_regs *regs) 35 { 36 show_regs_print_info(KERN_DEFAULT); 37 38 pr_cont("epc: " REG_FMT " ra : " REG_FMT " sp : " REG_FMT "\n", 39 regs->epc, regs->ra, regs->sp); 40 pr_cont(" gp : " REG_FMT " tp : " REG_FMT " t0 : " REG_FMT "\n", 41 regs->gp, regs->tp, regs->t0); 42 pr_cont(" t1 : " REG_FMT " t2 : " REG_FMT " s0 : " REG_FMT "\n", 43 regs->t1, regs->t2, regs->s0); 44 pr_cont(" s1 : " REG_FMT " a0 : " REG_FMT " a1 : " REG_FMT "\n", 45 regs->s1, regs->a0, regs->a1); 46 pr_cont(" a2 : " REG_FMT " a3 : " REG_FMT " a4 : " REG_FMT "\n", 47 regs->a2, regs->a3, regs->a4); 48 pr_cont(" a5 : " REG_FMT " a6 : " REG_FMT " a7 : " REG_FMT "\n", 49 regs->a5, regs->a6, regs->a7); 50 pr_cont(" s2 : " REG_FMT " s3 : " REG_FMT " s4 : " REG_FMT "\n", 51 regs->s2, regs->s3, regs->s4); 52 pr_cont(" s5 : " REG_FMT " s6 : " REG_FMT " s7 : " REG_FMT "\n", 53 regs->s5, regs->s6, regs->s7); 54 pr_cont(" s8 : " REG_FMT " s9 : " REG_FMT " s10: " REG_FMT "\n", 55 regs->s8, regs->s9, regs->s10); 56 pr_cont(" s11: " REG_FMT " t3 : " REG_FMT " t4 : " REG_FMT "\n", 57 regs->s11, regs->t3, regs->t4); 58 pr_cont(" t5 : " REG_FMT " t6 : " REG_FMT "\n", 59 regs->t5, regs->t6); 60 61 pr_cont("status: " REG_FMT " badaddr: " REG_FMT " cause: " REG_FMT "\n", 62 regs->status, regs->badaddr, regs->cause); 63 } 64 65 void start_thread(struct pt_regs *regs, unsigned long pc, 66 unsigned long sp) 67 { 68 regs->status = SR_PIE; 69 if (has_fpu) { 70 regs->status |= SR_FS_INITIAL; 71 /* 72 * Restore the initial value to the FP register 73 * before starting the user program. 74 */ 75 fstate_restore(current, regs); 76 } 77 regs->epc = pc; 78 regs->sp = sp; 79 set_fs(USER_DS); 80 } 81 82 void flush_thread(void) 83 { 84 #ifdef CONFIG_FPU 85 /* 86 * Reset FPU state and context 87 * frm: round to nearest, ties to even (IEEE default) 88 * fflags: accrued exceptions cleared 89 */ 90 fstate_off(current, task_pt_regs(current)); 91 memset(¤t->thread.fstate, 0, sizeof(current->thread.fstate)); 92 #endif 93 } 94 95 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) 96 { 97 fstate_save(src, task_pt_regs(src)); 98 *dst = *src; 99 return 0; 100 } 101 102 int copy_thread(unsigned long clone_flags, unsigned long usp, 103 unsigned long arg, struct task_struct *p) 104 { 105 struct pt_regs *childregs = task_pt_regs(p); 106 107 /* p->thread holds context to be restored by __switch_to() */ 108 if (unlikely(p->flags & PF_KTHREAD)) { 109 /* Kernel thread */ 110 const register unsigned long gp __asm__ ("gp"); 111 memset(childregs, 0, sizeof(struct pt_regs)); 112 childregs->gp = gp; 113 /* Supervisor/Machine, irqs on: */ 114 childregs->status = SR_PP | SR_PIE; 115 116 p->thread.ra = (unsigned long)ret_from_kernel_thread; 117 p->thread.s[0] = usp; /* fn */ 118 p->thread.s[1] = arg; 119 } else { 120 *childregs = *(current_pt_regs()); 121 if (usp) /* User fork */ 122 childregs->sp = usp; 123 if (clone_flags & CLONE_SETTLS) 124 childregs->tp = childregs->a5; 125 childregs->a0 = 0; /* Return value of fork() */ 126 p->thread.ra = (unsigned long)ret_from_fork; 127 } 128 p->thread.sp = (unsigned long)childregs; /* kernel sp */ 129 return 0; 130 } 131