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 register unsigned long gp_in_global __asm__("gp"); 26 27 extern asmlinkage void ret_from_fork(void); 28 extern asmlinkage void ret_from_kernel_thread(void); 29 30 void arch_cpu_idle(void) 31 { 32 wait_for_interrupt(); 33 local_irq_enable(); 34 } 35 36 void show_regs(struct pt_regs *regs) 37 { 38 show_regs_print_info(KERN_DEFAULT); 39 40 pr_cont("epc: " REG_FMT " ra : " REG_FMT " sp : " REG_FMT "\n", 41 regs->epc, regs->ra, regs->sp); 42 pr_cont(" gp : " REG_FMT " tp : " REG_FMT " t0 : " REG_FMT "\n", 43 regs->gp, regs->tp, regs->t0); 44 pr_cont(" t1 : " REG_FMT " t2 : " REG_FMT " s0 : " REG_FMT "\n", 45 regs->t1, regs->t2, regs->s0); 46 pr_cont(" s1 : " REG_FMT " a0 : " REG_FMT " a1 : " REG_FMT "\n", 47 regs->s1, regs->a0, regs->a1); 48 pr_cont(" a2 : " REG_FMT " a3 : " REG_FMT " a4 : " REG_FMT "\n", 49 regs->a2, regs->a3, regs->a4); 50 pr_cont(" a5 : " REG_FMT " a6 : " REG_FMT " a7 : " REG_FMT "\n", 51 regs->a5, regs->a6, regs->a7); 52 pr_cont(" s2 : " REG_FMT " s3 : " REG_FMT " s4 : " REG_FMT "\n", 53 regs->s2, regs->s3, regs->s4); 54 pr_cont(" s5 : " REG_FMT " s6 : " REG_FMT " s7 : " REG_FMT "\n", 55 regs->s5, regs->s6, regs->s7); 56 pr_cont(" s8 : " REG_FMT " s9 : " REG_FMT " s10: " REG_FMT "\n", 57 regs->s8, regs->s9, regs->s10); 58 pr_cont(" s11: " REG_FMT " t3 : " REG_FMT " t4 : " REG_FMT "\n", 59 regs->s11, regs->t3, regs->t4); 60 pr_cont(" t5 : " REG_FMT " t6 : " REG_FMT "\n", 61 regs->t5, regs->t6); 62 63 pr_cont("status: " REG_FMT " badaddr: " REG_FMT " cause: " REG_FMT "\n", 64 regs->status, regs->badaddr, regs->cause); 65 } 66 67 void start_thread(struct pt_regs *regs, unsigned long pc, 68 unsigned long sp) 69 { 70 regs->status = SR_PIE; 71 if (has_fpu) { 72 regs->status |= SR_FS_INITIAL; 73 /* 74 * Restore the initial value to the FP register 75 * before starting the user program. 76 */ 77 fstate_restore(current, regs); 78 } 79 regs->epc = pc; 80 regs->sp = sp; 81 set_fs(USER_DS); 82 } 83 84 void flush_thread(void) 85 { 86 #ifdef CONFIG_FPU 87 /* 88 * Reset FPU state and context 89 * frm: round to nearest, ties to even (IEEE default) 90 * fflags: accrued exceptions cleared 91 */ 92 fstate_off(current, task_pt_regs(current)); 93 memset(¤t->thread.fstate, 0, sizeof(current->thread.fstate)); 94 #endif 95 } 96 97 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) 98 { 99 fstate_save(src, task_pt_regs(src)); 100 *dst = *src; 101 return 0; 102 } 103 104 int copy_thread_tls(unsigned long clone_flags, unsigned long usp, 105 unsigned long arg, struct task_struct *p, unsigned long tls) 106 { 107 struct pt_regs *childregs = task_pt_regs(p); 108 109 /* p->thread holds context to be restored by __switch_to() */ 110 if (unlikely(p->flags & PF_KTHREAD)) { 111 /* Kernel thread */ 112 memset(childregs, 0, sizeof(struct pt_regs)); 113 childregs->gp = gp_in_global; 114 /* Supervisor/Machine, irqs on: */ 115 childregs->status = SR_PP | SR_PIE; 116 117 p->thread.ra = (unsigned long)ret_from_kernel_thread; 118 p->thread.s[0] = usp; /* fn */ 119 p->thread.s[1] = arg; 120 } else { 121 *childregs = *(current_pt_regs()); 122 if (usp) /* User fork */ 123 childregs->sp = usp; 124 if (clone_flags & CLONE_SETTLS) 125 childregs->tp = tls; 126 childregs->a0 = 0; /* Return value of fork() */ 127 p->thread.ra = (unsigned long)ret_from_fork; 128 } 129 p->thread.sp = (unsigned long)childregs; /* kernel sp */ 130 return 0; 131 } 132