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/debug.h> 14 #include <linux/sched/task_stack.h> 15 #include <linux/tick.h> 16 #include <linux/ptrace.h> 17 #include <linux/uaccess.h> 18 19 #include <asm/unistd.h> 20 #include <asm/processor.h> 21 #include <asm/csr.h> 22 #include <asm/stacktrace.h> 23 #include <asm/string.h> 24 #include <asm/switch_to.h> 25 #include <asm/thread_info.h> 26 #include <asm/cpuidle.h> 27 28 register unsigned long gp_in_global __asm__("gp"); 29 30 #if defined(CONFIG_STACKPROTECTOR) && !defined(CONFIG_STACKPROTECTOR_PER_TASK) 31 #include <linux/stackprotector.h> 32 unsigned long __stack_chk_guard __read_mostly; 33 EXPORT_SYMBOL(__stack_chk_guard); 34 #endif 35 36 extern asmlinkage void ret_from_fork(void); 37 38 void arch_cpu_idle(void) 39 { 40 cpu_do_idle(); 41 } 42 43 void __show_regs(struct pt_regs *regs) 44 { 45 show_regs_print_info(KERN_DEFAULT); 46 47 if (!user_mode(regs)) { 48 pr_cont("epc : %pS\n", (void *)regs->epc); 49 pr_cont(" ra : %pS\n", (void *)regs->ra); 50 } 51 52 pr_cont("epc : " REG_FMT " ra : " REG_FMT " sp : " REG_FMT "\n", 53 regs->epc, regs->ra, regs->sp); 54 pr_cont(" gp : " REG_FMT " tp : " REG_FMT " t0 : " REG_FMT "\n", 55 regs->gp, regs->tp, regs->t0); 56 pr_cont(" t1 : " REG_FMT " t2 : " REG_FMT " s0 : " REG_FMT "\n", 57 regs->t1, regs->t2, regs->s0); 58 pr_cont(" s1 : " REG_FMT " a0 : " REG_FMT " a1 : " REG_FMT "\n", 59 regs->s1, regs->a0, regs->a1); 60 pr_cont(" a2 : " REG_FMT " a3 : " REG_FMT " a4 : " REG_FMT "\n", 61 regs->a2, regs->a3, regs->a4); 62 pr_cont(" a5 : " REG_FMT " a6 : " REG_FMT " a7 : " REG_FMT "\n", 63 regs->a5, regs->a6, regs->a7); 64 pr_cont(" s2 : " REG_FMT " s3 : " REG_FMT " s4 : " REG_FMT "\n", 65 regs->s2, regs->s3, regs->s4); 66 pr_cont(" s5 : " REG_FMT " s6 : " REG_FMT " s7 : " REG_FMT "\n", 67 regs->s5, regs->s6, regs->s7); 68 pr_cont(" s8 : " REG_FMT " s9 : " REG_FMT " s10: " REG_FMT "\n", 69 regs->s8, regs->s9, regs->s10); 70 pr_cont(" s11: " REG_FMT " t3 : " REG_FMT " t4 : " REG_FMT "\n", 71 regs->s11, regs->t3, regs->t4); 72 pr_cont(" t5 : " REG_FMT " t6 : " REG_FMT "\n", 73 regs->t5, regs->t6); 74 75 pr_cont("status: " REG_FMT " badaddr: " REG_FMT " cause: " REG_FMT "\n", 76 regs->status, regs->badaddr, regs->cause); 77 } 78 void show_regs(struct pt_regs *regs) 79 { 80 __show_regs(regs); 81 if (!user_mode(regs)) 82 dump_backtrace(regs, NULL, KERN_DEFAULT); 83 } 84 85 #ifdef CONFIG_COMPAT 86 static bool compat_mode_supported __read_mostly; 87 88 bool compat_elf_check_arch(Elf32_Ehdr *hdr) 89 { 90 return compat_mode_supported && 91 hdr->e_machine == EM_RISCV && 92 hdr->e_ident[EI_CLASS] == ELFCLASS32; 93 } 94 95 static int __init compat_mode_detect(void) 96 { 97 unsigned long tmp = csr_read(CSR_STATUS); 98 99 csr_write(CSR_STATUS, (tmp & ~SR_UXL) | SR_UXL_32); 100 compat_mode_supported = 101 (csr_read(CSR_STATUS) & SR_UXL) == SR_UXL_32; 102 103 csr_write(CSR_STATUS, tmp); 104 105 pr_info("riscv: ELF compat mode %s", 106 compat_mode_supported ? "supported" : "unsupported"); 107 108 return 0; 109 } 110 early_initcall(compat_mode_detect); 111 #endif 112 113 void start_thread(struct pt_regs *regs, unsigned long pc, 114 unsigned long sp) 115 { 116 regs->status = SR_PIE; 117 if (has_fpu()) { 118 regs->status |= SR_FS_INITIAL; 119 /* 120 * Restore the initial value to the FP register 121 * before starting the user program. 122 */ 123 fstate_restore(current, regs); 124 } 125 regs->epc = pc; 126 regs->sp = sp; 127 128 #ifdef CONFIG_64BIT 129 regs->status &= ~SR_UXL; 130 131 if (is_compat_task()) 132 regs->status |= SR_UXL_32; 133 else 134 regs->status |= SR_UXL_64; 135 #endif 136 } 137 138 void flush_thread(void) 139 { 140 #ifdef CONFIG_FPU 141 /* 142 * Reset FPU state and context 143 * frm: round to nearest, ties to even (IEEE default) 144 * fflags: accrued exceptions cleared 145 */ 146 fstate_off(current, task_pt_regs(current)); 147 memset(¤t->thread.fstate, 0, sizeof(current->thread.fstate)); 148 #endif 149 } 150 151 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) 152 { 153 fstate_save(src, task_pt_regs(src)); 154 *dst = *src; 155 return 0; 156 } 157 158 int copy_thread(struct task_struct *p, const struct kernel_clone_args *args) 159 { 160 unsigned long clone_flags = args->flags; 161 unsigned long usp = args->stack; 162 unsigned long tls = args->tls; 163 struct pt_regs *childregs = task_pt_regs(p); 164 165 memset(&p->thread.s, 0, sizeof(p->thread.s)); 166 167 /* p->thread holds context to be restored by __switch_to() */ 168 if (unlikely(args->fn)) { 169 /* Kernel thread */ 170 memset(childregs, 0, sizeof(struct pt_regs)); 171 childregs->gp = gp_in_global; 172 /* Supervisor/Machine, irqs on: */ 173 childregs->status = SR_PP | SR_PIE; 174 175 p->thread.s[0] = (unsigned long)args->fn; 176 p->thread.s[1] = (unsigned long)args->fn_arg; 177 } else { 178 *childregs = *(current_pt_regs()); 179 if (usp) /* User fork */ 180 childregs->sp = usp; 181 if (clone_flags & CLONE_SETTLS) 182 childregs->tp = tls; 183 childregs->a0 = 0; /* Return value of fork() */ 184 p->thread.s[0] = 0; 185 } 186 p->thread.ra = (unsigned long)ret_from_fork; 187 p->thread.sp = (unsigned long)childregs; /* kernel sp */ 188 return 0; 189 } 190