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 extern asmlinkage void ret_from_kernel_thread(void); 38 39 void arch_cpu_idle(void) 40 { 41 cpu_do_idle(); 42 } 43 44 void __show_regs(struct pt_regs *regs) 45 { 46 show_regs_print_info(KERN_DEFAULT); 47 48 if (!user_mode(regs)) { 49 pr_cont("epc : %pS\n", (void *)regs->epc); 50 pr_cont(" ra : %pS\n", (void *)regs->ra); 51 } 52 53 pr_cont("epc : " REG_FMT " ra : " REG_FMT " sp : " REG_FMT "\n", 54 regs->epc, regs->ra, regs->sp); 55 pr_cont(" gp : " REG_FMT " tp : " REG_FMT " t0 : " REG_FMT "\n", 56 regs->gp, regs->tp, regs->t0); 57 pr_cont(" t1 : " REG_FMT " t2 : " REG_FMT " s0 : " REG_FMT "\n", 58 regs->t1, regs->t2, regs->s0); 59 pr_cont(" s1 : " REG_FMT " a0 : " REG_FMT " a1 : " REG_FMT "\n", 60 regs->s1, regs->a0, regs->a1); 61 pr_cont(" a2 : " REG_FMT " a3 : " REG_FMT " a4 : " REG_FMT "\n", 62 regs->a2, regs->a3, regs->a4); 63 pr_cont(" a5 : " REG_FMT " a6 : " REG_FMT " a7 : " REG_FMT "\n", 64 regs->a5, regs->a6, regs->a7); 65 pr_cont(" s2 : " REG_FMT " s3 : " REG_FMT " s4 : " REG_FMT "\n", 66 regs->s2, regs->s3, regs->s4); 67 pr_cont(" s5 : " REG_FMT " s6 : " REG_FMT " s7 : " REG_FMT "\n", 68 regs->s5, regs->s6, regs->s7); 69 pr_cont(" s8 : " REG_FMT " s9 : " REG_FMT " s10: " REG_FMT "\n", 70 regs->s8, regs->s9, regs->s10); 71 pr_cont(" s11: " REG_FMT " t3 : " REG_FMT " t4 : " REG_FMT "\n", 72 regs->s11, regs->t3, regs->t4); 73 pr_cont(" t5 : " REG_FMT " t6 : " REG_FMT "\n", 74 regs->t5, regs->t6); 75 76 pr_cont("status: " REG_FMT " badaddr: " REG_FMT " cause: " REG_FMT "\n", 77 regs->status, regs->badaddr, regs->cause); 78 } 79 void show_regs(struct pt_regs *regs) 80 { 81 __show_regs(regs); 82 if (!user_mode(regs)) 83 dump_backtrace(regs, NULL, KERN_DEFAULT); 84 } 85 86 #ifdef CONFIG_COMPAT 87 static bool compat_mode_supported __read_mostly; 88 89 bool compat_elf_check_arch(Elf32_Ehdr *hdr) 90 { 91 return compat_mode_supported && 92 hdr->e_machine == EM_RISCV && 93 hdr->e_ident[EI_CLASS] == ELFCLASS32; 94 } 95 96 static int __init compat_mode_detect(void) 97 { 98 unsigned long tmp = csr_read(CSR_STATUS); 99 100 csr_write(CSR_STATUS, (tmp & ~SR_UXL) | SR_UXL_32); 101 compat_mode_supported = 102 (csr_read(CSR_STATUS) & SR_UXL) == SR_UXL_32; 103 104 csr_write(CSR_STATUS, tmp); 105 106 pr_info("riscv: ELF compat mode %s", 107 compat_mode_supported ? "supported" : "unsupported"); 108 109 return 0; 110 } 111 early_initcall(compat_mode_detect); 112 #endif 113 114 void start_thread(struct pt_regs *regs, unsigned long pc, 115 unsigned long sp) 116 { 117 regs->status = SR_PIE; 118 if (has_fpu()) { 119 regs->status |= SR_FS_INITIAL; 120 /* 121 * Restore the initial value to the FP register 122 * before starting the user program. 123 */ 124 fstate_restore(current, regs); 125 } 126 regs->epc = pc; 127 regs->sp = sp; 128 129 #ifdef CONFIG_64BIT 130 regs->status &= ~SR_UXL; 131 132 if (is_compat_task()) 133 regs->status |= SR_UXL_32; 134 else 135 regs->status |= SR_UXL_64; 136 #endif 137 } 138 139 void flush_thread(void) 140 { 141 #ifdef CONFIG_FPU 142 /* 143 * Reset FPU state and context 144 * frm: round to nearest, ties to even (IEEE default) 145 * fflags: accrued exceptions cleared 146 */ 147 fstate_off(current, task_pt_regs(current)); 148 memset(¤t->thread.fstate, 0, sizeof(current->thread.fstate)); 149 #endif 150 } 151 152 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) 153 { 154 fstate_save(src, task_pt_regs(src)); 155 *dst = *src; 156 return 0; 157 } 158 159 int copy_thread(struct task_struct *p, const struct kernel_clone_args *args) 160 { 161 unsigned long clone_flags = args->flags; 162 unsigned long usp = args->stack; 163 unsigned long tls = args->tls; 164 struct pt_regs *childregs = task_pt_regs(p); 165 166 memset(&p->thread.s, 0, sizeof(p->thread.s)); 167 168 /* p->thread holds context to be restored by __switch_to() */ 169 if (unlikely(args->fn)) { 170 /* Kernel thread */ 171 memset(childregs, 0, sizeof(struct pt_regs)); 172 childregs->gp = gp_in_global; 173 /* Supervisor/Machine, irqs on: */ 174 childregs->status = SR_PP | SR_PIE; 175 176 p->thread.ra = (unsigned long)ret_from_kernel_thread; 177 p->thread.s[0] = (unsigned long)args->fn; 178 p->thread.s[1] = (unsigned long)args->fn_arg; 179 } else { 180 *childregs = *(current_pt_regs()); 181 if (usp) /* User fork */ 182 childregs->sp = usp; 183 if (clone_flags & CLONE_SETTLS) 184 childregs->tp = tls; 185 childregs->a0 = 0; /* Return value of fork() */ 186 p->thread.ra = (unsigned long)ret_from_fork; 187 } 188 p->thread.sp = (unsigned long)childregs; /* kernel sp */ 189 return 0; 190 } 191