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 #include <asm/vector.h> 28 #include <asm/cpufeature.h> 29 30 register unsigned long gp_in_global __asm__("gp"); 31 32 #if defined(CONFIG_STACKPROTECTOR) && !defined(CONFIG_STACKPROTECTOR_PER_TASK) 33 #include <linux/stackprotector.h> 34 unsigned long __stack_chk_guard __read_mostly; 35 EXPORT_SYMBOL(__stack_chk_guard); 36 #endif 37 38 extern asmlinkage void ret_from_fork(void); 39 40 void arch_cpu_idle(void) 41 { 42 cpu_do_idle(); 43 } 44 45 int set_unalign_ctl(struct task_struct *tsk, unsigned int val) 46 { 47 if (!unaligned_ctl_available()) 48 return -EINVAL; 49 50 tsk->thread.align_ctl = val; 51 return 0; 52 } 53 54 int get_unalign_ctl(struct task_struct *tsk, unsigned long adr) 55 { 56 if (!unaligned_ctl_available()) 57 return -EINVAL; 58 59 return put_user(tsk->thread.align_ctl, (unsigned long __user *)adr); 60 } 61 62 void __show_regs(struct pt_regs *regs) 63 { 64 show_regs_print_info(KERN_DEFAULT); 65 66 if (!user_mode(regs)) { 67 pr_cont("epc : %pS\n", (void *)regs->epc); 68 pr_cont(" ra : %pS\n", (void *)regs->ra); 69 } 70 71 pr_cont("epc : " REG_FMT " ra : " REG_FMT " sp : " REG_FMT "\n", 72 regs->epc, regs->ra, regs->sp); 73 pr_cont(" gp : " REG_FMT " tp : " REG_FMT " t0 : " REG_FMT "\n", 74 regs->gp, regs->tp, regs->t0); 75 pr_cont(" t1 : " REG_FMT " t2 : " REG_FMT " s0 : " REG_FMT "\n", 76 regs->t1, regs->t2, regs->s0); 77 pr_cont(" s1 : " REG_FMT " a0 : " REG_FMT " a1 : " REG_FMT "\n", 78 regs->s1, regs->a0, regs->a1); 79 pr_cont(" a2 : " REG_FMT " a3 : " REG_FMT " a4 : " REG_FMT "\n", 80 regs->a2, regs->a3, regs->a4); 81 pr_cont(" a5 : " REG_FMT " a6 : " REG_FMT " a7 : " REG_FMT "\n", 82 regs->a5, regs->a6, regs->a7); 83 pr_cont(" s2 : " REG_FMT " s3 : " REG_FMT " s4 : " REG_FMT "\n", 84 regs->s2, regs->s3, regs->s4); 85 pr_cont(" s5 : " REG_FMT " s6 : " REG_FMT " s7 : " REG_FMT "\n", 86 regs->s5, regs->s6, regs->s7); 87 pr_cont(" s8 : " REG_FMT " s9 : " REG_FMT " s10: " REG_FMT "\n", 88 regs->s8, regs->s9, regs->s10); 89 pr_cont(" s11: " REG_FMT " t3 : " REG_FMT " t4 : " REG_FMT "\n", 90 regs->s11, regs->t3, regs->t4); 91 pr_cont(" t5 : " REG_FMT " t6 : " REG_FMT "\n", 92 regs->t5, regs->t6); 93 94 pr_cont("status: " REG_FMT " badaddr: " REG_FMT " cause: " REG_FMT "\n", 95 regs->status, regs->badaddr, regs->cause); 96 } 97 void show_regs(struct pt_regs *regs) 98 { 99 __show_regs(regs); 100 if (!user_mode(regs)) 101 dump_backtrace(regs, NULL, KERN_DEFAULT); 102 } 103 104 #ifdef CONFIG_COMPAT 105 static bool compat_mode_supported __read_mostly; 106 107 bool compat_elf_check_arch(Elf32_Ehdr *hdr) 108 { 109 return compat_mode_supported && 110 hdr->e_machine == EM_RISCV && 111 hdr->e_ident[EI_CLASS] == ELFCLASS32; 112 } 113 114 static int __init compat_mode_detect(void) 115 { 116 unsigned long tmp = csr_read(CSR_STATUS); 117 118 csr_write(CSR_STATUS, (tmp & ~SR_UXL) | SR_UXL_32); 119 compat_mode_supported = 120 (csr_read(CSR_STATUS) & SR_UXL) == SR_UXL_32; 121 122 csr_write(CSR_STATUS, tmp); 123 124 pr_info("riscv: ELF compat mode %s", 125 compat_mode_supported ? "supported" : "unsupported"); 126 127 return 0; 128 } 129 early_initcall(compat_mode_detect); 130 #endif 131 132 void start_thread(struct pt_regs *regs, unsigned long pc, 133 unsigned long sp) 134 { 135 regs->status = SR_PIE; 136 if (has_fpu()) { 137 regs->status |= SR_FS_INITIAL; 138 /* 139 * Restore the initial value to the FP register 140 * before starting the user program. 141 */ 142 fstate_restore(current, regs); 143 } 144 regs->epc = pc; 145 regs->sp = sp; 146 147 #ifdef CONFIG_64BIT 148 regs->status &= ~SR_UXL; 149 150 if (is_compat_task()) 151 regs->status |= SR_UXL_32; 152 else 153 regs->status |= SR_UXL_64; 154 #endif 155 } 156 157 void flush_thread(void) 158 { 159 #ifdef CONFIG_FPU 160 /* 161 * Reset FPU state and context 162 * frm: round to nearest, ties to even (IEEE default) 163 * fflags: accrued exceptions cleared 164 */ 165 fstate_off(current, task_pt_regs(current)); 166 memset(¤t->thread.fstate, 0, sizeof(current->thread.fstate)); 167 #endif 168 #ifdef CONFIG_RISCV_ISA_V 169 /* Reset vector state */ 170 riscv_v_vstate_ctrl_init(current); 171 riscv_v_vstate_off(task_pt_regs(current)); 172 kfree(current->thread.vstate.datap); 173 memset(¤t->thread.vstate, 0, sizeof(struct __riscv_v_ext_state)); 174 clear_tsk_thread_flag(current, TIF_RISCV_V_DEFER_RESTORE); 175 #endif 176 } 177 178 void arch_release_task_struct(struct task_struct *tsk) 179 { 180 /* Free the vector context of datap. */ 181 if (has_vector()) 182 riscv_v_thread_free(tsk); 183 } 184 185 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) 186 { 187 fstate_save(src, task_pt_regs(src)); 188 *dst = *src; 189 /* clear entire V context, including datap for a new task */ 190 memset(&dst->thread.vstate, 0, sizeof(struct __riscv_v_ext_state)); 191 memset(&dst->thread.kernel_vstate, 0, sizeof(struct __riscv_v_ext_state)); 192 clear_tsk_thread_flag(dst, TIF_RISCV_V_DEFER_RESTORE); 193 194 return 0; 195 } 196 197 int copy_thread(struct task_struct *p, const struct kernel_clone_args *args) 198 { 199 unsigned long clone_flags = args->flags; 200 unsigned long usp = args->stack; 201 unsigned long tls = args->tls; 202 struct pt_regs *childregs = task_pt_regs(p); 203 204 memset(&p->thread.s, 0, sizeof(p->thread.s)); 205 206 /* p->thread holds context to be restored by __switch_to() */ 207 if (unlikely(args->fn)) { 208 /* Kernel thread */ 209 memset(childregs, 0, sizeof(struct pt_regs)); 210 childregs->gp = gp_in_global; 211 /* Supervisor/Machine, irqs on: */ 212 childregs->status = SR_PP | SR_PIE; 213 214 p->thread.s[0] = (unsigned long)args->fn; 215 p->thread.s[1] = (unsigned long)args->fn_arg; 216 } else { 217 *childregs = *(current_pt_regs()); 218 /* Turn off status.VS */ 219 riscv_v_vstate_off(childregs); 220 if (usp) /* User fork */ 221 childregs->sp = usp; 222 if (clone_flags & CLONE_SETTLS) 223 childregs->tp = tls; 224 childregs->a0 = 0; /* Return value of fork() */ 225 p->thread.s[0] = 0; 226 } 227 p->thread.riscv_v_flags = 0; 228 if (has_vector()) 229 riscv_v_thread_alloc(p); 230 p->thread.ra = (unsigned long)ret_from_fork; 231 p->thread.sp = (unsigned long)childregs; /* kernel sp */ 232 return 0; 233 } 234 235 void __init arch_task_cache_init(void) 236 { 237 riscv_v_setup_ctx_cache(); 238 } 239