1 // SPDX-License-Identifier: GPL-2.0-or-later
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
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>
19 #include <asm/unistd.h>
20 #include <asm/processor.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>
28 #if defined(CONFIG_STACKPROTECTOR) && !defined(CONFIG_STACKPROTECTOR_PER_TASK)
29 #include <linux/stackprotector.h>
30 unsigned long __stack_chk_guard __read_mostly;
31 EXPORT_SYMBOL(__stack_chk_guard);
34 extern asmlinkage void ret_from_fork(void);
35 extern asmlinkage void ret_from_kernel_thread(void);
37 void arch_cpu_idle(void)
40 raw_local_irq_enable();
43 void __show_regs(struct pt_regs *regs)
45 show_regs_print_info(KERN_DEFAULT);
47 if (!user_mode(regs)) {
48 pr_cont("epc : %pS\n", (void *)regs->epc);
49 pr_cont(" ra : %pS\n", (void *)regs->ra);
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",
75 pr_cont("status: " REG_FMT " badaddr: " REG_FMT " cause: " REG_FMT "\n",
76 regs->status, regs->badaddr, regs->cause);
78 void show_regs(struct pt_regs *regs)
82 dump_backtrace(regs, NULL, KERN_DEFAULT);
86 static bool compat_mode_supported __read_mostly;
88 bool compat_elf_check_arch(Elf32_Ehdr *hdr)
90 return compat_mode_supported &&
91 hdr->e_machine == EM_RISCV &&
92 hdr->e_ident[EI_CLASS] == ELFCLASS32;
95 static int __init compat_mode_detect(void)
97 unsigned long tmp = csr_read(CSR_STATUS);
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;
103 csr_write(CSR_STATUS, tmp);
105 pr_info("riscv: ELF compat mode %s",
106 compat_mode_supported ? "supported" : "unsupported");
110 early_initcall(compat_mode_detect);
113 void start_thread(struct pt_regs *regs, unsigned long pc,
116 regs->status = SR_PIE;
118 regs->status |= SR_FS_INITIAL;
120 * Restore the initial value to the FP register
121 * before starting the user program.
123 fstate_restore(current, regs);
129 regs->status &= ~SR_UXL;
131 if (is_compat_task())
132 regs->status |= SR_UXL_32;
134 regs->status |= SR_UXL_64;
138 void flush_thread(void)
142 * Reset FPU state and context
143 * frm: round to nearest, ties to even (IEEE default)
144 * fflags: accrued exceptions cleared
146 fstate_off(current, task_pt_regs(current));
147 memset(¤t->thread.fstate, 0, sizeof(current->thread.fstate));
151 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
153 fstate_save(src, task_pt_regs(src));
158 int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
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);
165 memset(&p->thread.s, 0, sizeof(p->thread.s));
167 /* p->thread holds context to be restored by __switch_to() */
168 if (unlikely(args->fn)) {
170 memset(childregs, 0, sizeof(struct pt_regs));
171 /* Supervisor/Machine, irqs on: */
172 childregs->status = SR_PP | SR_PIE;
174 p->thread.ra = (unsigned long)ret_from_kernel_thread;
175 p->thread.s[0] = (unsigned long)args->fn;
176 p->thread.s[1] = (unsigned long)args->fn_arg;
178 *childregs = *(current_pt_regs());
179 if (usp) /* User fork */
181 if (clone_flags & CLONE_SETTLS)
183 childregs->a0 = 0; /* Return value of fork() */
184 p->thread.ra = (unsigned long)ret_from_fork;
186 p->thread.sp = (unsigned long)childregs; /* kernel sp */