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>
27 #include <asm/vector.h>
28 #include <asm/cpufeature.h>
30 register unsigned long gp_in_global __asm__("gp");
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);
38 extern asmlinkage void ret_from_fork(void);
40 void arch_cpu_idle(void)
45 int set_unalign_ctl(struct task_struct *tsk, unsigned int val)
47 if (!unaligned_ctl_available())
50 tsk->thread.align_ctl = val;
54 int get_unalign_ctl(struct task_struct *tsk, unsigned long adr)
56 if (!unaligned_ctl_available())
59 return put_user(tsk->thread.align_ctl, (unsigned long __user *)adr);
62 void __show_regs(struct pt_regs *regs)
64 show_regs_print_info(KERN_DEFAULT);
66 if (!user_mode(regs)) {
67 pr_cont("epc : %pS\n", (void *)regs->epc);
68 pr_cont(" ra : %pS\n", (void *)regs->ra);
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",
94 pr_cont("status: " REG_FMT " badaddr: " REG_FMT " cause: " REG_FMT "\n",
95 regs->status, regs->badaddr, regs->cause);
97 void show_regs(struct pt_regs *regs)
100 if (!user_mode(regs))
101 dump_backtrace(regs, NULL, KERN_DEFAULT);
105 static bool compat_mode_supported __read_mostly;
107 bool compat_elf_check_arch(Elf32_Ehdr *hdr)
109 return compat_mode_supported &&
110 hdr->e_machine == EM_RISCV &&
111 hdr->e_ident[EI_CLASS] == ELFCLASS32;
114 static int __init compat_mode_detect(void)
116 unsigned long tmp = csr_read(CSR_STATUS);
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;
122 csr_write(CSR_STATUS, tmp);
124 pr_info("riscv: ELF compat mode %s",
125 compat_mode_supported ? "supported" : "unsupported");
129 early_initcall(compat_mode_detect);
132 void start_thread(struct pt_regs *regs, unsigned long pc,
135 regs->status = SR_PIE;
137 regs->status |= SR_FS_INITIAL;
139 * Restore the initial value to the FP register
140 * before starting the user program.
142 fstate_restore(current, regs);
148 regs->status &= ~SR_UXL;
150 if (is_compat_task())
151 regs->status |= SR_UXL_32;
153 regs->status |= SR_UXL_64;
157 void flush_thread(void)
161 * Reset FPU state and context
162 * frm: round to nearest, ties to even (IEEE default)
163 * fflags: accrued exceptions cleared
165 fstate_off(current, task_pt_regs(current));
166 memset(¤t->thread.fstate, 0, sizeof(current->thread.fstate));
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));
177 void arch_release_task_struct(struct task_struct *tsk)
179 /* Free the vector context of datap. */
181 kfree(tsk->thread.vstate.datap);
184 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
186 fstate_save(src, task_pt_regs(src));
188 /* clear entire V context, including datap for a new task */
189 memset(&dst->thread.vstate, 0, sizeof(struct __riscv_v_ext_state));
194 int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
196 unsigned long clone_flags = args->flags;
197 unsigned long usp = args->stack;
198 unsigned long tls = args->tls;
199 struct pt_regs *childregs = task_pt_regs(p);
201 memset(&p->thread.s, 0, sizeof(p->thread.s));
203 /* p->thread holds context to be restored by __switch_to() */
204 if (unlikely(args->fn)) {
206 memset(childregs, 0, sizeof(struct pt_regs));
207 childregs->gp = gp_in_global;
208 /* Supervisor/Machine, irqs on: */
209 childregs->status = SR_PP | SR_PIE;
211 p->thread.s[0] = (unsigned long)args->fn;
212 p->thread.s[1] = (unsigned long)args->fn_arg;
214 *childregs = *(current_pt_regs());
215 /* Turn off status.VS */
216 riscv_v_vstate_off(childregs);
217 if (usp) /* User fork */
219 if (clone_flags & CLONE_SETTLS)
221 childregs->a0 = 0; /* Return value of fork() */
224 p->thread.ra = (unsigned long)ret_from_fork;
225 p->thread.sp = (unsigned long)childregs; /* kernel sp */