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/task_stack.h>
14 #include <linux/tick.h>
15 #include <linux/ptrace.h>
16 #include <linux/uaccess.h>
17
18 #include <asm/unistd.h>
19 #include <asm/processor.h>
20 #include <asm/csr.h>
21 #include <asm/string.h>
22 #include <asm/switch_to.h>
23 #include <asm/thread_info.h>
24
25 register unsigned long gp_in_global __asm__("gp");
26
27 #ifdef CONFIG_STACKPROTECTOR
28 #include <linux/stackprotector.h>
29 unsigned long __stack_chk_guard __read_mostly;
30 EXPORT_SYMBOL(__stack_chk_guard);
31 #endif
32
33 extern asmlinkage void ret_from_fork(void);
34 extern asmlinkage void ret_from_kernel_thread(void);
35
arch_cpu_idle(void)36 void arch_cpu_idle(void)
37 {
38 wait_for_interrupt();
39 raw_local_irq_enable();
40 }
41
show_regs(struct pt_regs * regs)42 void show_regs(struct pt_regs *regs)
43 {
44 show_regs_print_info(KERN_DEFAULT);
45
46 pr_cont("epc: " REG_FMT " ra : " REG_FMT " sp : " REG_FMT "\n",
47 regs->epc, regs->ra, regs->sp);
48 pr_cont(" gp : " REG_FMT " tp : " REG_FMT " t0 : " REG_FMT "\n",
49 regs->gp, regs->tp, regs->t0);
50 pr_cont(" t1 : " REG_FMT " t2 : " REG_FMT " s0 : " REG_FMT "\n",
51 regs->t1, regs->t2, regs->s0);
52 pr_cont(" s1 : " REG_FMT " a0 : " REG_FMT " a1 : " REG_FMT "\n",
53 regs->s1, regs->a0, regs->a1);
54 pr_cont(" a2 : " REG_FMT " a3 : " REG_FMT " a4 : " REG_FMT "\n",
55 regs->a2, regs->a3, regs->a4);
56 pr_cont(" a5 : " REG_FMT " a6 : " REG_FMT " a7 : " REG_FMT "\n",
57 regs->a5, regs->a6, regs->a7);
58 pr_cont(" s2 : " REG_FMT " s3 : " REG_FMT " s4 : " REG_FMT "\n",
59 regs->s2, regs->s3, regs->s4);
60 pr_cont(" s5 : " REG_FMT " s6 : " REG_FMT " s7 : " REG_FMT "\n",
61 regs->s5, regs->s6, regs->s7);
62 pr_cont(" s8 : " REG_FMT " s9 : " REG_FMT " s10: " REG_FMT "\n",
63 regs->s8, regs->s9, regs->s10);
64 pr_cont(" s11: " REG_FMT " t3 : " REG_FMT " t4 : " REG_FMT "\n",
65 regs->s11, regs->t3, regs->t4);
66 pr_cont(" t5 : " REG_FMT " t6 : " REG_FMT "\n",
67 regs->t5, regs->t6);
68
69 pr_cont("status: " REG_FMT " badaddr: " REG_FMT " cause: " REG_FMT "\n",
70 regs->status, regs->badaddr, regs->cause);
71 }
72
start_thread(struct pt_regs * regs,unsigned long pc,unsigned long sp)73 void start_thread(struct pt_regs *regs, unsigned long pc,
74 unsigned long sp)
75 {
76 regs->status = SR_PIE;
77 if (has_fpu) {
78 regs->status |= SR_FS_INITIAL;
79 /*
80 * Restore the initial value to the FP register
81 * before starting the user program.
82 */
83 fstate_restore(current, regs);
84 }
85 regs->epc = pc;
86 regs->sp = sp;
87 }
88
flush_thread(void)89 void flush_thread(void)
90 {
91 #ifdef CONFIG_FPU
92 /*
93 * Reset FPU state and context
94 * frm: round to nearest, ties to even (IEEE default)
95 * fflags: accrued exceptions cleared
96 */
97 fstate_off(current, task_pt_regs(current));
98 memset(¤t->thread.fstate, 0, sizeof(current->thread.fstate));
99 #endif
100 }
101
arch_dup_task_struct(struct task_struct * dst,struct task_struct * src)102 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
103 {
104 fstate_save(src, task_pt_regs(src));
105 *dst = *src;
106 return 0;
107 }
108
copy_thread(unsigned long clone_flags,unsigned long usp,unsigned long arg,struct task_struct * p,unsigned long tls)109 int copy_thread(unsigned long clone_flags, unsigned long usp, unsigned long arg,
110 struct task_struct *p, unsigned long tls)
111 {
112 struct pt_regs *childregs = task_pt_regs(p);
113
114 /* p->thread holds context to be restored by __switch_to() */
115 if (unlikely(p->flags & PF_KTHREAD)) {
116 /* Kernel thread */
117 memset(childregs, 0, sizeof(struct pt_regs));
118 childregs->gp = gp_in_global;
119 /* Supervisor/Machine, irqs on: */
120 childregs->status = SR_PP | SR_PIE;
121
122 p->thread.ra = (unsigned long)ret_from_kernel_thread;
123 p->thread.s[0] = usp; /* fn */
124 p->thread.s[1] = arg;
125 } else {
126 *childregs = *(current_pt_regs());
127 if (usp) /* User fork */
128 childregs->sp = usp;
129 if (clone_flags & CLONE_SETTLS)
130 childregs->tp = tls;
131 childregs->a0 = 0; /* Return value of fork() */
132 p->thread.ra = (unsigned long)ret_from_fork;
133 }
134 p->thread.sp = (unsigned long)childregs; /* kernel sp */
135 return 0;
136 }
137