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