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
27 register unsigned long gp_in_global __asm__("gp");
28
29 #if defined(CONFIG_STACKPROTECTOR) && !defined(CONFIG_STACKPROTECTOR_PER_TASK)
30 #include <linux/stackprotector.h>
31 unsigned long __stack_chk_guard __read_mostly;
32 EXPORT_SYMBOL(__stack_chk_guard);
33 #endif
34
35 extern asmlinkage void ret_from_fork(void);
36 extern asmlinkage void ret_from_kernel_thread(void);
37
arch_cpu_idle(void)38 void arch_cpu_idle(void)
39 {
40 wait_for_interrupt();
41 raw_local_irq_enable();
42 }
43
__show_regs(struct pt_regs * regs)44 void __show_regs(struct pt_regs *regs)
45 {
46 show_regs_print_info(KERN_DEFAULT);
47
48 if (!user_mode(regs)) {
49 pr_cont("epc : %pS\n", (void *)regs->epc);
50 pr_cont(" ra : %pS\n", (void *)regs->ra);
51 }
52
53 pr_cont("epc : " REG_FMT " ra : " REG_FMT " sp : " REG_FMT "\n",
54 regs->epc, regs->ra, regs->sp);
55 pr_cont(" gp : " REG_FMT " tp : " REG_FMT " t0 : " REG_FMT "\n",
56 regs->gp, regs->tp, regs->t0);
57 pr_cont(" t1 : " REG_FMT " t2 : " REG_FMT " s0 : " REG_FMT "\n",
58 regs->t1, regs->t2, regs->s0);
59 pr_cont(" s1 : " REG_FMT " a0 : " REG_FMT " a1 : " REG_FMT "\n",
60 regs->s1, regs->a0, regs->a1);
61 pr_cont(" a2 : " REG_FMT " a3 : " REG_FMT " a4 : " REG_FMT "\n",
62 regs->a2, regs->a3, regs->a4);
63 pr_cont(" a5 : " REG_FMT " a6 : " REG_FMT " a7 : " REG_FMT "\n",
64 regs->a5, regs->a6, regs->a7);
65 pr_cont(" s2 : " REG_FMT " s3 : " REG_FMT " s4 : " REG_FMT "\n",
66 regs->s2, regs->s3, regs->s4);
67 pr_cont(" s5 : " REG_FMT " s6 : " REG_FMT " s7 : " REG_FMT "\n",
68 regs->s5, regs->s6, regs->s7);
69 pr_cont(" s8 : " REG_FMT " s9 : " REG_FMT " s10: " REG_FMT "\n",
70 regs->s8, regs->s9, regs->s10);
71 pr_cont(" s11: " REG_FMT " t3 : " REG_FMT " t4 : " REG_FMT "\n",
72 regs->s11, regs->t3, regs->t4);
73 pr_cont(" t5 : " REG_FMT " t6 : " REG_FMT "\n",
74 regs->t5, regs->t6);
75
76 pr_cont("status: " REG_FMT " badaddr: " REG_FMT " cause: " REG_FMT "\n",
77 regs->status, regs->badaddr, regs->cause);
78 }
show_regs(struct pt_regs * regs)79 void show_regs(struct pt_regs *regs)
80 {
81 __show_regs(regs);
82 if (!user_mode(regs))
83 dump_backtrace(regs, NULL, KERN_DEFAULT);
84 }
85
start_thread(struct pt_regs * regs,unsigned long pc,unsigned long sp)86 void start_thread(struct pt_regs *regs, unsigned long pc,
87 unsigned long sp)
88 {
89 regs->status = SR_PIE;
90 if (has_fpu()) {
91 regs->status |= SR_FS_INITIAL;
92 /*
93 * Restore the initial value to the FP register
94 * before starting the user program.
95 */
96 fstate_restore(current, regs);
97 }
98 regs->epc = pc;
99 regs->sp = sp;
100 }
101
flush_thread(void)102 void flush_thread(void)
103 {
104 #ifdef CONFIG_FPU
105 /*
106 * Reset FPU state and context
107 * frm: round to nearest, ties to even (IEEE default)
108 * fflags: accrued exceptions cleared
109 */
110 fstate_off(current, task_pt_regs(current));
111 memset(¤t->thread.fstate, 0, sizeof(current->thread.fstate));
112 #endif
113 }
114
arch_dup_task_struct(struct task_struct * dst,struct task_struct * src)115 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
116 {
117 fstate_save(src, task_pt_regs(src));
118 *dst = *src;
119 return 0;
120 }
121
copy_thread(unsigned long clone_flags,unsigned long usp,unsigned long arg,struct task_struct * p,unsigned long tls)122 int copy_thread(unsigned long clone_flags, unsigned long usp, unsigned long arg,
123 struct task_struct *p, unsigned long tls)
124 {
125 struct pt_regs *childregs = task_pt_regs(p);
126
127 memset(&p->thread.s, 0, sizeof(p->thread.s));
128
129 /* p->thread holds context to be restored by __switch_to() */
130 if (unlikely(p->flags & (PF_KTHREAD | PF_IO_WORKER))) {
131 /* Kernel thread */
132 memset(childregs, 0, sizeof(struct pt_regs));
133 childregs->gp = gp_in_global;
134 /* Supervisor/Machine, irqs on: */
135 childregs->status = SR_PP | SR_PIE;
136
137 p->thread.ra = (unsigned long)ret_from_kernel_thread;
138 p->thread.s[0] = usp; /* fn */
139 p->thread.s[1] = arg;
140 } else {
141 *childregs = *(current_pt_regs());
142 if (usp) /* User fork */
143 childregs->sp = usp;
144 if (clone_flags & CLONE_SETTLS)
145 childregs->tp = tls;
146 childregs->a0 = 0; /* Return value of fork() */
147 p->thread.ra = (unsigned long)ret_from_fork;
148 }
149 p->thread.sp = (unsigned long)childregs; /* kernel sp */
150 return 0;
151 }
152