xref: /linux/arch/csky/kernel/process.c (revision b8265621f4888af9494e1d685620871ec81bc33d)
1 // SPDX-License-Identifier: GPL-2.0
2 // Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
3 
4 #include <linux/module.h>
5 #include <linux/version.h>
6 #include <linux/sched.h>
7 #include <linux/sched/task_stack.h>
8 #include <linux/sched/debug.h>
9 #include <linux/delay.h>
10 #include <linux/kallsyms.h>
11 #include <linux/uaccess.h>
12 #include <linux/ptrace.h>
13 
14 #include <asm/elf.h>
15 #include <abi/reg_ops.h>
16 
17 struct cpuinfo_csky cpu_data[NR_CPUS];
18 
19 #ifdef CONFIG_STACKPROTECTOR
20 #include <linux/stackprotector.h>
21 unsigned long __stack_chk_guard __read_mostly;
22 EXPORT_SYMBOL(__stack_chk_guard);
23 #endif
24 
25 asmlinkage void ret_from_fork(void);
26 asmlinkage void ret_from_kernel_thread(void);
27 
28 /*
29  * Some archs flush debug and FPU info here
30  */
31 void flush_thread(void){}
32 
33 /*
34  * Return saved PC from a blocked thread
35  */
36 unsigned long thread_saved_pc(struct task_struct *tsk)
37 {
38 	struct switch_stack *sw = (struct switch_stack *)tsk->thread.sp;
39 
40 	return sw->r15;
41 }
42 
43 int copy_thread_tls(unsigned long clone_flags,
44 		unsigned long usp,
45 		unsigned long kthread_arg,
46 		struct task_struct *p,
47 		unsigned long tls)
48 {
49 	struct switch_stack *childstack;
50 	struct pt_regs *childregs = task_pt_regs(p);
51 
52 #ifdef CONFIG_CPU_HAS_FPU
53 	save_to_user_fp(&p->thread.user_fp);
54 #endif
55 
56 	childstack = ((struct switch_stack *) childregs) - 1;
57 	memset(childstack, 0, sizeof(struct switch_stack));
58 
59 	/* setup thread.sp for switch_to !!! */
60 	p->thread.sp = (unsigned long)childstack;
61 
62 	if (unlikely(p->flags & PF_KTHREAD)) {
63 		memset(childregs, 0, sizeof(struct pt_regs));
64 		childstack->r15 = (unsigned long) ret_from_kernel_thread;
65 		childstack->r10 = kthread_arg;
66 		childstack->r9 = usp;
67 		childregs->sr = mfcr("psr");
68 	} else {
69 		*childregs = *(current_pt_regs());
70 		if (usp)
71 			childregs->usp = usp;
72 		if (clone_flags & CLONE_SETTLS)
73 			task_thread_info(p)->tp_value = childregs->tls
74 						      = tls;
75 
76 		childregs->a0 = 0;
77 		childstack->r15 = (unsigned long) ret_from_fork;
78 	}
79 
80 	return 0;
81 }
82 
83 /* Fill in the fpu structure for a core dump.  */
84 int dump_fpu(struct pt_regs *regs, struct user_fp *fpu)
85 {
86 	memcpy(fpu, &current->thread.user_fp, sizeof(*fpu));
87 	return 1;
88 }
89 EXPORT_SYMBOL(dump_fpu);
90 
91 int dump_task_regs(struct task_struct *tsk, elf_gregset_t *pr_regs)
92 {
93 	struct pt_regs *regs = task_pt_regs(tsk);
94 
95 	/* NOTE: usp is error value. */
96 	ELF_CORE_COPY_REGS((*pr_regs), regs)
97 
98 	return 1;
99 }
100 
101 #ifndef CONFIG_CPU_PM_NONE
102 void arch_cpu_idle(void)
103 {
104 #ifdef CONFIG_CPU_PM_WAIT
105 	asm volatile("wait\n");
106 #endif
107 
108 #ifdef CONFIG_CPU_PM_DOZE
109 	asm volatile("doze\n");
110 #endif
111 
112 #ifdef CONFIG_CPU_PM_STOP
113 	asm volatile("stop\n");
114 #endif
115 	local_irq_enable();
116 }
117 #endif
118