summaryrefslogtreecommitdiff
path: root/arch/riscv/kernel/process.c
blob: 2b97c493427c9e6b2210990d687d72f0e4abb21d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (C) 2009 Sunplus Core Technology Co., Ltd.
 *  Chen Liqin <liqin.chen@sunplusct.com>
 *  Lennox Wu <lennox.wu@sunplusct.com>
 * Copyright (C) 2012 Regents of the University of California
 * Copyright (C) 2017 SiFive
 */

#include <linux/cpu.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/sched/task_stack.h>
#include <linux/tick.h>
#include <linux/ptrace.h>
#include <linux/uaccess.h>

#include <asm/unistd.h>
#include <asm/processor.h>
#include <asm/csr.h>
#include <asm/string.h>
#include <asm/switch_to.h>
#include <asm/thread_info.h>

register unsigned long gp_in_global __asm__("gp");

#ifdef CONFIG_STACKPROTECTOR
#include <linux/stackprotector.h>
unsigned long __stack_chk_guard __read_mostly;
EXPORT_SYMBOL(__stack_chk_guard);
#endif

extern asmlinkage void ret_from_fork(void);
extern asmlinkage void ret_from_kernel_thread(void);

void arch_cpu_idle(void)
{
	wait_for_interrupt();
	local_irq_enable();
}

void show_regs(struct pt_regs *regs)
{
	show_regs_print_info(KERN_DEFAULT);

	pr_cont("epc: " REG_FMT " ra : " REG_FMT " sp : " REG_FMT "\n",
		regs->epc, regs->ra, regs->sp);
	pr_cont(" gp : " REG_FMT " tp : " REG_FMT " t0 : " REG_FMT "\n",
		regs->gp, regs->tp, regs->t0);
	pr_cont(" t1 : " REG_FMT " t2 : " REG_FMT " s0 : " REG_FMT "\n",
		regs->t1, regs->t2, regs->s0);
	pr_cont(" s1 : " REG_FMT " a0 : " REG_FMT " a1 : " REG_FMT "\n",
		regs->s1, regs->a0, regs->a1);
	pr_cont(" a2 : " REG_FMT " a3 : " REG_FMT " a4 : " REG_FMT "\n",
		regs->a2, regs->a3, regs->a4);
	pr_cont(" a5 : " REG_FMT " a6 : " REG_FMT " a7 : " REG_FMT "\n",
		regs->a5, regs->a6, regs->a7);
	pr_cont(" s2 : " REG_FMT " s3 : " REG_FMT " s4 : " REG_FMT "\n",
		regs->s2, regs->s3, regs->s4);
	pr_cont(" s5 : " REG_FMT " s6 : " REG_FMT " s7 : " REG_FMT "\n",
		regs->s5, regs->s6, regs->s7);
	pr_cont(" s8 : " REG_FMT " s9 : " REG_FMT " s10: " REG_FMT "\n",
		regs->s8, regs->s9, regs->s10);
	pr_cont(" s11: " REG_FMT " t3 : " REG_FMT " t4 : " REG_FMT "\n",
		regs->s11, regs->t3, regs->t4);
	pr_cont(" t5 : " REG_FMT " t6 : " REG_FMT "\n",
		regs->t5, regs->t6);

	pr_cont("status: " REG_FMT " badaddr: " REG_FMT " cause: " REG_FMT "\n",
		regs->status, regs->badaddr, regs->cause);
}

void start_thread(struct pt_regs *regs, unsigned long pc,
	unsigned long sp)
{
	regs->status = SR_PIE;
	if (has_fpu) {
		regs->status |= SR_FS_INITIAL;
		/*
		 * Restore the initial value to the FP register
		 * before starting the user program.
		 */
		fstate_restore(current, regs);
	}
	regs->epc = pc;
	regs->sp = sp;
	set_fs(USER_DS);
}

void flush_thread(void)
{
#ifdef CONFIG_FPU
	/*
	 * Reset FPU state and context
	 *	frm: round to nearest, ties to even (IEEE default)
	 *	fflags: accrued exceptions cleared
	 */
	fstate_off(current, task_pt_regs(current));
	memset(&current->thread.fstate, 0, sizeof(current->thread.fstate));
#endif
}

int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
{
	fstate_save(src, task_pt_regs(src));
	*dst = *src;
	return 0;
}

int copy_thread(unsigned long clone_flags, unsigned long usp, unsigned long arg,
		struct task_struct *p, unsigned long tls)
{
	struct pt_regs *childregs = task_pt_regs(p);

	/* p->thread holds context to be restored by __switch_to() */
	if (unlikely(p->flags & PF_KTHREAD)) {
		/* Kernel thread */
		memset(childregs, 0, sizeof(struct pt_regs));
		childregs->gp = gp_in_global;
		/* Supervisor/Machine, irqs on: */
		childregs->status = SR_PP | SR_PIE;

		p->thread.ra = (unsigned long)ret_from_kernel_thread;
		p->thread.s[0] = usp; /* fn */
		p->thread.s[1] = arg;
	} else {
		*childregs = *(current_pt_regs());
		if (usp) /* User fork */
			childregs->sp = usp;
		if (clone_flags & CLONE_SETTLS)
			childregs->tp = tls;
		childregs->a0 = 0; /* Return value of fork() */
		p->thread.ra = (unsigned long)ret_from_fork;
	}
	p->thread.sp = (unsigned long)childregs; /* kernel sp */
	return 0;
}