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
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
|
/*
* Port on Texas Instruments TMS320C6x architecture
*
* Copyright (C) 2004, 2006, 2009, 2010, 2011 Texas Instruments Incorporated
* Author: Aurelien Jacquiot (aurelien.jacquiot@jaluna.com)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
*/
#include <linux/module.h>
#include <linux/unistd.h>
#include <linux/ptrace.h>
#include <linux/init_task.h>
#include <linux/tick.h>
#include <linux/mqueue.h>
#include <linux/syscalls.h>
#include <linux/reboot.h>
#include <asm/syscalls.h>
/* hooks for board specific support */
void (*c6x_restart)(void);
void (*c6x_halt)(void);
extern asmlinkage void ret_from_fork(void);
extern asmlinkage void ret_from_kernel_thread(void);
/*
* power off function, if any
*/
void (*pm_power_off)(void);
EXPORT_SYMBOL(pm_power_off);
static void c6x_idle(void)
{
unsigned long tmp;
/*
* Put local_irq_enable and idle in same execute packet
* to make them atomic and avoid race to idle with
* interrupts enabled.
*/
asm volatile (" mvc .s2 CSR,%0\n"
" or .d2 1,%0,%0\n"
" mvc .s2 %0,CSR\n"
"|| idle\n"
: "=b"(tmp));
}
/*
* The idle loop for C64x
*/
void cpu_idle(void)
{
/* endless idle loop with no priority at all */
while (1) {
tick_nohz_idle_enter();
rcu_idle_enter();
while (1) {
local_irq_disable();
if (need_resched()) {
local_irq_enable();
break;
}
c6x_idle(); /* enables local irqs */
}
rcu_idle_exit();
tick_nohz_idle_exit();
preempt_enable_no_resched();
schedule();
preempt_disable();
}
}
static void halt_loop(void)
{
printk(KERN_EMERG "System Halted, OK to turn off power\n");
local_irq_disable();
while (1)
asm volatile("idle\n");
}
void machine_restart(char *__unused)
{
if (c6x_restart)
c6x_restart();
halt_loop();
}
void machine_halt(void)
{
if (c6x_halt)
c6x_halt();
halt_loop();
}
void machine_power_off(void)
{
if (pm_power_off)
pm_power_off();
halt_loop();
}
void flush_thread(void)
{
}
void exit_thread(void)
{
}
SYSCALL_DEFINE1(c6x_clone, struct pt_regs *, regs)
{
unsigned long clone_flags;
unsigned long newsp;
/* syscall puts clone_flags in A4 and usp in B4 */
clone_flags = regs->orig_a4;
if (regs->b4)
newsp = regs->b4;
else
newsp = regs->sp;
return do_fork(clone_flags, newsp, regs, 0, (int __user *)regs->a6,
(int __user *)regs->b6);
}
/*
* Do necessary setup to start up a newly executed thread.
*/
void start_thread(struct pt_regs *regs, unsigned int pc, unsigned long usp)
{
/*
* The binfmt loader will setup a "full" stack, but the C6X
* operates an "empty" stack. So we adjust the usp so that
* argc doesn't get destroyed if an interrupt is taken before
* it is read from the stack.
*
* NB: Library startup code needs to match this.
*/
usp -= 8;
set_fs(USER_DS);
regs->pc = pc;
regs->sp = usp;
regs->tsr |= 0x40; /* set user mode */
current->thread.usp = usp;
}
/*
* Copy a new thread context in its stack.
*/
int copy_thread(unsigned long clone_flags, unsigned long usp,
unsigned long ustk_size,
struct task_struct *p, struct pt_regs *regs)
{
struct pt_regs *childregs;
childregs = task_pt_regs(p);
if (!regs) {
/* case of __kernel_thread: we return to supervisor space */
memset(childregs, 0, sizeof(struct pt_regs));
childregs->sp = (unsigned long)(childregs + 1);
p->thread.pc = (unsigned long) ret_from_kernel_thread;
childregs->a0 = usp; /* function */
childregs->a1 = ustk_size; /* argument */
} else {
/* Otherwise use the given stack */
*childregs = *regs;
childregs->sp = usp;
p->thread.pc = (unsigned long) ret_from_fork;
}
/* Set usp/ksp */
p->thread.usp = childregs->sp;
thread_saved_ksp(p) = (unsigned long)childregs - 8;
p->thread.wchan = p->thread.pc;
#ifdef __DSBT__
{
unsigned long dp;
asm volatile ("mv .S2 b14,%0\n" : "=b"(dp));
thread_saved_dp(p) = dp;
if (usp == -1)
childregs->dp = dp;
}
#endif
return 0;
}
unsigned long get_wchan(struct task_struct *p)
{
return p->thread.wchan;
}
|
