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687b12ba AJ |
1 | /* |
2 | * Port on Texas Instruments TMS320C6x architecture | |
3 | * | |
4 | * Copyright (C) 2004, 2006, 2009, 2010, 2011 Texas Instruments Incorporated | |
5 | * Author: Aurelien Jacquiot (aurelien.jacquiot@jaluna.com) | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify | |
8 | * it under the terms of the GNU General Public License version 2 as | |
9 | * published by the Free Software Foundation. | |
10 | * | |
11 | */ | |
12 | #include <linux/module.h> | |
13 | #include <linux/unistd.h> | |
14 | #include <linux/ptrace.h> | |
15 | #include <linux/init_task.h> | |
16 | #include <linux/tick.h> | |
17 | #include <linux/mqueue.h> | |
18 | #include <linux/syscalls.h> | |
19 | #include <linux/reboot.h> | |
20 | ||
21 | #include <asm/syscalls.h> | |
22 | ||
23 | /* hooks for board specific support */ | |
24 | void (*c6x_restart)(void); | |
25 | void (*c6x_halt)(void); | |
26 | ||
27 | extern asmlinkage void ret_from_fork(void); | |
46f15067 | 28 | extern asmlinkage void ret_from_kernel_thread(void); |
687b12ba | 29 | |
687b12ba AJ |
30 | /* |
31 | * power off function, if any | |
32 | */ | |
33 | void (*pm_power_off)(void); | |
34 | EXPORT_SYMBOL(pm_power_off); | |
35 | ||
36 | static void c6x_idle(void) | |
37 | { | |
38 | unsigned long tmp; | |
39 | ||
40 | /* | |
41 | * Put local_irq_enable and idle in same execute packet | |
42 | * to make them atomic and avoid race to idle with | |
43 | * interrupts enabled. | |
44 | */ | |
45 | asm volatile (" mvc .s2 CSR,%0\n" | |
46 | " or .d2 1,%0,%0\n" | |
47 | " mvc .s2 %0,CSR\n" | |
48 | "|| idle\n" | |
49 | : "=b"(tmp)); | |
50 | } | |
51 | ||
52 | /* | |
53 | * The idle loop for C64x | |
54 | */ | |
55 | void cpu_idle(void) | |
56 | { | |
57 | /* endless idle loop with no priority at all */ | |
58 | while (1) { | |
166c0eae MS |
59 | tick_nohz_idle_enter(); |
60 | rcu_idle_enter(); | |
687b12ba AJ |
61 | while (1) { |
62 | local_irq_disable(); | |
63 | if (need_resched()) { | |
64 | local_irq_enable(); | |
65 | break; | |
66 | } | |
67 | c6x_idle(); /* enables local irqs */ | |
68 | } | |
166c0eae MS |
69 | rcu_idle_exit(); |
70 | tick_nohz_idle_exit(); | |
687b12ba AJ |
71 | |
72 | preempt_enable_no_resched(); | |
73 | schedule(); | |
74 | preempt_disable(); | |
75 | } | |
76 | } | |
77 | ||
78 | static void halt_loop(void) | |
79 | { | |
80 | printk(KERN_EMERG "System Halted, OK to turn off power\n"); | |
81 | local_irq_disable(); | |
82 | while (1) | |
83 | asm volatile("idle\n"); | |
84 | } | |
85 | ||
86 | void machine_restart(char *__unused) | |
87 | { | |
88 | if (c6x_restart) | |
89 | c6x_restart(); | |
90 | halt_loop(); | |
91 | } | |
92 | ||
93 | void machine_halt(void) | |
94 | { | |
95 | if (c6x_halt) | |
96 | c6x_halt(); | |
97 | halt_loop(); | |
98 | } | |
99 | ||
100 | void machine_power_off(void) | |
101 | { | |
102 | if (pm_power_off) | |
103 | pm_power_off(); | |
104 | halt_loop(); | |
105 | } | |
106 | ||
687b12ba AJ |
107 | /* |
108 | * Create a kernel thread | |
109 | */ | |
110 | int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags) | |
111 | { | |
46f15067 MS |
112 | struct pt_regs regs = { |
113 | .a0 = (unsigned long)fn, | |
114 | .a1 = (unsigned long)arg, | |
115 | .tsr = 0, /* kernel mode */ | |
116 | }; | |
687b12ba AJ |
117 | |
118 | /* Ok, create the new process.. */ | |
119 | return do_fork(flags | CLONE_VM | CLONE_UNTRACED, -1, ®s, | |
120 | 0, NULL, NULL); | |
121 | } | |
687b12ba AJ |
122 | |
123 | void flush_thread(void) | |
124 | { | |
125 | } | |
126 | ||
127 | void exit_thread(void) | |
128 | { | |
129 | } | |
130 | ||
131 | SYSCALL_DEFINE1(c6x_clone, struct pt_regs *, regs) | |
132 | { | |
133 | unsigned long clone_flags; | |
134 | unsigned long newsp; | |
135 | ||
136 | /* syscall puts clone_flags in A4 and usp in B4 */ | |
137 | clone_flags = regs->orig_a4; | |
138 | if (regs->b4) | |
139 | newsp = regs->b4; | |
140 | else | |
141 | newsp = regs->sp; | |
142 | ||
143 | return do_fork(clone_flags, newsp, regs, 0, (int __user *)regs->a6, | |
144 | (int __user *)regs->b6); | |
145 | } | |
146 | ||
147 | /* | |
148 | * Do necessary setup to start up a newly executed thread. | |
149 | */ | |
150 | void start_thread(struct pt_regs *regs, unsigned int pc, unsigned long usp) | |
151 | { | |
152 | /* | |
153 | * The binfmt loader will setup a "full" stack, but the C6X | |
154 | * operates an "empty" stack. So we adjust the usp so that | |
155 | * argc doesn't get destroyed if an interrupt is taken before | |
156 | * it is read from the stack. | |
157 | * | |
158 | * NB: Library startup code needs to match this. | |
159 | */ | |
160 | usp -= 8; | |
161 | ||
162 | set_fs(USER_DS); | |
163 | regs->pc = pc; | |
164 | regs->sp = usp; | |
165 | regs->tsr |= 0x40; /* set user mode */ | |
166 | current->thread.usp = usp; | |
167 | } | |
168 | ||
169 | /* | |
170 | * Copy a new thread context in its stack. | |
171 | */ | |
172 | int copy_thread(unsigned long clone_flags, unsigned long usp, | |
173 | unsigned long ustk_size, | |
174 | struct task_struct *p, struct pt_regs *regs) | |
175 | { | |
176 | struct pt_regs *childregs; | |
177 | ||
178 | childregs = task_pt_regs(p); | |
179 | ||
180 | *childregs = *regs; | |
687b12ba | 181 | |
46f15067 | 182 | if (usp == -1) { |
687b12ba AJ |
183 | /* case of __kernel_thread: we return to supervisor space */ |
184 | childregs->sp = (unsigned long)(childregs + 1); | |
46f15067 MS |
185 | p->thread.pc = (unsigned long) ret_from_kernel_thread; |
186 | } else { | |
687b12ba AJ |
187 | /* Otherwise use the given stack */ |
188 | childregs->sp = usp; | |
46f15067 MS |
189 | p->thread.pc = (unsigned long) ret_from_fork; |
190 | } | |
687b12ba AJ |
191 | |
192 | /* Set usp/ksp */ | |
193 | p->thread.usp = childregs->sp; | |
687b12ba | 194 | thread_saved_ksp(p) = (unsigned long)childregs - 8; |
46f15067 | 195 | p->thread.wchan = p->thread.pc; |
687b12ba AJ |
196 | #ifdef __DSBT__ |
197 | { | |
198 | unsigned long dp; | |
199 | ||
200 | asm volatile ("mv .S2 b14,%0\n" : "=b"(dp)); | |
201 | ||
202 | thread_saved_dp(p) = dp; | |
203 | if (usp == -1) | |
204 | childregs->dp = dp; | |
205 | } | |
206 | #endif | |
207 | return 0; | |
208 | } | |
209 | ||
210 | /* | |
211 | * c6x_execve() executes a new program. | |
212 | */ | |
213 | SYSCALL_DEFINE4(c6x_execve, const char __user *, name, | |
214 | const char __user *const __user *, argv, | |
215 | const char __user *const __user *, envp, | |
216 | struct pt_regs *, regs) | |
217 | { | |
218 | int error; | |
219 | char *filename; | |
220 | ||
221 | filename = getname(name); | |
222 | error = PTR_ERR(filename); | |
223 | if (IS_ERR(filename)) | |
224 | goto out; | |
225 | ||
226 | error = do_execve(filename, argv, envp, regs); | |
227 | putname(filename); | |
228 | out: | |
229 | return error; | |
230 | } | |
231 | ||
232 | unsigned long get_wchan(struct task_struct *p) | |
233 | { | |
234 | return p->thread.wchan; | |
235 | } |