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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Port on Texas Instruments TMS320C6x architecture
4 *
5 * Copyright (C) 2004, 2006, 2009, 2010, 2011 Texas Instruments Incorporated
6 * Author: Aurelien Jacquiot (aurelien.jacquiot@jaluna.com)
7 */
8#include <linux/module.h>
9#include <linux/unistd.h>
10#include <linux/ptrace.h>
11#include <linux/init_task.h>
12#include <linux/tick.h>
13#include <linux/mqueue.h>
14#include <linux/syscalls.h>
15#include <linux/reboot.h>
16#include <linux/sched/task.h>
17#include <linux/sched/task_stack.h>
18
19#include <asm/syscalls.h>
20
21/* hooks for board specific support */
22void (*c6x_restart)(void);
23void (*c6x_halt)(void);
24
25extern asmlinkage void ret_from_fork(void);
26extern asmlinkage void ret_from_kernel_thread(void);
27
28/*
29 * power off function, if any
30 */
31void (*pm_power_off)(void);
32EXPORT_SYMBOL(pm_power_off);
33
34void arch_cpu_idle(void)
35{
36 unsigned long tmp;
37
38 /*
39 * Put local_irq_enable and idle in same execute packet
40 * to make them atomic and avoid race to idle with
41 * interrupts enabled.
42 */
43 asm volatile (" mvc .s2 CSR,%0\n"
44 " or .d2 1,%0,%0\n"
45 " mvc .s2 %0,CSR\n"
46 "|| idle\n"
47 : "=b"(tmp));
48}
49
50static void halt_loop(void)
51{
52 printk(KERN_EMERG "System Halted, OK to turn off power\n");
53 local_irq_disable();
54 while (1)
55 asm volatile("idle\n");
56}
57
58void machine_restart(char *__unused)
59{
60 if (c6x_restart)
61 c6x_restart();
62 halt_loop();
63}
64
65void machine_halt(void)
66{
67 if (c6x_halt)
68 c6x_halt();
69 halt_loop();
70}
71
72void machine_power_off(void)
73{
74 if (pm_power_off)
75 pm_power_off();
76 halt_loop();
77}
78
79void flush_thread(void)
80{
81}
82
83/*
84 * Do necessary setup to start up a newly executed thread.
85 */
86void start_thread(struct pt_regs *regs, unsigned int pc, unsigned long usp)
87{
88 /*
89 * The binfmt loader will setup a "full" stack, but the C6X
90 * operates an "empty" stack. So we adjust the usp so that
91 * argc doesn't get destroyed if an interrupt is taken before
92 * it is read from the stack.
93 *
94 * NB: Library startup code needs to match this.
95 */
96 usp -= 8;
97
98 regs->pc = pc;
99 regs->sp = usp;
100 regs->tsr |= 0x40; /* set user mode */
101 current->thread.usp = usp;
102}
103
104/*
105 * Copy a new thread context in its stack.
106 */
107int copy_thread(unsigned long clone_flags, unsigned long usp,
108 unsigned long ustk_size,
109 struct task_struct *p)
110{
111 struct pt_regs *childregs;
112
113 childregs = task_pt_regs(p);
114
115 if (unlikely(p->flags & PF_KTHREAD)) {
116 /* case of __kernel_thread: we return to supervisor space */
117 memset(childregs, 0, sizeof(struct pt_regs));
118 childregs->sp = (unsigned long)(childregs + 1);
119 p->thread.pc = (unsigned long) ret_from_kernel_thread;
120 childregs->a0 = usp; /* function */
121 childregs->a1 = ustk_size; /* argument */
122 } else {
123 /* Otherwise use the given stack */
124 *childregs = *current_pt_regs();
125 if (usp)
126 childregs->sp = usp;
127 p->thread.pc = (unsigned long) ret_from_fork;
128 }
129
130 /* Set usp/ksp */
131 p->thread.usp = childregs->sp;
132 thread_saved_ksp(p) = (unsigned long)childregs - 8;
133 p->thread.wchan = p->thread.pc;
134#ifdef __DSBT__
135 {
136 unsigned long dp;
137
138 asm volatile ("mv .S2 b14,%0\n" : "=b"(dp));
139
140 thread_saved_dp(p) = dp;
141 if (usp == -1)
142 childregs->dp = dp;
143 }
144#endif
145 return 0;
146}
147
148unsigned long get_wchan(struct task_struct *p)
149{
150 return p->thread.wchan;
151}
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 */
24void (*c6x_restart)(void);
25void (*c6x_halt)(void);
26
27extern asmlinkage void ret_from_fork(void);
28
29/*
30 * power off function, if any
31 */
32void (*pm_power_off)(void);
33EXPORT_SYMBOL(pm_power_off);
34
35static void c6x_idle(void)
36{
37 unsigned long tmp;
38
39 /*
40 * Put local_irq_enable and idle in same execute packet
41 * to make them atomic and avoid race to idle with
42 * interrupts enabled.
43 */
44 asm volatile (" mvc .s2 CSR,%0\n"
45 " or .d2 1,%0,%0\n"
46 " mvc .s2 %0,CSR\n"
47 "|| idle\n"
48 : "=b"(tmp));
49}
50
51/*
52 * The idle loop for C64x
53 */
54void cpu_idle(void)
55{
56 /* endless idle loop with no priority at all */
57 while (1) {
58 tick_nohz_idle_enter();
59 rcu_idle_enter();
60 while (1) {
61 local_irq_disable();
62 if (need_resched()) {
63 local_irq_enable();
64 break;
65 }
66 c6x_idle(); /* enables local irqs */
67 }
68 rcu_idle_exit();
69 tick_nohz_idle_exit();
70
71 preempt_enable_no_resched();
72 schedule();
73 preempt_disable();
74 }
75}
76
77static void halt_loop(void)
78{
79 printk(KERN_EMERG "System Halted, OK to turn off power\n");
80 local_irq_disable();
81 while (1)
82 asm volatile("idle\n");
83}
84
85void machine_restart(char *__unused)
86{
87 if (c6x_restart)
88 c6x_restart();
89 halt_loop();
90}
91
92void machine_halt(void)
93{
94 if (c6x_halt)
95 c6x_halt();
96 halt_loop();
97}
98
99void machine_power_off(void)
100{
101 if (pm_power_off)
102 pm_power_off();
103 halt_loop();
104}
105
106static void kernel_thread_helper(int dummy, void *arg, int (*fn)(void *))
107{
108 do_exit(fn(arg));
109}
110
111/*
112 * Create a kernel thread
113 */
114int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
115{
116 struct pt_regs regs;
117
118 /*
119 * copy_thread sets a4 to zero (child return from fork)
120 * so we can't just set things up to directly return to
121 * fn.
122 */
123 memset(®s, 0, sizeof(regs));
124 regs.b4 = (unsigned long) arg;
125 regs.a6 = (unsigned long) fn;
126 regs.pc = (unsigned long) kernel_thread_helper;
127 local_save_flags(regs.csr);
128 regs.csr |= 1;
129 regs.tsr = 5; /* Set GEE and GIE in TSR */
130
131 /* Ok, create the new process.. */
132 return do_fork(flags | CLONE_VM | CLONE_UNTRACED, -1, ®s,
133 0, NULL, NULL);
134}
135EXPORT_SYMBOL(kernel_thread);
136
137void flush_thread(void)
138{
139}
140
141void exit_thread(void)
142{
143}
144
145SYSCALL_DEFINE1(c6x_clone, struct pt_regs *, regs)
146{
147 unsigned long clone_flags;
148 unsigned long newsp;
149
150 /* syscall puts clone_flags in A4 and usp in B4 */
151 clone_flags = regs->orig_a4;
152 if (regs->b4)
153 newsp = regs->b4;
154 else
155 newsp = regs->sp;
156
157 return do_fork(clone_flags, newsp, regs, 0, (int __user *)regs->a6,
158 (int __user *)regs->b6);
159}
160
161/*
162 * Do necessary setup to start up a newly executed thread.
163 */
164void start_thread(struct pt_regs *regs, unsigned int pc, unsigned long usp)
165{
166 /*
167 * The binfmt loader will setup a "full" stack, but the C6X
168 * operates an "empty" stack. So we adjust the usp so that
169 * argc doesn't get destroyed if an interrupt is taken before
170 * it is read from the stack.
171 *
172 * NB: Library startup code needs to match this.
173 */
174 usp -= 8;
175
176 set_fs(USER_DS);
177 regs->pc = pc;
178 regs->sp = usp;
179 regs->tsr |= 0x40; /* set user mode */
180 current->thread.usp = usp;
181}
182
183/*
184 * Copy a new thread context in its stack.
185 */
186int copy_thread(unsigned long clone_flags, unsigned long usp,
187 unsigned long ustk_size,
188 struct task_struct *p, struct pt_regs *regs)
189{
190 struct pt_regs *childregs;
191
192 childregs = task_pt_regs(p);
193
194 *childregs = *regs;
195 childregs->a4 = 0;
196
197 if (usp == -1)
198 /* case of __kernel_thread: we return to supervisor space */
199 childregs->sp = (unsigned long)(childregs + 1);
200 else
201 /* Otherwise use the given stack */
202 childregs->sp = usp;
203
204 /* Set usp/ksp */
205 p->thread.usp = childregs->sp;
206 /* switch_to uses stack to save/restore 14 callee-saved regs */
207 thread_saved_ksp(p) = (unsigned long)childregs - 8;
208 p->thread.pc = (unsigned int) ret_from_fork;
209 p->thread.wchan = (unsigned long) ret_from_fork;
210#ifdef __DSBT__
211 {
212 unsigned long dp;
213
214 asm volatile ("mv .S2 b14,%0\n" : "=b"(dp));
215
216 thread_saved_dp(p) = dp;
217 if (usp == -1)
218 childregs->dp = dp;
219 }
220#endif
221 return 0;
222}
223
224/*
225 * c6x_execve() executes a new program.
226 */
227SYSCALL_DEFINE4(c6x_execve, const char __user *, name,
228 const char __user *const __user *, argv,
229 const char __user *const __user *, envp,
230 struct pt_regs *, regs)
231{
232 int error;
233 char *filename;
234
235 filename = getname(name);
236 error = PTR_ERR(filename);
237 if (IS_ERR(filename))
238 goto out;
239
240 error = do_execve(filename, argv, envp, regs);
241 putname(filename);
242out:
243 return error;
244}
245
246unsigned long get_wchan(struct task_struct *p)
247{
248 return p->thread.wchan;
249}