1 /*
2 * Copyright (C) 2000-2003 Axis Communications AB
3 *
4 * Authors: Bjorn Wesen (bjornw@axis.com)
5 * Mikael Starvik (starvik@axis.com)
6 * Tobias Anderberg (tobiasa@axis.com), CRISv32 port.
7 *
8 * This file handles the architecture-dependent parts of process handling..
9 */
10
11 #include <linux/sched.h>
12 #include <linux/slab.h>
13 #include <linux/err.h>
14 #include <linux/fs.h>
15 #include <hwregs/reg_rdwr.h>
16 #include <hwregs/reg_map.h>
17 #include <hwregs/timer_defs.h>
18 #include <hwregs/intr_vect_defs.h>
19 #include <linux/ptrace.h>
20
21 extern void stop_watchdog(void);
22
23 /* We use this if we don't have any better idle routine. */
default_idle(void)24 void default_idle(void)
25 {
26 /* Halt until exception. */
27 __asm__ volatile("ei \n\t"
28 "halt ");
29 }
30
31 /*
32 * Free current thread data structures etc..
33 */
34
35 extern void deconfigure_bp(long pid);
exit_thread(struct task_struct * tsk)36 void exit_thread(struct task_struct *tsk)
37 {
38 deconfigure_bp(tsk->pid);
39 }
40
41 /*
42 * If the watchdog is enabled, disable interrupts and enter an infinite loop.
43 * The watchdog will reset the CPU after 0.1s. If the watchdog isn't enabled
44 * then enable it and wait.
45 */
46 extern void arch_enable_nmi(void);
47
48 void
hard_reset_now(void)49 hard_reset_now(void)
50 {
51 /*
52 * Don't declare this variable elsewhere. We don't want any other
53 * code to know about it than the watchdog handler in entry.S and
54 * this code, implementing hard reset through the watchdog.
55 */
56 #if defined(CONFIG_ETRAX_WATCHDOG)
57 extern int cause_of_death;
58 #endif
59
60 printk("*** HARD RESET ***\n");
61 local_irq_disable();
62
63 #if defined(CONFIG_ETRAX_WATCHDOG)
64 cause_of_death = 0xbedead;
65 #else
66 {
67 reg_timer_rw_wd_ctrl wd_ctrl = {0};
68
69 stop_watchdog();
70
71 wd_ctrl.key = 16; /* Arbitrary key. */
72 wd_ctrl.cnt = 1; /* Minimum time. */
73 wd_ctrl.cmd = regk_timer_start;
74
75 arch_enable_nmi();
76 REG_WR(timer, regi_timer0, rw_wd_ctrl, wd_ctrl);
77 }
78 #endif
79
80 while (1)
81 ; /* Wait for reset. */
82 }
83
84 /*
85 * Return saved PC of a blocked thread.
86 */
thread_saved_pc(struct task_struct * t)87 unsigned long thread_saved_pc(struct task_struct *t)
88 {
89 return task_pt_regs(t)->erp;
90 }
91
92 /*
93 * Setup the child's kernel stack with a pt_regs and call switch_stack() on it.
94 * It will be unnested during _resume and _ret_from_sys_call when the new thread
95 * is scheduled.
96 *
97 * Also setup the thread switching structure which is used to keep
98 * thread-specific data during _resumes.
99 */
100
101 extern asmlinkage void ret_from_fork(void);
102 extern asmlinkage void ret_from_kernel_thread(void);
103
104 int
copy_thread(unsigned long clone_flags,unsigned long usp,unsigned long arg,struct task_struct * p)105 copy_thread(unsigned long clone_flags, unsigned long usp,
106 unsigned long arg, struct task_struct *p)
107 {
108 struct pt_regs *childregs = task_pt_regs(p);
109 struct switch_stack *swstack = ((struct switch_stack *) childregs) - 1;
110
111 /*
112 * Put the pt_regs structure at the end of the new kernel stack page and
113 * fix it up. Note: the task_struct doubles as the kernel stack for the
114 * task.
115 */
116 if (unlikely(p->flags & PF_KTHREAD)) {
117 memset(swstack, 0,
118 sizeof(struct switch_stack) + sizeof(struct pt_regs));
119 swstack->r1 = usp;
120 swstack->r2 = arg;
121 childregs->ccs = 1 << (I_CCS_BITNR + CCS_SHIFT);
122 swstack->return_ip = (unsigned long) ret_from_kernel_thread;
123 p->thread.ksp = (unsigned long) swstack;
124 p->thread.usp = 0;
125 return 0;
126 }
127 *childregs = *current_pt_regs(); /* Struct copy of pt_regs. */
128 childregs->r10 = 0; /* Child returns 0 after a fork/clone. */
129
130 /* Set a new TLS ?
131 * The TLS is in $mof because it is the 5th argument to sys_clone.
132 */
133 if (p->mm && (clone_flags & CLONE_SETTLS)) {
134 task_thread_info(p)->tls = childregs->mof;
135 }
136
137 /* Put the switch stack right below the pt_regs. */
138
139 /* Parameter to ret_from_sys_call. 0 is don't restart the syscall. */
140 swstack->r9 = 0;
141
142 /*
143 * We want to return into ret_from_sys_call after the _resume.
144 * ret_from_fork will call ret_from_sys_call.
145 */
146 swstack->return_ip = (unsigned long) ret_from_fork;
147
148 /* Fix the user-mode and kernel-mode stackpointer. */
149 p->thread.usp = usp ?: rdusp();
150 p->thread.ksp = (unsigned long) swstack;
151
152 return 0;
153 }
154
155 unsigned long
get_wchan(struct task_struct * p)156 get_wchan(struct task_struct *p)
157 {
158 /* TODO */
159 return 0;
160 }
161 #undef last_sched
162 #undef first_sched
163
show_regs(struct pt_regs * regs)164 void show_regs(struct pt_regs * regs)
165 {
166 unsigned long usp = rdusp();
167
168 show_regs_print_info(KERN_DEFAULT);
169
170 printk("ERP: %08lx SRP: %08lx CCS: %08lx USP: %08lx MOF: %08lx\n",
171 regs->erp, regs->srp, regs->ccs, usp, regs->mof);
172
173 printk(" r0: %08lx r1: %08lx r2: %08lx r3: %08lx\n",
174 regs->r0, regs->r1, regs->r2, regs->r3);
175
176 printk(" r4: %08lx r5: %08lx r6: %08lx r7: %08lx\n",
177 regs->r4, regs->r5, regs->r6, regs->r7);
178
179 printk(" r8: %08lx r9: %08lx r10: %08lx r11: %08lx\n",
180 regs->r8, regs->r9, regs->r10, regs->r11);
181
182 printk("r12: %08lx r13: %08lx oR10: %08lx\n",
183 regs->r12, regs->r13, regs->orig_r10);
184 }
185