blob: 00c233bf0d0626f82e5f03eecd6e2e14659a4d49 [file] [log] [blame]
Jonas Bonn88ef7f32011-06-04 22:30:12 +03001/*
2 * OpenRISC process.c
3 *
4 * Linux architectural port borrowing liberally from similar works of
5 * others. All original copyrights apply as per the original source
6 * declaration.
7 *
8 * Modifications for the OpenRISC architecture:
9 * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
10 * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
11 *
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU General Public License
14 * as published by the Free Software Foundation; either version
15 * 2 of the License, or (at your option) any later version.
16 *
17 * This file handles the architecture-dependent parts of process handling...
18 */
19
20#define __KERNEL_SYSCALLS__
21#include <stdarg.h>
22
23#include <linux/errno.h>
24#include <linux/sched.h>
25#include <linux/kernel.h>
26#include <linux/module.h>
27#include <linux/mm.h>
28#include <linux/stddef.h>
29#include <linux/unistd.h>
30#include <linux/ptrace.h>
31#include <linux/slab.h>
32#include <linux/elfcore.h>
33#include <linux/interrupt.h>
34#include <linux/delay.h>
35#include <linux/init_task.h>
36#include <linux/mqueue.h>
37#include <linux/fs.h>
38
39#include <asm/uaccess.h>
40#include <asm/pgtable.h>
Jonas Bonn88ef7f32011-06-04 22:30:12 +030041#include <asm/io.h>
42#include <asm/processor.h>
43#include <asm/spr_defs.h>
44
45#include <linux/smp.h>
46
47/*
48 * Pointer to Current thread info structure.
49 *
50 * Used at user space -> kernel transitions.
51 */
52struct thread_info *current_thread_info_set[NR_CPUS] = { &init_thread_info, };
53
54void machine_restart(void)
55{
56 printk(KERN_INFO "*** MACHINE RESTART ***\n");
57 __asm__("l.nop 1");
58}
59
60/*
61 * Similar to machine_power_off, but don't shut off power. Add code
62 * here to freeze the system for e.g. post-mortem debug purpose when
63 * possible. This halt has nothing to do with the idle halt.
64 */
65void machine_halt(void)
66{
67 printk(KERN_INFO "*** MACHINE HALT ***\n");
68 __asm__("l.nop 1");
69}
70
71/* If or when software power-off is implemented, add code here. */
72void machine_power_off(void)
73{
74 printk(KERN_INFO "*** MACHINE POWER OFF ***\n");
75 __asm__("l.nop 1");
76}
77
78void (*pm_power_off) (void) = machine_power_off;
79
80/*
81 * When a process does an "exec", machine state like FPU and debug
82 * registers need to be reset. This is a hook function for that.
83 * Currently we don't have any such state to reset, so this is empty.
84 */
85void flush_thread(void)
86{
87}
88
89void show_regs(struct pt_regs *regs)
90{
91 extern void show_registers(struct pt_regs *regs);
92
93 /* __PHX__ cleanup this mess */
94 show_registers(regs);
95}
96
97unsigned long thread_saved_pc(struct task_struct *t)
98{
99 return (unsigned long)user_regs(t->stack)->pc;
100}
101
102void release_thread(struct task_struct *dead_task)
103{
104}
105
106/*
107 * Copy the thread-specific (arch specific) info from the current
108 * process to the new one p
109 */
110extern asmlinkage void ret_from_fork(void);
111
Jonas Bonncbf23cf2012-10-19 18:07:44 +0200112/*
113 * copy_thread
114 * @clone_flags: flags
115 * @usp: user stack pointer or fn for kernel thread
116 * @arg: arg to fn for kernel thread; always NULL for userspace thread
117 * @p: the newly created task
118 * @regs: CPU context to copy for userspace thread; always NULL for kthread
119 *
120 * At the top of a newly initialized kernel stack are two stacked pt_reg
121 * structures. The first (topmost) is the userspace context of the thread.
122 * The second is the kernelspace context of the thread.
123 *
124 * A kernel thread will not be returning to userspace, so the topmost pt_regs
125 * struct can be uninitialized; it _does_ need to exist, though, because
126 * a kernel thread can become a userspace thread by doing a kernel_execve, in
127 * which case the topmost context will be initialized and used for 'returning'
128 * to userspace.
129 *
130 * The second pt_reg struct needs to be initialized to 'return' to
131 * ret_from_fork. A kernel thread will need to set r20 to the address of
132 * a function to call into (with arg in r22); userspace threads need to set
133 * r20 to NULL in which case ret_from_fork will just continue a return to
134 * userspace.
135 *
136 * A kernel thread 'fn' may return; this is effectively what happens when
137 * kernel_execve is called. In that case, the userspace pt_regs must have
138 * been initialized (which kernel_execve takes care of, see start_thread
139 * below); ret_from_fork will then continue its execution causing the
140 * 'kernel thread' to return to userspace as a userspace thread.
141 */
142
Jonas Bonn88ef7f32011-06-04 22:30:12 +0300143int
144copy_thread(unsigned long clone_flags, unsigned long usp,
Al Viroafa86fc2012-10-22 22:51:14 -0400145 unsigned long arg, struct task_struct *p)
Jonas Bonn88ef7f32011-06-04 22:30:12 +0300146{
Jonas Bonncbf23cf2012-10-19 18:07:44 +0200147 struct pt_regs *userregs;
Jonas Bonn88ef7f32011-06-04 22:30:12 +0300148 struct pt_regs *kregs;
149 unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
Jonas Bonn88ef7f32011-06-04 22:30:12 +0300150 unsigned long top_of_kernel_stack;
151
152 top_of_kernel_stack = sp;
153
154 p->set_child_tid = p->clear_child_tid = NULL;
155
Jonas Bonncbf23cf2012-10-19 18:07:44 +0200156 /* Locate userspace context on stack... */
157 sp -= STACK_FRAME_OVERHEAD; /* redzone */
Jonas Bonn88ef7f32011-06-04 22:30:12 +0300158 sp -= sizeof(struct pt_regs);
Jonas Bonncbf23cf2012-10-19 18:07:44 +0200159 userregs = (struct pt_regs *) sp;
Jonas Bonn88ef7f32011-06-04 22:30:12 +0300160
Jonas Bonncbf23cf2012-10-19 18:07:44 +0200161 /* ...and kernel context */
162 sp -= STACK_FRAME_OVERHEAD; /* redzone */
Jonas Bonn88ef7f32011-06-04 22:30:12 +0300163 sp -= sizeof(struct pt_regs);
164 kregs = (struct pt_regs *)sp;
165
Jonas Bonncbf23cf2012-10-19 18:07:44 +0200166 if (unlikely(p->flags & PF_KTHREAD)) {
167 memset(kregs, 0, sizeof(struct pt_regs));
168 kregs->gpr[20] = usp; /* fn, kernel thread */
169 kregs->gpr[22] = arg;
170 } else {
Al Viro39d91a92012-10-26 19:37:49 -0400171 *userregs = *current_pt_regs();
Jonas Bonn88ef7f32011-06-04 22:30:12 +0300172
Al Viro39d91a92012-10-26 19:37:49 -0400173 if (usp)
174 userregs->sp = usp;
Jonas Bonncbf23cf2012-10-19 18:07:44 +0200175 userregs->gpr[11] = 0; /* Result from fork() */
176
177 kregs->gpr[20] = 0; /* Userspace thread */
178 }
179
180 /*
181 * _switch wants the kernel stack page in pt_regs->sp so that it
182 * can restore it to thread_info->ksp... see _switch for details.
Jonas Bonn88ef7f32011-06-04 22:30:12 +0300183 */
184 kregs->sp = top_of_kernel_stack;
Jonas Bonn88ef7f32011-06-04 22:30:12 +0300185 kregs->gpr[9] = (unsigned long)ret_from_fork;
186
Jonas Bonncbf23cf2012-10-19 18:07:44 +0200187 task_thread_info(p)->ksp = (unsigned long)kregs;
188
Jonas Bonn88ef7f32011-06-04 22:30:12 +0300189 return 0;
190}
191
192/*
193 * Set up a thread for executing a new program
194 */
195void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long sp)
196{
Jonas Bonncbf23cf2012-10-19 18:07:44 +0200197 unsigned long sr = mfspr(SPR_SR) & ~SPR_SR_SM;
Jonas Bonn88ef7f32011-06-04 22:30:12 +0300198
199 set_fs(USER_DS);
Jonas Bonncbf23cf2012-10-19 18:07:44 +0200200 memset(regs, 0, sizeof(struct pt_regs));
Jonas Bonn88ef7f32011-06-04 22:30:12 +0300201
202 regs->pc = pc;
203 regs->sr = sr;
204 regs->sp = sp;
Jonas Bonn88ef7f32011-06-04 22:30:12 +0300205}
206
207/* Fill in the fpu structure for a core dump. */
208int dump_fpu(struct pt_regs *regs, elf_fpregset_t * fpu)
209{
210 /* TODO */
211 return 0;
212}
213
214extern struct thread_info *_switch(struct thread_info *old_ti,
215 struct thread_info *new_ti);
216
217struct task_struct *__switch_to(struct task_struct *old,
218 struct task_struct *new)
219{
220 struct task_struct *last;
221 struct thread_info *new_ti, *old_ti;
222 unsigned long flags;
223
224 local_irq_save(flags);
225
226 /* current_set is an array of saved current pointers
227 * (one for each cpu). we need them at user->kernel transition,
228 * while we save them at kernel->user transition
229 */
230 new_ti = new->stack;
231 old_ti = old->stack;
232
233 current_thread_info_set[smp_processor_id()] = new_ti;
234 last = (_switch(old_ti, new_ti))->task;
235
236 local_irq_restore(flags);
237
238 return last;
239}
240
241/*
242 * Write out registers in core dump format, as defined by the
243 * struct user_regs_struct
244 */
245void dump_elf_thread(elf_greg_t *dest, struct pt_regs* regs)
246{
247 dest[0] = 0; /* r0 */
248 memcpy(dest+1, regs->gpr+1, 31*sizeof(unsigned long));
249 dest[32] = regs->pc;
250 dest[33] = regs->sr;
251 dest[34] = 0;
252 dest[35] = 0;
253}
254
Jonas Bonn88ef7f32011-06-04 22:30:12 +0300255unsigned long get_wchan(struct task_struct *p)
256{
257 /* TODO */
258
259 return 0;
260}