2 * This file is subject to the terms and conditions of the GNU General Public
3 * License. See the file "COPYING" in the main directory of this archive
6 * Copyright (C) 1994 - 1999, 2000 by Ralf Baechle and others.
7 * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
8 * Copyright (C) 2004 Thiemo Seufer
10 #include <linux/config.h>
11 #include <linux/errno.h>
12 #include <linux/module.h>
13 #include <linux/sched.h>
14 #include <linux/kernel.h>
16 #include <linux/stddef.h>
17 #include <linux/unistd.h>
18 #include <linux/ptrace.h>
19 #include <linux/slab.h>
20 #include <linux/mman.h>
21 #include <linux/personality.h>
22 #include <linux/sys.h>
23 #include <linux/user.h>
24 #include <linux/a.out.h>
25 #include <linux/init.h>
26 #include <linux/completion.h>
28 #include <asm/bootinfo.h>
31 #include <asm/pgtable.h>
32 #include <asm/system.h>
33 #include <asm/mipsregs.h>
34 #include <asm/processor.h>
35 #include <asm/uaccess.h>
38 #include <asm/isadep.h>
42 * The idle thread. There's no useful work to be done, so just try to conserve
43 * power and have a low exit latency (ie sit in a loop waiting for somebody to
44 * say that they'd like to reschedule)
46 ATTRIB_NORET void cpu_idle(void)
48 /* endless idle loop with no priority at all */
50 while (!need_resched())
57 asmlinkage void ret_from_fork(void);
59 void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp)
63 /* New thread loses kernel privileges. */
64 status = regs->cp0_status & ~(ST0_CU0|ST0_CU1|KU_MASK);
67 status |= (current->thread.mflags & MF_32BIT_REGS) ? 0 : ST0_FR;
70 regs->cp0_status = status;
75 current_thread_info()->addr_limit = USER_DS;
78 void exit_thread(void)
82 void flush_thread(void)
86 int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
87 unsigned long unused, struct task_struct *p, struct pt_regs *regs)
89 struct thread_info *ti = p->thread_info;
90 struct pt_regs *childregs;
93 childksp = (unsigned long)ti + THREAD_SIZE - 32;
103 /* set up new TSS. */
104 childregs = (struct pt_regs *) childksp - 1;
106 childregs->regs[7] = 0; /* Clear error flag */
108 #if defined(CONFIG_BINFMT_IRIX)
109 if (current->personality != PER_LINUX) {
110 /* Under IRIX things are a little different. */
111 childregs->regs[3] = 1;
115 childregs->regs[2] = 0; /* Child gets zero as return value */
116 regs->regs[2] = p->pid;
118 if (childregs->cp0_status & ST0_CU0) {
119 childregs->regs[28] = (unsigned long) ti;
120 childregs->regs[29] = childksp;
121 ti->addr_limit = KERNEL_DS;
123 childregs->regs[29] = usp;
124 ti->addr_limit = USER_DS;
126 p->thread.reg29 = (unsigned long) childregs;
127 p->thread.reg31 = (unsigned long) ret_from_fork;
130 * New tasks lose permission to use the fpu. This accelerates context
131 * switching for most programs since they don't use the fpu.
133 p->thread.cp0_status = read_c0_status() & ~(ST0_CU2|ST0_CU1);
134 childregs->cp0_status &= ~(ST0_CU2|ST0_CU1);
135 clear_tsk_thread_flag(p, TIF_USEDFPU);
140 /* Fill in the fpu structure for a core dump.. */
141 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *r)
143 memcpy(r, ¤t->thread.fpu, sizeof(current->thread.fpu));
148 void dump_regs(elf_greg_t *gp, struct pt_regs *regs)
152 for (i = 0; i < EF_R0; i++)
155 for (i = 1; i <= 31; i++)
156 gp[EF_R0 + i] = regs->regs[i];
159 gp[EF_LO] = regs->lo;
160 gp[EF_HI] = regs->hi;
161 gp[EF_CP0_EPC] = regs->cp0_epc;
162 gp[EF_CP0_BADVADDR] = regs->cp0_badvaddr;
163 gp[EF_CP0_STATUS] = regs->cp0_status;
164 gp[EF_CP0_CAUSE] = regs->cp0_cause;
170 int dump_task_regs (struct task_struct *tsk, elf_gregset_t *regs)
172 struct thread_info *ti = tsk->thread_info;
173 long ksp = (unsigned long)ti + THREAD_SIZE - 32;
174 dump_regs(&(*regs)[0], (struct pt_regs *) ksp - 1);
178 int dump_task_fpu (struct task_struct *t, elf_fpregset_t *fpr)
180 memcpy(fpr, &t->thread.fpu, sizeof(current->thread.fpu));
186 * Create a kernel thread
188 ATTRIB_NORET void kernel_thread_helper(void *arg, int (*fn)(void *))
193 long kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
197 memset(®s, 0, sizeof(regs));
199 regs.regs[4] = (unsigned long) arg;
200 regs.regs[5] = (unsigned long) fn;
201 regs.cp0_epc = (unsigned long) kernel_thread_helper;
202 regs.cp0_status = read_c0_status();
203 #if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
204 regs.cp0_status &= ~(ST0_KUP | ST0_IEC);
205 regs.cp0_status |= ST0_IEP;
207 regs.cp0_status |= ST0_EXL;
210 /* Ok, create the new process.. */
211 return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, ®s, 0, NULL, NULL);
214 static struct mips_frame_info {
216 int omit_fp; /* compiled without fno-omit-frame-pointer */
219 } schedule_frame, mfinfo[] = {
220 { schedule, 0 }, /* must be first */
221 /* arch/mips/kernel/semaphore.c */
223 { __down_interruptible, 1 },
225 #ifdef CONFIG_PREEMPT
226 { preempt_schedule, 0 },
228 { wait_for_completion, 0 },
229 { interruptible_sleep_on, 0 },
230 { interruptible_sleep_on_timeout, 0 },
232 { sleep_on_timeout, 0 },
235 { io_schedule_timeout, 0 },
236 #if defined(CONFIG_SMP) && defined(CONFIG_PREEMPT)
237 { __preempt_spin_lock, 0 },
238 { __preempt_write_lock, 0 },
241 { schedule_timeout, 1 },
242 /* { nanosleep_restart, 1 }, */
243 /* lib/rwsem-spinlock.c */
248 static int mips_frame_info_initialized;
249 static int __init get_frame_info(struct mips_frame_info *info)
252 void *func = info->func;
253 union mips_instruction *ip = (union mips_instruction *)func;
254 info->pc_offset = -1;
255 info->frame_offset = info->omit_fp ? 0 : -1;
256 for (i = 0; i < 128; i++, ip++) {
257 /* if jal, jalr, jr, stop. */
258 if (ip->j_format.opcode == jal_op ||
259 (ip->r_format.opcode == spec_op &&
260 (ip->r_format.func == jalr_op ||
261 ip->r_format.func == jr_op)))
266 ip->i_format.opcode == sw_op &&
269 ip->i_format.opcode == sd_op &&
271 ip->i_format.rs == 29)
273 /* sw / sd $ra, offset($sp) */
274 if (ip->i_format.rt == 31) {
275 if (info->pc_offset != -1)
278 ip->i_format.simmediate / sizeof(long);
280 /* sw / sd $s8, offset($sp) */
281 if (ip->i_format.rt == 30) {
282 //#if 0 /* gcc 3.4 does aggressive optimization... */
283 if (info->frame_offset != -1)
287 ip->i_format.simmediate / sizeof(long);
291 if (info->pc_offset == -1 || info->frame_offset == -1) {
292 printk("Can't analyze prologue code at %p\n", func);
293 info->pc_offset = -1;
294 info->frame_offset = -1;
301 static int __init frame_info_init(void)
304 for (i = 0; i < ARRAY_SIZE(mfinfo); i++)
305 if (get_frame_info(&mfinfo[i]))
307 schedule_frame = mfinfo[0];
310 struct mips_frame_info tmp;
312 for (i = 1; i < ARRAY_SIZE(mfinfo); i++) {
313 if (mfinfo[i-1].func > mfinfo[i].func) {
315 mfinfo[i] = mfinfo[i-1];
321 mips_frame_info_initialized = 1;
325 arch_initcall(frame_info_init);
328 * Return saved PC of a blocked thread.
330 unsigned long thread_saved_pc(struct task_struct *tsk)
332 struct thread_struct *t = &tsk->thread;
334 /* New born processes are a special case */
335 if (t->reg31 == (unsigned long) ret_from_fork)
338 if (schedule_frame.pc_offset < 0)
340 return ((unsigned long *)t->reg29)[schedule_frame.pc_offset];
343 /* get_wchan - a maintenance nightmare^W^Wpain in the ass ... */
344 unsigned long get_wchan(struct task_struct *p)
346 unsigned long stack_page;
347 unsigned long frame, pc;
349 if (!p || p == current || p->state == TASK_RUNNING)
352 stack_page = (unsigned long)p->thread_info;
353 if (!stack_page || !mips_frame_info_initialized)
356 pc = thread_saved_pc(p);
357 if (!in_sched_functions(pc))
360 frame = ((unsigned long *)p->thread.reg30)[schedule_frame.frame_offset];
364 if (frame < stack_page || frame > stack_page + THREAD_SIZE - 32)
367 for (i = ARRAY_SIZE(mfinfo) - 1; i >= 0; i--) {
368 if (pc >= (unsigned long) mfinfo[i].func)
374 if (mfinfo[i].omit_fp)
376 pc = ((unsigned long *)frame)[mfinfo[i].pc_offset];
377 frame = ((unsigned long *)frame)[mfinfo[i].frame_offset];
378 } while (in_sched_functions(pc));
383 EXPORT_SYMBOL(get_wchan);