2 * arch/sh/kernel/process.c
4 * This file handles the architecture-dependent parts of process handling..
6 * Copyright (C) 1995 Linus Torvalds
8 * SuperH version: Copyright (C) 1999, 2000 Niibe Yutaka & Kaz Kojima
9 * Copyright (C) 2006 Lineo Solutions Inc. support SH4A UBC
10 * Copyright (C) 2002 - 2007 Paul Mundt
12 #include <linux/module.h>
14 #include <linux/elfcore.h>
16 #include <linux/kallsyms.h>
17 #include <linux/kexec.h>
18 #include <linux/kdebug.h>
19 #include <linux/tick.h>
20 #include <linux/reboot.h>
22 #include <asm/uaccess.h>
23 #include <asm/mmu_context.h>
24 #include <asm/pgalloc.h>
25 #include <asm/system.h>
28 static int hlt_counter;
31 void (*pm_idle)(void);
32 void (*pm_power_off)(void);
33 EXPORT_SYMBOL(pm_power_off);
35 void disable_hlt(void)
39 EXPORT_SYMBOL(disable_hlt);
45 EXPORT_SYMBOL(enable_hlt);
47 static int __init nohlt_setup(char *__unused)
52 __setup("nohlt", nohlt_setup);
54 static int __init hlt_setup(char *__unused)
59 __setup("hlt", hlt_setup);
61 void default_idle(void)
64 clear_thread_flag(TIF_POLLING_NRFLAG);
65 smp_mb__after_clear_bit();
67 while (!need_resched())
70 set_thread_flag(TIF_POLLING_NRFLAG);
72 while (!need_resched())
78 set_thread_flag(TIF_POLLING_NRFLAG);
80 /* endless idle loop with no priority at all */
82 void (*idle)(void) = pm_idle;
87 tick_nohz_stop_sched_tick();
88 while (!need_resched())
90 tick_nohz_restart_sched_tick();
92 preempt_enable_no_resched();
99 void machine_restart(char * __unused)
101 /* SR.BL=1 and invoke address error to let CPU reset (manual reset) */
102 asm volatile("ldc %0, sr\n\t"
103 "mov.l @%1, %0" : : "r" (0x10000000), "r" (0x80000001));
106 void machine_halt(void)
114 void machine_power_off(void)
120 void show_regs(struct pt_regs * regs)
123 printk("Pid : %d, Comm: %20s\n", current->pid, current->comm);
124 print_symbol("PC is at %s\n", instruction_pointer(regs));
125 printk("PC : %08lx SP : %08lx SR : %08lx ",
126 regs->pc, regs->regs[15], regs->sr);
128 printk("TEA : %08x ", ctrl_inl(MMU_TEA));
132 printk("%s\n", print_tainted());
134 printk("R0 : %08lx R1 : %08lx R2 : %08lx R3 : %08lx\n",
135 regs->regs[0],regs->regs[1],
136 regs->regs[2],regs->regs[3]);
137 printk("R4 : %08lx R5 : %08lx R6 : %08lx R7 : %08lx\n",
138 regs->regs[4],regs->regs[5],
139 regs->regs[6],regs->regs[7]);
140 printk("R8 : %08lx R9 : %08lx R10 : %08lx R11 : %08lx\n",
141 regs->regs[8],regs->regs[9],
142 regs->regs[10],regs->regs[11]);
143 printk("R12 : %08lx R13 : %08lx R14 : %08lx\n",
144 regs->regs[12],regs->regs[13],
146 printk("MACH: %08lx MACL: %08lx GBR : %08lx PR : %08lx\n",
147 regs->mach, regs->macl, regs->gbr, regs->pr);
149 show_trace(NULL, (unsigned long *)regs->regs[15], regs);
153 * Create a kernel thread
157 * This is the mechanism for creating a new kernel thread.
160 extern void kernel_thread_helper(void);
162 "kernel_thread_helper:\n\t"
171 /* Don't use this in BL=1(cli). Or else, CPU resets! */
172 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
176 memset(®s, 0, sizeof(regs));
177 regs.regs[4] = (unsigned long)arg;
178 regs.regs[5] = (unsigned long)fn;
180 regs.pc = (unsigned long)kernel_thread_helper;
183 /* Ok, create the new process.. */
184 return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0,
185 ®s, 0, NULL, NULL);
189 * Free current thread data structures etc..
191 void exit_thread(void)
193 if (current->thread.ubc_pc) {
194 current->thread.ubc_pc = 0;
199 void flush_thread(void)
201 #if defined(CONFIG_SH_FPU)
202 struct task_struct *tsk = current;
203 /* Forget lazy FPU state */
204 clear_fpu(tsk, task_pt_regs(tsk));
209 void release_thread(struct task_struct *dead_task)
214 /* Fill in the fpu structure for a core dump.. */
215 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
219 #if defined(CONFIG_SH_FPU)
220 struct task_struct *tsk = current;
222 fpvalid = !!tsk_used_math(tsk);
224 unlazy_fpu(tsk, regs);
225 memcpy(fpu, &tsk->thread.fpu.hard, sizeof(*fpu));
233 * Capture the user space registers if the task is not running (in user space)
235 int dump_task_regs(struct task_struct *tsk, elf_gregset_t *regs)
237 struct pt_regs ptregs;
239 ptregs = *task_pt_regs(tsk);
240 elf_core_copy_regs(regs, &ptregs);
245 int dump_task_fpu(struct task_struct *tsk, elf_fpregset_t *fpu)
249 #if defined(CONFIG_SH_FPU)
250 fpvalid = !!tsk_used_math(tsk);
252 unlazy_fpu(tsk, task_pt_regs(tsk));
253 memcpy(fpu, &tsk->thread.fpu.hard, sizeof(*fpu));
260 asmlinkage void ret_from_fork(void);
262 int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
263 unsigned long unused,
264 struct task_struct *p, struct pt_regs *regs)
266 struct thread_info *ti = task_thread_info(p);
267 struct pt_regs *childregs;
268 #if defined(CONFIG_SH_FPU)
269 struct task_struct *tsk = current;
271 unlazy_fpu(tsk, regs);
272 p->thread.fpu = tsk->thread.fpu;
273 copy_to_stopped_child_used_math(p);
276 childregs = task_pt_regs(p);
279 if (user_mode(regs)) {
280 childregs->regs[15] = usp;
281 ti->addr_limit = USER_DS;
283 childregs->regs[15] = (unsigned long)childregs;
284 ti->addr_limit = KERNEL_DS;
287 if (clone_flags & CLONE_SETTLS)
288 childregs->gbr = childregs->regs[0];
290 childregs->regs[0] = 0; /* Set return value for child */
292 p->thread.sp = (unsigned long) childregs;
293 p->thread.pc = (unsigned long) ret_from_fork;
295 p->thread.ubc_pc = 0;
300 /* Tracing by user break controller. */
301 static void ubc_set_tracing(int asid, unsigned long pc)
303 #if defined(CONFIG_CPU_SH4A)
306 val = (UBC_CBR_ID_INST | UBC_CBR_RW_READ | UBC_CBR_CE);
307 val |= (UBC_CBR_AIE | UBC_CBR_AIV_SET(asid));
309 ctrl_outl(val, UBC_CBR0);
310 ctrl_outl(pc, UBC_CAR0);
311 ctrl_outl(0x0, UBC_CAMR0);
312 ctrl_outl(0x0, UBC_CBCR);
314 val = (UBC_CRR_RES | UBC_CRR_PCB | UBC_CRR_BIE);
315 ctrl_outl(val, UBC_CRR0);
317 /* Read UBC register that we wrote last, for checking update */
318 val = ctrl_inl(UBC_CRR0);
320 #else /* CONFIG_CPU_SH4A */
321 ctrl_outl(pc, UBC_BARA);
324 ctrl_outb(asid, UBC_BASRA);
327 ctrl_outl(0, UBC_BAMRA);
329 if (current_cpu_data.type == CPU_SH7729 ||
330 current_cpu_data.type == CPU_SH7710 ||
331 current_cpu_data.type == CPU_SH7712) {
332 ctrl_outw(BBR_INST | BBR_READ | BBR_CPU, UBC_BBRA);
333 ctrl_outl(BRCR_PCBA | BRCR_PCTE, UBC_BRCR);
335 ctrl_outw(BBR_INST | BBR_READ, UBC_BBRA);
336 ctrl_outw(BRCR_PCBA, UBC_BRCR);
338 #endif /* CONFIG_CPU_SH4A */
342 * switch_to(x,y) should switch tasks from x to y.
345 struct task_struct *__switch_to(struct task_struct *prev,
346 struct task_struct *next)
348 #if defined(CONFIG_SH_FPU)
349 unlazy_fpu(prev, task_pt_regs(prev));
352 #ifdef CONFIG_PREEMPT
355 struct pt_regs *regs;
357 local_irq_save(flags);
358 regs = task_pt_regs(prev);
359 if (user_mode(regs) && regs->regs[15] >= 0xc0000000) {
360 int offset = (int)regs->regs[15];
362 /* Reset stack pointer: clear critical region mark */
363 regs->regs[15] = regs->regs[1];
364 if (regs->pc < regs->regs[0])
365 /* Go to rewind point */
366 regs->pc = regs->regs[0] + offset;
368 local_irq_restore(flags);
374 * Restore the kernel mode register
377 asm volatile("ldc %0, r7_bank"
379 : "r" (task_thread_info(next)));
382 /* If no tasks are using the UBC, we're done */
383 if (ubc_usercnt == 0)
384 /* If no tasks are using the UBC, we're done */;
385 else if (next->thread.ubc_pc && next->mm) {
388 asid |= cpu_asid(smp_processor_id(), next->mm);
390 ubc_set_tracing(asid, next->thread.ubc_pc);
392 #if defined(CONFIG_CPU_SH4A)
393 ctrl_outl(UBC_CBR_INIT, UBC_CBR0);
394 ctrl_outl(UBC_CRR_INIT, UBC_CRR0);
396 ctrl_outw(0, UBC_BBRA);
397 ctrl_outw(0, UBC_BBRB);
404 asmlinkage int sys_fork(unsigned long r4, unsigned long r5,
405 unsigned long r6, unsigned long r7,
406 struct pt_regs __regs)
409 struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
410 return do_fork(SIGCHLD, regs->regs[15], regs, 0, NULL, NULL);
412 /* fork almost works, enough to trick you into looking elsewhere :-( */
417 asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp,
418 unsigned long parent_tidptr,
419 unsigned long child_tidptr,
420 struct pt_regs __regs)
422 struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
424 newsp = regs->regs[15];
425 return do_fork(clone_flags, newsp, regs, 0,
426 (int __user *)parent_tidptr,
427 (int __user *)child_tidptr);
431 * This is trivial, and on the face of it looks like it
432 * could equally well be done in user mode.
434 * Not so, for quite unobvious reasons - register pressure.
435 * In user mode vfork() cannot have a stack frame, and if
436 * done by calling the "clone()" system call directly, you
437 * do not have enough call-clobbered registers to hold all
438 * the information you need.
440 asmlinkage int sys_vfork(unsigned long r4, unsigned long r5,
441 unsigned long r6, unsigned long r7,
442 struct pt_regs __regs)
444 struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
445 return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->regs[15], regs,
450 * sys_execve() executes a new program.
452 asmlinkage int sys_execve(char __user *ufilename, char __user * __user *uargv,
453 char __user * __user *uenvp, unsigned long r7,
454 struct pt_regs __regs)
456 struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
460 filename = getname(ufilename);
461 error = PTR_ERR(filename);
462 if (IS_ERR(filename))
465 error = do_execve(filename, uargv, uenvp, regs);
468 current->ptrace &= ~PT_DTRACE;
469 task_unlock(current);
476 unsigned long get_wchan(struct task_struct *p)
480 if (!p || p == current || p->state == TASK_RUNNING)
484 * The same comment as on the Alpha applies here, too ...
486 pc = thread_saved_pc(p);
488 #ifdef CONFIG_FRAME_POINTER
489 if (in_sched_functions(pc)) {
490 unsigned long schedule_frame = (unsigned long)p->thread.sp;
491 return ((unsigned long *)schedule_frame)[21];
498 asmlinkage void break_point_trap(void)
501 #if defined(CONFIG_CPU_SH4A)
502 ctrl_outl(UBC_CBR_INIT, UBC_CBR0);
503 ctrl_outl(UBC_CRR_INIT, UBC_CRR0);
505 ctrl_outw(0, UBC_BBRA);
506 ctrl_outw(0, UBC_BBRB);
508 current->thread.ubc_pc = 0;
511 force_sig(SIGTRAP, current);
515 * Generic trap handler.
517 asmlinkage void debug_trap_handler(unsigned long r4, unsigned long r5,
518 unsigned long r6, unsigned long r7,
519 struct pt_regs __regs)
521 struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
524 regs->pc -= instruction_size(ctrl_inw(regs->pc - 4));
526 if (notify_die(DIE_TRAP, "debug trap", regs, 0, regs->tra & 0xff,
527 SIGTRAP) == NOTIFY_STOP)
530 force_sig(SIGTRAP, current);
534 * Special handler for BUG() traps.
536 asmlinkage void bug_trap_handler(unsigned long r4, unsigned long r5,
537 unsigned long r6, unsigned long r7,
538 struct pt_regs __regs)
540 struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
543 regs->pc -= instruction_size(ctrl_inw(regs->pc - 4));
545 if (notify_die(DIE_TRAP, "bug trap", regs, 0, TRAPA_BUG_OPCODE & 0xff,
546 SIGTRAP) == NOTIFY_STOP)
550 if (__kernel_text_address(instruction_pointer(regs))) {
551 u16 insn = *(u16 *)instruction_pointer(regs);
552 if (insn == TRAPA_BUG_OPCODE)
557 force_sig(SIGTRAP, current);