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 - 2008 Paul Mundt
12 * This file is subject to the terms and conditions of the GNU General Public
13 * License. See the file "COPYING" in the main directory of this archive
16 #include <linux/module.h>
18 #include <linux/elfcore.h>
20 #include <linux/kallsyms.h>
21 #include <linux/kexec.h>
22 #include <linux/kdebug.h>
23 #include <linux/tick.h>
24 #include <linux/reboot.h>
26 #include <linux/ftrace.h>
27 #include <linux/preempt.h>
28 #include <linux/hw_breakpoint.h>
29 #include <asm/uaccess.h>
30 #include <asm/mmu_context.h>
31 #include <asm/pgalloc.h>
32 #include <asm/system.h>
34 #include <asm/syscalls.h>
35 #include <asm/watchdog.h>
38 static void watchdog_trigger_immediate(void)
40 sh_wdt_write_cnt(0xFF);
41 sh_wdt_write_csr(0xC2);
44 void machine_restart(char * __unused)
48 /* Use watchdog timer to trigger reset */
49 watchdog_trigger_immediate();
55 void machine_restart(char * __unused)
57 /* SR.BL=1 and invoke address error to let CPU reset (manual reset) */
58 asm volatile("ldc %0, sr\n\t"
59 "mov.l @%1, %0" : : "r" (0x10000000), "r" (0x80000001));
63 void machine_halt(void)
71 void machine_power_off(void)
77 void show_regs(struct pt_regs * regs)
80 printk("Pid : %d, Comm: \t\t%s\n", task_pid_nr(current), current->comm);
81 printk("CPU : %d \t\t%s (%s %.*s)\n\n",
82 smp_processor_id(), print_tainted(), init_utsname()->release,
83 (int)strcspn(init_utsname()->version, " "),
84 init_utsname()->version);
86 print_symbol("PC is at %s\n", instruction_pointer(regs));
87 print_symbol("PR is at %s\n", regs->pr);
89 printk("PC : %08lx SP : %08lx SR : %08lx ",
90 regs->pc, regs->regs[15], regs->sr);
92 printk("TEA : %08x\n", ctrl_inl(MMU_TEA));
97 printk("R0 : %08lx R1 : %08lx R2 : %08lx R3 : %08lx\n",
98 regs->regs[0],regs->regs[1],
99 regs->regs[2],regs->regs[3]);
100 printk("R4 : %08lx R5 : %08lx R6 : %08lx R7 : %08lx\n",
101 regs->regs[4],regs->regs[5],
102 regs->regs[6],regs->regs[7]);
103 printk("R8 : %08lx R9 : %08lx R10 : %08lx R11 : %08lx\n",
104 regs->regs[8],regs->regs[9],
105 regs->regs[10],regs->regs[11]);
106 printk("R12 : %08lx R13 : %08lx R14 : %08lx\n",
107 regs->regs[12],regs->regs[13],
109 printk("MACH: %08lx MACL: %08lx GBR : %08lx PR : %08lx\n",
110 regs->mach, regs->macl, regs->gbr, regs->pr);
112 show_trace(NULL, (unsigned long *)regs->regs[15], regs);
117 * Create a kernel thread
119 ATTRIB_NORET void kernel_thread_helper(void *arg, int (*fn)(void *))
124 /* Don't use this in BL=1(cli). Or else, CPU resets! */
125 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
130 memset(®s, 0, sizeof(regs));
131 regs.regs[4] = (unsigned long)arg;
132 regs.regs[5] = (unsigned long)fn;
134 regs.pc = (unsigned long)kernel_thread_helper;
136 #if defined(CONFIG_SH_FPU)
140 /* Ok, create the new process.. */
141 pid = do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0,
142 ®s, 0, NULL, NULL);
146 EXPORT_SYMBOL(kernel_thread);
149 * Free current thread data structures etc..
151 void exit_thread(void)
155 void flush_thread(void)
157 struct task_struct *tsk = current;
159 flush_ptrace_hw_breakpoint(tsk);
161 #if defined(CONFIG_SH_FPU)
162 /* Forget lazy FPU state */
163 clear_fpu(tsk, task_pt_regs(tsk));
168 void release_thread(struct task_struct *dead_task)
173 /* Fill in the fpu structure for a core dump.. */
174 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
178 #if defined(CONFIG_SH_FPU)
179 struct task_struct *tsk = current;
181 fpvalid = !!tsk_used_math(tsk);
183 fpvalid = !fpregs_get(tsk, NULL, 0,
184 sizeof(struct user_fpu_struct),
190 EXPORT_SYMBOL(dump_fpu);
193 * This gets called before we allocate a new thread and copy
194 * the current task into it.
196 void prepare_to_copy(struct task_struct *tsk)
198 unlazy_fpu(tsk, task_pt_regs(tsk));
201 asmlinkage void ret_from_fork(void);
203 int copy_thread(unsigned long clone_flags, unsigned long usp,
204 unsigned long unused,
205 struct task_struct *p, struct pt_regs *regs)
207 struct thread_info *ti = task_thread_info(p);
208 struct pt_regs *childregs;
210 #if defined(CONFIG_SH_DSP)
211 struct task_struct *tsk = current;
213 if (is_dsp_enabled(tsk)) {
214 /* We can use the __save_dsp or just copy the struct:
216 * p->thread.dsp_status.status |= SR_DSP
218 p->thread.dsp_status = tsk->thread.dsp_status;
222 childregs = task_pt_regs(p);
225 if (user_mode(regs)) {
226 childregs->regs[15] = usp;
227 ti->addr_limit = USER_DS;
229 childregs->regs[15] = (unsigned long)childregs;
230 ti->addr_limit = KERNEL_DS;
231 ti->status &= ~TS_USEDFPU;
235 if (clone_flags & CLONE_SETTLS)
236 childregs->gbr = childregs->regs[0];
238 childregs->regs[0] = 0; /* Set return value for child */
240 p->thread.sp = (unsigned long) childregs;
241 p->thread.pc = (unsigned long) ret_from_fork;
243 memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps));
249 * switch_to(x,y) should switch tasks from x to y.
252 __notrace_funcgraph struct task_struct *
253 __switch_to(struct task_struct *prev, struct task_struct *next)
255 struct thread_struct *next_t = &next->thread;
257 unlazy_fpu(prev, task_pt_regs(prev));
259 /* we're going to use this soon, after a few expensive things */
260 if (next->fpu_counter > 5)
261 prefetch(&next_t->fpu.hard);
265 * Restore the kernel mode register
268 asm volatile("ldc %0, r7_bank"
270 : "r" (task_thread_info(next)));
274 * If the task has used fpu the last 5 timeslices, just do a full
275 * restore of the math state immediately to avoid the trap; the
276 * chances of needing FPU soon are obviously high now
278 if (next->fpu_counter > 5)
279 fpu_state_restore(task_pt_regs(next));
284 asmlinkage int sys_fork(unsigned long r4, unsigned long r5,
285 unsigned long r6, unsigned long r7,
286 struct pt_regs __regs)
289 struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
290 return do_fork(SIGCHLD, regs->regs[15], regs, 0, NULL, NULL);
292 /* fork almost works, enough to trick you into looking elsewhere :-( */
297 asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp,
298 unsigned long parent_tidptr,
299 unsigned long child_tidptr,
300 struct pt_regs __regs)
302 struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
304 newsp = regs->regs[15];
305 return do_fork(clone_flags, newsp, regs, 0,
306 (int __user *)parent_tidptr,
307 (int __user *)child_tidptr);
311 * This is trivial, and on the face of it looks like it
312 * could equally well be done in user mode.
314 * Not so, for quite unobvious reasons - register pressure.
315 * In user mode vfork() cannot have a stack frame, and if
316 * done by calling the "clone()" system call directly, you
317 * do not have enough call-clobbered registers to hold all
318 * the information you need.
320 asmlinkage int sys_vfork(unsigned long r4, unsigned long r5,
321 unsigned long r6, unsigned long r7,
322 struct pt_regs __regs)
324 struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
325 return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->regs[15], regs,
330 * sys_execve() executes a new program.
332 asmlinkage int sys_execve(char __user *ufilename, char __user * __user *uargv,
333 char __user * __user *uenvp, unsigned long r7,
334 struct pt_regs __regs)
336 struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
340 filename = getname(ufilename);
341 error = PTR_ERR(filename);
342 if (IS_ERR(filename))
345 error = do_execve(filename, uargv, uenvp, regs);
351 unsigned long get_wchan(struct task_struct *p)
355 if (!p || p == current || p->state == TASK_RUNNING)
359 * The same comment as on the Alpha applies here, too ...
361 pc = thread_saved_pc(p);
363 #ifdef CONFIG_FRAME_POINTER
364 if (in_sched_functions(pc)) {
365 unsigned long schedule_frame = (unsigned long)p->thread.sp;
366 return ((unsigned long *)schedule_frame)[21];