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/slab.h>
19 #include <linux/elfcore.h>
20 #include <linux/kallsyms.h>
22 #include <linux/ftrace.h>
23 #include <linux/hw_breakpoint.h>
24 #include <linux/prefetch.h>
25 #include <linux/stackprotector.h>
26 #include <asm/uaccess.h>
27 #include <asm/mmu_context.h>
29 #include <asm/syscalls.h>
30 #include <asm/switch_to.h>
32 void show_regs(struct pt_regs * regs)
35 printk("Pid : %d, Comm: \t\t%s\n", task_pid_nr(current), current->comm);
36 printk("CPU : %d \t\t%s (%s %.*s)\n\n",
37 smp_processor_id(), print_tainted(), init_utsname()->release,
38 (int)strcspn(init_utsname()->version, " "),
39 init_utsname()->version);
41 print_symbol("PC is at %s\n", instruction_pointer(regs));
42 print_symbol("PR is at %s\n", regs->pr);
44 printk("PC : %08lx SP : %08lx SR : %08lx ",
45 regs->pc, regs->regs[15], regs->sr);
47 printk("TEA : %08x\n", __raw_readl(MMU_TEA));
52 printk("R0 : %08lx R1 : %08lx R2 : %08lx R3 : %08lx\n",
53 regs->regs[0],regs->regs[1],
54 regs->regs[2],regs->regs[3]);
55 printk("R4 : %08lx R5 : %08lx R6 : %08lx R7 : %08lx\n",
56 regs->regs[4],regs->regs[5],
57 regs->regs[6],regs->regs[7]);
58 printk("R8 : %08lx R9 : %08lx R10 : %08lx R11 : %08lx\n",
59 regs->regs[8],regs->regs[9],
60 regs->regs[10],regs->regs[11]);
61 printk("R12 : %08lx R13 : %08lx R14 : %08lx\n",
62 regs->regs[12],regs->regs[13],
64 printk("MACH: %08lx MACL: %08lx GBR : %08lx PR : %08lx\n",
65 regs->mach, regs->macl, regs->gbr, regs->pr);
67 show_trace(NULL, (unsigned long *)regs->regs[15], regs);
72 * Create a kernel thread
74 __noreturn void kernel_thread_helper(void *arg, int (*fn)(void *))
79 /* Don't use this in BL=1(cli). Or else, CPU resets! */
80 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
85 memset(®s, 0, sizeof(regs));
86 regs.regs[4] = (unsigned long)arg;
87 regs.regs[5] = (unsigned long)fn;
89 regs.pc = (unsigned long)kernel_thread_helper;
91 #if defined(CONFIG_SH_FPU)
95 /* Ok, create the new process.. */
96 pid = do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0,
97 ®s, 0, NULL, NULL);
101 EXPORT_SYMBOL(kernel_thread);
103 void start_thread(struct pt_regs *regs, unsigned long new_pc,
104 unsigned long new_sp)
109 regs->regs[15] = new_sp;
111 free_thread_xstate(current);
113 EXPORT_SYMBOL(start_thread);
116 * Free current thread data structures etc..
118 void exit_thread(void)
122 void flush_thread(void)
124 struct task_struct *tsk = current;
126 flush_ptrace_hw_breakpoint(tsk);
128 #if defined(CONFIG_SH_FPU)
129 /* Forget lazy FPU state */
130 clear_fpu(tsk, task_pt_regs(tsk));
135 void release_thread(struct task_struct *dead_task)
140 /* Fill in the fpu structure for a core dump.. */
141 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
145 #if defined(CONFIG_SH_FPU)
146 struct task_struct *tsk = current;
148 fpvalid = !!tsk_used_math(tsk);
150 fpvalid = !fpregs_get(tsk, NULL, 0,
151 sizeof(struct user_fpu_struct),
157 EXPORT_SYMBOL(dump_fpu);
159 asmlinkage void ret_from_fork(void);
161 int copy_thread(unsigned long clone_flags, unsigned long usp,
162 unsigned long unused,
163 struct task_struct *p, struct pt_regs *regs)
165 struct thread_info *ti = task_thread_info(p);
166 struct pt_regs *childregs;
168 #if defined(CONFIG_SH_DSP)
169 struct task_struct *tsk = current;
171 if (is_dsp_enabled(tsk)) {
172 /* We can use the __save_dsp or just copy the struct:
174 * p->thread.dsp_status.status |= SR_DSP
176 p->thread.dsp_status = tsk->thread.dsp_status;
180 childregs = task_pt_regs(p);
183 if (user_mode(regs)) {
184 childregs->regs[15] = usp;
185 ti->addr_limit = USER_DS;
187 childregs->regs[15] = (unsigned long)childregs;
188 ti->addr_limit = KERNEL_DS;
189 ti->status &= ~TS_USEDFPU;
193 if (clone_flags & CLONE_SETTLS)
194 childregs->gbr = childregs->regs[0];
196 childregs->regs[0] = 0; /* Set return value for child */
198 p->thread.sp = (unsigned long) childregs;
199 p->thread.pc = (unsigned long) ret_from_fork;
201 memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps));
207 * switch_to(x,y) should switch tasks from x to y.
210 __notrace_funcgraph struct task_struct *
211 __switch_to(struct task_struct *prev, struct task_struct *next)
213 struct thread_struct *next_t = &next->thread;
215 #if defined(CONFIG_CC_STACKPROTECTOR) && !defined(CONFIG_SMP)
216 __stack_chk_guard = next->stack_canary;
219 unlazy_fpu(prev, task_pt_regs(prev));
221 /* we're going to use this soon, after a few expensive things */
222 if (next->fpu_counter > 5)
223 prefetch(next_t->xstate);
227 * Restore the kernel mode register
230 asm volatile("ldc %0, r7_bank"
232 : "r" (task_thread_info(next)));
236 * If the task has used fpu the last 5 timeslices, just do a full
237 * restore of the math state immediately to avoid the trap; the
238 * chances of needing FPU soon are obviously high now
240 if (next->fpu_counter > 5)
241 __fpu_state_restore();
246 asmlinkage int sys_fork(unsigned long r4, unsigned long r5,
247 unsigned long r6, unsigned long r7,
248 struct pt_regs __regs)
251 struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
252 return do_fork(SIGCHLD, regs->regs[15], regs, 0, NULL, NULL);
254 /* fork almost works, enough to trick you into looking elsewhere :-( */
259 asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp,
260 unsigned long parent_tidptr,
261 unsigned long child_tidptr,
262 struct pt_regs __regs)
264 struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
266 newsp = regs->regs[15];
267 return do_fork(clone_flags, newsp, regs, 0,
268 (int __user *)parent_tidptr,
269 (int __user *)child_tidptr);
273 * This is trivial, and on the face of it looks like it
274 * could equally well be done in user mode.
276 * Not so, for quite unobvious reasons - register pressure.
277 * In user mode vfork() cannot have a stack frame, and if
278 * done by calling the "clone()" system call directly, you
279 * do not have enough call-clobbered registers to hold all
280 * the information you need.
282 asmlinkage int sys_vfork(unsigned long r4, unsigned long r5,
283 unsigned long r6, unsigned long r7,
284 struct pt_regs __regs)
286 struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
287 return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->regs[15], regs,
292 * sys_execve() executes a new program.
294 asmlinkage int sys_execve(const char __user *ufilename,
295 const char __user *const __user *uargv,
296 const char __user *const __user *uenvp,
297 unsigned long r7, struct pt_regs __regs)
299 struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
303 filename = getname(ufilename);
304 error = PTR_ERR(filename);
305 if (IS_ERR(filename))
308 error = do_execve(filename, uargv, uenvp, regs);
314 unsigned long get_wchan(struct task_struct *p)
318 if (!p || p == current || p->state == TASK_RUNNING)
322 * The same comment as on the Alpha applies here, too ...
324 pc = thread_saved_pc(p);
326 #ifdef CONFIG_FRAME_POINTER
327 if (in_sched_functions(pc)) {
328 unsigned long schedule_frame = (unsigned long)p->thread.sp;
329 return ((unsigned long *)schedule_frame)[21];