1 /* 2 * arch/sh/kernel/process.c 3 * 4 * This file handles the architecture-dependent parts of process handling.. 5 * 6 * Copyright (C) 1995 Linus Torvalds 7 * 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 11 * 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 14 * for more details. 15 */ 16 #include <linux/module.h> 17 #include <linux/mm.h> 18 #include <linux/elfcore.h> 19 #include <linux/pm.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> 25 #include <linux/fs.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> 33 #include <asm/fpu.h> 34 #include <asm/syscalls.h> 35 #include <asm/watchdog.h> 36 37 #ifdef CONFIG_32BIT 38 static void watchdog_trigger_immediate(void) 39 { 40 sh_wdt_write_cnt(0xFF); 41 sh_wdt_write_csr(0xC2); 42 } 43 44 void machine_restart(char * __unused) 45 { 46 local_irq_disable(); 47 48 /* Use watchdog timer to trigger reset */ 49 watchdog_trigger_immediate(); 50 51 while (1) 52 cpu_sleep(); 53 } 54 #else 55 void machine_restart(char * __unused) 56 { 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)); 60 } 61 #endif 62 63 void machine_halt(void) 64 { 65 local_irq_disable(); 66 67 while (1) 68 cpu_sleep(); 69 } 70 71 void machine_power_off(void) 72 { 73 if (pm_power_off) 74 pm_power_off(); 75 } 76 77 void show_regs(struct pt_regs * regs) 78 { 79 printk("\n"); 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); 85 86 print_symbol("PC is at %s\n", instruction_pointer(regs)); 87 print_symbol("PR is at %s\n", regs->pr); 88 89 printk("PC : %08lx SP : %08lx SR : %08lx ", 90 regs->pc, regs->regs[15], regs->sr); 91 #ifdef CONFIG_MMU 92 printk("TEA : %08x\n", ctrl_inl(MMU_TEA)); 93 #else 94 printk("\n"); 95 #endif 96 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], 108 regs->regs[14]); 109 printk("MACH: %08lx MACL: %08lx GBR : %08lx PR : %08lx\n", 110 regs->mach, regs->macl, regs->gbr, regs->pr); 111 112 show_trace(NULL, (unsigned long *)regs->regs[15], regs); 113 show_code(regs); 114 } 115 116 /* 117 * Create a kernel thread 118 */ 119 ATTRIB_NORET void kernel_thread_helper(void *arg, int (*fn)(void *)) 120 { 121 do_exit(fn(arg)); 122 } 123 124 /* Don't use this in BL=1(cli). Or else, CPU resets! */ 125 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags) 126 { 127 struct pt_regs regs; 128 int pid; 129 130 memset(®s, 0, sizeof(regs)); 131 regs.regs[4] = (unsigned long)arg; 132 regs.regs[5] = (unsigned long)fn; 133 134 regs.pc = (unsigned long)kernel_thread_helper; 135 regs.sr = SR_MD; 136 #if defined(CONFIG_SH_FPU) 137 regs.sr |= SR_FD; 138 #endif 139 140 /* Ok, create the new process.. */ 141 pid = do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, 142 ®s, 0, NULL, NULL); 143 144 return pid; 145 } 146 EXPORT_SYMBOL(kernel_thread); 147 148 void start_thread(struct pt_regs *regs, unsigned long new_pc, 149 unsigned long new_sp) 150 { 151 set_fs(USER_DS); 152 153 regs->pr = 0; 154 regs->sr = SR_FD; 155 regs->pc = new_pc; 156 regs->regs[15] = new_sp; 157 158 free_thread_xstate(current); 159 } 160 EXPORT_SYMBOL(start_thread); 161 162 /* 163 * Free current thread data structures etc.. 164 */ 165 void exit_thread(void) 166 { 167 } 168 169 void flush_thread(void) 170 { 171 struct task_struct *tsk = current; 172 173 flush_ptrace_hw_breakpoint(tsk); 174 175 #if defined(CONFIG_SH_FPU) 176 /* Forget lazy FPU state */ 177 clear_fpu(tsk, task_pt_regs(tsk)); 178 clear_used_math(); 179 #endif 180 } 181 182 void release_thread(struct task_struct *dead_task) 183 { 184 /* do nothing */ 185 } 186 187 /* Fill in the fpu structure for a core dump.. */ 188 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu) 189 { 190 int fpvalid = 0; 191 192 #if defined(CONFIG_SH_FPU) 193 struct task_struct *tsk = current; 194 195 fpvalid = !!tsk_used_math(tsk); 196 if (fpvalid) 197 fpvalid = !fpregs_get(tsk, NULL, 0, 198 sizeof(struct user_fpu_struct), 199 fpu, NULL); 200 #endif 201 202 return fpvalid; 203 } 204 EXPORT_SYMBOL(dump_fpu); 205 206 /* 207 * This gets called before we allocate a new thread and copy 208 * the current task into it. 209 */ 210 void prepare_to_copy(struct task_struct *tsk) 211 { 212 unlazy_fpu(tsk, task_pt_regs(tsk)); 213 } 214 215 asmlinkage void ret_from_fork(void); 216 217 int copy_thread(unsigned long clone_flags, unsigned long usp, 218 unsigned long unused, 219 struct task_struct *p, struct pt_regs *regs) 220 { 221 struct thread_info *ti = task_thread_info(p); 222 struct pt_regs *childregs; 223 224 #if defined(CONFIG_SH_DSP) 225 struct task_struct *tsk = current; 226 227 if (is_dsp_enabled(tsk)) { 228 /* We can use the __save_dsp or just copy the struct: 229 * __save_dsp(p); 230 * p->thread.dsp_status.status |= SR_DSP 231 */ 232 p->thread.dsp_status = tsk->thread.dsp_status; 233 } 234 #endif 235 236 childregs = task_pt_regs(p); 237 *childregs = *regs; 238 239 if (user_mode(regs)) { 240 childregs->regs[15] = usp; 241 ti->addr_limit = USER_DS; 242 } else { 243 childregs->regs[15] = (unsigned long)childregs; 244 ti->addr_limit = KERNEL_DS; 245 ti->status &= ~TS_USEDFPU; 246 p->fpu_counter = 0; 247 } 248 249 if (clone_flags & CLONE_SETTLS) 250 childregs->gbr = childregs->regs[0]; 251 252 childregs->regs[0] = 0; /* Set return value for child */ 253 254 p->thread.sp = (unsigned long) childregs; 255 p->thread.pc = (unsigned long) ret_from_fork; 256 257 memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps)); 258 259 return 0; 260 } 261 262 /* 263 * switch_to(x,y) should switch tasks from x to y. 264 * 265 */ 266 __notrace_funcgraph struct task_struct * 267 __switch_to(struct task_struct *prev, struct task_struct *next) 268 { 269 struct thread_struct *next_t = &next->thread; 270 271 unlazy_fpu(prev, task_pt_regs(prev)); 272 273 /* we're going to use this soon, after a few expensive things */ 274 if (next->fpu_counter > 5) 275 prefetch(next_t->xstate); 276 277 #ifdef CONFIG_MMU 278 /* 279 * Restore the kernel mode register 280 * k7 (r7_bank1) 281 */ 282 asm volatile("ldc %0, r7_bank" 283 : /* no output */ 284 : "r" (task_thread_info(next))); 285 #endif 286 287 /* 288 * If the task has used fpu the last 5 timeslices, just do a full 289 * restore of the math state immediately to avoid the trap; the 290 * chances of needing FPU soon are obviously high now 291 */ 292 if (next->fpu_counter > 5) 293 __fpu_state_restore(); 294 295 return prev; 296 } 297 298 asmlinkage int sys_fork(unsigned long r4, unsigned long r5, 299 unsigned long r6, unsigned long r7, 300 struct pt_regs __regs) 301 { 302 #ifdef CONFIG_MMU 303 struct pt_regs *regs = RELOC_HIDE(&__regs, 0); 304 return do_fork(SIGCHLD, regs->regs[15], regs, 0, NULL, NULL); 305 #else 306 /* fork almost works, enough to trick you into looking elsewhere :-( */ 307 return -EINVAL; 308 #endif 309 } 310 311 asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp, 312 unsigned long parent_tidptr, 313 unsigned long child_tidptr, 314 struct pt_regs __regs) 315 { 316 struct pt_regs *regs = RELOC_HIDE(&__regs, 0); 317 if (!newsp) 318 newsp = regs->regs[15]; 319 return do_fork(clone_flags, newsp, regs, 0, 320 (int __user *)parent_tidptr, 321 (int __user *)child_tidptr); 322 } 323 324 /* 325 * This is trivial, and on the face of it looks like it 326 * could equally well be done in user mode. 327 * 328 * Not so, for quite unobvious reasons - register pressure. 329 * In user mode vfork() cannot have a stack frame, and if 330 * done by calling the "clone()" system call directly, you 331 * do not have enough call-clobbered registers to hold all 332 * the information you need. 333 */ 334 asmlinkage int sys_vfork(unsigned long r4, unsigned long r5, 335 unsigned long r6, unsigned long r7, 336 struct pt_regs __regs) 337 { 338 struct pt_regs *regs = RELOC_HIDE(&__regs, 0); 339 return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->regs[15], regs, 340 0, NULL, NULL); 341 } 342 343 /* 344 * sys_execve() executes a new program. 345 */ 346 asmlinkage int sys_execve(char __user *ufilename, char __user * __user *uargv, 347 char __user * __user *uenvp, unsigned long r7, 348 struct pt_regs __regs) 349 { 350 struct pt_regs *regs = RELOC_HIDE(&__regs, 0); 351 int error; 352 char *filename; 353 354 filename = getname(ufilename); 355 error = PTR_ERR(filename); 356 if (IS_ERR(filename)) 357 goto out; 358 359 error = do_execve(filename, uargv, uenvp, regs); 360 putname(filename); 361 out: 362 return error; 363 } 364 365 unsigned long get_wchan(struct task_struct *p) 366 { 367 unsigned long pc; 368 369 if (!p || p == current || p->state == TASK_RUNNING) 370 return 0; 371 372 /* 373 * The same comment as on the Alpha applies here, too ... 374 */ 375 pc = thread_saved_pc(p); 376 377 #ifdef CONFIG_FRAME_POINTER 378 if (in_sched_functions(pc)) { 379 unsigned long schedule_frame = (unsigned long)p->thread.sp; 380 return ((unsigned long *)schedule_frame)[21]; 381 } 382 #endif 383 384 return pc; 385 } 386