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 - 2007 Paul Mundt 11 */ 12 #include <linux/module.h> 13 #include <linux/mm.h> 14 #include <linux/elfcore.h> 15 #include <linux/pm.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> 21 #include <linux/fs.h> 22 #include <linux/preempt.h> 23 #include <asm/uaccess.h> 24 #include <asm/mmu_context.h> 25 #include <asm/pgalloc.h> 26 #include <asm/system.h> 27 #include <asm/ubc.h> 28 29 static int hlt_counter; 30 int ubc_usercnt = 0; 31 32 void (*pm_idle)(void); 33 void (*pm_power_off)(void); 34 EXPORT_SYMBOL(pm_power_off); 35 36 void disable_hlt(void) 37 { 38 hlt_counter++; 39 } 40 EXPORT_SYMBOL(disable_hlt); 41 42 void enable_hlt(void) 43 { 44 hlt_counter--; 45 } 46 EXPORT_SYMBOL(enable_hlt); 47 48 static int __init nohlt_setup(char *__unused) 49 { 50 hlt_counter = 1; 51 return 1; 52 } 53 __setup("nohlt", nohlt_setup); 54 55 static int __init hlt_setup(char *__unused) 56 { 57 hlt_counter = 0; 58 return 1; 59 } 60 __setup("hlt", hlt_setup); 61 62 void default_idle(void) 63 { 64 if (!hlt_counter) { 65 clear_thread_flag(TIF_POLLING_NRFLAG); 66 smp_mb__after_clear_bit(); 67 set_bl_bit(); 68 while (!need_resched()) 69 cpu_sleep(); 70 clear_bl_bit(); 71 set_thread_flag(TIF_POLLING_NRFLAG); 72 } else 73 while (!need_resched()) 74 cpu_relax(); 75 } 76 77 void cpu_idle(void) 78 { 79 set_thread_flag(TIF_POLLING_NRFLAG); 80 81 /* endless idle loop with no priority at all */ 82 while (1) { 83 void (*idle)(void) = pm_idle; 84 85 if (!idle) 86 idle = default_idle; 87 88 tick_nohz_stop_sched_tick(); 89 while (!need_resched()) 90 idle(); 91 tick_nohz_restart_sched_tick(); 92 93 preempt_enable_no_resched(); 94 schedule(); 95 preempt_disable(); 96 check_pgt_cache(); 97 } 98 } 99 100 void machine_restart(char * __unused) 101 { 102 /* SR.BL=1 and invoke address error to let CPU reset (manual reset) */ 103 asm volatile("ldc %0, sr\n\t" 104 "mov.l @%1, %0" : : "r" (0x10000000), "r" (0x80000001)); 105 } 106 107 void machine_halt(void) 108 { 109 local_irq_disable(); 110 111 while (1) 112 cpu_sleep(); 113 } 114 115 void machine_power_off(void) 116 { 117 if (pm_power_off) 118 pm_power_off(); 119 } 120 121 void show_regs(struct pt_regs * regs) 122 { 123 printk("\n"); 124 printk("Pid : %d, Comm: %20s\n", task_pid_nr(current), current->comm); 125 print_symbol("PC is at %s\n", instruction_pointer(regs)); 126 printk("PC : %08lx SP : %08lx SR : %08lx ", 127 regs->pc, regs->regs[15], regs->sr); 128 #ifdef CONFIG_MMU 129 printk("TEA : %08x ", ctrl_inl(MMU_TEA)); 130 #else 131 printk(" "); 132 #endif 133 printk("%s\n", print_tainted()); 134 135 printk("R0 : %08lx R1 : %08lx R2 : %08lx R3 : %08lx\n", 136 regs->regs[0],regs->regs[1], 137 regs->regs[2],regs->regs[3]); 138 printk("R4 : %08lx R5 : %08lx R6 : %08lx R7 : %08lx\n", 139 regs->regs[4],regs->regs[5], 140 regs->regs[6],regs->regs[7]); 141 printk("R8 : %08lx R9 : %08lx R10 : %08lx R11 : %08lx\n", 142 regs->regs[8],regs->regs[9], 143 regs->regs[10],regs->regs[11]); 144 printk("R12 : %08lx R13 : %08lx R14 : %08lx\n", 145 regs->regs[12],regs->regs[13], 146 regs->regs[14]); 147 printk("MACH: %08lx MACL: %08lx GBR : %08lx PR : %08lx\n", 148 regs->mach, regs->macl, regs->gbr, regs->pr); 149 150 show_trace(NULL, (unsigned long *)regs->regs[15], regs); 151 } 152 153 /* 154 * Create a kernel thread 155 */ 156 157 /* 158 * This is the mechanism for creating a new kernel thread. 159 * 160 */ 161 extern void kernel_thread_helper(void); 162 __asm__(".align 5\n" 163 "kernel_thread_helper:\n\t" 164 "jsr @r5\n\t" 165 " nop\n\t" 166 "mov.l 1f, r1\n\t" 167 "jsr @r1\n\t" 168 " mov r0, r4\n\t" 169 ".align 2\n\t" 170 "1:.long do_exit"); 171 172 /* Don't use this in BL=1(cli). Or else, CPU resets! */ 173 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags) 174 { 175 struct pt_regs regs; 176 177 memset(®s, 0, sizeof(regs)); 178 regs.regs[4] = (unsigned long)arg; 179 regs.regs[5] = (unsigned long)fn; 180 181 regs.pc = (unsigned long)kernel_thread_helper; 182 regs.sr = (1 << 30); 183 184 /* Ok, create the new process.. */ 185 return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, 186 ®s, 0, NULL, NULL); 187 } 188 189 /* 190 * Free current thread data structures etc.. 191 */ 192 void exit_thread(void) 193 { 194 if (current->thread.ubc_pc) { 195 current->thread.ubc_pc = 0; 196 ubc_usercnt -= 1; 197 } 198 } 199 200 void flush_thread(void) 201 { 202 #if defined(CONFIG_SH_FPU) 203 struct task_struct *tsk = current; 204 /* Forget lazy FPU state */ 205 clear_fpu(tsk, task_pt_regs(tsk)); 206 clear_used_math(); 207 #endif 208 } 209 210 void release_thread(struct task_struct *dead_task) 211 { 212 /* do nothing */ 213 } 214 215 /* Fill in the fpu structure for a core dump.. */ 216 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu) 217 { 218 int fpvalid = 0; 219 220 #if defined(CONFIG_SH_FPU) 221 struct task_struct *tsk = current; 222 223 fpvalid = !!tsk_used_math(tsk); 224 if (fpvalid) { 225 unlazy_fpu(tsk, regs); 226 memcpy(fpu, &tsk->thread.fpu.hard, sizeof(*fpu)); 227 } 228 #endif 229 230 return fpvalid; 231 } 232 233 asmlinkage void ret_from_fork(void); 234 235 int copy_thread(int nr, unsigned long clone_flags, unsigned long usp, 236 unsigned long unused, 237 struct task_struct *p, struct pt_regs *regs) 238 { 239 struct thread_info *ti = task_thread_info(p); 240 struct pt_regs *childregs; 241 #if defined(CONFIG_SH_FPU) 242 struct task_struct *tsk = current; 243 244 unlazy_fpu(tsk, regs); 245 p->thread.fpu = tsk->thread.fpu; 246 copy_to_stopped_child_used_math(p); 247 #endif 248 249 childregs = task_pt_regs(p); 250 *childregs = *regs; 251 252 if (user_mode(regs)) { 253 childregs->regs[15] = usp; 254 ti->addr_limit = USER_DS; 255 } else { 256 childregs->regs[15] = (unsigned long)childregs; 257 ti->addr_limit = KERNEL_DS; 258 } 259 260 if (clone_flags & CLONE_SETTLS) 261 childregs->gbr = childregs->regs[0]; 262 263 childregs->regs[0] = 0; /* Set return value for child */ 264 265 p->thread.sp = (unsigned long) childregs; 266 p->thread.pc = (unsigned long) ret_from_fork; 267 268 p->thread.ubc_pc = 0; 269 270 return 0; 271 } 272 273 /* Tracing by user break controller. */ 274 static void ubc_set_tracing(int asid, unsigned long pc) 275 { 276 #if defined(CONFIG_CPU_SH4A) 277 unsigned long val; 278 279 val = (UBC_CBR_ID_INST | UBC_CBR_RW_READ | UBC_CBR_CE); 280 val |= (UBC_CBR_AIE | UBC_CBR_AIV_SET(asid)); 281 282 ctrl_outl(val, UBC_CBR0); 283 ctrl_outl(pc, UBC_CAR0); 284 ctrl_outl(0x0, UBC_CAMR0); 285 ctrl_outl(0x0, UBC_CBCR); 286 287 val = (UBC_CRR_RES | UBC_CRR_PCB | UBC_CRR_BIE); 288 ctrl_outl(val, UBC_CRR0); 289 290 /* Read UBC register that we wrote last, for checking update */ 291 val = ctrl_inl(UBC_CRR0); 292 293 #else /* CONFIG_CPU_SH4A */ 294 ctrl_outl(pc, UBC_BARA); 295 296 #ifdef CONFIG_MMU 297 ctrl_outb(asid, UBC_BASRA); 298 #endif 299 300 ctrl_outl(0, UBC_BAMRA); 301 302 if (current_cpu_data.type == CPU_SH7729 || 303 current_cpu_data.type == CPU_SH7710 || 304 current_cpu_data.type == CPU_SH7712) { 305 ctrl_outw(BBR_INST | BBR_READ | BBR_CPU, UBC_BBRA); 306 ctrl_outl(BRCR_PCBA | BRCR_PCTE, UBC_BRCR); 307 } else { 308 ctrl_outw(BBR_INST | BBR_READ, UBC_BBRA); 309 ctrl_outw(BRCR_PCBA, UBC_BRCR); 310 } 311 #endif /* CONFIG_CPU_SH4A */ 312 } 313 314 /* 315 * switch_to(x,y) should switch tasks from x to y. 316 * 317 */ 318 struct task_struct *__switch_to(struct task_struct *prev, 319 struct task_struct *next) 320 { 321 #if defined(CONFIG_SH_FPU) 322 unlazy_fpu(prev, task_pt_regs(prev)); 323 #endif 324 325 #ifdef CONFIG_MMU 326 /* 327 * Restore the kernel mode register 328 * k7 (r7_bank1) 329 */ 330 asm volatile("ldc %0, r7_bank" 331 : /* no output */ 332 : "r" (task_thread_info(next))); 333 #endif 334 335 /* If no tasks are using the UBC, we're done */ 336 if (ubc_usercnt == 0) 337 /* If no tasks are using the UBC, we're done */; 338 else if (next->thread.ubc_pc && next->mm) { 339 int asid = 0; 340 #ifdef CONFIG_MMU 341 asid |= cpu_asid(smp_processor_id(), next->mm); 342 #endif 343 ubc_set_tracing(asid, next->thread.ubc_pc); 344 } else { 345 #if defined(CONFIG_CPU_SH4A) 346 ctrl_outl(UBC_CBR_INIT, UBC_CBR0); 347 ctrl_outl(UBC_CRR_INIT, UBC_CRR0); 348 #else 349 ctrl_outw(0, UBC_BBRA); 350 ctrl_outw(0, UBC_BBRB); 351 #endif 352 } 353 354 return prev; 355 } 356 357 asmlinkage int sys_fork(unsigned long r4, unsigned long r5, 358 unsigned long r6, unsigned long r7, 359 struct pt_regs __regs) 360 { 361 #ifdef CONFIG_MMU 362 struct pt_regs *regs = RELOC_HIDE(&__regs, 0); 363 return do_fork(SIGCHLD, regs->regs[15], regs, 0, NULL, NULL); 364 #else 365 /* fork almost works, enough to trick you into looking elsewhere :-( */ 366 return -EINVAL; 367 #endif 368 } 369 370 asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp, 371 unsigned long parent_tidptr, 372 unsigned long child_tidptr, 373 struct pt_regs __regs) 374 { 375 struct pt_regs *regs = RELOC_HIDE(&__regs, 0); 376 if (!newsp) 377 newsp = regs->regs[15]; 378 return do_fork(clone_flags, newsp, regs, 0, 379 (int __user *)parent_tidptr, 380 (int __user *)child_tidptr); 381 } 382 383 /* 384 * This is trivial, and on the face of it looks like it 385 * could equally well be done in user mode. 386 * 387 * Not so, for quite unobvious reasons - register pressure. 388 * In user mode vfork() cannot have a stack frame, and if 389 * done by calling the "clone()" system call directly, you 390 * do not have enough call-clobbered registers to hold all 391 * the information you need. 392 */ 393 asmlinkage int sys_vfork(unsigned long r4, unsigned long r5, 394 unsigned long r6, unsigned long r7, 395 struct pt_regs __regs) 396 { 397 struct pt_regs *regs = RELOC_HIDE(&__regs, 0); 398 return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->regs[15], regs, 399 0, NULL, NULL); 400 } 401 402 /* 403 * sys_execve() executes a new program. 404 */ 405 asmlinkage int sys_execve(char __user *ufilename, char __user * __user *uargv, 406 char __user * __user *uenvp, unsigned long r7, 407 struct pt_regs __regs) 408 { 409 struct pt_regs *regs = RELOC_HIDE(&__regs, 0); 410 int error; 411 char *filename; 412 413 filename = getname(ufilename); 414 error = PTR_ERR(filename); 415 if (IS_ERR(filename)) 416 goto out; 417 418 error = do_execve(filename, uargv, uenvp, regs); 419 if (error == 0) { 420 task_lock(current); 421 current->ptrace &= ~PT_DTRACE; 422 task_unlock(current); 423 } 424 putname(filename); 425 out: 426 return error; 427 } 428 429 unsigned long get_wchan(struct task_struct *p) 430 { 431 unsigned long pc; 432 433 if (!p || p == current || p->state == TASK_RUNNING) 434 return 0; 435 436 /* 437 * The same comment as on the Alpha applies here, too ... 438 */ 439 pc = thread_saved_pc(p); 440 441 #ifdef CONFIG_FRAME_POINTER 442 if (in_sched_functions(pc)) { 443 unsigned long schedule_frame = (unsigned long)p->thread.sp; 444 return ((unsigned long *)schedule_frame)[21]; 445 } 446 #endif 447 448 return pc; 449 } 450 451 asmlinkage void break_point_trap(void) 452 { 453 /* Clear tracing. */ 454 #if defined(CONFIG_CPU_SH4A) 455 ctrl_outl(UBC_CBR_INIT, UBC_CBR0); 456 ctrl_outl(UBC_CRR_INIT, UBC_CRR0); 457 #else 458 ctrl_outw(0, UBC_BBRA); 459 ctrl_outw(0, UBC_BBRB); 460 #endif 461 current->thread.ubc_pc = 0; 462 ubc_usercnt -= 1; 463 464 force_sig(SIGTRAP, current); 465 } 466