arch/sh/kernel/process_32.c

   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 <asm/uaccess.h>
  29 #include <asm/mmu_context.h>
  30 #include <asm/pgalloc.h>
  31 #include <asm/system.h>
  32 #include <asm/ubc.h>
  33 #include <asm/fpu.h>
  34 #include <asm/syscalls.h>
  35 #include <asm/watchdog.h>
  36
  37 int ubc_usercnt = 0;
  38
  39 #ifdef CONFIG_32BIT
  40 static void watchdog_trigger_immediate(void)
  41 {
  42         sh_wdt_write_cnt(0xFF);
  43         sh_wdt_write_csr(0xC2);
  44 }
  45
  46 void machine_restart(char * __unused)
  47 {
  48         local_irq_disable();
  49
  50         /* Use watchdog timer to trigger reset */
  51         watchdog_trigger_immediate();
  52
  53         while (1)
  54                 cpu_sleep();
  55 }
  56 #else
  57 void machine_restart(char * __unused)
  58 {
  59         /* SR.BL=1 and invoke address error to let CPU reset (manual reset) */
  60         asm volatile("ldc %0, sr\n\t"
  61                      "mov.l @%1, %0" : : "r" (0x10000000), "r" (0x80000001));
  62 }
  63 #endif
  64
  65 void machine_halt(void)
  66 {
  67         local_irq_disable();
  68
  69         while (1)
  70                 cpu_sleep();
  71 }
  72
  73 void machine_power_off(void)
  74 {
  75         if (pm_power_off)
  76                 pm_power_off();
  77 }
  78
  79 void show_regs(struct pt_regs * regs)
  80 {
  81         printk("\n");
  82         printk("Pid : %d, Comm: \t\t%s\n", task_pid_nr(current), current->comm);
  83         printk("CPU : %d        \t\t%s  (%s %.*s)\n\n",
  84                smp_processor_id(), print_tainted(), init_utsname()->release,
  85                (int)strcspn(init_utsname()->version, " "),
  86                init_utsname()->version);
  87
  88         print_symbol("PC is at %s\n", instruction_pointer(regs));
  89         print_symbol("PR is at %s\n", regs->pr);
  90
  91         printk("PC  : %08lx SP  : %08lx SR  : %08lx ",
  92                regs->pc, regs->regs[15], regs->sr);
  93 #ifdef CONFIG_MMU
  94         printk("TEA : %08x\n", ctrl_inl(MMU_TEA));
  95 #else
  96         printk("\n");
  97 #endif
  98
  99         printk("R0  : %08lx R1  : %08lx R2  : %08lx R3  : %08lx\n",
 100                regs->regs[0],regs->regs[1],
 101                regs->regs[2],regs->regs[3]);
 102         printk("R4  : %08lx R5  : %08lx R6  : %08lx R7  : %08lx\n",
 103                regs->regs[4],regs->regs[5],
 104                regs->regs[6],regs->regs[7]);
 105         printk("R8  : %08lx R9  : %08lx R10 : %08lx R11 : %08lx\n",
 106                regs->regs[8],regs->regs[9],
 107                regs->regs[10],regs->regs[11]);
 108         printk("R12 : %08lx R13 : %08lx R14 : %08lx\n",
 109                regs->regs[12],regs->regs[13],
 110                regs->regs[14]);
 111         printk("MACH: %08lx MACL: %08lx GBR : %08lx PR  : %08lx\n",
 112                regs->mach, regs->macl, regs->gbr, regs->pr);
 113
 114         show_trace(NULL, (unsigned long *)regs->regs[15], regs);
 115         show_code(regs);
 116 }
 117
 118 /*
 119  * Create a kernel thread
 120  */
 121 ATTRIB_NORET void kernel_thread_helper(void *arg, int (*fn)(void *))
 122 {
 123         do_exit(fn(arg));
 124 }
 125
 126 /* Don't use this in BL=1(cli).  Or else, CPU resets! */
 127 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
 128 {
 129         struct pt_regs regs;
 130         int pid;
 131
 132         memset(&regs, 0, sizeof(regs));
 133         regs.regs[4] = (unsigned long)arg;
 134         regs.regs[5] = (unsigned long)fn;
 135
 136         regs.pc = (unsigned long)kernel_thread_helper;
 137         regs.sr = SR_MD;
 138 #if defined(CONFIG_SH_FPU)
 139         regs.sr |= SR_FD;
 140 #endif
 141
 142         /* Ok, create the new process.. */
 143         pid = do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0,
 144                       &regs, 0, NULL, NULL);
 145
 146         return pid;
 147 }
 148 EXPORT_SYMBOL(kernel_thread);
 149
 150 /*
 151  * Free current thread data structures etc..
 152  */
 153 void exit_thread(void)
 154 {
 155         if (current->thread.ubc_pc) {
 156                 current->thread.ubc_pc = 0;
 157                 ubc_usercnt -= 1;
 158         }
 159 }
 160
 161 void flush_thread(void)
 162 {
 163 #if defined(CONFIG_SH_FPU)
 164         struct task_struct *tsk = current;
 165         /* Forget lazy FPU state */
 166         clear_fpu(tsk, task_pt_regs(tsk));
 167         clear_used_math();
 168 #endif
 169 }
 170
 171 void release_thread(struct task_struct *dead_task)
 172 {
 173         /* do nothing */
 174 }
 175
 176 /* Fill in the fpu structure for a core dump.. */
 177 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
 178 {
 179         int fpvalid = 0;
 180
 181 #if defined(CONFIG_SH_FPU)
 182         struct task_struct *tsk = current;
 183
 184         fpvalid = !!tsk_used_math(tsk);
 185         if (fpvalid)
 186                 fpvalid = !fpregs_get(tsk, NULL, 0,
 187                                       sizeof(struct user_fpu_struct),
 188                                       fpu, NULL);
 189 #endif
 190
 191         return fpvalid;
 192 }
 193 EXPORT_SYMBOL(dump_fpu);
 194
 195 /*
 196  * This gets called before we allocate a new thread and copy
 197  * the current task into it.
 198  */
 199 void prepare_to_copy(struct task_struct *tsk)
 200 {
 201         unlazy_fpu(tsk, task_pt_regs(tsk));
 202 }
 203
 204 asmlinkage void ret_from_fork(void);
 205
 206 int copy_thread(unsigned long clone_flags, unsigned long usp,
 207                 unsigned long unused,
 208                 struct task_struct *p, struct pt_regs *regs)
 209 {
 210         struct thread_info *ti = task_thread_info(p);
 211         struct pt_regs *childregs;
 212 #if defined(CONFIG_SH_DSP)
 213         struct task_struct *tsk = current;
 214 #endif
 215
 216 #if defined(CONFIG_SH_DSP)
 217         if (is_dsp_enabled(tsk)) {
 218                 /* We can use the __save_dsp or just copy the struct:
 219                  * __save_dsp(p);
 220                  * p->thread.dsp_status.status |= SR_DSP
 221                  */
 222                 p->thread.dsp_status = tsk->thread.dsp_status;
 223         }
 224 #endif
 225
 226         childregs = task_pt_regs(p);
 227         *childregs = *regs;
 228
 229         if (user_mode(regs)) {
 230                 childregs->regs[15] = usp;
 231                 ti->addr_limit = USER_DS;
 232         } else {
 233                 childregs->regs[15] = (unsigned long)childregs;
 234                 ti->addr_limit = KERNEL_DS;
 235                 ti->status &= ~TS_USEDFPU;
 236                 p->fpu_counter = 0;
 237         }
 238
 239         if (clone_flags & CLONE_SETTLS)
 240                 childregs->gbr = childregs->regs[0];
 241
 242         childregs->regs[0] = 0; /* Set return value for child */
 243
 244         p->thread.sp = (unsigned long) childregs;
 245         p->thread.pc = (unsigned long) ret_from_fork;
 246
 247         p->thread.ubc_pc = 0;
 248
 249         return 0;
 250 }
 251
 252 /* Tracing by user break controller.  */
 253 static void ubc_set_tracing(int asid, unsigned long pc)
 254 {
 255 #if defined(CONFIG_CPU_SH4A)
 256         unsigned long val;
 257
 258         val = (UBC_CBR_ID_INST | UBC_CBR_RW_READ | UBC_CBR_CE);
 259         val |= (UBC_CBR_AIE | UBC_CBR_AIV_SET(asid));
 260
 261         ctrl_outl(val, UBC_CBR0);
 262         ctrl_outl(pc,  UBC_CAR0);
 263         ctrl_outl(0x0, UBC_CAMR0);
 264         ctrl_outl(0x0, UBC_CBCR);
 265
 266         val = (UBC_CRR_RES | UBC_CRR_PCB | UBC_CRR_BIE);
 267         ctrl_outl(val, UBC_CRR0);
 268
 269         /* Read UBC register that we wrote last, for checking update */
 270         val = ctrl_inl(UBC_CRR0);
 271
 272 #else   /* CONFIG_CPU_SH4A */
 273         ctrl_outl(pc, UBC_BARA);
 274
 275 #ifdef CONFIG_MMU
 276         ctrl_outb(asid, UBC_BASRA);
 277 #endif
 278
 279         ctrl_outl(0, UBC_BAMRA);
 280
 281         if (current_cpu_data.type == CPU_SH7729 ||
 282             current_cpu_data.type == CPU_SH7710 ||
 283             current_cpu_data.type == CPU_SH7712 ||
 284             current_cpu_data.type == CPU_SH7203){
 285                 ctrl_outw(BBR_INST | BBR_READ | BBR_CPU, UBC_BBRA);
 286                 ctrl_outl(BRCR_PCBA | BRCR_PCTE, UBC_BRCR);
 287         } else {
 288                 ctrl_outw(BBR_INST | BBR_READ, UBC_BBRA);
 289                 ctrl_outw(BRCR_PCBA, UBC_BRCR);
 290         }
 291 #endif  /* CONFIG_CPU_SH4A */
 292 }
 293
 294 /*
 295  *      switch_to(x,y) should switch tasks from x to y.
 296  *
 297  */
 298 __notrace_funcgraph struct task_struct *
 299 __switch_to(struct task_struct *prev, struct task_struct *next)
 300 {
 301         struct thread_struct *next_t = &next->thread;
 302
 303         unlazy_fpu(prev, task_pt_regs(prev));
 304
 305         /* we're going to use this soon, after a few expensive things */
 306         if (next->fpu_counter > 5)
 307                 prefetch(&next_t->fpu.hard);
 308
 309 #ifdef CONFIG_MMU
 310         /*
 311          * Restore the kernel mode register
 312          *      k7 (r7_bank1)
 313          */
 314         asm volatile("ldc       %0, r7_bank"
 315                      : /* no output */
 316                      : "r" (task_thread_info(next)));
 317 #endif
 318
 319         /* If no tasks are using the UBC, we're done */
 320         if (ubc_usercnt == 0)
 321                 /* If no tasks are using the UBC, we're done */;
 322         else if (next->thread.ubc_pc && next->mm) {
 323                 int asid = 0;
 324 #ifdef CONFIG_MMU
 325                 asid |= cpu_asid(smp_processor_id(), next->mm);
 326 #endif
 327                 ubc_set_tracing(asid, next->thread.ubc_pc);
 328         } else {
 329 #if defined(CONFIG_CPU_SH4A)
 330                 ctrl_outl(UBC_CBR_INIT, UBC_CBR0);
 331                 ctrl_outl(UBC_CRR_INIT, UBC_CRR0);
 332 #else
 333                 ctrl_outw(0, UBC_BBRA);
 334                 ctrl_outw(0, UBC_BBRB);
 335 #endif
 336         }
 337
 338         /*
 339          * If the task has used fpu the last 5 timeslices, just do a full
 340          * restore of the math state immediately to avoid the trap; the
 341          * chances of needing FPU soon are obviously high now
 342          */
 343         if (next->fpu_counter > 5)
 344                 fpu_state_restore(task_pt_regs(next));
 345
 346         return prev;
 347 }
 348
 349 asmlinkage int sys_fork(unsigned long r4, unsigned long r5,
 350                         unsigned long r6, unsigned long r7,
 351                         struct pt_regs __regs)
 352 {
 353 #ifdef CONFIG_MMU
 354         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 355         return do_fork(SIGCHLD, regs->regs[15], regs, 0, NULL, NULL);
 356 #else
 357         /* fork almost works, enough to trick you into looking elsewhere :-( */
 358         return -EINVAL;
 359 #endif
 360 }
 361
 362 asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp,
 363                          unsigned long parent_tidptr,
 364                          unsigned long child_tidptr,
 365                          struct pt_regs __regs)
 366 {
 367         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 368         if (!newsp)
 369                 newsp = regs->regs[15];
 370         return do_fork(clone_flags, newsp, regs, 0,
 371                         (int __user *)parent_tidptr,
 372                         (int __user *)child_tidptr);
 373 }
 374
 375 /*
 376  * This is trivial, and on the face of it looks like it
 377  * could equally well be done in user mode.
 378  *
 379  * Not so, for quite unobvious reasons - register pressure.
 380  * In user mode vfork() cannot have a stack frame, and if
 381  * done by calling the "clone()" system call directly, you
 382  * do not have enough call-clobbered registers to hold all
 383  * the information you need.
 384  */
 385 asmlinkage int sys_vfork(unsigned long r4, unsigned long r5,
 386                          unsigned long r6, unsigned long r7,
 387                          struct pt_regs __regs)
 388 {
 389         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 390         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->regs[15], regs,
 391                        0, NULL, NULL);
 392 }
 393
 394 /*
 395  * sys_execve() executes a new program.
 396  */
 397 asmlinkage int sys_execve(char __user *ufilename, char __user * __user *uargv,
 398                           char __user * __user *uenvp, unsigned long r7,
 399                           struct pt_regs __regs)
 400 {
 401         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 402         int error;
 403         char *filename;
 404
 405         filename = getname(ufilename);
 406         error = PTR_ERR(filename);
 407         if (IS_ERR(filename))
 408                 goto out;
 409
 410         error = do_execve(filename, uargv, uenvp, regs);
 411         putname(filename);
 412 out:
 413         return error;
 414 }
 415
 416 unsigned long get_wchan(struct task_struct *p)
 417 {
 418         unsigned long pc;
 419
 420         if (!p || p == current || p->state == TASK_RUNNING)
 421                 return 0;
 422
 423         /*
 424          * The same comment as on the Alpha applies here, too ...
 425          */
 426         pc = thread_saved_pc(p);
 427
 428 #ifdef CONFIG_FRAME_POINTER
 429         if (in_sched_functions(pc)) {
 430                 unsigned long schedule_frame = (unsigned long)p->thread.sp;
 431                 return ((unsigned long *)schedule_frame)[21];
 432         }
 433 #endif
 434
 435         return pc;
 436 }
 437
 438 asmlinkage void break_point_trap(void)
 439 {
 440         /* Clear tracing.  */
 441 #if defined(CONFIG_CPU_SH4A)
 442         ctrl_outl(UBC_CBR_INIT, UBC_CBR0);
 443         ctrl_outl(UBC_CRR_INIT, UBC_CRR0);
 444 #else
 445         ctrl_outw(0, UBC_BBRA);
 446         ctrl_outw(0, UBC_BBRB);
 447         ctrl_outl(0, UBC_BRCR);
 448 #endif
 449         current->thread.ubc_pc = 0;
 450         ubc_usercnt -= 1;
 451
 452         force_sig(SIGTRAP, current);
 453 }