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 = (1 << 30);
 138
 139         /* Ok, create the new process.. */
 140         pid = do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0,
 141                       &regs, 0, NULL, NULL);
 142
 143         return pid;
 144 }
 145 EXPORT_SYMBOL(kernel_thread);
 146
 147 /*
 148  * Free current thread data structures etc..
 149  */
 150 void exit_thread(void)
 151 {
 152         if (current->thread.ubc_pc) {
 153                 current->thread.ubc_pc = 0;
 154                 ubc_usercnt -= 1;
 155         }
 156 }
 157
 158 void flush_thread(void)
 159 {
 160 #if defined(CONFIG_SH_FPU)
 161         struct task_struct *tsk = current;
 162         /* Forget lazy FPU state */
 163         clear_fpu(tsk, task_pt_regs(tsk));
 164         clear_used_math();
 165 #endif
 166 }
 167
 168 void release_thread(struct task_struct *dead_task)
 169 {
 170         /* do nothing */
 171 }
 172
 173 /* Fill in the fpu structure for a core dump.. */
 174 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
 175 {
 176         int fpvalid = 0;
 177
 178 #if defined(CONFIG_SH_FPU)
 179         struct task_struct *tsk = current;
 180
 181         fpvalid = !!tsk_used_math(tsk);
 182         if (fpvalid)
 183                 fpvalid = !fpregs_get(tsk, NULL, 0,
 184                                       sizeof(struct user_fpu_struct),
 185                                       fpu, NULL);
 186 #endif
 187
 188         return fpvalid;
 189 }
 190 EXPORT_SYMBOL(dump_fpu);
 191
 192 asmlinkage void ret_from_fork(void);
 193
 194 int copy_thread(unsigned long clone_flags, unsigned long usp,
 195                 unsigned long unused,
 196                 struct task_struct *p, struct pt_regs *regs)
 197 {
 198         struct thread_info *ti = task_thread_info(p);
 199         struct pt_regs *childregs;
 200 #if defined(CONFIG_SH_FPU) || defined(CONFIG_SH_DSP)
 201         struct task_struct *tsk = current;
 202 #endif
 203
 204 #if defined(CONFIG_SH_FPU)
 205         unlazy_fpu(tsk, regs);
 206         p->thread.fpu = tsk->thread.fpu;
 207         copy_to_stopped_child_used_math(p);
 208 #endif
 209
 210 #if defined(CONFIG_SH_DSP)
 211         if (is_dsp_enabled(tsk)) {
 212                 /* We can use the __save_dsp or just copy the struct:
 213                  * __save_dsp(p);
 214                  * p->thread.dsp_status.status |= SR_DSP
 215                  */
 216                 p->thread.dsp_status = tsk->thread.dsp_status;
 217         }
 218 #endif
 219
 220         childregs = task_pt_regs(p);
 221         *childregs = *regs;
 222
 223         if (user_mode(regs)) {
 224                 childregs->regs[15] = usp;
 225                 ti->addr_limit = USER_DS;
 226         } else {
 227                 childregs->regs[15] = (unsigned long)childregs;
 228                 ti->addr_limit = KERNEL_DS;
 229         }
 230
 231         if (clone_flags & CLONE_SETTLS)
 232                 childregs->gbr = childregs->regs[0];
 233
 234         childregs->regs[0] = 0; /* Set return value for child */
 235
 236         p->thread.sp = (unsigned long) childregs;
 237         p->thread.pc = (unsigned long) ret_from_fork;
 238
 239         p->thread.ubc_pc = 0;
 240
 241         return 0;
 242 }
 243
 244 /* Tracing by user break controller.  */
 245 static void ubc_set_tracing(int asid, unsigned long pc)
 246 {
 247 #if defined(CONFIG_CPU_SH4A)
 248         unsigned long val;
 249
 250         val = (UBC_CBR_ID_INST | UBC_CBR_RW_READ | UBC_CBR_CE);
 251         val |= (UBC_CBR_AIE | UBC_CBR_AIV_SET(asid));
 252
 253         ctrl_outl(val, UBC_CBR0);
 254         ctrl_outl(pc,  UBC_CAR0);
 255         ctrl_outl(0x0, UBC_CAMR0);
 256         ctrl_outl(0x0, UBC_CBCR);
 257
 258         val = (UBC_CRR_RES | UBC_CRR_PCB | UBC_CRR_BIE);
 259         ctrl_outl(val, UBC_CRR0);
 260
 261         /* Read UBC register that we wrote last, for checking update */
 262         val = ctrl_inl(UBC_CRR0);
 263
 264 #else   /* CONFIG_CPU_SH4A */
 265         ctrl_outl(pc, UBC_BARA);
 266
 267 #ifdef CONFIG_MMU
 268         ctrl_outb(asid, UBC_BASRA);
 269 #endif
 270
 271         ctrl_outl(0, UBC_BAMRA);
 272
 273         if (current_cpu_data.type == CPU_SH7729 ||
 274             current_cpu_data.type == CPU_SH7710 ||
 275             current_cpu_data.type == CPU_SH7712 ||
 276             current_cpu_data.type == CPU_SH7203){
 277                 ctrl_outw(BBR_INST | BBR_READ | BBR_CPU, UBC_BBRA);
 278                 ctrl_outl(BRCR_PCBA | BRCR_PCTE, UBC_BRCR);
 279         } else {
 280                 ctrl_outw(BBR_INST | BBR_READ, UBC_BBRA);
 281                 ctrl_outw(BRCR_PCBA, UBC_BRCR);
 282         }
 283 #endif  /* CONFIG_CPU_SH4A */
 284 }
 285
 286 /*
 287  *      switch_to(x,y) should switch tasks from x to y.
 288  *
 289  */
 290 __notrace_funcgraph struct task_struct *
 291 __switch_to(struct task_struct *prev, struct task_struct *next)
 292 {
 293         struct thread_struct *next_t = &next->thread;
 294
 295 #if defined(CONFIG_SH_FPU)
 296         unlazy_fpu(prev, task_pt_regs(prev));
 297
 298         /* we're going to use this soon, after a few expensive things */
 299         if (next->fpu_counter > 5)
 300                 prefetch(&next_t->fpu.hard);
 301 #endif
 302
 303 #ifdef CONFIG_MMU
 304         /*
 305          * Restore the kernel mode register
 306          *      k7 (r7_bank1)
 307          */
 308         asm volatile("ldc       %0, r7_bank"
 309                      : /* no output */
 310                      : "r" (task_thread_info(next)));
 311 #endif
 312
 313         /* If no tasks are using the UBC, we're done */
 314         if (ubc_usercnt == 0)
 315                 /* If no tasks are using the UBC, we're done */;
 316         else if (next->thread.ubc_pc && next->mm) {
 317                 int asid = 0;
 318 #ifdef CONFIG_MMU
 319                 asid |= cpu_asid(smp_processor_id(), next->mm);
 320 #endif
 321                 ubc_set_tracing(asid, next->thread.ubc_pc);
 322         } else {
 323 #if defined(CONFIG_CPU_SH4A)
 324                 ctrl_outl(UBC_CBR_INIT, UBC_CBR0);
 325                 ctrl_outl(UBC_CRR_INIT, UBC_CRR0);
 326 #else
 327                 ctrl_outw(0, UBC_BBRA);
 328                 ctrl_outw(0, UBC_BBRB);
 329 #endif
 330         }
 331
 332 #if defined(CONFIG_SH_FPU)
 333         /* If the task has used fpu the last 5 timeslices, just do a full
 334          * restore of the math state immediately to avoid the trap; the
 335          * chances of needing FPU soon are obviously high now
 336          */
 337         if (next->fpu_counter > 5) {
 338                 fpu_state_restore(task_pt_regs(next));
 339         }
 340 #endif
 341
 342         return prev;
 343 }
 344
 345 asmlinkage int sys_fork(unsigned long r4, unsigned long r5,
 346                         unsigned long r6, unsigned long r7,
 347                         struct pt_regs __regs)
 348 {
 349 #ifdef CONFIG_MMU
 350         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 351         return do_fork(SIGCHLD, regs->regs[15], regs, 0, NULL, NULL);
 352 #else
 353         /* fork almost works, enough to trick you into looking elsewhere :-( */
 354         return -EINVAL;
 355 #endif
 356 }
 357
 358 asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp,
 359                          unsigned long parent_tidptr,
 360                          unsigned long child_tidptr,
 361                          struct pt_regs __regs)
 362 {
 363         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 364         if (!newsp)
 365                 newsp = regs->regs[15];
 366         return do_fork(clone_flags, newsp, regs, 0,
 367                         (int __user *)parent_tidptr,
 368                         (int __user *)child_tidptr);
 369 }
 370
 371 /*
 372  * This is trivial, and on the face of it looks like it
 373  * could equally well be done in user mode.
 374  *
 375  * Not so, for quite unobvious reasons - register pressure.
 376  * In user mode vfork() cannot have a stack frame, and if
 377  * done by calling the "clone()" system call directly, you
 378  * do not have enough call-clobbered registers to hold all
 379  * the information you need.
 380  */
 381 asmlinkage int sys_vfork(unsigned long r4, unsigned long r5,
 382                          unsigned long r6, unsigned long r7,
 383                          struct pt_regs __regs)
 384 {
 385         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 386         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->regs[15], regs,
 387                        0, NULL, NULL);
 388 }
 389
 390 /*
 391  * sys_execve() executes a new program.
 392  */
 393 asmlinkage int sys_execve(char __user *ufilename, char __user * __user *uargv,
 394                           char __user * __user *uenvp, unsigned long r7,
 395                           struct pt_regs __regs)
 396 {
 397         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 398         int error;
 399         char *filename;
 400
 401         filename = getname(ufilename);
 402         error = PTR_ERR(filename);
 403         if (IS_ERR(filename))
 404                 goto out;
 405
 406         error = do_execve(filename, uargv, uenvp, regs);
 407         putname(filename);
 408 out:
 409         return error;
 410 }
 411
 412 unsigned long get_wchan(struct task_struct *p)
 413 {
 414         unsigned long pc;
 415
 416         if (!p || p == current || p->state == TASK_RUNNING)
 417                 return 0;
 418
 419         /*
 420          * The same comment as on the Alpha applies here, too ...
 421          */
 422         pc = thread_saved_pc(p);
 423
 424 #ifdef CONFIG_FRAME_POINTER
 425         if (in_sched_functions(pc)) {
 426                 unsigned long schedule_frame = (unsigned long)p->thread.sp;
 427                 return ((unsigned long *)schedule_frame)[21];
 428         }
 429 #endif
 430
 431         return pc;
 432 }
 433
 434 asmlinkage void break_point_trap(void)
 435 {
 436         /* Clear tracing.  */
 437 #if defined(CONFIG_CPU_SH4A)
 438         ctrl_outl(UBC_CBR_INIT, UBC_CBR0);
 439         ctrl_outl(UBC_CRR_INIT, UBC_CRR0);
 440 #else
 441         ctrl_outw(0, UBC_BBRA);
 442         ctrl_outw(0, UBC_BBRB);
 443         ctrl_outl(0, UBC_BRCR);
 444 #endif
 445         current->thread.ubc_pc = 0;
 446         ubc_usercnt -= 1;
 447
 448         force_sig(SIGTRAP, current);
 449 }