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