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