arch/avr32/kernel/process.c

   1 /*
   2  * Copyright (C) 2004-2006 Atmel Corporation
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  */
   8 #include <linux/sched.h>
   9 #include <linux/module.h>
  10 #include <linux/kallsyms.h>
  11 #include <linux/fs.h>
  12 #include <linux/ptrace.h>
  13 #include <linux/reboot.h>
  14 #include <linux/unistd.h>
  15
  16 #include <asm/sysreg.h>
  17 #include <asm/ocd.h>
  18
  19 void (*pm_power_off)(void) = NULL;
  20 EXPORT_SYMBOL(pm_power_off);
  21
  22 extern void cpu_idle_sleep(void);
  23
  24 /*
  25  * This file handles the architecture-dependent parts of process handling..
  26  */
  27
  28 void cpu_idle(void)
  29 {
  30         /* endless idle loop with no priority at all */
  31         while (1) {
  32                 while (!need_resched())
  33                         cpu_idle_sleep();
  34                 preempt_enable_no_resched();
  35                 schedule();
  36                 preempt_disable();
  37         }
  38 }
  39
  40 void machine_halt(void)
  41 {
  42         /*
  43          * Enter Stop mode. The 32 kHz oscillator will keep running so
  44          * the RTC will keep the time properly and the system will
  45          * boot quickly.
  46          */
  47         asm volatile("sleep 3\n\t"
  48                      "sub pc, -2");
  49 }
  50
  51 void machine_power_off(void)
  52 {
  53 }
  54
  55 void machine_restart(char *cmd)
  56 {
  57         __mtdr(DBGREG_DC, DC_DBE);
  58         __mtdr(DBGREG_DC, DC_RES);
  59         while (1) ;
  60 }
  61
  62 /*
  63  * PC is actually discarded when returning from a system call -- the
  64  * return address must be stored in LR. This function will make sure
  65  * LR points to do_exit before starting the thread.
  66  *
  67  * Also, when returning from fork(), r12 is 0, so we must copy the
  68  * argument as well.
  69  *
  70  *  r0 : The argument to the main thread function
  71  *  r1 : The address of do_exit
  72  *  r2 : The address of the main thread function
  73  */
  74 asmlinkage extern void kernel_thread_helper(void);
  75 __asm__("       .type   kernel_thread_helper, @function\n"
  76         "kernel_thread_helper:\n"
  77         "       mov     r12, r0\n"
  78         "       mov     lr, r2\n"
  79         "       mov     pc, r1\n"
  80         "       .size   kernel_thread_helper, . - kernel_thread_helper");
  81
  82 int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
  83 {
  84         struct pt_regs regs;
  85
  86         memset(&regs, 0, sizeof(regs));
  87
  88         regs.r0 = (unsigned long)arg;
  89         regs.r1 = (unsigned long)fn;
  90         regs.r2 = (unsigned long)do_exit;
  91         regs.lr = (unsigned long)kernel_thread_helper;
  92         regs.pc = (unsigned long)kernel_thread_helper;
  93         regs.sr = MODE_SUPERVISOR;
  94
  95         return do_fork(flags | CLONE_VM | CLONE_UNTRACED,
  96                        0, &regs, 0, NULL, NULL);
  97 }
  98 EXPORT_SYMBOL(kernel_thread);
  99
 100 /*
 101  * Free current thread data structures etc
 102  */
 103 void exit_thread(void)
 104 {
 105         /* nothing to do */
 106 }
 107
 108 void flush_thread(void)
 109 {
 110         /* nothing to do */
 111 }
 112
 113 void release_thread(struct task_struct *dead_task)
 114 {
 115         /* do nothing */
 116 }
 117
 118 static const char *cpu_modes[] = {
 119         "Application", "Supervisor", "Interrupt level 0", "Interrupt level 1",
 120         "Interrupt level 2", "Interrupt level 3", "Exception", "NMI"
 121 };
 122
 123 void show_regs(struct pt_regs *regs)
 124 {
 125         unsigned long sp = regs->sp;
 126         unsigned long lr = regs->lr;
 127         unsigned long mode = (regs->sr & MODE_MASK) >> MODE_SHIFT;
 128
 129         if (!user_mode(regs))
 130                 sp = (unsigned long)regs + FRAME_SIZE_FULL;
 131
 132         print_symbol("PC is at %s\n", instruction_pointer(regs));
 133         print_symbol("LR is at %s\n", lr);
 134         printk("pc : [<%08lx>]    lr : [<%08lx>]    %s\n"
 135                "sp : %08lx  r12: %08lx  r11: %08lx\n",
 136                instruction_pointer(regs),
 137                lr, print_tainted(), sp, regs->r12, regs->r11);
 138         printk("r10: %08lx  r9 : %08lx  r8 : %08lx\n",
 139                regs->r10, regs->r9, regs->r8);
 140         printk("r7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
 141                regs->r7, regs->r6, regs->r5, regs->r4);
 142         printk("r3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
 143                regs->r3, regs->r2, regs->r1, regs->r0);
 144         printk("Flags: %c%c%c%c%c\n",
 145                regs->sr & SR_Q ? 'Q' : 'q',
 146                regs->sr & SR_V ? 'V' : 'v',
 147                regs->sr & SR_N ? 'N' : 'n',
 148                regs->sr & SR_Z ? 'Z' : 'z',
 149                regs->sr & SR_C ? 'C' : 'c');
 150         printk("Mode bits: %c%c%c%c%c%c%c%c%c\n",
 151                regs->sr & SR_H ? 'H' : 'h',
 152                regs->sr & SR_R ? 'R' : 'r',
 153                regs->sr & SR_J ? 'J' : 'j',
 154                regs->sr & SR_EM ? 'E' : 'e',
 155                regs->sr & SR_I3M ? '3' : '.',
 156                regs->sr & SR_I2M ? '2' : '.',
 157                regs->sr & SR_I1M ? '1' : '.',
 158                regs->sr & SR_I0M ? '0' : '.',
 159                regs->sr & SR_GM ? 'G' : 'g');
 160         printk("CPU Mode: %s\n", cpu_modes[mode]);
 161
 162         show_trace(NULL, (unsigned long *)sp, regs);
 163 }
 164 EXPORT_SYMBOL(show_regs);
 165
 166 /* Fill in the fpu structure for a core dump. This is easy -- we don't have any */
 167 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
 168 {
 169         /* Not valid */
 170         return 0;
 171 }
 172
 173 asmlinkage void ret_from_fork(void);
 174
 175 int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
 176                 unsigned long unused,
 177                 struct task_struct *p, struct pt_regs *regs)
 178 {
 179         struct pt_regs *childregs;
 180
 181         childregs = ((struct pt_regs *)(THREAD_SIZE + (unsigned long)p->thread_info)) - 1;
 182         *childregs = *regs;
 183
 184         if (user_mode(regs))
 185                 childregs->sp = usp;
 186         else
 187                 childregs->sp = (unsigned long)p->thread_info + THREAD_SIZE;
 188
 189         childregs->r12 = 0; /* Set return value for child */
 190
 191         p->thread.cpu_context.sr = MODE_SUPERVISOR | SR_GM;
 192         p->thread.cpu_context.ksp = (unsigned long)childregs;
 193         p->thread.cpu_context.pc = (unsigned long)ret_from_fork;
 194
 195         return 0;
 196 }
 197
 198 /* r12-r8 are dummy parameters to force the compiler to use the stack */
 199 asmlinkage int sys_fork(struct pt_regs *regs)
 200 {
 201         return do_fork(SIGCHLD, regs->sp, regs, 0, NULL, NULL);
 202 }
 203
 204 asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp,
 205                          unsigned long parent_tidptr,
 206                          unsigned long child_tidptr, struct pt_regs *regs)
 207 {
 208         if (!newsp)
 209                 newsp = regs->sp;
 210         return do_fork(clone_flags, newsp, regs, 0,
 211                        (int __user *)parent_tidptr,
 212                        (int __user *)child_tidptr);
 213 }
 214
 215 asmlinkage int sys_vfork(struct pt_regs *regs)
 216 {
 217         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->sp, regs,
 218                        0, NULL, NULL);
 219 }
 220
 221 asmlinkage int sys_execve(char __user *ufilename, char __user *__user *uargv,
 222                           char __user *__user *uenvp, struct pt_regs *regs)
 223 {
 224         int error;
 225         char *filename;
 226
 227         filename = getname(ufilename);
 228         error = PTR_ERR(filename);
 229         if (IS_ERR(filename))
 230                 goto out;
 231
 232         error = do_execve(filename, uargv, uenvp, regs);
 233         if (error == 0)
 234                 current->ptrace &= ~PT_DTRACE;
 235         putname(filename);
 236
 237 out:
 238         return error;
 239 }
 240
 241
 242 /*
 243  * This function is supposed to answer the question "who called
 244  * schedule()?"
 245  */
 246 unsigned long get_wchan(struct task_struct *p)
 247 {
 248         unsigned long pc;
 249         unsigned long stack_page;
 250
 251         if (!p || p == current || p->state == TASK_RUNNING)
 252                 return 0;
 253
 254         stack_page = (unsigned long)p->thread_info;
 255         BUG_ON(!stack_page);
 256
 257         /*
 258          * The stored value of PC is either the address right after
 259          * the call to __switch_to() or ret_from_fork.
 260          */
 261         pc = thread_saved_pc(p);
 262         if (in_sched_functions(pc)) {
 263 #ifdef CONFIG_FRAME_POINTER
 264                 unsigned long fp = p->thread.cpu_context.r7;
 265                 BUG_ON(fp < stack_page || fp > (THREAD_SIZE + stack_page));
 266                 pc = *(unsigned long *)fp;
 267 #else
 268                 /*
 269                  * We depend on the frame size of schedule here, which
 270                  * is actually quite ugly. It might be possible to
 271                  * determine the frame size automatically at build
 272                  * time by doing this:
 273                  *   - compile sched.c
 274                  *   - disassemble the resulting sched.o
 275                  *   - look for 'sub sp,??' shortly after '<schedule>:'
 276                  */
 277                 unsigned long sp = p->thread.cpu_context.ksp + 16;
 278                 BUG_ON(sp < stack_page || sp > (THREAD_SIZE + stack_page));
 279                 pc = *(unsigned long *)sp;
 280 #endif
 281         }
 282
 283         return pc;
 284 }