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