arch/cris/arch-v32/kernel/process.c

   1 /*
   2  *  Copyright (C) 2000-2003  Axis Communications AB
   3  *
   4  *  Authors:   Bjorn Wesen (bjornw@axis.com)
   5  *             Mikael Starvik (starvik@axis.com)
   6  *             Tobias Anderberg (tobiasa@axis.com), CRISv32 port.
   7  *
   8  * This file handles the architecture-dependent parts of process handling..
   9  */
  10
  11 #include <linux/config.h>
  12 #include <linux/sched.h>
  13 #include <linux/err.h>
  14 #include <linux/fs.h>
  15 #include <linux/slab.h>
  16 #include <asm/arch/hwregs/reg_rdwr.h>
  17 #include <asm/arch/hwregs/reg_map.h>
  18 #include <asm/arch/hwregs/timer_defs.h>
  19 #include <asm/arch/hwregs/intr_vect_defs.h>
  20
  21 extern void stop_watchdog(void);
  22
  23 #ifdef CONFIG_ETRAX_GPIO
  24 extern void etrax_gpio_wake_up_check(void); /* Defined in drivers/gpio.c. */
  25 #endif
  26
  27 extern int cris_hlt_counter;
  28
  29 /* We use this if we don't have any better idle routine. */
  30 void default_idle(void)
  31 {
  32         local_irq_disable();
  33         if (!need_resched() && !cris_hlt_counter) {
  34                 /* Halt until exception. */
  35                 __asm__ volatile("ei    \n\t"
  36                                  "halt      ");
  37         }
  38         local_irq_enable();
  39 }
  40
  41 /*
  42  * Free current thread data structures etc..
  43  */
  44
  45 extern void deconfigure_bp(long pid);
  46 void exit_thread(void)
  47 {
  48         deconfigure_bp(current->pid);
  49 }
  50
  51 /*
  52  * If the watchdog is enabled, disable interrupts and enter an infinite loop.
  53  * The watchdog will reset the CPU after 0.1s. If the watchdog isn't enabled
  54  * then enable it and wait.
  55  */
  56 extern void arch_enable_nmi(void);
  57
  58 void
  59 hard_reset_now(void)
  60 {
  61         /*
  62          * Don't declare this variable elsewhere.  We don't want any other
  63          * code to know about it than the watchdog handler in entry.S and
  64          * this code, implementing hard reset through the watchdog.
  65          */
  66 #if defined(CONFIG_ETRAX_WATCHDOG)
  67         extern int cause_of_death;
  68 #endif
  69
  70         printk("*** HARD RESET ***\n");
  71         local_irq_disable();
  72
  73 #if defined(CONFIG_ETRAX_WATCHDOG)
  74         cause_of_death = 0xbedead;
  75 #else
  76 {
  77         reg_timer_rw_wd_ctrl wd_ctrl = {0};
  78
  79         stop_watchdog();
  80
  81         wd_ctrl.key = 16;       /* Arbitrary key. */
  82         wd_ctrl.cnt = 1;        /* Minimum time. */
  83         wd_ctrl.cmd = regk_timer_start;
  84
  85         arch_enable_nmi();
  86         REG_WR(timer, regi_timer, rw_wd_ctrl, wd_ctrl);
  87 }
  88 #endif
  89
  90         while (1)
  91                 ; /* Wait for reset. */
  92 }
  93
  94 /*
  95  * Return saved PC of a blocked thread.
  96  */
  97 unsigned long thread_saved_pc(struct task_struct *t)
  98 {
  99         return (unsigned long)user_regs(t->thread_info)->erp;
 100 }
 101
 102 static void
 103 kernel_thread_helper(void* dummy, int (*fn)(void *), void * arg)
 104 {
 105         fn(arg);
 106         do_exit(-1); /* Should never be called, return bad exit value. */
 107 }
 108
 109 /* Create a kernel thread. */
 110 int
 111 kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
 112 {
 113         struct pt_regs regs;
 114
 115         memset(&regs, 0, sizeof(regs));
 116
 117         /* Don't use r10 since that is set to 0 in copy_thread. */
 118         regs.r11 = (unsigned long) fn;
 119         regs.r12 = (unsigned long) arg;
 120         regs.erp = (unsigned long) kernel_thread_helper;
 121         regs.ccs = 1 << (I_CCS_BITNR + CCS_SHIFT);
 122
 123         /* Create the new process. */
 124         return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
 125 }
 126
 127 /*
 128  * Setup the child's kernel stack with a pt_regs and call switch_stack() on it.
 129  * It will be unnested during _resume and _ret_from_sys_call when the new thread
 130  * is scheduled.
 131  *
 132  * Also setup the thread switching structure which is used to keep
 133  * thread-specific data during _resumes.
 134  */
 135
 136 extern asmlinkage void ret_from_fork(void);
 137
 138 int
 139 copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
 140         unsigned long unused,
 141         struct task_struct *p, struct pt_regs *regs)
 142 {
 143         struct pt_regs *childregs;
 144         struct switch_stack *swstack;
 145
 146         /*
 147          * Put the pt_regs structure at the end of the new kernel stack page and
 148          * fix it up. Note: the task_struct doubles as the kernel stack for the
 149          * task.
 150          */
 151         childregs = user_regs(p->thread_info);
 152         *childregs = *regs;     /* Struct copy of pt_regs. */
 153         p->set_child_tid = p->clear_child_tid = NULL;
 154         childregs->r10 = 0;     /* Child returns 0 after a fork/clone. */
 155
 156         /* Set a new TLS ?
 157          * The TLS is in $mof beacuse it is the 5th argument to sys_clone.
 158          */
 159         if (p->mm && (clone_flags & CLONE_SETTLS)) {
 160                 p->thread_info->tls = regs->mof;
 161         }
 162
 163         /* Put the switch stack right below the pt_regs. */
 164         swstack = ((struct switch_stack *) childregs) - 1;
 165
 166         /* Paramater to ret_from_sys_call. 0 is don't restart the syscall. */
 167         swstack->r9 = 0;
 168
 169         /*
 170          * We want to return into ret_from_sys_call after the _resume.
 171          * ret_from_fork will call ret_from_sys_call.
 172          */
 173         swstack->return_ip = (unsigned long) ret_from_fork;
 174
 175         /* Fix the user-mode and kernel-mode stackpointer. */
 176         p->thread.usp = usp;
 177         p->thread.ksp = (unsigned long) swstack;
 178
 179         return 0;
 180 }
 181
 182 /*
 183  * Be aware of the "magic" 7th argument in the four system-calls below.
 184  * They need the latest stackframe, which is put as the 7th argument by
 185  * entry.S. The previous arguments are dummies or actually used, but need
 186  * to be defined to reach the 7th argument.
 187  *
 188  * N.B.: Another method to get the stackframe is to use current_regs(). But
 189  * it returns the latest stack-frame stacked when going from _user mode_ and
 190  * some of these (at least sys_clone) are called from kernel-mode sometimes
 191  * (for example during kernel_thread, above) and thus cannot use it. Thus,
 192  * to be sure not to get any surprises, we use the method for the other calls
 193  * as well.
 194  */
 195 asmlinkage int
 196 sys_fork(long r10, long r11, long r12, long r13, long mof, long srp,
 197         struct pt_regs *regs)
 198 {
 199         return do_fork(SIGCHLD, rdusp(), regs, 0, NULL, NULL);
 200 }
 201
 202 /* FIXME: Is parent_tid/child_tid really third/fourth argument? Update lib? */
 203 asmlinkage int
 204 sys_clone(unsigned long newusp, unsigned long flags, int *parent_tid, int *child_tid,
 205         unsigned long tls, long srp, struct pt_regs *regs)
 206 {
 207         if (!newusp)
 208                 newusp = rdusp();
 209
 210         return do_fork(flags, newusp, regs, 0, parent_tid, child_tid);
 211 }
 212
 213 /*
 214  * vfork is a system call in i386 because of register-pressure - maybe
 215  * we can remove it and handle it in libc but we put it here until then.
 216  */
 217 asmlinkage int
 218 sys_vfork(long r10, long r11, long r12, long r13, long mof, long srp,
 219         struct pt_regs *regs)
 220 {
 221         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), regs, 0, NULL, NULL);
 222 }
 223
 224 /* sys_execve() executes a new program. */
 225 asmlinkage int
 226 sys_execve(const char *fname, char **argv, char **envp, long r13, long mof, long srp,
 227         struct pt_regs *regs)
 228 {
 229         int error;
 230         char *filename;
 231
 232         filename = getname(fname);
 233         error = PTR_ERR(filename);
 234
 235         if (IS_ERR(filename))
 236                 goto out;
 237
 238         error = do_execve(filename, argv, envp, regs);
 239         putname(filename);
 240  out:
 241         return error;
 242 }
 243
 244 unsigned long
 245 get_wchan(struct task_struct *p)
 246 {
 247         /* TODO */
 248         return 0;
 249 }
 250 #undef last_sched
 251 #undef first_sched
 252
 253 void show_regs(struct pt_regs * regs)
 254 {
 255         unsigned long usp = rdusp();
 256         printk("ERP: %08lx SRP: %08lx  CCS: %08lx USP: %08lx MOF: %08lx\n",
 257                 regs->erp, regs->srp, regs->ccs, usp, regs->mof);
 258
 259         printk(" r0: %08lx  r1: %08lx   r2: %08lx  r3: %08lx\n",
 260                 regs->r0, regs->r1, regs->r2, regs->r3);
 261
 262         printk(" r4: %08lx  r5: %08lx   r6: %08lx  r7: %08lx\n",
 263                 regs->r4, regs->r5, regs->r6, regs->r7);
 264
 265         printk(" r8: %08lx  r9: %08lx  r10: %08lx r11: %08lx\n",
 266                 regs->r8, regs->r9, regs->r10, regs->r11);
 267
 268         printk("r12: %08lx r13: %08lx oR10: %08lx\n",
 269                 regs->r12, regs->r13, regs->orig_r10);
 270 }