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