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/slab.h>
  13 #include <linux/err.h>
  14 #include <linux/fs.h>
  15 #include <hwregs/reg_rdwr.h>
  16 #include <hwregs/reg_map.h>
  17 #include <hwregs/timer_defs.h>
  18 #include <hwregs/intr_vect_defs.h>
  19
  20 extern void stop_watchdog(void);
  21
  22 extern int cris_hlt_counter;
  23
  24 /* We use this if we don't have any better idle routine. */
  25 void default_idle(void)
  26 {
  27         local_irq_disable();
  28         if (!need_resched() && !cris_hlt_counter) {
  29                 /* Halt until exception. */
  30                 __asm__ volatile("ei    \n\t"
  31                                  "halt      ");
  32         }
  33         local_irq_enable();
  34 }
  35
  36 /*
  37  * Free current thread data structures etc..
  38  */
  39
  40 extern void deconfigure_bp(long pid);
  41 void exit_thread(void)
  42 {
  43         deconfigure_bp(current->pid);
  44 }
  45
  46 /*
  47  * If the watchdog is enabled, disable interrupts and enter an infinite loop.
  48  * The watchdog will reset the CPU after 0.1s. If the watchdog isn't enabled
  49  * then enable it and wait.
  50  */
  51 extern void arch_enable_nmi(void);
  52
  53 void
  54 hard_reset_now(void)
  55 {
  56         /*
  57          * Don't declare this variable elsewhere.  We don't want any other
  58          * code to know about it than the watchdog handler in entry.S and
  59          * this code, implementing hard reset through the watchdog.
  60          */
  61 #if defined(CONFIG_ETRAX_WATCHDOG)
  62         extern int cause_of_death;
  63 #endif
  64
  65         printk("*** HARD RESET ***\n");
  66         local_irq_disable();
  67
  68 #if defined(CONFIG_ETRAX_WATCHDOG)
  69         cause_of_death = 0xbedead;
  70 #else
  71 {
  72         reg_timer_rw_wd_ctrl wd_ctrl = {0};
  73
  74         stop_watchdog();
  75
  76         wd_ctrl.key = 16;       /* Arbitrary key. */
  77         wd_ctrl.cnt = 1;        /* Minimum time. */
  78         wd_ctrl.cmd = regk_timer_start;
  79
  80         arch_enable_nmi();
  81         REG_WR(timer, regi_timer0, rw_wd_ctrl, wd_ctrl);
  82 }
  83 #endif
  84
  85         while (1)
  86                 ; /* Wait for reset. */
  87 }
  88
  89 /*
  90  * Return saved PC of a blocked thread.
  91  */
  92 unsigned long thread_saved_pc(struct task_struct *t)
  93 {
  94         return task_pt_regs(t)->erp;
  95 }
  96
  97 static void
  98 kernel_thread_helper(void* dummy, int (*fn)(void *), void * arg)
  99 {
 100         fn(arg);
 101         do_exit(-1); /* Should never be called, return bad exit value. */
 102 }
 103
 104 /* Create a kernel thread. */
 105 int
 106 kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
 107 {
 108         struct pt_regs regs;
 109
 110         memset(&regs, 0, sizeof(regs));
 111
 112         /* Don't use r10 since that is set to 0 in copy_thread. */
 113         regs.r11 = (unsigned long) fn;
 114         regs.r12 = (unsigned long) arg;
 115         regs.erp = (unsigned long) kernel_thread_helper;
 116         regs.ccs = 1 << (I_CCS_BITNR + CCS_SHIFT);
 117
 118         /* Create the new process. */
 119         return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
 120 }
 121
 122 /*
 123  * Setup the child's kernel stack with a pt_regs and call switch_stack() on it.
 124  * It will be unnested during _resume and _ret_from_sys_call when the new thread
 125  * is scheduled.
 126  *
 127  * Also setup the thread switching structure which is used to keep
 128  * thread-specific data during _resumes.
 129  */
 130
 131 extern asmlinkage void ret_from_fork(void);
 132
 133 int
 134 copy_thread(unsigned long clone_flags, unsigned long usp,
 135         unsigned long unused,
 136         struct task_struct *p, struct pt_regs *regs)
 137 {
 138         struct pt_regs *childregs;
 139         struct switch_stack *swstack;
 140
 141         /*
 142          * Put the pt_regs structure at the end of the new kernel stack page and
 143          * fix it up. Note: the task_struct doubles as the kernel stack for the
 144          * task.
 145          */
 146         childregs = task_pt_regs(p);
 147         *childregs = *regs;     /* Struct copy of pt_regs. */
 148         p->set_child_tid = p->clear_child_tid = NULL;
 149         childregs->r10 = 0;     /* Child returns 0 after a fork/clone. */
 150
 151         /* Set a new TLS ?
 152          * The TLS is in $mof because it is the 5th argument to sys_clone.
 153          */
 154         if (p->mm && (clone_flags & CLONE_SETTLS)) {
 155                 task_thread_info(p)->tls = regs->mof;
 156         }
 157
 158         /* Put the switch stack right below the pt_regs. */
 159         swstack = ((struct switch_stack *) childregs) - 1;
 160
 161         /* Parameter to ret_from_sys_call. 0 is don't restart the syscall. */
 162         swstack->r9 = 0;
 163
 164         /*
 165          * We want to return into ret_from_sys_call after the _resume.
 166          * ret_from_fork will call ret_from_sys_call.
 167          */
 168         swstack->return_ip = (unsigned long) ret_from_fork;
 169
 170         /* Fix the user-mode and kernel-mode stackpointer. */
 171         p->thread.usp = usp;
 172         p->thread.ksp = (unsigned long) swstack;
 173
 174         return 0;
 175 }
 176
 177 /*
 178  * Be aware of the "magic" 7th argument in the four system-calls below.
 179  * They need the latest stackframe, which is put as the 7th argument by
 180  * entry.S. The previous arguments are dummies or actually used, but need
 181  * to be defined to reach the 7th argument.
 182  *
 183  * N.B.: Another method to get the stackframe is to use current_regs(). But
 184  * it returns the latest stack-frame stacked when going from _user mode_ and
 185  * some of these (at least sys_clone) are called from kernel-mode sometimes
 186  * (for example during kernel_thread, above) and thus cannot use it. Thus,
 187  * to be sure not to get any surprises, we use the method for the other calls
 188  * as well.
 189  */
 190 asmlinkage int
 191 sys_fork(long r10, long r11, long r12, long r13, long mof, long srp,
 192         struct pt_regs *regs)
 193 {
 194         return do_fork(SIGCHLD, rdusp(), regs, 0, NULL, NULL);
 195 }
 196
 197 /* FIXME: Is parent_tid/child_tid really third/fourth argument? Update lib? */
 198 asmlinkage int
 199 sys_clone(unsigned long newusp, unsigned long flags, int *parent_tid, int *child_tid,
 200         unsigned long tls, long srp, struct pt_regs *regs)
 201 {
 202         if (!newusp)
 203                 newusp = rdusp();
 204
 205         return do_fork(flags, newusp, regs, 0, parent_tid, child_tid);
 206 }
 207
 208 /*
 209  * vfork is a system call in i386 because of register-pressure - maybe
 210  * we can remove it and handle it in libc but we put it here until then.
 211  */
 212 asmlinkage int
 213 sys_vfork(long r10, long r11, long r12, long r13, long mof, long srp,
 214         struct pt_regs *regs)
 215 {
 216         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), regs, 0, NULL, NULL);
 217 }
 218
 219 /* sys_execve() executes a new program. */
 220 asmlinkage int
 221 sys_execve(const char *fname,
 222            const char *const *argv,
 223            const char *const *envp, long r13, long mof, long srp,
 224            struct pt_regs *regs)
 225 {
 226         int error;
 227         char *filename;
 228
 229         filename = getname(fname);
 230         error = PTR_ERR(filename);
 231
 232         if (IS_ERR(filename))
 233                 goto out;
 234
 235         error = do_execve(filename, argv, envp, regs);
 236         putname(filename);
 237  out:
 238         return error;
 239 }
 240
 241 unsigned long
 242 get_wchan(struct task_struct *p)
 243 {
 244         /* TODO */
 245         return 0;
 246 }
 247 #undef last_sched
 248 #undef first_sched
 249
 250 void show_regs(struct pt_regs * regs)
 251 {
 252         unsigned long usp = rdusp();
 253         printk("ERP: %08lx SRP: %08lx  CCS: %08lx USP: %08lx MOF: %08lx\n",
 254                 regs->erp, regs->srp, regs->ccs, usp, regs->mof);
 255
 256         printk(" r0: %08lx  r1: %08lx   r2: %08lx  r3: %08lx\n",
 257                 regs->r0, regs->r1, regs->r2, regs->r3);
 258
 259         printk(" r4: %08lx  r5: %08lx   r6: %08lx  r7: %08lx\n",
 260                 regs->r4, regs->r5, regs->r6, regs->r7);
 261
 262         printk(" r8: %08lx  r9: %08lx  r10: %08lx r11: %08lx\n",
 263                 regs->r8, regs->r9, regs->r10, regs->r11);
 264
 265         printk("r12: %08lx r13: %08lx oR10: %08lx\n",
 266                 regs->r12, regs->r13, regs->orig_r10);
 267 }