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 20extern void stop_watchdog(void); 21 22extern int cris_hlt_counter; 23 24/* We use this if we don't have any better idle routine. */ 25void 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 40extern void deconfigure_bp(long pid); 41void 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 */ 51extern void arch_enable_nmi(void); 52 53void 54hard_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 */ 92unsigned long thread_saved_pc(struct task_struct *t) 93{ 94 return task_pt_regs(t)->erp; 95} 96 97static void 98kernel_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. */ 105int 106kernel_thread(int (*fn)(void *), void * arg, unsigned long flags) 107{ 108 struct pt_regs regs; 109 110 memset(®s, 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, ®s, 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 131extern asmlinkage void ret_from_fork(void); 132 133int 134copy_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 */ 190asmlinkage int 191sys_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? */ 198asmlinkage int 199sys_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 */ 212asmlinkage int 213sys_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. */ 220asmlinkage int 221sys_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 241unsigned long 242get_wchan(struct task_struct *p) 243{ 244 /* TODO */ 245 return 0; 246} 247#undef last_sched 248#undef first_sched 249 250void 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} 268