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 20extern void stop_watchdog(void); 21 22#ifdef CONFIG_ETRAX_GPIO 23extern void etrax_gpio_wake_up_check(void); /* Defined in drivers/gpio.c. */ 24#endif 25 26extern int cris_hlt_counter; 27 28/* We use this if we don't have any better idle routine. */ 29void 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 44extern void deconfigure_bp(long pid); 45void 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 */ 55extern void arch_enable_nmi(void); 56 57void 58hard_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 */ 96unsigned long thread_saved_pc(struct task_struct *t) 97{ 98 return task_pt_regs(t)->erp; 99} 100 101static void 102kernel_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. */ 109int 110kernel_thread(int (*fn)(void *), void * arg, unsigned long flags) 111{ 112 struct pt_regs regs; 113 114 memset(®s, 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, ®s, 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 135extern asmlinkage void ret_from_fork(void); 136 137int 138copy_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 */ 194asmlinkage int 195sys_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 201asmlinkage int 202sys_clone(unsigned long newusp, unsigned long flags, int *parent_tid, int *child_tid, 203 unsigned long tls, long srp, struct pt_regs *regs) 204{ 205 if (!newusp) 206 newusp = rdusp(); 207 208 return do_fork(flags, newusp, regs, 0, parent_tid, child_tid); 209} 210 211/* 212 * vfork is a system call in i386 because of register-pressure - maybe 213 * we can remove it and handle it in libc but we put it here until then. 214 */ 215asmlinkage int 216sys_vfork(long r10, long r11, long r12, long r13, long mof, long srp, 217 struct pt_regs *regs) 218{ 219 return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), regs, 0, NULL, NULL); 220} 221 222/* sys_execve() executes a new program. */ 223asmlinkage int 224sys_execve(const char *fname, char **argv, char **envp, long r13, long mof, long srp, 225 struct pt_regs *regs) 226{ 227 int error; 228 char *filename; 229 230 filename = getname(fname); 231 error = PTR_ERR(filename); 232 233 if (IS_ERR(filename)) 234 goto out; 235 236 error = do_execve(filename, argv, envp, regs); 237 putname(filename); 238 out: 239 return error; 240} 241 242unsigned long 243get_wchan(struct task_struct *p) 244{ 245 /* TODO */ 246 return 0; 247} 248#undef last_sched 249#undef first_sched 250 251void show_regs(struct pt_regs * regs) 252{ 253 unsigned long usp = rdusp(); 254 printk("ERP: %08lx SRP: %08lx CCS: %08lx USP: %08lx MOF: %08lx\n", 255 regs->erp, regs->srp, regs->ccs, usp, regs->mof); 256 257 printk(" r0: %08lx r1: %08lx r2: %08lx r3: %08lx\n", 258 regs->r0, regs->r1, regs->r2, regs->r3); 259 260 printk(" r4: %08lx r5: %08lx r6: %08lx r7: %08lx\n", 261 regs->r4, regs->r5, regs->r6, regs->r7); 262 263 printk(" r8: %08lx r9: %08lx r10: %08lx r11: %08lx\n", 264 regs->r8, regs->r9, regs->r10, regs->r11); 265 266 printk("r12: %08lx r13: %08lx oR10: %08lx\n", 267 regs->r12, regs->r13, regs->orig_r10); 268} 269