/* $Id: process.c,v 1.24 2003/03/06 14:19:32 pkj Exp $ * * linux/arch/cris/kernel/process.c * * Copyright (C) 1995 Linus Torvalds * Copyright (C) 2000, 2001 Axis Communications AB * * Authors: Bjorn Wesen (bjornw@axis.com) * * $Log: process.c,v $ * Revision 1.24 2003/03/06 14:19:32 pkj * Use a cpu_idle() function identical to the one used by i386. * * Revision 1.23 2002/10/14 18:29:27 johana * Call etrax_gpio_wake_up_check() from cpu_idle() to reduce gpio latency * from ~15 ms to ~6 ms. * * Revision 1.22 2001/11/13 09:40:43 orjanf * Added dump_fpu (needed for core dumps). * * Revision 1.21 2001/11/12 18:26:21 pkj * Fixed compiler warnings. * * Revision 1.20 2001/10/03 08:21:39 jonashg * cause_of_death does not exist if CONFIG_SVINTO_SIM is defined. * * Revision 1.19 2001/09/26 11:52:54 bjornw * INIT_MMAP is gone in 2.4.10 * * Revision 1.18 2001/08/21 21:43:51 hp * Move last watchdog fix inside #ifdef CONFIG_ETRAX_WATCHDOG * * Revision 1.17 2001/08/21 13:48:01 jonashg * Added fix by HP to avoid oops when doing a hard_reset_now. * * Revision 1.16 2001/06/21 02:00:40 hp * * entry.S: Include asm/unistd.h. * (_sys_call_table): Use section .rodata, not .data. * (_kernel_thread): Move from... * * process.c: ... here. * * entryoffsets.c (VAL): Break out from... * (OF): Use VAL. * (LCLONE_VM): New asmified value from CLONE_VM. * * Revision 1.15 2001/06/20 16:31:57 hp * Add comments to describe empty functions according to review. * * Revision 1.14 2001/05/29 11:27:59 markusl * Fixed so that hard_reset_now will do reset even if watchdog wasn't enabled * * Revision 1.13 2001/03/20 19:44:06 bjornw * Use the 7th syscall argument for regs instead of current_regs * */ /* * This file handles the architecture-dependent parts of process handling.. */ #define __KERNEL_SYSCALLS__ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include //#define DEBUG /* * Initial task structure. Make this a per-architecture thing, * because different architectures tend to have different * alignment requirements and potentially different initial * setup. */ static struct fs_struct init_fs = INIT_FS; static struct files_struct init_files = INIT_FILES; static struct signal_struct init_signals = INIT_SIGNALS; struct mm_struct init_mm = INIT_MM(init_mm); /* * Initial task structure. * * We need to make sure that this is 8192-byte aligned due to the * way process stacks are handled. This is done by having a special * "init_task" linker map entry.. */ union task_union init_task_union __attribute__((__section__(".data.init_task"))) = { INIT_TASK(init_task_union.task) }; /* * The hlt_counter, disable_hlt and enable_hlt is just here as a hook if * there would ever be a halt sequence (for power save when idle) with * some largish delay when halting or resuming *and* a driver that can't * afford that delay. The hlt_counter would then be checked before * executing the halt sequence, and the driver marks the unhaltable * region by enable_hlt/disable_hlt. */ static int hlt_counter; /* * Powermanagement idle function, if any.. */ void (*pm_idle)(void); /* * Power off function, if any */ void (*pm_power_off)(void); void disable_hlt(void) { hlt_counter++; } void enable_hlt(void) { hlt_counter--; } /* * We use this if we don't have any better * idle routine.. */ static void default_idle(void) { #ifdef CONFIG_ETRAX_GPIO extern void etrax_gpio_wake_up_check(void); /* drivers/gpio.c */ /* This can reduce latency from 15 ms to 6 ms */ etrax_gpio_wake_up_check(); /* drivers/gpio.c */ #endif } /* * The idle thread. There's no useful work to be * done, so just try to conserve power and have a * low exit latency (ie sit in a loop waiting for * somebody to say that they'd like to reschedule) */ void cpu_idle(void) { /* endless idle loop with no priority at all */ init_idle(); current->nice = 20; current->counter = -100; while(1) { void (*idle)(void) = pm_idle; if (!idle) idle = default_idle; while (!current->need_resched) idle(); schedule(); check_pgt_cache(); } } /* if the watchdog is enabled, we can simply disable interrupts and go * into an eternal loop, and the watchdog will reset the CPU after 0.1s * if on the other hand the watchdog wasn't enabled, we just enable it and wait */ void hard_reset_now (void) { /* * Don't declare this variable elsewhere. We don't want any other * code to know about it than the watchdog handler in entry.S and * this code, implementing hard reset through the watchdog. */ #if defined(CONFIG_ETRAX_WATCHDOG) && !defined(CONFIG_SVINTO_SIM) extern int cause_of_death; #endif printk("*** HARD RESET ***\n"); cli(); #if defined(CONFIG_ETRAX_WATCHDOG) && !defined(CONFIG_SVINTO_SIM) cause_of_death = 0xbedead; #else /* Since we dont plan to keep on reseting the watchdog, the key can be arbitrary hence three */ *R_WATCHDOG = IO_FIELD(R_WATCHDOG, key, 3) | IO_STATE(R_WATCHDOG, enable, start); #endif while(1) /* waiting for RETRIBUTION! */ ; } void machine_restart(void) { hard_reset_now(); } /* * Similar to machine_power_off, but don't shut off power. Add code * here to freeze the system for e.g. post-mortem debug purpose when * possible. This halt has nothing to do with the idle halt. */ void machine_halt(void) { } /* If or when software power-off is implemented, add code here. */ void machine_power_off(void) { if (pm_power_off) pm_power_off(); } /* * When a process does an "exec", machine state like FPU and debug * registers need to be reset. This is a hook function for that. * Currently we don't have any such state to reset, so this is empty. */ void flush_thread(void) { } asmlinkage void ret_from_sys_call(void); /* setup the child's kernel stack with a pt_regs and switch_stack on it. * it will be un-nested during _resume and _ret_from_sys_call when the * new thread is scheduled. * * also setup the thread switching structure which is used to keep * thread-specific data during _resumes. * */ int copy_thread(int nr, unsigned long clone_flags, unsigned long usp, unsigned long unused, struct task_struct *p, struct pt_regs *regs) { struct pt_regs * childregs; struct switch_stack *swstack; /* put the pt_regs structure at the end of the new kernel stack page and fix it up * remember that the task_struct doubles as the kernel stack for the task */ childregs = user_regs(p); *childregs = *regs; /* struct copy of pt_regs */ childregs->r10 = 0; /* child returns 0 after a fork/clone */ /* put the switch stack right below the pt_regs */ swstack = ((struct switch_stack *)childregs) - 1; swstack->r9 = 0; /* parameter to ret_from_sys_call, 0 == dont restart the syscall */ /* we want to return into ret_from_sys_call after the _resume */ swstack->return_ip = (unsigned long) ret_from_sys_call; /* fix the user-mode stackpointer */ p->thread.usp = usp; /* and the kernel-mode one */ p->thread.ksp = (unsigned long) swstack; #ifdef DEBUG printk("copy_thread: new regs at 0x%p, as shown below:\n", childregs); show_registers(childregs); #endif return 0; } /* * fill in the user structure for a core dump.. */ void dump_thread(struct pt_regs * regs, struct user * dump) { #if 0 int i; /* changed the size calculations - should hopefully work better. lbt */ dump->magic = CMAGIC; dump->start_code = 0; dump->start_stack = regs->esp & ~(PAGE_SIZE - 1); dump->u_tsize = ((unsigned long) current->mm->end_code) >> PAGE_SHIFT; dump->u_dsize = ((unsigned long) (current->mm->brk + (PAGE_SIZE-1))) >> PAGE_SHIFT; dump->u_dsize -= dump->u_tsize; dump->u_ssize = 0; for (i = 0; i < 8; i++) dump->u_debugreg[i] = current->debugreg[i]; if (dump->start_stack < TASK_SIZE) dump->u_ssize = ((unsigned long) (TASK_SIZE - dump->start_stack)) >> PAGE_SHIFT; dump->regs = *regs; dump->u_fpvalid = dump_fpu (regs, &dump->i387); #endif } /* Fill in the fpu structure for a core dump. */ int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu) { return 0; } /* * Be aware of the "magic" 7th argument in the four system-calls below. * They need the latest stackframe, which is put as the 7th argument by * entry.S. The previous arguments are dummies or actually used, but need * to be defined to reach the 7th argument. * * N.B.: Another method to get the stackframe is to use current_regs(). But * it returns the latest stack-frame stacked when going from _user mode_ and * some of these (at least sys_clone) are called from kernel-mode sometimes * (for example during kernel_thread, above) and thus cannot use it. Thus, * to be sure not to get any surprises, we use the method for the other calls * as well. */ asmlinkage int sys_fork(long r10, long r11, long r12, long r13, long mof, long srp, struct pt_regs *regs) { return do_fork(SIGCHLD, rdusp(), regs, 0); } /* if newusp is 0, we just grab the old usp */ asmlinkage int sys_clone(unsigned long newusp, unsigned long flags, long r12, long r13, long mof, long srp, struct pt_regs *regs) { if (!newusp) newusp = rdusp(); return do_fork(flags, newusp, regs, 0); } /* vfork is a system call in i386 because of register-pressure - maybe * we can remove it and handle it in libc but we put it here until then. */ asmlinkage int sys_vfork(long r10, long r11, long r12, long r13, long mof, long srp, struct pt_regs *regs) { return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), regs, 0); } /* * sys_execve() executes a new program. */ asmlinkage int sys_execve(const char *fname, char **argv, char **envp, long r13, long mof, long srp, struct pt_regs *regs) { int error; char *filename; filename = getname(fname); error = PTR_ERR(filename); if (IS_ERR(filename)) goto out; error = do_execve(filename, argv, envp, regs); putname(filename); out: return error; } /* * These bracket the sleeping functions.. */ extern void scheduling_functions_start_here(void); extern void scheduling_functions_end_here(void); #define first_sched ((unsigned long) scheduling_functions_start_here) #define last_sched ((unsigned long) scheduling_functions_end_here) unsigned long get_wchan(struct task_struct *p) { #if 0 /* YURGH. TODO. */ unsigned long ebp, esp, eip; unsigned long stack_page; int count = 0; if (!p || p == current || p->state == TASK_RUNNING) return 0; stack_page = (unsigned long)p; esp = p->thread.esp; if (!stack_page || esp < stack_page || esp > 8188+stack_page) return 0; /* include/asm-i386/system.h:switch_to() pushes ebp last. */ ebp = *(unsigned long *) esp; do { if (ebp < stack_page || ebp > 8184+stack_page) return 0; eip = *(unsigned long *) (ebp+4); if (eip < first_sched || eip >= last_sched) return eip; ebp = *(unsigned long *) ebp; } while (count++ < 16); #endif return 0; } #undef last_sched #undef first_sched