From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sat, 16 Apr 2005 15:20:36 -0700 Subject: Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip! --- arch/v850/kernel/process.c | 236 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 236 insertions(+) create mode 100644 arch/v850/kernel/process.c (limited to 'arch/v850/kernel/process.c') diff --git a/arch/v850/kernel/process.c b/arch/v850/kernel/process.c new file mode 100644 index 00000000000..9c708c32c1f --- /dev/null +++ b/arch/v850/kernel/process.c @@ -0,0 +1,236 @@ +/* + * arch/v850/kernel/process.c -- Arch-dependent process handling + * + * Copyright (C) 2001,02,03 NEC Electronics Corporation + * Copyright (C) 2001,02,03 Miles Bader + * + * This file is subject to the terms and conditions of the GNU General + * Public License. See the file COPYING in the main directory of this + * archive for more details. + * + * Written by Miles Bader + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include + +extern void ret_from_fork (void); + + +/* The idle loop. */ +void default_idle (void) +{ + while (1) { + while (! need_resched ()) + asm ("halt; nop; nop; nop; nop; nop" ::: "cc"); + schedule (); + } +} + +void (*idle)(void) = default_idle; + +/* + * 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 */ + (*idle) (); +} + +/* + * This is the mechanism for creating a new kernel thread. + * + * NOTE! Only a kernel-only process (ie the swapper or direct descendants who + * haven't done an "execve()") should use this: it will work within a system + * call from a "real" process, but the process memory space will not be free'd + * until both the parent and the child have exited. + */ +int kernel_thread (int (*fn)(void *), void *arg, unsigned long flags) +{ + register mm_segment_t fs = get_fs (); + register unsigned long syscall asm (SYSCALL_NUM); + register unsigned long arg0 asm (SYSCALL_ARG0); + register unsigned long ret asm (SYSCALL_RET); + + set_fs (KERNEL_DS); + + /* Clone this thread. Note that we don't pass the clone syscall's + second argument -- it's ignored for calls from kernel mode (the + child's SP is always set to the top of the kernel stack). */ + arg0 = flags | CLONE_VM; + syscall = __NR_clone; + asm volatile ("trap " SYSCALL_SHORT_TRAP + : "=r" (ret), "=r" (syscall) + : "1" (syscall), "r" (arg0) + : SYSCALL_SHORT_CLOBBERS); + + if (ret == 0) { + /* In child thread, call FN and exit. */ + arg0 = (*fn) (arg); + syscall = __NR_exit; + asm volatile ("trap " SYSCALL_SHORT_TRAP + : "=r" (ret), "=r" (syscall) + : "1" (syscall), "r" (arg0) + : SYSCALL_SHORT_CLOBBERS); + } + + /* In parent. */ + set_fs (fs); + + return ret; +} + +void flush_thread (void) +{ + set_fs (USER_DS); +} + +int copy_thread (int nr, unsigned long clone_flags, + unsigned long stack_start, unsigned long stack_size, + struct task_struct *p, struct pt_regs *regs) +{ + /* Start pushing stuff from the top of the child's kernel stack. */ + unsigned long orig_ksp = (unsigned long)p->thread_info + THREAD_SIZE; + unsigned long ksp = orig_ksp; + /* We push two `state save' stack fames (see entry.S) on the new + kernel stack: + 1) The innermost one is what switch_thread would have + pushed, and is used when we context switch to the child + thread for the first time. It's set up to return to + ret_from_fork in entry.S. + 2) The outermost one (nearest the top) is what a syscall + trap would have pushed, and is set up to return to the + same location as the parent thread, but with a return + value of 0. */ + struct pt_regs *child_switch_regs, *child_trap_regs; + + /* Trap frame. */ + ksp -= STATE_SAVE_SIZE; + child_trap_regs = (struct pt_regs *)(ksp + STATE_SAVE_PT_OFFSET); + /* Switch frame. */ + ksp -= STATE_SAVE_SIZE; + child_switch_regs = (struct pt_regs *)(ksp + STATE_SAVE_PT_OFFSET); + + /* First copy parent's register state to child. */ + *child_switch_regs = *regs; + *child_trap_regs = *regs; + + /* switch_thread returns to the restored value of the lp + register (r31), so we make that the place where we want to + jump when the child thread begins running. */ + child_switch_regs->gpr[GPR_LP] = (v850_reg_t)ret_from_fork; + + if (regs->kernel_mode) + /* Since we're returning to kernel-mode, make sure the child's + stored kernel stack pointer agrees with what the actual + stack pointer will be at that point (the trap return code + always restores the SP, even when returning to + kernel-mode). */ + child_trap_regs->gpr[GPR_SP] = orig_ksp; + else + /* Set the child's user-mode stack-pointer (the name + `stack_start' is a misnomer, it's just the initial SP + value). */ + child_trap_regs->gpr[GPR_SP] = stack_start; + + /* Thread state for the child (everything else is on the stack). */ + p->thread.ksp = ksp; + + return 0; +} + +/* + * fill in the user structure for a core dump.. + */ +void dump_thread (struct pt_regs *regs, struct user *dump) +{ +#if 0 /* Later. XXX */ + dump->magic = CMAGIC; + dump->start_code = 0; + dump->start_stack = regs->gpr[GPR_SP]; + 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; + + if (dump->start_stack < TASK_SIZE) + dump->u_ssize = ((unsigned long) (TASK_SIZE - dump->start_stack)) >> PAGE_SHIFT; + + dump->u_ar0 = (struct user_regs_struct *)((int)&dump->regs - (int)dump); + dump->regs = *regs; + dump->u_fpvalid = 0; +#endif +} + +/* + * sys_execve() executes a new program. + */ +int sys_execve (char *name, char **argv, char **envp, struct pt_regs *regs) +{ + char *filename = getname (name); + int error = PTR_ERR (filename); + + if (! IS_ERR (filename)) { + error = do_execve (filename, argv, envp, regs); + putname (filename); + } + + return error; +} + + +/* + * These bracket the sleeping functions.. + */ +#define first_sched ((unsigned long)__sched_text_start) +#define last_sched ((unsigned long)__sched_text_end) + +unsigned long get_wchan (struct task_struct *p) +{ +#if 0 /* Barf. Figure out the stack-layout later. XXX */ + unsigned long fp, pc; + int count = 0; + + if (!p || p == current || p->state == TASK_RUNNING) + return 0; + + pc = thread_saved_pc (p); + + /* This quite disgusting function walks up the stack, following + saved return address, until it something that's out of bounds + (as defined by `first_sched' and `last_sched'). It then + returns the last PC that was in-bounds. */ + do { + if (fp < stack_page + sizeof (struct task_struct) || + fp >= 8184+stack_page) + return 0; + pc = ((unsigned long *)fp)[1]; + if (pc < first_sched || pc >= last_sched) + return pc; + fp = *(unsigned long *) fp; + } while (count++ < 16); +#endif + + return 0; +} -- cgit v1.2.3