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-rw-r--r--arch/v850/kernel/process.c236
1 files changed, 236 insertions, 0 deletions
diff --git a/arch/v850/kernel/process.c b/arch/v850/kernel/process.c
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+/*
+ * arch/v850/kernel/process.c -- Arch-dependent process handling
+ *
+ * Copyright (C) 2001,02,03 NEC Electronics Corporation
+ * Copyright (C) 2001,02,03 Miles Bader <miles@gnu.org>
+ *
+ * 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 <miles@gnu.org>
+ */
+
+#include <linux/config.h>
+#include <linux/errno.h>
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/smp.h>
+#include <linux/smp_lock.h>
+#include <linux/stddef.h>
+#include <linux/unistd.h>
+#include <linux/ptrace.h>
+#include <linux/slab.h>
+#include <linux/user.h>
+#include <linux/a.out.h>
+#include <linux/reboot.h>
+
+#include <asm/uaccess.h>
+#include <asm/system.h>
+#include <asm/pgtable.h>
+
+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;
+}