1 files changed, 812 insertions, 0 deletions

diff --git a/arch/sparc/kernel/process_64.c b/arch/sparc/kernel/process_64.c
new file mode 100644
index 000000000000..d5e2acef9877
--- /dev/null
+++ b/arch/sparc/kernel/process_64.c
@@ -0,0 +1,812 @@
+/*  arch/sparc64/kernel/process.c
+ *
+ *  Copyright (C) 1995, 1996, 2008 David S. Miller (davem@davemloft.net)
+ *  Copyright (C) 1996       Eddie C. Dost   (ecd@skynet.be)
+ *  Copyright (C) 1997, 1998 Jakub Jelinek   (jj@sunsite.mff.cuni.cz)
+ */
+
+/*
+ * This file handles the architecture-dependent parts of process handling..
+ */
+
+#include <stdarg.h>
+
+#include <linux/errno.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/fs.h>
+#include <linux/smp.h>
+#include <linux/stddef.h>
+#include <linux/ptrace.h>
+#include <linux/slab.h>
+#include <linux/user.h>
+#include <linux/delay.h>
+#include <linux/compat.h>
+#include <linux/tick.h>
+#include <linux/init.h>
+#include <linux/cpu.h>
+#include <linux/elfcore.h>
+#include <linux/sysrq.h>
+
+#include <asm/uaccess.h>
+#include <asm/system.h>
+#include <asm/page.h>
+#include <asm/pgalloc.h>
+#include <asm/pgtable.h>
+#include <asm/processor.h>
+#include <asm/pstate.h>
+#include <asm/elf.h>
+#include <asm/fpumacro.h>
+#include <asm/head.h>
+#include <asm/cpudata.h>
+#include <asm/mmu_context.h>
+#include <asm/unistd.h>
+#include <asm/hypervisor.h>
+#include <asm/syscalls.h>
+#include <asm/irq_regs.h>
+#include <asm/smp.h>
+
+#include "kstack.h"
+
+static void sparc64_yield(int cpu)
+{
+	if (tlb_type != hypervisor)
+		return;
+
+	clear_thread_flag(TIF_POLLING_NRFLAG);
+	smp_mb__after_clear_bit();
+
+	while (!need_resched() && !cpu_is_offline(cpu)) {
+		unsigned long pstate;
+
+		/* Disable interrupts. */
+		__asm__ __volatile__(
+			"rdpr %%pstate, %0\n\t"
+			"andn %0, %1, %0\n\t"
+			"wrpr %0, %%g0, %%pstate"
+			: "=&r" (pstate)
+			: "i" (PSTATE_IE));
+
+		if (!need_resched() && !cpu_is_offline(cpu))
+			sun4v_cpu_yield();
+
+		/* Re-enable interrupts. */
+		__asm__ __volatile__(
+			"rdpr %%pstate, %0\n\t"
+			"or %0, %1, %0\n\t"
+			"wrpr %0, %%g0, %%pstate"
+			: "=&r" (pstate)
+			: "i" (PSTATE_IE));
+	}
+
+	set_thread_flag(TIF_POLLING_NRFLAG);
+}
+
+/* The idle loop on sparc64. */
+void cpu_idle(void)
+{
+	int cpu = smp_processor_id();
+
+	set_thread_flag(TIF_POLLING_NRFLAG);
+
+	while(1) {
+		tick_nohz_stop_sched_tick(1);
+
+		while (!need_resched() && !cpu_is_offline(cpu))
+			sparc64_yield(cpu);
+
+		tick_nohz_restart_sched_tick();
+
+		preempt_enable_no_resched();
+
+#ifdef CONFIG_HOTPLUG_CPU
+		if (cpu_is_offline(cpu))
+			cpu_play_dead();
+#endif
+
+		schedule();
+		preempt_disable();
+	}
+}
+
+#ifdef CONFIG_COMPAT
+static void show_regwindow32(struct pt_regs *regs)
+{
+	struct reg_window32 __user *rw;
+	struct reg_window32 r_w;
+	mm_segment_t old_fs;
+	
+	__asm__ __volatile__ ("flushw");
+	rw = compat_ptr((unsigned)regs->u_regs[14]);
+	old_fs = get_fs();
+	set_fs (USER_DS);
+	if (copy_from_user (&r_w, rw, sizeof(r_w))) {
+		set_fs (old_fs);
+		return;
+	}
+
+	set_fs (old_fs);			
+	printk("l0: %08x l1: %08x l2: %08x l3: %08x "
+	       "l4: %08x l5: %08x l6: %08x l7: %08x\n",
+	       r_w.locals[0], r_w.locals[1], r_w.locals[2], r_w.locals[3],
+	       r_w.locals[4], r_w.locals[5], r_w.locals[6], r_w.locals[7]);
+	printk("i0: %08x i1: %08x i2: %08x i3: %08x "
+	       "i4: %08x i5: %08x i6: %08x i7: %08x\n",
+	       r_w.ins[0], r_w.ins[1], r_w.ins[2], r_w.ins[3],
+	       r_w.ins[4], r_w.ins[5], r_w.ins[6], r_w.ins[7]);
+}
+#else
+#define show_regwindow32(regs)	do { } while (0)
+#endif
+
+static void show_regwindow(struct pt_regs *regs)
+{
+	struct reg_window __user *rw;
+	struct reg_window *rwk;
+	struct reg_window r_w;
+	mm_segment_t old_fs;
+
+	if ((regs->tstate & TSTATE_PRIV) || !(test_thread_flag(TIF_32BIT))) {
+		__asm__ __volatile__ ("flushw");
+		rw = (struct reg_window __user *)
+			(regs->u_regs[14] + STACK_BIAS);
+		rwk = (struct reg_window *)
+			(regs->u_regs[14] + STACK_BIAS);
+		if (!(regs->tstate & TSTATE_PRIV)) {
+			old_fs = get_fs();
+			set_fs (USER_DS);
+			if (copy_from_user (&r_w, rw, sizeof(r_w))) {
+				set_fs (old_fs);
+				return;
+			}
+			rwk = &r_w;
+			set_fs (old_fs);			
+		}
+	} else {
+		show_regwindow32(regs);
+		return;
+	}
+	printk("l0: %016lx l1: %016lx l2: %016lx l3: %016lx\n",
+	       rwk->locals[0], rwk->locals[1], rwk->locals[2], rwk->locals[3]);
+	printk("l4: %016lx l5: %016lx l6: %016lx l7: %016lx\n",
+	       rwk->locals[4], rwk->locals[5], rwk->locals[6], rwk->locals[7]);
+	printk("i0: %016lx i1: %016lx i2: %016lx i3: %016lx\n",
+	       rwk->ins[0], rwk->ins[1], rwk->ins[2], rwk->ins[3]);
+	printk("i4: %016lx i5: %016lx i6: %016lx i7: %016lx\n",
+	       rwk->ins[4], rwk->ins[5], rwk->ins[6], rwk->ins[7]);
+	if (regs->tstate & TSTATE_PRIV)
+		printk("I7: <%pS>\n", (void *) rwk->ins[7]);
+}
+
+void show_regs(struct pt_regs *regs)
+{
+	printk("TSTATE: %016lx TPC: %016lx TNPC: %016lx Y: %08x    %s\n", regs->tstate,
+	       regs->tpc, regs->tnpc, regs->y, print_tainted());
+	printk("TPC: <%pS>\n", (void *) regs->tpc);
+	printk("g0: %016lx g1: %016lx g2: %016lx g3: %016lx\n",
+	       regs->u_regs[0], regs->u_regs[1], regs->u_regs[2],
+	       regs->u_regs[3]);
+	printk("g4: %016lx g5: %016lx g6: %016lx g7: %016lx\n",
+	       regs->u_regs[4], regs->u_regs[5], regs->u_regs[6],
+	       regs->u_regs[7]);
+	printk("o0: %016lx o1: %016lx o2: %016lx o3: %016lx\n",
+	       regs->u_regs[8], regs->u_regs[9], regs->u_regs[10],
+	       regs->u_regs[11]);
+	printk("o4: %016lx o5: %016lx sp: %016lx ret_pc: %016lx\n",
+	       regs->u_regs[12], regs->u_regs[13], regs->u_regs[14],
+	       regs->u_regs[15]);
+	printk("RPC: <%pS>\n", (void *) regs->u_regs[15]);
+	show_regwindow(regs);
+}
+
+struct global_reg_snapshot global_reg_snapshot[NR_CPUS];
+static DEFINE_SPINLOCK(global_reg_snapshot_lock);
+
+static void __global_reg_self(struct thread_info *tp, struct pt_regs *regs,
+			      int this_cpu)
+{
+	flushw_all();
+
+	global_reg_snapshot[this_cpu].tstate = regs->tstate;
+	global_reg_snapshot[this_cpu].tpc = regs->tpc;
+	global_reg_snapshot[this_cpu].tnpc = regs->tnpc;
+	global_reg_snapshot[this_cpu].o7 = regs->u_regs[UREG_I7];
+
+	if (regs->tstate & TSTATE_PRIV) {
+		struct reg_window *rw;
+
+		rw = (struct reg_window *)
+			(regs->u_regs[UREG_FP] + STACK_BIAS);
+		if (kstack_valid(tp, (unsigned long) rw)) {
+			global_reg_snapshot[this_cpu].i7 = rw->ins[7];
+			rw = (struct reg_window *)
+				(rw->ins[6] + STACK_BIAS);
+			if (kstack_valid(tp, (unsigned long) rw))
+				global_reg_snapshot[this_cpu].rpc = rw->ins[7];
+		}
+	} else {
+		global_reg_snapshot[this_cpu].i7 = 0;
+		global_reg_snapshot[this_cpu].rpc = 0;
+	}
+	global_reg_snapshot[this_cpu].thread = tp;
+}
+
+/* In order to avoid hangs we do not try to synchronize with the
+ * global register dump client cpus.  The last store they make is to
+ * the thread pointer, so do a short poll waiting for that to become
+ * non-NULL.
+ */
+static void __global_reg_poll(struct global_reg_snapshot *gp)
+{
+	int limit = 0;
+
+	while (!gp->thread && ++limit < 100) {
+		barrier();
+		udelay(1);
+	}
+}
+
+void __trigger_all_cpu_backtrace(void)
+{
+	struct thread_info *tp = current_thread_info();
+	struct pt_regs *regs = get_irq_regs();
+	unsigned long flags;
+	int this_cpu, cpu;
+
+	if (!regs)
+		regs = tp->kregs;
+
+	spin_lock_irqsave(&global_reg_snapshot_lock, flags);
+
+	memset(global_reg_snapshot, 0, sizeof(global_reg_snapshot));
+
+	this_cpu = raw_smp_processor_id();
+
+	__global_reg_self(tp, regs, this_cpu);
+
+	smp_fetch_global_regs();
+
+	for_each_online_cpu(cpu) {
+		struct global_reg_snapshot *gp = &global_reg_snapshot[cpu];
+
+		__global_reg_poll(gp);
+
+		tp = gp->thread;
+		printk("%c CPU[%3d]: TSTATE[%016lx] TPC[%016lx] TNPC[%016lx] TASK[%s:%d]\n",
+		       (cpu == this_cpu ? '*' : ' '), cpu,
+		       gp->tstate, gp->tpc, gp->tnpc,
+		       ((tp && tp->task) ? tp->task->comm : "NULL"),
+		       ((tp && tp->task) ? tp->task->pid : -1));
+
+		if (gp->tstate & TSTATE_PRIV) {
+			printk("             TPC[%pS] O7[%pS] I7[%pS] RPC[%pS]\n",
+			       (void *) gp->tpc,
+			       (void *) gp->o7,
+			       (void *) gp->i7,
+			       (void *) gp->rpc);
+		} else {
+			printk("             TPC[%lx] O7[%lx] I7[%lx] RPC[%lx]\n",
+			       gp->tpc, gp->o7, gp->i7, gp->rpc);
+		}
+	}
+
+	memset(global_reg_snapshot, 0, sizeof(global_reg_snapshot));
+
+	spin_unlock_irqrestore(&global_reg_snapshot_lock, flags);
+}
+
+#ifdef CONFIG_MAGIC_SYSRQ
+
+static void sysrq_handle_globreg(int key, struct tty_struct *tty)
+{
+	__trigger_all_cpu_backtrace();
+}
+
+static struct sysrq_key_op sparc_globalreg_op = {
+	.handler	= sysrq_handle_globreg,
+	.help_msg	= "Globalregs",
+	.action_msg	= "Show Global CPU Regs",
+};
+
+static int __init sparc_globreg_init(void)
+{
+	return register_sysrq_key('y', &sparc_globalreg_op);
+}
+
+core_initcall(sparc_globreg_init);
+
+#endif
+
+unsigned long thread_saved_pc(struct task_struct *tsk)
+{
+	struct thread_info *ti = task_thread_info(tsk);
+	unsigned long ret = 0xdeadbeefUL;
+	
+	if (ti && ti->ksp) {
+		unsigned long *sp;
+		sp = (unsigned long *)(ti->ksp + STACK_BIAS);
+		if (((unsigned long)sp & (sizeof(long) - 1)) == 0UL &&
+		    sp[14]) {
+			unsigned long *fp;
+			fp = (unsigned long *)(sp[14] + STACK_BIAS);
+			if (((unsigned long)fp & (sizeof(long) - 1)) == 0UL)
+				ret = fp[15];
+		}
+	}
+	return ret;
+}
+
+/* Free current thread data structures etc.. */
+void exit_thread(void)
+{
+	struct thread_info *t = current_thread_info();
+
+	if (t->utraps) {
+		if (t->utraps[0] < 2)
+			kfree (t->utraps);
+		else
+			t->utraps[0]--;
+	}
+
+	if (test_and_clear_thread_flag(TIF_PERFCTR)) {
+		t->user_cntd0 = t->user_cntd1 = NULL;
+		t->pcr_reg = 0;
+		write_pcr(0);
+	}
+}
+
+void flush_thread(void)
+{
+	struct thread_info *t = current_thread_info();
+	struct mm_struct *mm;
+
+	if (test_ti_thread_flag(t, TIF_ABI_PENDING)) {
+		clear_ti_thread_flag(t, TIF_ABI_PENDING);
+		if (test_ti_thread_flag(t, TIF_32BIT))
+			clear_ti_thread_flag(t, TIF_32BIT);
+		else
+			set_ti_thread_flag(t, TIF_32BIT);
+	}
+
+	mm = t->task->mm;
+	if (mm)
+		tsb_context_switch(mm);
+
+	set_thread_wsaved(0);
+
+	/* Turn off performance counters if on. */
+	if (test_and_clear_thread_flag(TIF_PERFCTR)) {
+		t->user_cntd0 = t->user_cntd1 = NULL;
+		t->pcr_reg = 0;
+		write_pcr(0);
+	}
+
+	/* Clear FPU register state. */
+	t->fpsaved[0] = 0;
+	
+	if (get_thread_current_ds() != ASI_AIUS)
+		set_fs(USER_DS);
+}
+
+/* It's a bit more tricky when 64-bit tasks are involved... */
+static unsigned long clone_stackframe(unsigned long csp, unsigned long psp)
+{
+	unsigned long fp, distance, rval;
+
+	if (!(test_thread_flag(TIF_32BIT))) {
+		csp += STACK_BIAS;
+		psp += STACK_BIAS;
+		__get_user(fp, &(((struct reg_window __user *)psp)->ins[6]));
+		fp += STACK_BIAS;
+	} else
+		__get_user(fp, &(((struct reg_window32 __user *)psp)->ins[6]));
+
+	/* Now 8-byte align the stack as this is mandatory in the
+	 * Sparc ABI due to how register windows work.  This hides
+	 * the restriction from thread libraries etc.  -DaveM
+	 */
+	csp &= ~7UL;
+
+	distance = fp - psp;
+	rval = (csp - distance);
+	if (copy_in_user((void __user *) rval, (void __user *) psp, distance))
+		rval = 0;
+	else if (test_thread_flag(TIF_32BIT)) {
+		if (put_user(((u32)csp),
+			     &(((struct reg_window32 __user *)rval)->ins[6])))
+			rval = 0;
+	} else {
+		if (put_user(((u64)csp - STACK_BIAS),
+			     &(((struct reg_window __user *)rval)->ins[6])))
+			rval = 0;
+		else
+			rval = rval - STACK_BIAS;
+	}
+
+	return rval;
+}
+
+/* Standard stuff. */
+static inline void shift_window_buffer(int first_win, int last_win,
+				       struct thread_info *t)
+{
+	int i;
+
+	for (i = first_win; i < last_win; i++) {
+		t->rwbuf_stkptrs[i] = t->rwbuf_stkptrs[i+1];
+		memcpy(&t->reg_window[i], &t->reg_window[i+1],
+		       sizeof(struct reg_window));
+	}
+}
+
+void synchronize_user_stack(void)
+{
+	struct thread_info *t = current_thread_info();
+	unsigned long window;
+
+	flush_user_windows();
+	if ((window = get_thread_wsaved()) != 0) {
+		int winsize = sizeof(struct reg_window);
+		int bias = 0;
+
+		if (test_thread_flag(TIF_32BIT))
+			winsize = sizeof(struct reg_window32);
+		else
+			bias = STACK_BIAS;
+
+		window -= 1;
+		do {
+			unsigned long sp = (t->rwbuf_stkptrs[window] + bias);
+			struct reg_window *rwin = &t->reg_window[window];
+
+			if (!copy_to_user((char __user *)sp, rwin, winsize)) {
+				shift_window_buffer(window, get_thread_wsaved() - 1, t);
+				set_thread_wsaved(get_thread_wsaved() - 1);
+			}
+		} while (window--);
+	}
+}
+
+static void stack_unaligned(unsigned long sp)
+{
+	siginfo_t info;
+
+	info.si_signo = SIGBUS;
+	info.si_errno = 0;
+	info.si_code = BUS_ADRALN;
+	info.si_addr = (void __user *) sp;
+	info.si_trapno = 0;
+	force_sig_info(SIGBUS, &info, current);
+}
+
+void fault_in_user_windows(void)
+{
+	struct thread_info *t = current_thread_info();
+	unsigned long window;
+	int winsize = sizeof(struct reg_window);
+	int bias = 0;
+
+	if (test_thread_flag(TIF_32BIT))
+		winsize = sizeof(struct reg_window32);
+	else
+		bias = STACK_BIAS;
+
+	flush_user_windows();
+	window = get_thread_wsaved();
+
+	if (likely(window != 0)) {
+		window -= 1;
+		do {
+			unsigned long sp = (t->rwbuf_stkptrs[window] + bias);
+			struct reg_window *rwin = &t->reg_window[window];
+
+			if (unlikely(sp & 0x7UL))
+				stack_unaligned(sp);
+
+			if (unlikely(copy_to_user((char __user *)sp,
+						  rwin, winsize)))
+				goto barf;
+		} while (window--);
+	}
+	set_thread_wsaved(0);
+	return;
+
+barf:
+	set_thread_wsaved(window + 1);
+	do_exit(SIGILL);
+}
+
+asmlinkage long sparc_do_fork(unsigned long clone_flags,
+			      unsigned long stack_start,
+			      struct pt_regs *regs,
+			      unsigned long stack_size)
+{
+	int __user *parent_tid_ptr, *child_tid_ptr;
+	unsigned long orig_i1 = regs->u_regs[UREG_I1];
+	long ret;
+
+#ifdef CONFIG_COMPAT
+	if (test_thread_flag(TIF_32BIT)) {
+		parent_tid_ptr = compat_ptr(regs->u_regs[UREG_I2]);
+		child_tid_ptr = compat_ptr(regs->u_regs[UREG_I4]);
+	} else
+#endif
+	{
+		parent_tid_ptr = (int __user *) regs->u_regs[UREG_I2];
+		child_tid_ptr = (int __user *) regs->u_regs[UREG_I4];
+	}
+
+	ret = do_fork(clone_flags, stack_start,
+		      regs, stack_size,
+		      parent_tid_ptr, child_tid_ptr);
+
+	/* If we get an error and potentially restart the system
+	 * call, we're screwed because copy_thread() clobbered
+	 * the parent's %o1.  So detect that case and restore it
+	 * here.
+	 */
+	if ((unsigned long)ret >= -ERESTART_RESTARTBLOCK)
+		regs->u_regs[UREG_I1] = orig_i1;
+
+	return ret;
+}
+
+/* Copy a Sparc thread.  The fork() return value conventions
+ * under SunOS are nothing short of bletcherous:
+ * Parent -->  %o0 == childs  pid, %o1 == 0
+ * Child  -->  %o0 == parents pid, %o1 == 1
+ */
+int copy_thread(int nr, unsigned long clone_flags, unsigned long sp,
+		unsigned long unused,
+		struct task_struct *p, struct pt_regs *regs)
+{
+	struct thread_info *t = task_thread_info(p);
+	struct sparc_stackf *parent_sf;
+	unsigned long child_stack_sz;
+	char *child_trap_frame;
+	int kernel_thread;
+
+	kernel_thread = (regs->tstate & TSTATE_PRIV) ? 1 : 0;
+	parent_sf = ((struct sparc_stackf *) regs) - 1;
+
+	/* Calculate offset to stack_frame & pt_regs */
+	child_stack_sz = ((STACKFRAME_SZ + TRACEREG_SZ) +
+			  (kernel_thread ? STACKFRAME_SZ : 0));
+	child_trap_frame = (task_stack_page(p) +
+			    (THREAD_SIZE - child_stack_sz));
+	memcpy(child_trap_frame, parent_sf, child_stack_sz);
+
+	t->flags = (t->flags & ~((0xffUL << TI_FLAG_CWP_SHIFT) |
+				 (0xffUL << TI_FLAG_CURRENT_DS_SHIFT))) |
+		(((regs->tstate + 1) & TSTATE_CWP) << TI_FLAG_CWP_SHIFT);
+	t->new_child = 1;
+	t->ksp = ((unsigned long) child_trap_frame) - STACK_BIAS;
+	t->kregs = (struct pt_regs *) (child_trap_frame +
+				       sizeof(struct sparc_stackf));
+	t->fpsaved[0] = 0;
+
+	if (kernel_thread) {
+		struct sparc_stackf *child_sf = (struct sparc_stackf *)
+			(child_trap_frame + (STACKFRAME_SZ + TRACEREG_SZ));
+
+		/* Zero terminate the stack backtrace.  */
+		child_sf->fp = NULL;
+		t->kregs->u_regs[UREG_FP] =
+		  ((unsigned long) child_sf) - STACK_BIAS;
+
+		/* Special case, if we are spawning a kernel thread from
+		 * a userspace task (usermode helper, NFS or similar), we
+		 * must disable performance counters in the child because
+		 * the address space and protection realm are changing.
+		 */
+		if (t->flags & _TIF_PERFCTR) {
+			t->user_cntd0 = t->user_cntd1 = NULL;
+			t->pcr_reg = 0;
+			t->flags &= ~_TIF_PERFCTR;
+		}
+		t->flags |= ((long)ASI_P << TI_FLAG_CURRENT_DS_SHIFT);
+		t->kregs->u_regs[UREG_G6] = (unsigned long) t;
+		t->kregs->u_regs[UREG_G4] = (unsigned long) t->task;
+	} else {
+		if (t->flags & _TIF_32BIT) {
+			sp &= 0x00000000ffffffffUL;
+			regs->u_regs[UREG_FP] &= 0x00000000ffffffffUL;
+		}
+		t->kregs->u_regs[UREG_FP] = sp;
+		t->flags |= ((long)ASI_AIUS << TI_FLAG_CURRENT_DS_SHIFT);
+		if (sp != regs->u_regs[UREG_FP]) {
+			unsigned long csp;
+
+			csp = clone_stackframe(sp, regs->u_regs[UREG_FP]);
+			if (!csp)
+				return -EFAULT;
+			t->kregs->u_regs[UREG_FP] = csp;
+		}
+		if (t->utraps)
+			t->utraps[0]++;
+	}
+
+	/* Set the return value for the child. */
+	t->kregs->u_regs[UREG_I0] = current->pid;
+	t->kregs->u_regs[UREG_I1] = 1;
+
+	/* Set the second return value for the parent. */
+	regs->u_regs[UREG_I1] = 0;
+
+	if (clone_flags & CLONE_SETTLS)
+		t->kregs->u_regs[UREG_G7] = regs->u_regs[UREG_I3];
+
+	return 0;
+}
+
+/*
+ * 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 freed until both the parent and the child have exited.
+ */
+pid_t kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
+{
+	long retval;
+
+	/* If the parent runs before fn(arg) is called by the child,
+	 * the input registers of this function can be clobbered.
+	 * So we stash 'fn' and 'arg' into global registers which
+	 * will not be modified by the parent.
+	 */
+	__asm__ __volatile__("mov %4, %%g2\n\t"	   /* Save FN into global */
+			     "mov %5, %%g3\n\t"	   /* Save ARG into global */
+			     "mov %1, %%g1\n\t"	   /* Clone syscall nr. */
+			     "mov %2, %%o0\n\t"	   /* Clone flags. */
+			     "mov 0, %%o1\n\t"	   /* usp arg == 0 */
+			     "t 0x6d\n\t"	   /* Linux/Sparc clone(). */
+			     "brz,a,pn %%o1, 1f\n\t" /* Parent, just return. */
+			     " mov %%o0, %0\n\t"
+			     "jmpl %%g2, %%o7\n\t"   /* Call the function. */
+			     " mov %%g3, %%o0\n\t"   /* Set arg in delay. */
+			     "mov %3, %%g1\n\t"
+			     "t 0x6d\n\t"	   /* Linux/Sparc exit(). */
+			     /* Notreached by child. */
+			     "1:" :
+			     "=r" (retval) :
+			     "i" (__NR_clone), "r" (flags | CLONE_VM | CLONE_UNTRACED),
+			     "i" (__NR_exit),  "r" (fn), "r" (arg) :
+			     "g1", "g2", "g3", "o0", "o1", "memory", "cc");
+	return retval;
+}
+
+typedef struct {
+	union {
+		unsigned int	pr_regs[32];
+		unsigned long	pr_dregs[16];
+	} pr_fr;
+	unsigned int __unused;
+	unsigned int	pr_fsr;
+	unsigned char	pr_qcnt;
+	unsigned char	pr_q_entrysize;
+	unsigned char	pr_en;
+	unsigned int	pr_q[64];
+} elf_fpregset_t32;
+
+/*
+ * fill in the fpu structure for a core dump.
+ */
+int dump_fpu (struct pt_regs * regs, elf_fpregset_t * fpregs)
+{
+	unsigned long *kfpregs = current_thread_info()->fpregs;
+	unsigned long fprs = current_thread_info()->fpsaved[0];
+
+	if (test_thread_flag(TIF_32BIT)) {
+		elf_fpregset_t32 *fpregs32 = (elf_fpregset_t32 *)fpregs;
+
+		if (fprs & FPRS_DL)
+			memcpy(&fpregs32->pr_fr.pr_regs[0], kfpregs,
+			       sizeof(unsigned int) * 32);
+		else
+			memset(&fpregs32->pr_fr.pr_regs[0], 0,
+			       sizeof(unsigned int) * 32);
+		fpregs32->pr_qcnt = 0;
+		fpregs32->pr_q_entrysize = 8;
+		memset(&fpregs32->pr_q[0], 0,
+		       (sizeof(unsigned int) * 64));
+		if (fprs & FPRS_FEF) {
+			fpregs32->pr_fsr = (unsigned int) current_thread_info()->xfsr[0];
+			fpregs32->pr_en = 1;
+		} else {
+			fpregs32->pr_fsr = 0;
+			fpregs32->pr_en = 0;
+		}
+	} else {
+		if(fprs & FPRS_DL)
+			memcpy(&fpregs->pr_regs[0], kfpregs,
+			       sizeof(unsigned int) * 32);
+		else
+			memset(&fpregs->pr_regs[0], 0,
+			       sizeof(unsigned int) * 32);
+		if(fprs & FPRS_DU)
+			memcpy(&fpregs->pr_regs[16], kfpregs+16,
+			       sizeof(unsigned int) * 32);
+		else
+			memset(&fpregs->pr_regs[16], 0,
+			       sizeof(unsigned int) * 32);
+		if(fprs & FPRS_FEF) {
+			fpregs->pr_fsr = current_thread_info()->xfsr[0];
+			fpregs->pr_gsr = current_thread_info()->gsr[0];
+		} else {
+			fpregs->pr_fsr = fpregs->pr_gsr = 0;
+		}
+		fpregs->pr_fprs = fprs;
+	}
+	return 1;
+}
+
+/*
+ * sparc_execve() executes a new program after the asm stub has set
+ * things up for us.  This should basically do what I want it to.
+ */
+asmlinkage int sparc_execve(struct pt_regs *regs)
+{
+	int error, base = 0;
+	char *filename;
+
+	/* User register window flush is done by entry.S */
+
+	/* Check for indirect call. */
+	if (regs->u_regs[UREG_G1] == 0)
+		base = 1;
+
+	filename = getname((char __user *)regs->u_regs[base + UREG_I0]);
+	error = PTR_ERR(filename);
+	if (IS_ERR(filename))
+		goto out;
+	error = do_execve(filename,
+			  (char __user * __user *)
+			  regs->u_regs[base + UREG_I1],
+			  (char __user * __user *)
+			  regs->u_regs[base + UREG_I2], regs);
+	putname(filename);
+	if (!error) {
+		fprs_write(0);
+		current_thread_info()->xfsr[0] = 0;
+		current_thread_info()->fpsaved[0] = 0;
+		regs->tstate &= ~TSTATE_PEF;
+	}
+out:
+	return error;
+}
+
+unsigned long get_wchan(struct task_struct *task)
+{
+	unsigned long pc, fp, bias = 0;
+	struct thread_info *tp;
+	struct reg_window *rw;
+        unsigned long ret = 0;
+	int count = 0; 
+
+	if (!task || task == current ||
+            task->state == TASK_RUNNING)
+		goto out;
+
+	tp = task_thread_info(task);
+	bias = STACK_BIAS;
+	fp = task_thread_info(task)->ksp + bias;
+
+	do {
+		if (!kstack_valid(tp, fp))
+			break;
+		rw = (struct reg_window *) fp;
+		pc = rw->ins[7];
+		if (!in_sched_functions(pc)) {
+			ret = pc;
+			goto out;
+		}
+		fp = rw->ins[6] + bias;
+	} while (++count < 16);
+
+out:
+	return ret;
+}