Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2014 insertions, 0 deletions

diff --git a/arch/ia64/kernel/ptrace.c b/arch/ia64/kernel/ptrace.c
new file mode 100644
index 000000000..ab8aeb34d
--- /dev/null
+++ b/arch/ia64/kernel/ptrace.c
@@ -0,0 +1,2014 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Kernel support for the ptrace() and syscall tracing interfaces.
+ *
+ * Copyright (C) 1999-2005 Hewlett-Packard Co
+ *	David Mosberger-Tang <davidm@hpl.hp.com>
+ * Copyright (C) 2006 Intel Co
+ *  2006-08-12	- IA64 Native Utrace implementation support added by
+ *	Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
+ *
+ * Derived from the x86 and Alpha versions.
+ */
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/sched/task.h>
+#include <linux/sched/task_stack.h>
+#include <linux/mm.h>
+#include <linux/errno.h>
+#include <linux/ptrace.h>
+#include <linux/user.h>
+#include <linux/security.h>
+#include <linux/audit.h>
+#include <linux/signal.h>
+#include <linux/regset.h>
+#include <linux/elf.h>
+#include <linux/resume_user_mode.h>
+
+#include <asm/processor.h>
+#include <asm/ptrace_offsets.h>
+#include <asm/rse.h>
+#include <linux/uaccess.h>
+#include <asm/unwind.h>
+
+#include "entry.h"
+
+/*
+ * Bits in the PSR that we allow ptrace() to change:
+ *	be, up, ac, mfl, mfh (the user mask; five bits total)
+ *	db (debug breakpoint fault; one bit)
+ *	id (instruction debug fault disable; one bit)
+ *	dd (data debug fault disable; one bit)
+ *	ri (restart instruction; two bits)
+ *	is (instruction set; one bit)
+ */
+#define IPSR_MASK (IA64_PSR_UM | IA64_PSR_DB | IA64_PSR_IS	\
+		   | IA64_PSR_ID | IA64_PSR_DD | IA64_PSR_RI)
+
+#define MASK(nbits)	((1UL << (nbits)) - 1)	/* mask with NBITS bits set */
+#define PFM_MASK	MASK(38)
+
+#define PTRACE_DEBUG	0
+
+#if PTRACE_DEBUG
+# define dprintk(format...)	printk(format)
+# define inline
+#else
+# define dprintk(format...)
+#endif
+
+/* Return TRUE if PT was created due to kernel-entry via a system-call.  */
+
+static inline int
+in_syscall (struct pt_regs *pt)
+{
+	return (long) pt->cr_ifs >= 0;
+}
+
+/*
+ * Collect the NaT bits for r1-r31 from scratch_unat and return a NaT
+ * bitset where bit i is set iff the NaT bit of register i is set.
+ */
+unsigned long
+ia64_get_scratch_nat_bits (struct pt_regs *pt, unsigned long scratch_unat)
+{
+#	define GET_BITS(first, last, unat)				\
+	({								\
+		unsigned long bit = ia64_unat_pos(&pt->r##first);	\
+		unsigned long nbits = (last - first + 1);		\
+		unsigned long mask = MASK(nbits) << first;		\
+		unsigned long dist;					\
+		if (bit < first)					\
+			dist = 64 + bit - first;			\
+		else							\
+			dist = bit - first;				\
+		ia64_rotr(unat, dist) & mask;				\
+	})
+	unsigned long val;
+
+	/*
+	 * Registers that are stored consecutively in struct pt_regs
+	 * can be handled in parallel.  If the register order in
+	 * struct_pt_regs changes, this code MUST be updated.
+	 */
+	val  = GET_BITS( 1,  1, scratch_unat);
+	val |= GET_BITS( 2,  3, scratch_unat);
+	val |= GET_BITS(12, 13, scratch_unat);
+	val |= GET_BITS(14, 14, scratch_unat);
+	val |= GET_BITS(15, 15, scratch_unat);
+	val |= GET_BITS( 8, 11, scratch_unat);
+	val |= GET_BITS(16, 31, scratch_unat);
+	return val;
+
+#	undef GET_BITS
+}
+
+/*
+ * Set the NaT bits for the scratch registers according to NAT and
+ * return the resulting unat (assuming the scratch registers are
+ * stored in PT).
+ */
+unsigned long
+ia64_put_scratch_nat_bits (struct pt_regs *pt, unsigned long nat)
+{
+#	define PUT_BITS(first, last, nat)				\
+	({								\
+		unsigned long bit = ia64_unat_pos(&pt->r##first);	\
+		unsigned long nbits = (last - first + 1);		\
+		unsigned long mask = MASK(nbits) << first;		\
+		long dist;						\
+		if (bit < first)					\
+			dist = 64 + bit - first;			\
+		else							\
+			dist = bit - first;				\
+		ia64_rotl(nat & mask, dist);				\
+	})
+	unsigned long scratch_unat;
+
+	/*
+	 * Registers that are stored consecutively in struct pt_regs
+	 * can be handled in parallel.  If the register order in
+	 * struct_pt_regs changes, this code MUST be updated.
+	 */
+	scratch_unat  = PUT_BITS( 1,  1, nat);
+	scratch_unat |= PUT_BITS( 2,  3, nat);
+	scratch_unat |= PUT_BITS(12, 13, nat);
+	scratch_unat |= PUT_BITS(14, 14, nat);
+	scratch_unat |= PUT_BITS(15, 15, nat);
+	scratch_unat |= PUT_BITS( 8, 11, nat);
+	scratch_unat |= PUT_BITS(16, 31, nat);
+
+	return scratch_unat;
+
+#	undef PUT_BITS
+}
+
+#define IA64_MLX_TEMPLATE	0x2
+#define IA64_MOVL_OPCODE	6
+
+void
+ia64_increment_ip (struct pt_regs *regs)
+{
+	unsigned long w0, ri = ia64_psr(regs)->ri + 1;
+
+	if (ri > 2) {
+		ri = 0;
+		regs->cr_iip += 16;
+	} else if (ri == 2) {
+		get_user(w0, (char __user *) regs->cr_iip + 0);
+		if (((w0 >> 1) & 0xf) == IA64_MLX_TEMPLATE) {
+			/*
+			 * rfi'ing to slot 2 of an MLX bundle causes
+			 * an illegal operation fault.  We don't want
+			 * that to happen...
+			 */
+			ri = 0;
+			regs->cr_iip += 16;
+		}
+	}
+	ia64_psr(regs)->ri = ri;
+}
+
+void
+ia64_decrement_ip (struct pt_regs *regs)
+{
+	unsigned long w0, ri = ia64_psr(regs)->ri - 1;
+
+	if (ia64_psr(regs)->ri == 0) {
+		regs->cr_iip -= 16;
+		ri = 2;
+		get_user(w0, (char __user *) regs->cr_iip + 0);
+		if (((w0 >> 1) & 0xf) == IA64_MLX_TEMPLATE) {
+			/*
+			 * rfi'ing to slot 2 of an MLX bundle causes
+			 * an illegal operation fault.  We don't want
+			 * that to happen...
+			 */
+			ri = 1;
+		}
+	}
+	ia64_psr(regs)->ri = ri;
+}
+
+/*
+ * This routine is used to read an rnat bits that are stored on the
+ * kernel backing store.  Since, in general, the alignment of the user
+ * and kernel are different, this is not completely trivial.  In
+ * essence, we need to construct the user RNAT based on up to two
+ * kernel RNAT values and/or the RNAT value saved in the child's
+ * pt_regs.
+ *
+ * user rbs
+ *
+ * +--------+ <-- lowest address
+ * | slot62 |
+ * +--------+
+ * |  rnat  | 0x....1f8
+ * +--------+
+ * | slot00 | \
+ * +--------+ |
+ * | slot01 | > child_regs->ar_rnat
+ * +--------+ |
+ * | slot02 | /				kernel rbs
+ * +--------+				+--------+
+ *	    <- child_regs->ar_bspstore	| slot61 | <-- krbs
+ * +- - - - +				+--------+
+ *					| slot62 |
+ * +- - - - +				+--------+
+ *					|  rnat	 |
+ * +- - - - +				+--------+
+ *   vrnat				| slot00 |
+ * +- - - - +				+--------+
+ *					=	 =
+ *					+--------+
+ *					| slot00 | \
+ *					+--------+ |
+ *					| slot01 | > child_stack->ar_rnat
+ *					+--------+ |
+ *					| slot02 | /
+ *					+--------+
+ *						  <--- child_stack->ar_bspstore
+ *
+ * The way to think of this code is as follows: bit 0 in the user rnat
+ * corresponds to some bit N (0 <= N <= 62) in one of the kernel rnat
+ * value.  The kernel rnat value holding this bit is stored in
+ * variable rnat0.  rnat1 is loaded with the kernel rnat value that
+ * form the upper bits of the user rnat value.
+ *
+ * Boundary cases:
+ *
+ * o when reading the rnat "below" the first rnat slot on the kernel
+ *   backing store, rnat0/rnat1 are set to 0 and the low order bits are
+ *   merged in from pt->ar_rnat.
+ *
+ * o when reading the rnat "above" the last rnat slot on the kernel
+ *   backing store, rnat0/rnat1 gets its value from sw->ar_rnat.
+ */
+static unsigned long
+get_rnat (struct task_struct *task, struct switch_stack *sw,
+	  unsigned long *krbs, unsigned long *urnat_addr,
+	  unsigned long *urbs_end)
+{
+	unsigned long rnat0 = 0, rnat1 = 0, urnat = 0, *slot0_kaddr;
+	unsigned long umask = 0, mask, m;
+	unsigned long *kbsp, *ubspstore, *rnat0_kaddr, *rnat1_kaddr, shift;
+	long num_regs, nbits;
+	struct pt_regs *pt;
+
+	pt = task_pt_regs(task);
+	kbsp = (unsigned long *) sw->ar_bspstore;
+	ubspstore = (unsigned long *) pt->ar_bspstore;
+
+	if (urbs_end < urnat_addr)
+		nbits = ia64_rse_num_regs(urnat_addr - 63, urbs_end);
+	else
+		nbits = 63;
+	mask = MASK(nbits);
+	/*
+	 * First, figure out which bit number slot 0 in user-land maps
+	 * to in the kernel rnat.  Do this by figuring out how many
+	 * register slots we're beyond the user's backingstore and
+	 * then computing the equivalent address in kernel space.
+	 */
+	num_regs = ia64_rse_num_regs(ubspstore, urnat_addr + 1);
+	slot0_kaddr = ia64_rse_skip_regs(krbs, num_regs);
+	shift = ia64_rse_slot_num(slot0_kaddr);
+	rnat1_kaddr = ia64_rse_rnat_addr(slot0_kaddr);
+	rnat0_kaddr = rnat1_kaddr - 64;
+
+	if (ubspstore + 63 > urnat_addr) {
+		/* some bits need to be merged in from pt->ar_rnat */
+		umask = MASK(ia64_rse_slot_num(ubspstore)) & mask;
+		urnat = (pt->ar_rnat & umask);
+		mask &= ~umask;
+		if (!mask)
+			return urnat;
+	}
+
+	m = mask << shift;
+	if (rnat0_kaddr >= kbsp)
+		rnat0 = sw->ar_rnat;
+	else if (rnat0_kaddr > krbs)
+		rnat0 = *rnat0_kaddr;
+	urnat |= (rnat0 & m) >> shift;
+
+	m = mask >> (63 - shift);
+	if (rnat1_kaddr >= kbsp)
+		rnat1 = sw->ar_rnat;
+	else if (rnat1_kaddr > krbs)
+		rnat1 = *rnat1_kaddr;
+	urnat |= (rnat1 & m) << (63 - shift);
+	return urnat;
+}
+
+/*
+ * The reverse of get_rnat.
+ */
+static void
+put_rnat (struct task_struct *task, struct switch_stack *sw,
+	  unsigned long *krbs, unsigned long *urnat_addr, unsigned long urnat,
+	  unsigned long *urbs_end)
+{
+	unsigned long rnat0 = 0, rnat1 = 0, *slot0_kaddr, umask = 0, mask, m;
+	unsigned long *kbsp, *ubspstore, *rnat0_kaddr, *rnat1_kaddr, shift;
+	long num_regs, nbits;
+	struct pt_regs *pt;
+	unsigned long cfm, *urbs_kargs;
+
+	pt = task_pt_regs(task);
+	kbsp = (unsigned long *) sw->ar_bspstore;
+	ubspstore = (unsigned long *) pt->ar_bspstore;
+
+	urbs_kargs = urbs_end;
+	if (in_syscall(pt)) {
+		/*
+		 * If entered via syscall, don't allow user to set rnat bits
+		 * for syscall args.
+		 */
+		cfm = pt->cr_ifs;
+		urbs_kargs = ia64_rse_skip_regs(urbs_end, -(cfm & 0x7f));
+	}
+
+	if (urbs_kargs >= urnat_addr)
+		nbits = 63;
+	else {
+		if ((urnat_addr - 63) >= urbs_kargs)
+			return;
+		nbits = ia64_rse_num_regs(urnat_addr - 63, urbs_kargs);
+	}
+	mask = MASK(nbits);
+
+	/*
+	 * First, figure out which bit number slot 0 in user-land maps
+	 * to in the kernel rnat.  Do this by figuring out how many
+	 * register slots we're beyond the user's backingstore and
+	 * then computing the equivalent address in kernel space.
+	 */
+	num_regs = ia64_rse_num_regs(ubspstore, urnat_addr + 1);
+	slot0_kaddr = ia64_rse_skip_regs(krbs, num_regs);
+	shift = ia64_rse_slot_num(slot0_kaddr);
+	rnat1_kaddr = ia64_rse_rnat_addr(slot0_kaddr);
+	rnat0_kaddr = rnat1_kaddr - 64;
+
+	if (ubspstore + 63 > urnat_addr) {
+		/* some bits need to be place in pt->ar_rnat: */
+		umask = MASK(ia64_rse_slot_num(ubspstore)) & mask;
+		pt->ar_rnat = (pt->ar_rnat & ~umask) | (urnat & umask);
+		mask &= ~umask;
+		if (!mask)
+			return;
+	}
+	/*
+	 * Note: Section 11.1 of the EAS guarantees that bit 63 of an
+	 * rnat slot is ignored. so we don't have to clear it here.
+	 */
+	rnat0 = (urnat << shift);
+	m = mask << shift;
+	if (rnat0_kaddr >= kbsp)
+		sw->ar_rnat = (sw->ar_rnat & ~m) | (rnat0 & m);
+	else if (rnat0_kaddr > krbs)
+		*rnat0_kaddr = ((*rnat0_kaddr & ~m) | (rnat0 & m));
+
+	rnat1 = (urnat >> (63 - shift));
+	m = mask >> (63 - shift);
+	if (rnat1_kaddr >= kbsp)
+		sw->ar_rnat = (sw->ar_rnat & ~m) | (rnat1 & m);
+	else if (rnat1_kaddr > krbs)
+		*rnat1_kaddr = ((*rnat1_kaddr & ~m) | (rnat1 & m));
+}
+
+static inline int
+on_kernel_rbs (unsigned long addr, unsigned long bspstore,
+	       unsigned long urbs_end)
+{
+	unsigned long *rnat_addr = ia64_rse_rnat_addr((unsigned long *)
+						      urbs_end);
+	return (addr >= bspstore && addr <= (unsigned long) rnat_addr);
+}
+
+/*
+ * Read a word from the user-level backing store of task CHILD.  ADDR
+ * is the user-level address to read the word from, VAL a pointer to
+ * the return value, and USER_BSP gives the end of the user-level
+ * backing store (i.e., it's the address that would be in ar.bsp after
+ * the user executed a "cover" instruction).
+ *
+ * This routine takes care of accessing the kernel register backing
+ * store for those registers that got spilled there.  It also takes
+ * care of calculating the appropriate RNaT collection words.
+ */
+long
+ia64_peek (struct task_struct *child, struct switch_stack *child_stack,
+	   unsigned long user_rbs_end, unsigned long addr, long *val)
+{
+	unsigned long *bspstore, *krbs, regnum, *laddr, *urbs_end, *rnat_addr;
+	struct pt_regs *child_regs;
+	size_t copied;
+	long ret;
+
+	urbs_end = (long *) user_rbs_end;
+	laddr = (unsigned long *) addr;
+	child_regs = task_pt_regs(child);
+	bspstore = (unsigned long *) child_regs->ar_bspstore;
+	krbs = (unsigned long *) child + IA64_RBS_OFFSET/8;
+	if (on_kernel_rbs(addr, (unsigned long) bspstore,
+			  (unsigned long) urbs_end))
+	{
+		/*
+		 * Attempt to read the RBS in an area that's actually
+		 * on the kernel RBS => read the corresponding bits in
+		 * the kernel RBS.
+		 */
+		rnat_addr = ia64_rse_rnat_addr(laddr);
+		ret = get_rnat(child, child_stack, krbs, rnat_addr, urbs_end);
+
+		if (laddr == rnat_addr) {
+			/* return NaT collection word itself */
+			*val = ret;
+			return 0;
+		}
+
+		if (((1UL << ia64_rse_slot_num(laddr)) & ret) != 0) {
+			/*
+			 * It is implementation dependent whether the
+			 * data portion of a NaT value gets saved on a
+			 * st8.spill or RSE spill (e.g., see EAS 2.6,
+			 * 4.4.4.6 Register Spill and Fill).  To get
+			 * consistent behavior across all possible
+			 * IA-64 implementations, we return zero in
+			 * this case.
+			 */
+			*val = 0;
+			return 0;
+		}
+
+		if (laddr < urbs_end) {
+			/*
+			 * The desired word is on the kernel RBS and
+			 * is not a NaT.
+			 */
+			regnum = ia64_rse_num_regs(bspstore, laddr);
+			*val = *ia64_rse_skip_regs(krbs, regnum);
+			return 0;
+		}
+	}
+	copied = access_process_vm(child, addr, &ret, sizeof(ret), FOLL_FORCE);
+	if (copied != sizeof(ret))
+		return -EIO;
+	*val = ret;
+	return 0;
+}
+
+long
+ia64_poke (struct task_struct *child, struct switch_stack *child_stack,
+	   unsigned long user_rbs_end, unsigned long addr, long val)
+{
+	unsigned long *bspstore, *krbs, regnum, *laddr;
+	unsigned long *urbs_end = (long *) user_rbs_end;
+	struct pt_regs *child_regs;
+
+	laddr = (unsigned long *) addr;
+	child_regs = task_pt_regs(child);
+	bspstore = (unsigned long *) child_regs->ar_bspstore;
+	krbs = (unsigned long *) child + IA64_RBS_OFFSET/8;
+	if (on_kernel_rbs(addr, (unsigned long) bspstore,
+			  (unsigned long) urbs_end))
+	{
+		/*
+		 * Attempt to write the RBS in an area that's actually
+		 * on the kernel RBS => write the corresponding bits
+		 * in the kernel RBS.
+		 */
+		if (ia64_rse_is_rnat_slot(laddr))
+			put_rnat(child, child_stack, krbs, laddr, val,
+				 urbs_end);
+		else {
+			if (laddr < urbs_end) {
+				regnum = ia64_rse_num_regs(bspstore, laddr);
+				*ia64_rse_skip_regs(krbs, regnum) = val;
+			}
+		}
+	} else if (access_process_vm(child, addr, &val, sizeof(val),
+				FOLL_FORCE | FOLL_WRITE)
+		   != sizeof(val))
+		return -EIO;
+	return 0;
+}
+
+/*
+ * Calculate the address of the end of the user-level register backing
+ * store.  This is the address that would have been stored in ar.bsp
+ * if the user had executed a "cover" instruction right before
+ * entering the kernel.  If CFMP is not NULL, it is used to return the
+ * "current frame mask" that was active at the time the kernel was
+ * entered.
+ */
+unsigned long
+ia64_get_user_rbs_end (struct task_struct *child, struct pt_regs *pt,
+		       unsigned long *cfmp)
+{
+	unsigned long *krbs, *bspstore, cfm = pt->cr_ifs;
+	long ndirty;
+
+	krbs = (unsigned long *) child + IA64_RBS_OFFSET/8;
+	bspstore = (unsigned long *) pt->ar_bspstore;
+	ndirty = ia64_rse_num_regs(krbs, krbs + (pt->loadrs >> 19));
+
+	if (in_syscall(pt))
+		ndirty += (cfm & 0x7f);
+	else
+		cfm &= ~(1UL << 63);	/* clear valid bit */
+
+	if (cfmp)
+		*cfmp = cfm;
+	return (unsigned long) ia64_rse_skip_regs(bspstore, ndirty);
+}
+
+/*
+ * Synchronize (i.e, write) the RSE backing store living in kernel
+ * space to the VM of the CHILD task.  SW and PT are the pointers to
+ * the switch_stack and pt_regs structures, respectively.
+ * USER_RBS_END is the user-level address at which the backing store
+ * ends.
+ */
+long
+ia64_sync_user_rbs (struct task_struct *child, struct switch_stack *sw,
+		    unsigned long user_rbs_start, unsigned long user_rbs_end)
+{
+	unsigned long addr, val;
+	long ret;
+
+	/* now copy word for word from kernel rbs to user rbs: */
+	for (addr = user_rbs_start; addr < user_rbs_end; addr += 8) {
+		ret = ia64_peek(child, sw, user_rbs_end, addr, &val);
+		if (ret < 0)
+			return ret;
+		if (access_process_vm(child, addr, &val, sizeof(val),
+				FOLL_FORCE | FOLL_WRITE)
+		    != sizeof(val))
+			return -EIO;
+	}
+	return 0;
+}
+
+static long
+ia64_sync_kernel_rbs (struct task_struct *child, struct switch_stack *sw,
+		unsigned long user_rbs_start, unsigned long user_rbs_end)
+{
+	unsigned long addr, val;
+	long ret;
+
+	/* now copy word for word from user rbs to kernel rbs: */
+	for (addr = user_rbs_start; addr < user_rbs_end; addr += 8) {
+		if (access_process_vm(child, addr, &val, sizeof(val),
+				FOLL_FORCE)
+				!= sizeof(val))
+			return -EIO;
+
+		ret = ia64_poke(child, sw, user_rbs_end, addr, val);
+		if (ret < 0)
+			return ret;
+	}
+	return 0;
+}
+
+typedef long (*syncfunc_t)(struct task_struct *, struct switch_stack *,
+			    unsigned long, unsigned long);
+
+static void do_sync_rbs(struct unw_frame_info *info, void *arg)
+{
+	struct pt_regs *pt;
+	unsigned long urbs_end;
+	syncfunc_t fn = arg;
+
+	if (unw_unwind_to_user(info) < 0)
+		return;
+	pt = task_pt_regs(info->task);
+	urbs_end = ia64_get_user_rbs_end(info->task, pt, NULL);
+
+	fn(info->task, info->sw, pt->ar_bspstore, urbs_end);
+}
+
+/*
+ * when a thread is stopped (ptraced), debugger might change thread's user
+ * stack (change memory directly), and we must avoid the RSE stored in kernel
+ * to override user stack (user space's RSE is newer than kernel's in the
+ * case). To workaround the issue, we copy kernel RSE to user RSE before the
+ * task is stopped, so user RSE has updated data.  we then copy user RSE to
+ * kernel after the task is resummed from traced stop and kernel will use the
+ * newer RSE to return to user. TIF_RESTORE_RSE is the flag to indicate we need
+ * synchronize user RSE to kernel.
+ */
+void ia64_ptrace_stop(void)
+{
+	if (test_and_set_tsk_thread_flag(current, TIF_RESTORE_RSE))
+		return;
+	set_notify_resume(current);
+	unw_init_running(do_sync_rbs, ia64_sync_user_rbs);
+}
+
+/*
+ * This is called to read back the register backing store.
+ */
+void ia64_sync_krbs(void)
+{
+	clear_tsk_thread_flag(current, TIF_RESTORE_RSE);
+
+	unw_init_running(do_sync_rbs, ia64_sync_kernel_rbs);
+}
+
+/*
+ * Write f32-f127 back to task->thread.fph if it has been modified.
+ */
+inline void
+ia64_flush_fph (struct task_struct *task)
+{
+	struct ia64_psr *psr = ia64_psr(task_pt_regs(task));
+
+	/*
+	 * Prevent migrating this task while
+	 * we're fiddling with the FPU state
+	 */
+	preempt_disable();
+	if (ia64_is_local_fpu_owner(task) && psr->mfh) {
+		psr->mfh = 0;
+		task->thread.flags |= IA64_THREAD_FPH_VALID;
+		ia64_save_fpu(&task->thread.fph[0]);
+	}
+	preempt_enable();
+}
+
+/*
+ * Sync the fph state of the task so that it can be manipulated
+ * through thread.fph.  If necessary, f32-f127 are written back to
+ * thread.fph or, if the fph state hasn't been used before, thread.fph
+ * is cleared to zeroes.  Also, access to f32-f127 is disabled to
+ * ensure that the task picks up the state from thread.fph when it
+ * executes again.
+ */
+void
+ia64_sync_fph (struct task_struct *task)
+{
+	struct ia64_psr *psr = ia64_psr(task_pt_regs(task));
+
+	ia64_flush_fph(task);
+	if (!(task->thread.flags & IA64_THREAD_FPH_VALID)) {
+		task->thread.flags |= IA64_THREAD_FPH_VALID;
+		memset(&task->thread.fph, 0, sizeof(task->thread.fph));
+	}
+	ia64_drop_fpu(task);
+	psr->dfh = 1;
+}
+
+/*
+ * Change the machine-state of CHILD such that it will return via the normal
+ * kernel exit-path, rather than the syscall-exit path.
+ */
+static void
+convert_to_non_syscall (struct task_struct *child, struct pt_regs  *pt,
+			unsigned long cfm)
+{
+	struct unw_frame_info info, prev_info;
+	unsigned long ip, sp, pr;
+
+	unw_init_from_blocked_task(&info, child);
+	while (1) {
+		prev_info = info;
+		if (unw_unwind(&info) < 0)
+			return;
+
+		unw_get_sp(&info, &sp);
+		if ((long)((unsigned long)child + IA64_STK_OFFSET - sp)
+		    < IA64_PT_REGS_SIZE) {
+			dprintk("ptrace.%s: ran off the top of the kernel "
+				"stack\n", __func__);
+			return;
+		}
+		if (unw_get_pr (&prev_info, &pr) < 0) {
+			unw_get_rp(&prev_info, &ip);
+			dprintk("ptrace.%s: failed to read "
+				"predicate register (ip=0x%lx)\n",
+				__func__, ip);
+			return;
+		}
+		if (unw_is_intr_frame(&info)
+		    && (pr & (1UL << PRED_USER_STACK)))
+			break;
+	}
+
+	/*
+	 * Note: at the time of this call, the target task is blocked
+	 * in notify_resume_user() and by clearling PRED_LEAVE_SYSCALL
+	 * (aka, "pLvSys") we redirect execution from
+	 * .work_pending_syscall_end to .work_processed_kernel.
+	 */
+	unw_get_pr(&prev_info, &pr);
+	pr &= ~((1UL << PRED_SYSCALL) | (1UL << PRED_LEAVE_SYSCALL));
+	pr |=  (1UL << PRED_NON_SYSCALL);
+	unw_set_pr(&prev_info, pr);
+
+	pt->cr_ifs = (1UL << 63) | cfm;
+	/*
+	 * Clear the memory that is NOT written on syscall-entry to
+	 * ensure we do not leak kernel-state to user when execution
+	 * resumes.
+	 */
+	pt->r2 = 0;
+	pt->r3 = 0;
+	pt->r14 = 0;
+	memset(&pt->r16, 0, 16*8);	/* clear r16-r31 */
+	memset(&pt->f6, 0, 6*16);	/* clear f6-f11 */
+	pt->b7 = 0;
+	pt->ar_ccv = 0;
+	pt->ar_csd = 0;
+	pt->ar_ssd = 0;
+}
+
+static int
+access_nat_bits (struct task_struct *child, struct pt_regs *pt,
+		 struct unw_frame_info *info,
+		 unsigned long *data, int write_access)
+{
+	unsigned long regnum, nat_bits, scratch_unat, dummy = 0;
+	char nat = 0;
+
+	if (write_access) {
+		nat_bits = *data;
+		scratch_unat = ia64_put_scratch_nat_bits(pt, nat_bits);
+		if (unw_set_ar(info, UNW_AR_UNAT, scratch_unat) < 0) {
+			dprintk("ptrace: failed to set ar.unat\n");
+			return -1;
+		}
+		for (regnum = 4; regnum <= 7; ++regnum) {
+			unw_get_gr(info, regnum, &dummy, &nat);
+			unw_set_gr(info, regnum, dummy,
+				   (nat_bits >> regnum) & 1);
+		}
+	} else {
+		if (unw_get_ar(info, UNW_AR_UNAT, &scratch_unat) < 0) {
+			dprintk("ptrace: failed to read ar.unat\n");
+			return -1;
+		}
+		nat_bits = ia64_get_scratch_nat_bits(pt, scratch_unat);
+		for (regnum = 4; regnum <= 7; ++regnum) {
+			unw_get_gr(info, regnum, &dummy, &nat);
+			nat_bits |= (nat != 0) << regnum;
+		}
+		*data = nat_bits;
+	}
+	return 0;
+}
+
+static int
+access_elf_reg(struct task_struct *target, struct unw_frame_info *info,
+		unsigned long addr, unsigned long *data, int write_access);
+
+static long
+ptrace_getregs (struct task_struct *child, struct pt_all_user_regs __user *ppr)
+{
+	unsigned long psr, ec, lc, rnat, bsp, cfm, nat_bits, val;
+	struct unw_frame_info info;
+	struct ia64_fpreg fpval;
+	struct switch_stack *sw;
+	struct pt_regs *pt;
+	long ret, retval = 0;
+	char nat = 0;
+	int i;
+
+	if (!access_ok(ppr, sizeof(struct pt_all_user_regs)))
+		return -EIO;
+
+	pt = task_pt_regs(child);
+	sw = (struct switch_stack *) (child->thread.ksp + 16);
+	unw_init_from_blocked_task(&info, child);
+	if (unw_unwind_to_user(&info) < 0) {
+		return -EIO;
+	}
+
+	if (((unsigned long) ppr & 0x7) != 0) {
+		dprintk("ptrace:unaligned register address %p\n", ppr);
+		return -EIO;
+	}
+
+	if (access_elf_reg(child, &info, ELF_CR_IPSR_OFFSET, &psr, 0) < 0 ||
+	    access_elf_reg(child, &info, ELF_AR_EC_OFFSET, &ec, 0) < 0 ||
+	    access_elf_reg(child, &info, ELF_AR_LC_OFFSET, &lc, 0) < 0 ||
+	    access_elf_reg(child, &info, ELF_AR_RNAT_OFFSET, &rnat, 0) < 0 ||
+	    access_elf_reg(child, &info, ELF_AR_BSP_OFFSET, &bsp, 0) < 0 ||
+	    access_elf_reg(child, &info, ELF_CFM_OFFSET, &cfm, 0) < 0 ||
+	    access_elf_reg(child, &info, ELF_NAT_OFFSET, &nat_bits, 0) < 0)
+		return -EIO;
+
+	/* control regs */
+
+	retval |= __put_user(pt->cr_iip, &ppr->cr_iip);
+	retval |= __put_user(psr, &ppr->cr_ipsr);
+
+	/* app regs */
+
+	retval |= __put_user(pt->ar_pfs, &ppr->ar[PT_AUR_PFS]);
+	retval |= __put_user(pt->ar_rsc, &ppr->ar[PT_AUR_RSC]);
+	retval |= __put_user(pt->ar_bspstore, &ppr->ar[PT_AUR_BSPSTORE]);
+	retval |= __put_user(pt->ar_unat, &ppr->ar[PT_AUR_UNAT]);
+	retval |= __put_user(pt->ar_ccv, &ppr->ar[PT_AUR_CCV]);
+	retval |= __put_user(pt->ar_fpsr, &ppr->ar[PT_AUR_FPSR]);
+
+	retval |= __put_user(ec, &ppr->ar[PT_AUR_EC]);
+	retval |= __put_user(lc, &ppr->ar[PT_AUR_LC]);
+	retval |= __put_user(rnat, &ppr->ar[PT_AUR_RNAT]);
+	retval |= __put_user(bsp, &ppr->ar[PT_AUR_BSP]);
+	retval |= __put_user(cfm, &ppr->cfm);
+
+	/* gr1-gr3 */
+
+	retval |= __copy_to_user(&ppr->gr[1], &pt->r1, sizeof(long));
+	retval |= __copy_to_user(&ppr->gr[2], &pt->r2, sizeof(long) *2);
+
+	/* gr4-gr7 */
+
+	for (i = 4; i < 8; i++) {
+		if (unw_access_gr(&info, i, &val, &nat, 0) < 0)
+			return -EIO;
+		retval |= __put_user(val, &ppr->gr[i]);
+	}
+
+	/* gr8-gr11 */
+
+	retval |= __copy_to_user(&ppr->gr[8], &pt->r8, sizeof(long) * 4);
+
+	/* gr12-gr15 */
+
+	retval |= __copy_to_user(&ppr->gr[12], &pt->r12, sizeof(long) * 2);
+	retval |= __copy_to_user(&ppr->gr[14], &pt->r14, sizeof(long));
+	retval |= __copy_to_user(&ppr->gr[15], &pt->r15, sizeof(long));
+
+	/* gr16-gr31 */
+
+	retval |= __copy_to_user(&ppr->gr[16], &pt->r16, sizeof(long) * 16);
+
+	/* b0 */
+
+	retval |= __put_user(pt->b0, &ppr->br[0]);
+
+	/* b1-b5 */
+
+	for (i = 1; i < 6; i++) {
+		if (unw_access_br(&info, i, &val, 0) < 0)
+			return -EIO;
+		__put_user(val, &ppr->br[i]);
+	}
+
+	/* b6-b7 */
+
+	retval |= __put_user(pt->b6, &ppr->br[6]);
+	retval |= __put_user(pt->b7, &ppr->br[7]);
+
+	/* fr2-fr5 */
+
+	for (i = 2; i < 6; i++) {
+		if (unw_get_fr(&info, i, &fpval) < 0)
+			return -EIO;
+		retval |= __copy_to_user(&ppr->fr[i], &fpval, sizeof (fpval));
+	}
+
+	/* fr6-fr11 */
+
+	retval |= __copy_to_user(&ppr->fr[6], &pt->f6,
+				 sizeof(struct ia64_fpreg) * 6);
+
+	/* fp scratch regs(12-15) */
+
+	retval |= __copy_to_user(&ppr->fr[12], &sw->f12,
+				 sizeof(struct ia64_fpreg) * 4);
+
+	/* fr16-fr31 */
+
+	for (i = 16; i < 32; i++) {
+		if (unw_get_fr(&info, i, &fpval) < 0)
+			return -EIO;
+		retval |= __copy_to_user(&ppr->fr[i], &fpval, sizeof (fpval));
+	}
+
+	/* fph */
+
+	ia64_flush_fph(child);
+	retval |= __copy_to_user(&ppr->fr[32], &child->thread.fph,
+				 sizeof(ppr->fr[32]) * 96);
+
+	/*  preds */
+
+	retval |= __put_user(pt->pr, &ppr->pr);
+
+	/* nat bits */
+
+	retval |= __put_user(nat_bits, &ppr->nat);
+
+	ret = retval ? -EIO : 0;
+	return ret;
+}
+
+static long
+ptrace_setregs (struct task_struct *child, struct pt_all_user_regs __user *ppr)
+{
+	unsigned long psr, rsc, ec, lc, rnat, bsp, cfm, nat_bits, val = 0;
+	struct unw_frame_info info;
+	struct switch_stack *sw;
+	struct ia64_fpreg fpval;
+	struct pt_regs *pt;
+	long retval = 0;
+	int i;
+
+	memset(&fpval, 0, sizeof(fpval));
+
+	if (!access_ok(ppr, sizeof(struct pt_all_user_regs)))
+		return -EIO;
+
+	pt = task_pt_regs(child);
+	sw = (struct switch_stack *) (child->thread.ksp + 16);
+	unw_init_from_blocked_task(&info, child);
+	if (unw_unwind_to_user(&info) < 0) {
+		return -EIO;
+	}
+
+	if (((unsigned long) ppr & 0x7) != 0) {
+		dprintk("ptrace:unaligned register address %p\n", ppr);
+		return -EIO;
+	}
+
+	/* control regs */
+
+	retval |= __get_user(pt->cr_iip, &ppr->cr_iip);
+	retval |= __get_user(psr, &ppr->cr_ipsr);
+
+	/* app regs */
+
+	retval |= __get_user(pt->ar_pfs, &ppr->ar[PT_AUR_PFS]);
+	retval |= __get_user(rsc, &ppr->ar[PT_AUR_RSC]);
+	retval |= __get_user(pt->ar_bspstore, &ppr->ar[PT_AUR_BSPSTORE]);
+	retval |= __get_user(pt->ar_unat, &ppr->ar[PT_AUR_UNAT]);
+	retval |= __get_user(pt->ar_ccv, &ppr->ar[PT_AUR_CCV]);
+	retval |= __get_user(pt->ar_fpsr, &ppr->ar[PT_AUR_FPSR]);
+
+	retval |= __get_user(ec, &ppr->ar[PT_AUR_EC]);
+	retval |= __get_user(lc, &ppr->ar[PT_AUR_LC]);
+	retval |= __get_user(rnat, &ppr->ar[PT_AUR_RNAT]);
+	retval |= __get_user(bsp, &ppr->ar[PT_AUR_BSP]);
+	retval |= __get_user(cfm, &ppr->cfm);
+
+	/* gr1-gr3 */
+
+	retval |= __copy_from_user(&pt->r1, &ppr->gr[1], sizeof(long));
+	retval |= __copy_from_user(&pt->r2, &ppr->gr[2], sizeof(long) * 2);
+
+	/* gr4-gr7 */
+
+	for (i = 4; i < 8; i++) {
+		retval |= __get_user(val, &ppr->gr[i]);
+		/* NaT bit will be set via PT_NAT_BITS: */
+		if (unw_set_gr(&info, i, val, 0) < 0)
+			return -EIO;
+	}
+
+	/* gr8-gr11 */
+
+	retval |= __copy_from_user(&pt->r8, &ppr->gr[8], sizeof(long) * 4);
+
+	/* gr12-gr15 */
+
+	retval |= __copy_from_user(&pt->r12, &ppr->gr[12], sizeof(long) * 2);
+	retval |= __copy_from_user(&pt->r14, &ppr->gr[14], sizeof(long));
+	retval |= __copy_from_user(&pt->r15, &ppr->gr[15], sizeof(long));
+
+	/* gr16-gr31 */
+
+	retval |= __copy_from_user(&pt->r16, &ppr->gr[16], sizeof(long) * 16);
+
+	/* b0 */
+
+	retval |= __get_user(pt->b0, &ppr->br[0]);
+
+	/* b1-b5 */
+
+	for (i = 1; i < 6; i++) {
+		retval |= __get_user(val, &ppr->br[i]);
+		unw_set_br(&info, i, val);
+	}
+
+	/* b6-b7 */
+
+	retval |= __get_user(pt->b6, &ppr->br[6]);
+	retval |= __get_user(pt->b7, &ppr->br[7]);
+
+	/* fr2-fr5 */
+
+	for (i = 2; i < 6; i++) {
+		retval |= __copy_from_user(&fpval, &ppr->fr[i], sizeof(fpval));
+		if (unw_set_fr(&info, i, fpval) < 0)
+			return -EIO;
+	}
+
+	/* fr6-fr11 */
+
+	retval |= __copy_from_user(&pt->f6, &ppr->fr[6],
+				   sizeof(ppr->fr[6]) * 6);
+
+	/* fp scratch regs(12-15) */
+
+	retval |= __copy_from_user(&sw->f12, &ppr->fr[12],
+				   sizeof(ppr->fr[12]) * 4);
+
+	/* fr16-fr31 */
+
+	for (i = 16; i < 32; i++) {
+		retval |= __copy_from_user(&fpval, &ppr->fr[i],
+					   sizeof(fpval));
+		if (unw_set_fr(&info, i, fpval) < 0)
+			return -EIO;
+	}
+
+	/* fph */
+
+	ia64_sync_fph(child);
+	retval |= __copy_from_user(&child->thread.fph, &ppr->fr[32],
+				   sizeof(ppr->fr[32]) * 96);
+
+	/* preds */
+
+	retval |= __get_user(pt->pr, &ppr->pr);
+
+	/* nat bits */
+
+	retval |= __get_user(nat_bits, &ppr->nat);
+
+	retval |= access_elf_reg(child, &info, ELF_CR_IPSR_OFFSET, &psr, 1);
+	retval |= access_elf_reg(child, &info, ELF_AR_RSC_OFFSET, &rsc, 1);
+	retval |= access_elf_reg(child, &info, ELF_AR_EC_OFFSET, &ec, 1);
+	retval |= access_elf_reg(child, &info, ELF_AR_LC_OFFSET, &lc, 1);
+	retval |= access_elf_reg(child, &info, ELF_AR_RNAT_OFFSET, &rnat, 1);
+	retval |= access_elf_reg(child, &info, ELF_AR_BSP_OFFSET, &bsp, 1);
+	retval |= access_elf_reg(child, &info, ELF_CFM_OFFSET, &cfm, 1);
+	retval |= access_elf_reg(child, &info, ELF_NAT_OFFSET, &nat_bits, 1);
+
+	return retval ? -EIO : 0;
+}
+
+void
+user_enable_single_step (struct task_struct *child)
+{
+	struct ia64_psr *child_psr = ia64_psr(task_pt_regs(child));
+
+	set_tsk_thread_flag(child, TIF_SINGLESTEP);
+	child_psr->ss = 1;
+}
+
+void
+user_enable_block_step (struct task_struct *child)
+{
+	struct ia64_psr *child_psr = ia64_psr(task_pt_regs(child));
+
+	set_tsk_thread_flag(child, TIF_SINGLESTEP);
+	child_psr->tb = 1;
+}
+
+void
+user_disable_single_step (struct task_struct *child)
+{
+	struct ia64_psr *child_psr = ia64_psr(task_pt_regs(child));
+
+	/* make sure the single step/taken-branch trap bits are not set: */
+	clear_tsk_thread_flag(child, TIF_SINGLESTEP);
+	child_psr->ss = 0;
+	child_psr->tb = 0;
+}
+
+/*
+ * Called by kernel/ptrace.c when detaching..
+ *
+ * Make sure the single step bit is not set.
+ */
+void
+ptrace_disable (struct task_struct *child)
+{
+	user_disable_single_step(child);
+}
+
+static int
+access_uarea (struct task_struct *child, unsigned long addr,
+	      unsigned long *data, int write_access);
+
+long
+arch_ptrace (struct task_struct *child, long request,
+	     unsigned long addr, unsigned long data)
+{
+	switch (request) {
+	case PTRACE_PEEKTEXT:
+	case PTRACE_PEEKDATA:
+		/* read word at location addr */
+		if (ptrace_access_vm(child, addr, &data, sizeof(data),
+				FOLL_FORCE)
+		    != sizeof(data))
+			return -EIO;
+		/* ensure return value is not mistaken for error code */
+		force_successful_syscall_return();
+		return data;
+
+	/* PTRACE_POKETEXT and PTRACE_POKEDATA is handled
+	 * by the generic ptrace_request().
+	 */
+
+	case PTRACE_PEEKUSR:
+		/* read the word at addr in the USER area */
+		if (access_uarea(child, addr, &data, 0) < 0)
+			return -EIO;
+		/* ensure return value is not mistaken for error code */
+		force_successful_syscall_return();
+		return data;
+
+	case PTRACE_POKEUSR:
+		/* write the word at addr in the USER area */
+		if (access_uarea(child, addr, &data, 1) < 0)
+			return -EIO;
+		return 0;
+
+	case PTRACE_OLD_GETSIGINFO:
+		/* for backwards-compatibility */
+		return ptrace_request(child, PTRACE_GETSIGINFO, addr, data);
+
+	case PTRACE_OLD_SETSIGINFO:
+		/* for backwards-compatibility */
+		return ptrace_request(child, PTRACE_SETSIGINFO, addr, data);
+
+	case PTRACE_GETREGS:
+		return ptrace_getregs(child,
+				      (struct pt_all_user_regs __user *) data);
+
+	case PTRACE_SETREGS:
+		return ptrace_setregs(child,
+				      (struct pt_all_user_regs __user *) data);
+
+	default:
+		return ptrace_request(child, request, addr, data);
+	}
+}
+
+
+/* "asmlinkage" so the input arguments are preserved... */
+
+asmlinkage long
+syscall_trace_enter (long arg0, long arg1, long arg2, long arg3,
+		     long arg4, long arg5, long arg6, long arg7,
+		     struct pt_regs regs)
+{
+	if (test_thread_flag(TIF_SYSCALL_TRACE))
+		if (ptrace_report_syscall_entry(&regs))
+			return -ENOSYS;
+
+	/* copy user rbs to kernel rbs */
+	if (test_thread_flag(TIF_RESTORE_RSE))
+		ia64_sync_krbs();
+
+
+	audit_syscall_entry(regs.r15, arg0, arg1, arg2, arg3);
+
+	return 0;
+}
+
+/* "asmlinkage" so the input arguments are preserved... */
+
+asmlinkage void
+syscall_trace_leave (long arg0, long arg1, long arg2, long arg3,
+		     long arg4, long arg5, long arg6, long arg7,
+		     struct pt_regs regs)
+{
+	int step;
+
+	audit_syscall_exit(&regs);
+
+	step = test_thread_flag(TIF_SINGLESTEP);
+	if (step || test_thread_flag(TIF_SYSCALL_TRACE))
+		ptrace_report_syscall_exit(&regs, step);
+
+	/* copy user rbs to kernel rbs */
+	if (test_thread_flag(TIF_RESTORE_RSE))
+		ia64_sync_krbs();
+}
+
+/* Utrace implementation starts here */
+struct regset_get {
+	void *kbuf;
+	void __user *ubuf;
+};
+
+struct regset_set {
+	const void *kbuf;
+	const void __user *ubuf;
+};
+
+struct regset_getset {
+	struct task_struct *target;
+	const struct user_regset *regset;
+	union {
+		struct regset_get get;
+		struct regset_set set;
+	} u;
+	unsigned int pos;
+	unsigned int count;
+	int ret;
+};
+
+static const ptrdiff_t pt_offsets[32] =
+{
+#define R(n) offsetof(struct pt_regs, r##n)
+	[0] = -1, R(1), R(2), R(3),
+	[4] = -1, [5] = -1, [6] = -1, [7] = -1,
+	R(8), R(9), R(10), R(11), R(12), R(13), R(14), R(15),
+	R(16), R(17), R(18), R(19), R(20), R(21), R(22), R(23),
+	R(24), R(25), R(26), R(27), R(28), R(29), R(30), R(31),
+#undef R
+};
+
+static int
+access_elf_gpreg(struct task_struct *target, struct unw_frame_info *info,
+		unsigned long addr, unsigned long *data, int write_access)
+{
+	struct pt_regs *pt = task_pt_regs(target);
+	unsigned reg = addr / sizeof(unsigned long);
+	ptrdiff_t d = pt_offsets[reg];
+
+	if (d >= 0) {
+		unsigned long *ptr = (void *)pt + d;
+		if (write_access)
+			*ptr = *data;
+		else
+			*data = *ptr;
+		return 0;
+	} else {
+		char nat = 0;
+		if (write_access) {
+			/* read NaT bit first: */
+			unsigned long dummy;
+			int ret = unw_get_gr(info, reg, &dummy, &nat);
+			if (ret < 0)
+				return ret;
+		}
+		return unw_access_gr(info, reg, data, &nat, write_access);
+	}
+}
+
+static int
+access_elf_breg(struct task_struct *target, struct unw_frame_info *info,
+		unsigned long addr, unsigned long *data, int write_access)
+{
+	struct pt_regs *pt;
+	unsigned long *ptr = NULL;
+
+	pt = task_pt_regs(target);
+	switch (addr) {
+	case ELF_BR_OFFSET(0):
+		ptr = &pt->b0;
+		break;
+	case ELF_BR_OFFSET(1) ... ELF_BR_OFFSET(5):
+		return unw_access_br(info, (addr - ELF_BR_OFFSET(0))/8,
+				     data, write_access);
+	case ELF_BR_OFFSET(6):
+		ptr = &pt->b6;
+		break;
+	case ELF_BR_OFFSET(7):
+		ptr = &pt->b7;
+	}
+	if (write_access)
+		*ptr = *data;
+	else
+		*data = *ptr;
+	return 0;
+}
+
+static int
+access_elf_areg(struct task_struct *target, struct unw_frame_info *info,
+		unsigned long addr, unsigned long *data, int write_access)
+{
+	struct pt_regs *pt;
+	unsigned long cfm, urbs_end;
+	unsigned long *ptr = NULL;
+
+	pt = task_pt_regs(target);
+	if (addr >= ELF_AR_RSC_OFFSET && addr <= ELF_AR_SSD_OFFSET) {
+		switch (addr) {
+		case ELF_AR_RSC_OFFSET:
+			/* force PL3 */
+			if (write_access)
+				pt->ar_rsc = *data | (3 << 2);
+			else
+				*data = pt->ar_rsc;
+			return 0;
+		case ELF_AR_BSP_OFFSET:
+			/*
+			 * By convention, we use PT_AR_BSP to refer to
+			 * the end of the user-level backing store.
+			 * Use ia64_rse_skip_regs(PT_AR_BSP, -CFM.sof)
+			 * to get the real value of ar.bsp at the time
+			 * the kernel was entered.
+			 *
+			 * Furthermore, when changing the contents of
+			 * PT_AR_BSP (or PT_CFM) while the task is
+			 * blocked in a system call, convert the state
+			 * so that the non-system-call exit
+			 * path is used.  This ensures that the proper
+			 * state will be picked up when resuming
+			 * execution.  However, it *also* means that
+			 * once we write PT_AR_BSP/PT_CFM, it won't be
+			 * possible to modify the syscall arguments of
+			 * the pending system call any longer.  This
+			 * shouldn't be an issue because modifying
+			 * PT_AR_BSP/PT_CFM generally implies that
+			 * we're either abandoning the pending system
+			 * call or that we defer it's re-execution
+			 * (e.g., due to GDB doing an inferior
+			 * function call).
+			 */
+			urbs_end = ia64_get_user_rbs_end(target, pt, &cfm);
+			if (write_access) {
+				if (*data != urbs_end) {
+					if (in_syscall(pt))
+						convert_to_non_syscall(target,
+								       pt,
+								       cfm);
+					/*
+					 * Simulate user-level write
+					 * of ar.bsp:
+					 */
+					pt->loadrs = 0;
+					pt->ar_bspstore = *data;
+				}
+			} else
+				*data = urbs_end;
+			return 0;
+		case ELF_AR_BSPSTORE_OFFSET:
+			ptr = &pt->ar_bspstore;
+			break;
+		case ELF_AR_RNAT_OFFSET:
+			ptr = &pt->ar_rnat;
+			break;
+		case ELF_AR_CCV_OFFSET:
+			ptr = &pt->ar_ccv;
+			break;
+		case ELF_AR_UNAT_OFFSET:
+			ptr = &pt->ar_unat;
+			break;
+		case ELF_AR_FPSR_OFFSET:
+			ptr = &pt->ar_fpsr;
+			break;
+		case ELF_AR_PFS_OFFSET:
+			ptr = &pt->ar_pfs;
+			break;
+		case ELF_AR_LC_OFFSET:
+			return unw_access_ar(info, UNW_AR_LC, data,
+					     write_access);
+		case ELF_AR_EC_OFFSET:
+			return unw_access_ar(info, UNW_AR_EC, data,
+					     write_access);
+		case ELF_AR_CSD_OFFSET:
+			ptr = &pt->ar_csd;
+			break;
+		case ELF_AR_SSD_OFFSET:
+			ptr = &pt->ar_ssd;
+		}
+	} else if (addr >= ELF_CR_IIP_OFFSET && addr <= ELF_CR_IPSR_OFFSET) {
+		switch (addr) {
+		case ELF_CR_IIP_OFFSET:
+			ptr = &pt->cr_iip;
+			break;
+		case ELF_CFM_OFFSET:
+			urbs_end = ia64_get_user_rbs_end(target, pt, &cfm);
+			if (write_access) {
+				if (((cfm ^ *data) & PFM_MASK) != 0) {
+					if (in_syscall(pt))
+						convert_to_non_syscall(target,
+								       pt,
+								       cfm);
+					pt->cr_ifs = ((pt->cr_ifs & ~PFM_MASK)
+						      | (*data & PFM_MASK));
+				}
+			} else
+				*data = cfm;
+			return 0;
+		case ELF_CR_IPSR_OFFSET:
+			if (write_access) {
+				unsigned long tmp = *data;
+				/* psr.ri==3 is a reserved value: SDM 2:25 */
+				if ((tmp & IA64_PSR_RI) == IA64_PSR_RI)
+					tmp &= ~IA64_PSR_RI;
+				pt->cr_ipsr = ((tmp & IPSR_MASK)
+					       | (pt->cr_ipsr & ~IPSR_MASK));
+			} else
+				*data = (pt->cr_ipsr & IPSR_MASK);
+			return 0;
+		}
+	} else if (addr == ELF_NAT_OFFSET)
+		return access_nat_bits(target, pt, info,
+				       data, write_access);
+	else if (addr == ELF_PR_OFFSET)
+		ptr = &pt->pr;
+	else
+		return -1;
+
+	if (write_access)
+		*ptr = *data;
+	else
+		*data = *ptr;
+
+	return 0;
+}
+
+static int
+access_elf_reg(struct task_struct *target, struct unw_frame_info *info,
+		unsigned long addr, unsigned long *data, int write_access)
+{
+	if (addr >= ELF_GR_OFFSET(1) && addr <= ELF_GR_OFFSET(31))
+		return access_elf_gpreg(target, info, addr, data, write_access);
+	else if (addr >= ELF_BR_OFFSET(0) && addr <= ELF_BR_OFFSET(7))
+		return access_elf_breg(target, info, addr, data, write_access);
+	else
+		return access_elf_areg(target, info, addr, data, write_access);
+}
+
+struct regset_membuf {
+	struct membuf to;
+	int ret;
+};
+
+static void do_gpregs_get(struct unw_frame_info *info, void *arg)
+{
+	struct regset_membuf *dst = arg;
+	struct membuf to = dst->to;
+	unsigned int n;
+	elf_greg_t reg;
+
+	if (unw_unwind_to_user(info) < 0)
+		return;
+
+	/*
+	 * coredump format:
+	 *      r0-r31
+	 *      NaT bits (for r0-r31; bit N == 1 iff rN is a NaT)
+	 *      predicate registers (p0-p63)
+	 *      b0-b7
+	 *      ip cfm user-mask
+	 *      ar.rsc ar.bsp ar.bspstore ar.rnat
+	 *      ar.ccv ar.unat ar.fpsr ar.pfs ar.lc ar.ec
+	 */
+
+
+	/* Skip r0 */
+	membuf_zero(&to, 8);
+	for (n = 8; to.left && n < ELF_AR_END_OFFSET; n += 8) {
+		if (access_elf_reg(info->task, info, n, &reg, 0) < 0) {
+			dst->ret = -EIO;
+			return;
+		}
+		membuf_store(&to, reg);
+	}
+}
+
+static void do_gpregs_set(struct unw_frame_info *info, void *arg)
+{
+	struct regset_getset *dst = arg;
+
+	if (unw_unwind_to_user(info) < 0)
+		return;
+
+	if (!dst->count)
+		return;
+	/* Skip r0 */
+	if (dst->pos < ELF_GR_OFFSET(1)) {
+		dst->ret = user_regset_copyin_ignore(&dst->pos, &dst->count,
+						       &dst->u.set.kbuf,
+						       &dst->u.set.ubuf,
+						       0, ELF_GR_OFFSET(1));
+		if (dst->ret)
+			return;
+	}
+
+	while (dst->count && dst->pos < ELF_AR_END_OFFSET) {
+		unsigned int n, from, to;
+		elf_greg_t tmp[16];
+
+		from = dst->pos;
+		to = from + sizeof(tmp);
+		if (to > ELF_AR_END_OFFSET)
+			to = ELF_AR_END_OFFSET;
+		/* get up to 16 values */
+		dst->ret = user_regset_copyin(&dst->pos, &dst->count,
+				&dst->u.set.kbuf, &dst->u.set.ubuf, tmp,
+				from, to);
+		if (dst->ret)
+			return;
+		/* now copy them into registers */
+		for (n = 0; from < dst->pos; from += sizeof(elf_greg_t), n++)
+			if (access_elf_reg(dst->target, info, from,
+						&tmp[n], 1) < 0) {
+				dst->ret = -EIO;
+				return;
+			}
+	}
+}
+
+#define ELF_FP_OFFSET(i)	(i * sizeof(elf_fpreg_t))
+
+static void do_fpregs_get(struct unw_frame_info *info, void *arg)
+{
+	struct task_struct *task = info->task;
+	struct regset_membuf *dst = arg;
+	struct membuf to = dst->to;
+	elf_fpreg_t reg;
+	unsigned int n;
+
+	if (unw_unwind_to_user(info) < 0)
+		return;
+
+	/* Skip pos 0 and 1 */
+	membuf_zero(&to, 2 * sizeof(elf_fpreg_t));
+
+	/* fr2-fr31 */
+	for (n = 2; to.left && n < 32; n++) {
+		if (unw_get_fr(info, n, &reg)) {
+			dst->ret = -EIO;
+			return;
+		}
+		membuf_write(&to, &reg, sizeof(reg));
+	}
+
+	/* fph */
+	if (!to.left)
+		return;
+
+	ia64_flush_fph(task);
+	if (task->thread.flags & IA64_THREAD_FPH_VALID)
+		membuf_write(&to, &task->thread.fph, 96 * sizeof(reg));
+	else
+		membuf_zero(&to, 96 * sizeof(reg));
+}
+
+static void do_fpregs_set(struct unw_frame_info *info, void *arg)
+{
+	struct regset_getset *dst = arg;
+	elf_fpreg_t fpreg, tmp[30];
+	int index, start, end;
+
+	if (unw_unwind_to_user(info) < 0)
+		return;
+
+	/* Skip pos 0 and 1 */
+	if (dst->count > 0 && dst->pos < ELF_FP_OFFSET(2)) {
+		dst->ret = user_regset_copyin_ignore(&dst->pos, &dst->count,
+						       &dst->u.set.kbuf,
+						       &dst->u.set.ubuf,
+						       0, ELF_FP_OFFSET(2));
+		if (dst->count == 0 || dst->ret)
+			return;
+	}
+
+	/* fr2-fr31 */
+	if (dst->count > 0 && dst->pos < ELF_FP_OFFSET(32)) {
+		start = dst->pos;
+		end = min(((unsigned int)ELF_FP_OFFSET(32)),
+			 dst->pos + dst->count);
+		dst->ret = user_regset_copyin(&dst->pos, &dst->count,
+				&dst->u.set.kbuf, &dst->u.set.ubuf, tmp,
+				ELF_FP_OFFSET(2), ELF_FP_OFFSET(32));
+		if (dst->ret)
+			return;
+
+		if (start & 0xF) { /* only write high part */
+			if (unw_get_fr(info, start / sizeof(elf_fpreg_t),
+					 &fpreg)) {
+				dst->ret = -EIO;
+				return;
+			}
+			tmp[start / sizeof(elf_fpreg_t) - 2].u.bits[0]
+				= fpreg.u.bits[0];
+			start &= ~0xFUL;
+		}
+		if (end & 0xF) { /* only write low part */
+			if (unw_get_fr(info, end / sizeof(elf_fpreg_t),
+					&fpreg)) {
+				dst->ret = -EIO;
+				return;
+			}
+			tmp[end / sizeof(elf_fpreg_t) - 2].u.bits[1]
+				= fpreg.u.bits[1];
+			end = (end + 0xF) & ~0xFUL;
+		}
+
+		for ( ;	start < end ; start += sizeof(elf_fpreg_t)) {
+			index = start / sizeof(elf_fpreg_t);
+			if (unw_set_fr(info, index, tmp[index - 2])) {
+				dst->ret = -EIO;
+				return;
+			}
+		}
+		if (dst->ret || dst->count == 0)
+			return;
+	}
+
+	/* fph */
+	if (dst->count > 0 && dst->pos < ELF_FP_OFFSET(128)) {
+		ia64_sync_fph(dst->target);
+		dst->ret = user_regset_copyin(&dst->pos, &dst->count,
+						&dst->u.set.kbuf,
+						&dst->u.set.ubuf,
+						&dst->target->thread.fph,
+						ELF_FP_OFFSET(32), -1);
+	}
+}
+
+static void
+unwind_and_call(void (*call)(struct unw_frame_info *, void *),
+	       struct task_struct *target, void *data)
+{
+	if (target == current)
+		unw_init_running(call, data);
+	else {
+		struct unw_frame_info info;
+		memset(&info, 0, sizeof(info));
+		unw_init_from_blocked_task(&info, target);
+		(*call)(&info, data);
+	}
+}
+
+static int
+do_regset_call(void (*call)(struct unw_frame_info *, void *),
+	       struct task_struct *target,
+	       const struct user_regset *regset,
+	       unsigned int pos, unsigned int count,
+	       const void *kbuf, const void __user *ubuf)
+{
+	struct regset_getset info = { .target = target, .regset = regset,
+				 .pos = pos, .count = count,
+				 .u.set = { .kbuf = kbuf, .ubuf = ubuf },
+				 .ret = 0 };
+	unwind_and_call(call, target, &info);
+	return info.ret;
+}
+
+static int
+gpregs_get(struct task_struct *target,
+	   const struct user_regset *regset,
+	   struct membuf to)
+{
+	struct regset_membuf info = {.to = to};
+	unwind_and_call(do_gpregs_get, target, &info);
+	return info.ret;
+}
+
+static int gpregs_set(struct task_struct *target,
+		const struct user_regset *regset,
+		unsigned int pos, unsigned int count,
+		const void *kbuf, const void __user *ubuf)
+{
+	return do_regset_call(do_gpregs_set, target, regset, pos, count,
+		kbuf, ubuf);
+}
+
+static void do_gpregs_writeback(struct unw_frame_info *info, void *arg)
+{
+	do_sync_rbs(info, ia64_sync_user_rbs);
+}
+
+/*
+ * This is called to write back the register backing store.
+ * ptrace does this before it stops, so that a tracer reading the user
+ * memory after the thread stops will get the current register data.
+ */
+static int
+gpregs_writeback(struct task_struct *target,
+		 const struct user_regset *regset,
+		 int now)
+{
+	if (test_and_set_tsk_thread_flag(target, TIF_RESTORE_RSE))
+		return 0;
+	set_notify_resume(target);
+	return do_regset_call(do_gpregs_writeback, target, regset, 0, 0,
+		NULL, NULL);
+}
+
+static int
+fpregs_active(struct task_struct *target, const struct user_regset *regset)
+{
+	return (target->thread.flags & IA64_THREAD_FPH_VALID) ? 128 : 32;
+}
+
+static int fpregs_get(struct task_struct *target,
+		const struct user_regset *regset,
+		struct membuf to)
+{
+	struct regset_membuf info = {.to = to};
+	unwind_and_call(do_fpregs_get, target, &info);
+	return info.ret;
+}
+
+static int fpregs_set(struct task_struct *target,
+		const struct user_regset *regset,
+		unsigned int pos, unsigned int count,
+		const void *kbuf, const void __user *ubuf)
+{
+	return do_regset_call(do_fpregs_set, target, regset, pos, count,
+		kbuf, ubuf);
+}
+
+static int
+access_uarea(struct task_struct *child, unsigned long addr,
+	      unsigned long *data, int write_access)
+{
+	unsigned int pos = -1; /* an invalid value */
+	unsigned long *ptr, regnum;
+
+	if ((addr & 0x7) != 0) {
+		dprintk("ptrace: unaligned register address 0x%lx\n", addr);
+		return -1;
+	}
+	if ((addr >= PT_NAT_BITS + 8 && addr < PT_F2) ||
+		(addr >= PT_R7 + 8 && addr < PT_B1) ||
+		(addr >= PT_AR_LC + 8 && addr < PT_CR_IPSR) ||
+		(addr >= PT_AR_SSD + 8 && addr < PT_DBR)) {
+		dprintk("ptrace: rejecting access to register "
+					"address 0x%lx\n", addr);
+		return -1;
+	}
+
+	switch (addr) {
+	case PT_F32 ... (PT_F127 + 15):
+		pos = addr - PT_F32 + ELF_FP_OFFSET(32);
+		break;
+	case PT_F2 ... (PT_F5 + 15):
+		pos = addr - PT_F2 + ELF_FP_OFFSET(2);
+		break;
+	case PT_F10 ... (PT_F31 + 15):
+		pos = addr - PT_F10 + ELF_FP_OFFSET(10);
+		break;
+	case PT_F6 ... (PT_F9 + 15):
+		pos = addr - PT_F6 + ELF_FP_OFFSET(6);
+		break;
+	}
+
+	if (pos != -1) {
+		unsigned reg = pos / sizeof(elf_fpreg_t);
+		int which_half = (pos / sizeof(unsigned long)) & 1;
+
+		if (reg < 32) { /* fr2-fr31 */
+			struct unw_frame_info info;
+			elf_fpreg_t fpreg;
+
+			memset(&info, 0, sizeof(info));
+			unw_init_from_blocked_task(&info, child);
+			if (unw_unwind_to_user(&info) < 0)
+				return 0;
+
+			if (unw_get_fr(&info, reg, &fpreg))
+				return -1;
+			if (write_access) {
+				fpreg.u.bits[which_half] = *data;
+				if (unw_set_fr(&info, reg, fpreg))
+					return -1;
+			} else {
+				*data = fpreg.u.bits[which_half];
+			}
+		} else { /* fph */
+			elf_fpreg_t *p = &child->thread.fph[reg - 32];
+			unsigned long *bits = &p->u.bits[which_half];
+
+			ia64_sync_fph(child);
+			if (write_access)
+				*bits = *data;
+			else if (child->thread.flags & IA64_THREAD_FPH_VALID)
+				*data = *bits;
+			else
+				*data = 0;
+		}
+		return 0;
+	}
+
+	switch (addr) {
+	case PT_NAT_BITS:
+		pos = ELF_NAT_OFFSET;
+		break;
+	case PT_R4 ... PT_R7:
+		pos = addr - PT_R4 + ELF_GR_OFFSET(4);
+		break;
+	case PT_B1 ... PT_B5:
+		pos = addr - PT_B1 + ELF_BR_OFFSET(1);
+		break;
+	case PT_AR_EC:
+		pos = ELF_AR_EC_OFFSET;
+		break;
+	case PT_AR_LC:
+		pos = ELF_AR_LC_OFFSET;
+		break;
+	case PT_CR_IPSR:
+		pos = ELF_CR_IPSR_OFFSET;
+		break;
+	case PT_CR_IIP:
+		pos = ELF_CR_IIP_OFFSET;
+		break;
+	case PT_CFM:
+		pos = ELF_CFM_OFFSET;
+		break;
+	case PT_AR_UNAT:
+		pos = ELF_AR_UNAT_OFFSET;
+		break;
+	case PT_AR_PFS:
+		pos = ELF_AR_PFS_OFFSET;
+		break;
+	case PT_AR_RSC:
+		pos = ELF_AR_RSC_OFFSET;
+		break;
+	case PT_AR_RNAT:
+		pos = ELF_AR_RNAT_OFFSET;
+		break;
+	case PT_AR_BSPSTORE:
+		pos = ELF_AR_BSPSTORE_OFFSET;
+		break;
+	case PT_PR:
+		pos = ELF_PR_OFFSET;
+		break;
+	case PT_B6:
+		pos = ELF_BR_OFFSET(6);
+		break;
+	case PT_AR_BSP:
+		pos = ELF_AR_BSP_OFFSET;
+		break;
+	case PT_R1 ... PT_R3:
+		pos = addr - PT_R1 + ELF_GR_OFFSET(1);
+		break;
+	case PT_R12 ... PT_R15:
+		pos = addr - PT_R12 + ELF_GR_OFFSET(12);
+		break;
+	case PT_R8 ... PT_R11:
+		pos = addr - PT_R8 + ELF_GR_OFFSET(8);
+		break;
+	case PT_R16 ... PT_R31:
+		pos = addr - PT_R16 + ELF_GR_OFFSET(16);
+		break;
+	case PT_AR_CCV:
+		pos = ELF_AR_CCV_OFFSET;
+		break;
+	case PT_AR_FPSR:
+		pos = ELF_AR_FPSR_OFFSET;
+		break;
+	case PT_B0:
+		pos = ELF_BR_OFFSET(0);
+		break;
+	case PT_B7:
+		pos = ELF_BR_OFFSET(7);
+		break;
+	case PT_AR_CSD:
+		pos = ELF_AR_CSD_OFFSET;
+		break;
+	case PT_AR_SSD:
+		pos = ELF_AR_SSD_OFFSET;
+		break;
+	}
+
+	if (pos != -1) {
+		struct unw_frame_info info;
+
+		memset(&info, 0, sizeof(info));
+		unw_init_from_blocked_task(&info, child);
+		if (unw_unwind_to_user(&info) < 0)
+			return 0;
+
+		return access_elf_reg(child, &info, pos, data, write_access);
+	}
+
+	/* access debug registers */
+	if (addr >= PT_IBR) {
+		regnum = (addr - PT_IBR) >> 3;
+		ptr = &child->thread.ibr[0];
+	} else {
+		regnum = (addr - PT_DBR) >> 3;
+		ptr = &child->thread.dbr[0];
+	}
+
+	if (regnum >= 8) {
+		dprintk("ptrace: rejecting access to register "
+				"address 0x%lx\n", addr);
+		return -1;
+	}
+
+	if (!(child->thread.flags & IA64_THREAD_DBG_VALID)) {
+		child->thread.flags |= IA64_THREAD_DBG_VALID;
+		memset(child->thread.dbr, 0,
+				sizeof(child->thread.dbr));
+		memset(child->thread.ibr, 0,
+				sizeof(child->thread.ibr));
+	}
+
+	ptr += regnum;
+
+	if ((regnum & 1) && write_access) {
+		/* don't let the user set kernel-level breakpoints: */
+		*ptr = *data & ~(7UL << 56);
+		return 0;
+	}
+	if (write_access)
+		*ptr = *data;
+	else
+		*data = *ptr;
+	return 0;
+}
+
+static const struct user_regset native_regsets[] = {
+	{
+		.core_note_type = NT_PRSTATUS,
+		.n = ELF_NGREG,
+		.size = sizeof(elf_greg_t), .align = sizeof(elf_greg_t),
+		.regset_get = gpregs_get, .set = gpregs_set,
+		.writeback = gpregs_writeback
+	},
+	{
+		.core_note_type = NT_PRFPREG,
+		.n = ELF_NFPREG,
+		.size = sizeof(elf_fpreg_t), .align = sizeof(elf_fpreg_t),
+		.regset_get = fpregs_get, .set = fpregs_set, .active = fpregs_active
+	},
+};
+
+static const struct user_regset_view user_ia64_view = {
+	.name = "ia64",
+	.e_machine = EM_IA_64,
+	.regsets = native_regsets, .n = ARRAY_SIZE(native_regsets)
+};
+
+const struct user_regset_view *task_user_regset_view(struct task_struct *tsk)
+{
+	return &user_ia64_view;
+}
+
+struct syscall_get_args {
+	unsigned int i;
+	unsigned int n;
+	unsigned long *args;
+	struct pt_regs *regs;
+};
+
+static void syscall_get_args_cb(struct unw_frame_info *info, void *data)
+{
+	struct syscall_get_args *args = data;
+	struct pt_regs *pt = args->regs;
+	unsigned long *krbs, cfm, ndirty, nlocals, nouts;
+	int i, count;
+
+	if (unw_unwind_to_user(info) < 0)
+		return;
+
+	/*
+	 * We get here via a few paths:
+	 * - break instruction: cfm is shared with caller.
+	 *   syscall args are in out= regs, locals are non-empty.
+	 * - epsinstruction: cfm is set by br.call
+	 *   locals don't exist.
+	 *
+	 * For both cases arguments are reachable in cfm.sof - cfm.sol.
+	 * CFM: [ ... | sor: 17..14 | sol : 13..7 | sof : 6..0 ]
+	 */
+	cfm = pt->cr_ifs;
+	nlocals = (cfm >> 7) & 0x7f; /* aka sol */
+	nouts = (cfm & 0x7f) - nlocals; /* aka sof - sol */
+	krbs = (unsigned long *)info->task + IA64_RBS_OFFSET/8;
+	ndirty = ia64_rse_num_regs(krbs, krbs + (pt->loadrs >> 19));
+
+	count = 0;
+	if (in_syscall(pt))
+		count = min_t(int, args->n, nouts);
+
+	/* Iterate over outs. */
+	for (i = 0; i < count; i++) {
+		int j = ndirty + nlocals + i + args->i;
+		args->args[i] = *ia64_rse_skip_regs(krbs, j);
+	}
+
+	while (i < args->n) {
+		args->args[i] = 0;
+		i++;
+	}
+}
+
+void syscall_get_arguments(struct task_struct *task,
+	struct pt_regs *regs, unsigned long *args)
+{
+	struct syscall_get_args data = {
+		.i = 0,
+		.n = 6,
+		.args = args,
+		.regs = regs,
+	};
+
+	if (task == current)
+		unw_init_running(syscall_get_args_cb, &data);
+	else {
+		struct unw_frame_info ufi;
+		memset(&ufi, 0, sizeof(ufi));
+		unw_init_from_blocked_task(&ufi, task);
+		syscall_get_args_cb(&ufi, &data);
+	}
+}