[IA64] regset: 64-bit support

This is the 64-bit regset implementation under IA64. Basically register
read/write, which is derived from current ptrace register read/write.

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

2 files changed, 714 insertions, 0 deletions

diff --git a/arch/ia64/kernel/ptrace.c b/arch/ia64/kernel/ptrace.c
index ab784ec4319d..7136c7811efc 100644
--- a/arch/ia64/kernel/ptrace.c
+++ b/arch/ia64/kernel/ptrace.c
@@ -3,6 +3,9 @@
  *
  * 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.
  */
@@ -17,6 +20,8 @@
 #include <linux/security.h>
 #include <linux/audit.h>
 #include <linux/signal.h>
+#include <linux/regset.h>
+#include <linux/elf.h>
 
 #include <asm/pgtable.h>
 #include <asm/processor.h>
@@ -1626,3 +1631,688 @@ syscall_trace_leave (long arg0, long arg1, long arg2, long arg3,
         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 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;
+        unsigned long *ptr = NULL;
+        int ret;
+        char nat = 0;
+
+        pt = task_pt_regs(target);
+        switch (addr) {
+        case ELF_GR_OFFSET(1):
+                ptr = &pt->r1;
+                break;
+        case ELF_GR_OFFSET(2):
+        case ELF_GR_OFFSET(3):
+                ptr = (void *)&pt->r2 + (addr - ELF_GR_OFFSET(2));
+                break;
+        case ELF_GR_OFFSET(4) ... ELF_GR_OFFSET(7):
+                if (write_access) {
+                        /* read NaT bit first: */
+                        unsigned long dummy;
+
+                        ret = unw_get_gr(info, addr/8, &dummy, &nat);
+                        if (ret < 0)
+                                return ret;
+                }
+                return unw_access_gr(info, addr/8, data, &nat, write_access);
+        case ELF_GR_OFFSET(8) ... ELF_GR_OFFSET(11):
+                ptr = (void *)&pt->r8 + addr - ELF_GR_OFFSET(8);
+                break;
+        case ELF_GR_OFFSET(12):
+        case ELF_GR_OFFSET(13):
+                ptr = (void *)&pt->r12 + addr - ELF_GR_OFFSET(12);
+                break;
+        case ELF_GR_OFFSET(14):
+                ptr = &pt->r14;
+                break;
+        case ELF_GR_OFFSET(15):
+                ptr = &pt->r15;
+        }
+        if (write_access)
+                *ptr = *data;
+        else
+                *data = *ptr;
+        return 0;
+}
+
+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(15))
+                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);
+}
+
+void do_gpregs_get(struct unw_frame_info *info, void *arg)
+{
+        struct pt_regs *pt;
+        struct regset_getset *dst = arg;
+        elf_greg_t tmp[16];
+        unsigned int i, index, min_copy;
+
+        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 */
+        if (dst->count > 0 && dst->pos < ELF_GR_OFFSET(1)) {
+                dst->ret = user_regset_copyout_zero(&dst->pos, &dst->count,
+                                                      &dst->u.get.kbuf,
+                                                      &dst->u.get.ubuf,
+                                                      0, ELF_GR_OFFSET(1));
+                if (dst->ret || dst->count == 0)
+                        return;
+        }
+
+        /* gr1 - gr15 */
+        if (dst->count > 0 && dst->pos < ELF_GR_OFFSET(16)) {
+                index = (dst->pos - ELF_GR_OFFSET(1)) / sizeof(elf_greg_t);
+                min_copy = ELF_GR_OFFSET(16) > (dst->pos + dst->count) ?
+                         (dst->pos + dst->count) : ELF_GR_OFFSET(16);
+                for (i = dst->pos; i < min_copy; i += sizeof(elf_greg_t),
+                                index++)
+                        if (access_elf_reg(dst->target, info, i,
+                                                &tmp[index], 0) < 0) {
+                                dst->ret = -EIO;
+                                return;
+                        }
+                dst->ret = user_regset_copyout(&dst->pos, &dst->count,
+                                &dst->u.get.kbuf, &dst->u.get.ubuf, tmp,
+                                ELF_GR_OFFSET(1), ELF_GR_OFFSET(16));
+                if (dst->ret || dst->count == 0)
+                        return;
+        }
+
+        /* r16-r31 */
+        if (dst->count > 0 && dst->pos < ELF_NAT_OFFSET) {
+                pt = task_pt_regs(dst->target);
+                dst->ret = user_regset_copyout(&dst->pos, &dst->count,
+                                &dst->u.get.kbuf, &dst->u.get.ubuf, &pt->r16,
+                                ELF_GR_OFFSET(16), ELF_NAT_OFFSET);
+                if (dst->ret || dst->count == 0)
+                        return;
+        }
+
+        /* nat, pr, b0 - b7 */
+        if (dst->count > 0 && dst->pos < ELF_CR_IIP_OFFSET) {
+                index = (dst->pos - ELF_NAT_OFFSET) / sizeof(elf_greg_t);
+                min_copy = ELF_CR_IIP_OFFSET > (dst->pos + dst->count) ?
+                         (dst->pos + dst->count) : ELF_CR_IIP_OFFSET;
+                for (i = dst->pos; i < min_copy; i += sizeof(elf_greg_t),
+                                index++)
+                        if (access_elf_reg(dst->target, info, i,
+                                                &tmp[index], 0) < 0) {
+                                dst->ret = -EIO;
+                                return;
+                        }
+                dst->ret = user_regset_copyout(&dst->pos, &dst->count,
+                                &dst->u.get.kbuf, &dst->u.get.ubuf, tmp,
+                                ELF_NAT_OFFSET, ELF_CR_IIP_OFFSET);
+                if (dst->ret || dst->count == 0)
+                        return;
+        }
+
+        /* ip cfm psr ar.rsc ar.bsp ar.bspstore ar.rnat
+         * ar.ccv ar.unat ar.fpsr ar.pfs ar.lc ar.ec ar.csd ar.ssd
+         */
+        if (dst->count > 0 && dst->pos < (ELF_AR_END_OFFSET)) {
+                index = (dst->pos - ELF_CR_IIP_OFFSET) / sizeof(elf_greg_t);
+                min_copy = ELF_AR_END_OFFSET > (dst->pos + dst->count) ?
+                         (dst->pos + dst->count) : ELF_AR_END_OFFSET;
+                for (i = dst->pos; i < min_copy; i += sizeof(elf_greg_t),
+                                index++)
+                        if (access_elf_reg(dst->target, info, i,
+                                                &tmp[index], 0) < 0) {
+                                dst->ret = -EIO;
+                                return;
+                        }
+                dst->ret = user_regset_copyout(&dst->pos, &dst->count,
+                                &dst->u.get.kbuf, &dst->u.get.ubuf, tmp,
+                                ELF_CR_IIP_OFFSET, ELF_AR_END_OFFSET);
+        }
+}
+
+void do_gpregs_set(struct unw_frame_info *info, void *arg)
+{
+        struct pt_regs *pt;
+        struct regset_getset *dst = arg;
+        elf_greg_t tmp[16];
+        unsigned int i, index;
+
+        if (unw_unwind_to_user(info) < 0)
+                return;
+
+        /* Skip r0 */
+        if (dst->count > 0 && 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 || dst->count == 0)
+                        return;
+        }
+
+        /* gr1-gr15 */
+        if (dst->count > 0 && dst->pos < ELF_GR_OFFSET(16)) {
+                i = dst->pos;
+                index = (dst->pos - ELF_GR_OFFSET(1)) / sizeof(elf_greg_t);
+                dst->ret = user_regset_copyin(&dst->pos, &dst->count,
+                                &dst->u.set.kbuf, &dst->u.set.ubuf, tmp,
+                                ELF_GR_OFFSET(1), ELF_GR_OFFSET(16));
+                if (dst->ret)
+                        return;
+                for ( ; i < dst->pos; i += sizeof(elf_greg_t), index++)
+                        if (access_elf_reg(dst->target, info, i,
+                                                &tmp[index], 1) < 0) {
+                                dst->ret = -EIO;
+                                return;
+                        }
+                if (dst->count == 0)
+                        return;
+        }
+
+        /* gr16-gr31 */
+        if (dst->count > 0 && dst->pos < ELF_NAT_OFFSET) {
+                pt = task_pt_regs(dst->target);
+                dst->ret = user_regset_copyin(&dst->pos, &dst->count,
+                                &dst->u.set.kbuf, &dst->u.set.ubuf, &pt->r16,
+                                ELF_GR_OFFSET(16), ELF_NAT_OFFSET);
+                if (dst->ret || dst->count == 0)
+                        return;
+        }
+
+        /* nat, pr, b0 - b7 */
+        if (dst->count > 0 && dst->pos < ELF_CR_IIP_OFFSET) {
+                i = dst->pos;
+                index = (dst->pos - ELF_NAT_OFFSET) / sizeof(elf_greg_t);
+                dst->ret = user_regset_copyin(&dst->pos, &dst->count,
+                                &dst->u.set.kbuf, &dst->u.set.ubuf, tmp,
+                                ELF_NAT_OFFSET, ELF_CR_IIP_OFFSET);
+                if (dst->ret)
+                        return;
+                for (; i < dst->pos; i += sizeof(elf_greg_t), index++)
+                        if (access_elf_reg(dst->target, info, i,
+                                                &tmp[index], 1) < 0) {
+                                dst->ret = -EIO;
+                                return;
+                        }
+                if (dst->count == 0)
+                        return;
+        }
+
+        /* ip cfm psr ar.rsc ar.bsp ar.bspstore ar.rnat
+         * ar.ccv ar.unat ar.fpsr ar.pfs ar.lc ar.ec ar.csd ar.ssd
+         */
+        if (dst->count > 0 && dst->pos < (ELF_AR_END_OFFSET)) {
+                i = dst->pos;
+                index = (dst->pos - ELF_CR_IIP_OFFSET) / sizeof(elf_greg_t);
+                dst->ret = user_regset_copyin(&dst->pos, &dst->count,
+                                &dst->u.set.kbuf, &dst->u.set.ubuf, tmp,
+                                ELF_CR_IIP_OFFSET, ELF_AR_END_OFFSET);
+                if (dst->ret)
+                        return;
+                for ( ; i < dst->pos; i += sizeof(elf_greg_t), index++)
+                        if (access_elf_reg(dst->target, info, i,
+                                                &tmp[index], 1) < 0) {
+                                dst->ret = -EIO;
+                                return;
+                        }
+        }
+}
+
+#define ELF_FP_OFFSET(i)        (i * sizeof(elf_fpreg_t))
+
+void do_fpregs_get(struct unw_frame_info *info, void *arg)
+{
+        struct regset_getset *dst = arg;
+        struct task_struct *task = dst->target;
+        elf_fpreg_t tmp[30];
+        int index, min_copy, i;
+
+        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_copyout_zero(&dst->pos, &dst->count,
+                                                      &dst->u.get.kbuf,
+                                                      &dst->u.get.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)) {
+                index = (dst->pos - ELF_FP_OFFSET(2)) / sizeof(elf_fpreg_t);
+
+                min_copy = min(((unsigned int)ELF_FP_OFFSET(32)),
+                                dst->pos + dst->count);
+                for (i = dst->pos; i < min_copy; i += sizeof(elf_fpreg_t),
+                                index++)
+                        if (unw_get_fr(info, i / sizeof(elf_fpreg_t),
+                                         &tmp[index])) {
+                                dst->ret = -EIO;
+                                return;
+                        }
+                dst->ret = user_regset_copyout(&dst->pos, &dst->count,
+                                &dst->u.get.kbuf, &dst->u.get.ubuf, tmp,
+                                ELF_FP_OFFSET(2), ELF_FP_OFFSET(32));
+                if (dst->count == 0 || dst->ret)
+                        return;
+        }
+
+        /* fph */
+        if (dst->count > 0) {
+                ia64_flush_fph(dst->target);
+                if (task->thread.flags & IA64_THREAD_FPH_VALID)
+                        dst->ret = user_regset_copyout(
+                                &dst->pos, &dst->count,
+                                &dst->u.get.kbuf, &dst->u.get.ubuf,
+                                &dst->target->thread.fph,
+                                ELF_FP_OFFSET(32), -1);
+                else
+                        /* Zero fill instead.  */
+                        dst->ret = user_regset_copyout_zero(
+                                &dst->pos, &dst->count,
+                                &dst->u.get.kbuf, &dst->u.get.ubuf,
+                                ELF_FP_OFFSET(32), -1);
+        }
+}
+
+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 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 };
+
+        if (target == current)
+                unw_init_running(call, &info);
+        else {
+                struct unw_frame_info ufi;
+                memset(&ufi, 0, sizeof(ufi));
+                unw_init_from_blocked_task(&ufi, target);
+                (*call)(&ufi, &info);
+        }
+
+        return info.ret;
+}
+
+static int
+gpregs_get(struct task_struct *target,
+           const struct user_regset *regset,
+           unsigned int pos, unsigned int count,
+           void *kbuf, void __user *ubuf)
+{
+        return do_regset_call(do_gpregs_get, target, regset, pos, count,
+                kbuf, ubuf);
+}
+
+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;
+        tsk_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,
+                unsigned int pos, unsigned int count,
+                void *kbuf, void __user *ubuf)
+{
+        return do_regset_call(do_fpregs_get, target, regset, pos, count,
+                kbuf, ubuf);
+}
+
+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 const struct user_regset native_regsets[] = {
+        {
+                .core_note_type = NT_PRSTATUS,
+                .n = ELF_NGREG,
+                .size = sizeof(elf_greg_t), .align = sizeof(elf_greg_t),
+                .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),
+                .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;
+}
diff --git a/include/asm-ia64/elf.h b/include/asm-ia64/elf.h
index f8e83eca67a2..064cf7dcea8e 100644
--- a/include/asm-ia64/elf.h
+++ b/include/asm-ia64/elf.h
@@ -154,6 +154,30 @@ extern void ia64_init_addr_space (void);
 #define ELF_NGREG       128     /* we really need just 72 but let's leave some headroom... */
 #define ELF_NFPREG      128     /* f0 and f1 could be omitted, but so what... */
 
+/* elf_gregset_t register offsets */
+#define ELF_GR_0_OFFSET     0
+#define ELF_NAT_OFFSET     (32 * sizeof(elf_greg_t))
+#define ELF_PR_OFFSET      (33 * sizeof(elf_greg_t))
+#define ELF_BR_0_OFFSET    (34 * sizeof(elf_greg_t))
+#define ELF_CR_IIP_OFFSET  (42 * sizeof(elf_greg_t))
+#define ELF_CFM_OFFSET     (43 * sizeof(elf_greg_t))
+#define ELF_CR_IPSR_OFFSET (44 * sizeof(elf_greg_t))
+#define ELF_GR_OFFSET(i)   (ELF_GR_0_OFFSET + i * sizeof(elf_greg_t))
+#define ELF_BR_OFFSET(i)   (ELF_BR_0_OFFSET + i * sizeof(elf_greg_t))
+#define ELF_AR_RSC_OFFSET  (45 * sizeof(elf_greg_t))
+#define ELF_AR_BSP_OFFSET  (46 * sizeof(elf_greg_t))
+#define ELF_AR_BSPSTORE_OFFSET (47 * sizeof(elf_greg_t))
+#define ELF_AR_RNAT_OFFSET (48 * sizeof(elf_greg_t))
+#define ELF_AR_CCV_OFFSET  (49 * sizeof(elf_greg_t))
+#define ELF_AR_UNAT_OFFSET (50 * sizeof(elf_greg_t))
+#define ELF_AR_FPSR_OFFSET (51 * sizeof(elf_greg_t))
+#define ELF_AR_PFS_OFFSET  (52 * sizeof(elf_greg_t))
+#define ELF_AR_LC_OFFSET   (53 * sizeof(elf_greg_t))
+#define ELF_AR_EC_OFFSET   (54 * sizeof(elf_greg_t))
+#define ELF_AR_CSD_OFFSET  (55 * sizeof(elf_greg_t))
+#define ELF_AR_SSD_OFFSET  (56 * sizeof(elf_greg_t))
+#define ELF_AR_END_OFFSET  (57 * sizeof(elf_greg_t))
+
 typedef unsigned long elf_fpxregset_t;
 
 typedef unsigned long elf_greg_t;