[PowerPC] Fix access to VSCR in linux targets

The 4-byte VSCR register is found inside a 16-byte field in the regset
returned by ptrace and in core files. The position of VSCR depends on
the endianess of the target, which was previously assumed to be
big-endian for the purpose of getting VSCR. This patch removes this
assumption to fix access to VSCR in little-endian mode.

gdb/ChangeLog:
2018-05-22  Pedro Franco de Carvalho  <pedromfc@linux.vnet.ibm.com>

	* ppc-tdep.h (struct ppc_reg_offsets): Remove vector register
	offset fields.
	* ppc-fbsd-tdep.c (ppc32_fbsd_reg_offsets): Remove initializers
	for vector register offset fields.
	(ppc64_fbsd_reg_offsets): Likewise.
	* ppc-nbsd-tdep.c (_initialize_ppcnbsd_tdep): Remove assignment
	to vector register offset fields.
	* ppc-obsd-tdep.c (_initialize_ppcnbsd_tdep): Remove assignment
	to vector register offset fields.
	* ppc-obsd-nat.c (_initialize_ppcobsd_nat): Remove assignment to
	vector register offset fields.
	* rs6000-aix-tdep.c (rs6000_aix32_reg_offsets): Remove
	initializers for vector register offset fields.
	(rs6000_aix64_reg_offsets): Likewise.
	* rs6000-tdep.c (ppc_vrreg_offset): Remove.
	(ppc_supply_vrregset): Remove.
	(ppc_collect_vrregset): Remove.
	* ppc-linux-tdep.c (ppc_linux_collect_vrregset): New function.
	(ppc_linux_vrregset) : New function.
	(ppc32_le_linux_vrregmap, ppc32_be_linux_vrregmap)
	(ppc32_le_linux_vrregset, ppc32_be_linux_vrregset): New globals.
	(ppc32_linux_vrregset): Remove.
	(ppc_linux_iterate_over_regset_sections): Call ppc_linux_vrregset
	and use result instead of ppc32_linux_vrregset.
	(ppc32_linux_reg_offsets): Remove initializers for vector register
	offset fields.
	(ppc64_linux_reg_offsets): Likewise.
	* ppc-linux-tdep.h (ppc_linux_vrregset): New declaration.
	* ppc-linux-nat.c: Include regset.h.
	(gdb_vrregset_t): Adjust comment to account for little-endian
	mode.
	(supply_vrregset, fill_vrregset): Remove.
	(fetch_altivec_register, store_altivec_register): Remove.
	(fetch_altivec_registers): Add regno parameter. Get regset using
	ppc_linux_vrregset. Use regset to supply registers.
	(store_altivec_registers): Add regno parameter. Get regset using
	ppc_linux_vrregset. Use regset to collect registers.
	(fetch_register): Call fetch_altivec_registers instead of
	fetch_altivec_register.
	(store_register): Call store_altivec_registers instead of
	store_altivec_register.
	(fetch_ppc_registers): Call fetch_altivec_registers with -1 for
	the new regno parameter.
	(store_ppc_registers): Call store_altivec_registers with -1 for
	the new regno parameter.

gdb/gdbserver/ChangeLog:
2018-05-22  Pedro Franco de Carvalho  <pedromfc@linux.vnet.ibm.com>

	* linux-ppc-low.c (ppc_fill_vrregset): Add vscr_offset variable.
	Set vscr_offset to 0 in little-endian mode and 12 in big-endian
	mode. Call collect_register_by_name with vscr using
	vscr_offset. Zero-pad vscr and vrsave fields in collector buffer.
	(ppc_store_vrregset): Add and set vscr_offset variable as in
	ppc_fill_vrregset. Call supply_register_by_name with vscr using
	vscr_offset.

13 files changed, 170 insertions, 303 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index d99f5c078a5..b234da8ceb1 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,53 @@
 2018-05-22  Pedro Franco de Carvalho  <pedromfc@linux.vnet.ibm.com>
 
+	* ppc-tdep.h (struct ppc_reg_offsets): Remove vector register
+	offset fields.
+	* ppc-fbsd-tdep.c (ppc32_fbsd_reg_offsets): Remove initializers
+	for vector register offset fields.
+	(ppc64_fbsd_reg_offsets): Likewise.
+	* ppc-nbsd-tdep.c (_initialize_ppcnbsd_tdep): Remove assignment
+	to vector register offset fields.
+	* ppc-obsd-tdep.c (_initialize_ppcnbsd_tdep): Remove assignment
+	to vector register offset fields.
+	* ppc-obsd-nat.c (_initialize_ppcobsd_nat): Remove assignment to
+	vector register offset fields.
+	* rs6000-aix-tdep.c (rs6000_aix32_reg_offsets): Remove
+	initializers for vector register offset fields.
+	(rs6000_aix64_reg_offsets): Likewise.
+	* rs6000-tdep.c (ppc_vrreg_offset): Remove.
+	(ppc_supply_vrregset): Remove.
+	(ppc_collect_vrregset): Remove.
+	* ppc-linux-tdep.c (ppc_linux_collect_vrregset): New function.
+	(ppc_linux_vrregset) : New function.
+	(ppc32_le_linux_vrregmap, ppc32_be_linux_vrregmap)
+	(ppc32_le_linux_vrregset, ppc32_be_linux_vrregset): New globals.
+	(ppc32_linux_vrregset): Remove.
+	(ppc_linux_iterate_over_regset_sections): Call ppc_linux_vrregset
+	and use result instead of ppc32_linux_vrregset.
+	(ppc32_linux_reg_offsets): Remove initializers for vector register
+	offset fields.
+	(ppc64_linux_reg_offsets): Likewise.
+	* ppc-linux-tdep.h (ppc_linux_vrregset): New declaration.
+	* ppc-linux-nat.c: Include regset.h.
+	(gdb_vrregset_t): Adjust comment to account for little-endian
+	mode.
+	(supply_vrregset, fill_vrregset): Remove.
+	(fetch_altivec_register, store_altivec_register): Remove.
+	(fetch_altivec_registers): Add regno parameter. Get regset using
+	ppc_linux_vrregset. Use regset to supply registers.
+	(store_altivec_registers): Add regno parameter. Get regset using
+	ppc_linux_vrregset. Use regset to collect registers.
+	(fetch_register): Call fetch_altivec_registers instead of
+	fetch_altivec_register.
+	(store_register): Call store_altivec_registers instead of
+	store_altivec_register.
+	(fetch_ppc_registers): Call fetch_altivec_registers with -1 for
+	the new regno parameter.
+	(store_ppc_registers): Call store_altivec_registers with -1 for
+	the new regno parameter.
+
+2018-05-22  Pedro Franco de Carvalho  <pedromfc@linux.vnet.ibm.com>
+
 	* arch/ppc-linux-common.h (PPC_LINUX_SIZEOF_VRREGSET)
 	(PPC_LINUX_SIZEOF_VSXREGSET): Define.
 	* ppc-linux-nat.c (SIZEOF_VSXREGS, SIZEOF_VRREGS): Remove.
diff --git a/gdb/gdbserver/ChangeLog b/gdb/gdbserver/ChangeLog
index 1efddc44a15..13e34262ef5 100644
--- a/gdb/gdbserver/ChangeLog
+++ b/gdb/gdbserver/ChangeLog
@@ -1,5 +1,15 @@
 2018-05-22  Pedro Franco de Carvalho  <pedromfc@linux.vnet.ibm.com>
 
+	* linux-ppc-low.c (ppc_fill_vrregset): Add vscr_offset variable.
+	Set vscr_offset to 0 in little-endian mode and 12 in big-endian
+	mode. Call collect_register_by_name with vscr using
+	vscr_offset. Zero-pad vscr and vrsave fields in collector buffer.
+	(ppc_store_vrregset): Add and set vscr_offset variable as in
+	ppc_fill_vrregset. Call supply_register_by_name with vscr using
+	vscr_offset.
+
+2018-05-22  Pedro Franco de Carvalho  <pedromfc@linux.vnet.ibm.com>
+
 	* linux-ppc-low.c (SIZEOF_VSXREGS, SIZEOF_VRREGS): Remove.
 	(ppc_arch_setup): Change SIZEOF_VRREGS and SIZEOF_VSXREGS to
 	PPC_LINUX_SIZEOF_VRREGSET and PPC_LINUX_SIZEOF_VSXREGSET.
diff --git a/gdb/gdbserver/linux-ppc-low.c b/gdb/gdbserver/linux-ppc-low.c
index 367851836e4..c6e00b7eb8b 100644
--- a/gdb/gdbserver/linux-ppc-low.c
+++ b/gdb/gdbserver/linux-ppc-low.c
@@ -486,12 +486,22 @@ ppc_fill_vrregset (struct regcache *regcache, void *buf)
 {
   int i, base;
   char *regset = (char *) buf;
+  int vscr_offset = 0;
 
   base = find_regno (regcache->tdesc, "vr0");
   for (i = 0; i < 32; i++)
     collect_register (regcache, base + i, &regset[i * 16]);
 
-  collect_register_by_name (regcache, "vscr", &regset[32 * 16 + 12]);
+  if (__BYTE_ORDER == __BIG_ENDIAN)
+    vscr_offset = 12;
+
+  /* Zero-pad the unused bytes in the fields for vscr and vrsave in
+     case they get displayed somewhere.  */
+  memset (&regset[32 * 16], 0, 16);
+  collect_register_by_name (regcache, "vscr",
+			    &regset[32 * 16 + vscr_offset]);
+
+  memset (&regset[33 * 16], 0, 16);
   collect_register_by_name (regcache, "vrsave", &regset[33 * 16]);
 }
 
@@ -500,12 +510,17 @@ ppc_store_vrregset (struct regcache *regcache, const void *buf)
 {
   int i, base;
   const char *regset = (const char *) buf;
+  int vscr_offset = 0;
 
   base = find_regno (regcache->tdesc, "vr0");
   for (i = 0; i < 32; i++)
     supply_register (regcache, base + i, &regset[i * 16]);
 
-  supply_register_by_name (regcache, "vscr", &regset[32 * 16 + 12]);
+  if (__BYTE_ORDER == __BIG_ENDIAN)
+    vscr_offset = 12;
+
+  supply_register_by_name (regcache, "vscr",
+			   &regset[32 * 16 + vscr_offset]);
   supply_register_by_name (regcache, "vrsave", &regset[33 * 16]);
 }
 
diff --git a/gdb/ppc-fbsd-tdep.c b/gdb/ppc-fbsd-tdep.c
index 3ce4f0657e1..495ccca8f18 100644
--- a/gdb/ppc-fbsd-tdep.c
+++ b/gdb/ppc-fbsd-tdep.c
@@ -56,13 +56,7 @@ static const struct ppc_reg_offsets ppc32_fbsd_reg_offsets =
 	/* Floating-point registers.  */
 	/* .f0_offset = */     0,
 	/* .fpscr_offset = */  256,
-	/* .fpscr_size = */    8,
-#ifdef NOTYET
-	/* AltiVec registers.  */
-	/* .vr0_offset = */    0,
-	/* .vscr_offset = */   512 + 12,
-	/* .vrsave_offset = */ 512
-#endif
+	/* .fpscr_size = */    8
   };
 
 /* 64-bit regset descriptions.  */
@@ -84,13 +78,7 @@ static const struct ppc_reg_offsets ppc64_fbsd_reg_offsets =
 	/* Floating-point registers.  */
 	/* .f0_offset = */     0,
 	/* .fpscr_offset = */  256,
-	/* .fpscr_size = */    8,
-#ifdef NOYET
-	/* AltiVec registers.  */
-	/* .vr0_offset = */    0,
-	/* .vscr_offset = */   512 + 12,
-	/* .vrsave_offset = */ 528
-#endif
+	/* .fpscr_size = */    8
   };
 
 /* 32-bit general-purpose register set.  */
diff --git a/gdb/ppc-linux-nat.c b/gdb/ppc-linux-nat.c
index a8f202dd335..e00831a2483 100644
--- a/gdb/ppc-linux-nat.c
+++ b/gdb/ppc-linux-nat.c
@@ -24,6 +24,7 @@
 #include "gdbthread.h"
 #include "gdbcore.h"
 #include "regcache.h"
+#include "regset.h"
 #include "target.h"
 #include "linux-nat.h"
 #include <sys/types.h>
@@ -160,17 +161,18 @@ struct ppc_hw_breakpoint
    Even though this vrsave register is not included in the regset
    typedef, it is handled by the ptrace requests.
 
-   Note that GNU/Linux doesn't support little endian PPC hardware,
-   therefore the offset at which the real value of the VSCR register
-   is located will be always 12 bytes.
-
    The layout is like this (where x is the actual value of the vscr reg): */
 
 /* *INDENT-OFF* */
 /*
+Big-Endian:
    |.|.|.|.|.....|.|.|.|.||.|.|.|x||.|
    <------->     <-------><-------><->
      VR0           VR31     VSCR    VRSAVE
+Little-Endian:
+   |.|.|.|.|.....|.|.|.|.||X|.|.|.||.|
+   <------->     <-------><-------><->
+     VR0           VR31     VSCR    VRSAVE
 */
 /* *INDENT-ON* */
 
@@ -435,14 +437,13 @@ fetch_vsx_register (struct regcache *regcache, int tid, int regno)
    registers set mechanism, as opposed to the interface for all the
    other registers, that stores/fetches each register individually.  */
 static void
-fetch_altivec_register (struct regcache *regcache, int tid, int regno)
+fetch_altivec_registers (struct regcache *regcache, int tid,
+			 int regno)
 {
   int ret;
-  int offset = 0;
   gdb_vrregset_t regs;
   struct gdbarch *gdbarch = regcache->arch ();
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
-  int vrregsize = register_size (gdbarch, tdep->ppc_vr0_regnum);
+  const struct regset *vrregset = ppc_linux_vrregset (gdbarch);
 
   ret = ptrace (PTRACE_GETVRREGS, tid, 0, &regs);
   if (ret < 0)
@@ -452,19 +453,11 @@ fetch_altivec_register (struct regcache *regcache, int tid, int regno)
           have_ptrace_getvrregs = 0;
           return;
         }
-      perror_with_name (_("Unable to fetch AltiVec register"));
+      perror_with_name (_("Unable to fetch AltiVec registers"));
     }
- 
-  /* VSCR is fetched as a 16 bytes quantity, but it is really 4 bytes
-     long on the hardware.  We deal only with the lower 4 bytes of the
-     vector.  VRSAVE is at the end of the array in a 4 bytes slot, so
-     there is no need to define an offset for it.  */
-  if (regno == (tdep->ppc_vrsave_regnum - 1))
-    offset = vrregsize - register_size (gdbarch, tdep->ppc_vrsave_regnum);
-  
-  regcache_raw_supply (regcache, regno,
-		       regs + (regno
-			       - tdep->ppc_vr0_regnum) * vrregsize + offset);
+
+  vrregset->supply_regset (vrregset, regcache, regno, &regs,
+			   PPC_LINUX_SIZEOF_VRREGSET);
 }
 
 /* Fetch the top 32 bits of TID's general-purpose registers and the
@@ -559,7 +552,7 @@ fetch_register (struct regcache *regcache, int tid, int regno)
          register.  */
       if (have_ptrace_getvrregs)
        {
-         fetch_altivec_register (regcache, tid, regno);
+         fetch_altivec_registers (regcache, tid, regno);
          return;
        }
      /* If we have discovered that there is no ptrace support for
@@ -647,31 +640,6 @@ supply_vsxregset (struct regcache *regcache, gdb_vsxregset_t *vsxregsetp)
 }
 
 static void
-supply_vrregset (struct regcache *regcache, gdb_vrregset_t *vrregsetp)
-{
-  int i;
-  struct gdbarch *gdbarch = regcache->arch ();
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
-  int num_of_vrregs = tdep->ppc_vrsave_regnum - tdep->ppc_vr0_regnum + 1;
-  int vrregsize = register_size (gdbarch, tdep->ppc_vr0_regnum);
-  int offset = vrregsize - register_size (gdbarch, tdep->ppc_vrsave_regnum);
-
-  for (i = 0; i < num_of_vrregs; i++)
-    {
-      /* The last 2 registers of this set are only 32 bit long, not
-         128.  However an offset is necessary only for VSCR because it
-         occupies a whole vector, while VRSAVE occupies a full 4 bytes
-         slot.  */
-      if (i == (num_of_vrregs - 2))
-        regcache_raw_supply (regcache, tdep->ppc_vr0_regnum + i,
-			     *vrregsetp + i * vrregsize + offset);
-      else
-        regcache_raw_supply (regcache, tdep->ppc_vr0_regnum + i,
-			     *vrregsetp + i * vrregsize);
-    }
-}
-
-static void
 fetch_vsx_registers (struct regcache *regcache, int tid)
 {
   int ret;
@@ -690,25 +658,6 @@ fetch_vsx_registers (struct regcache *regcache, int tid)
   supply_vsxregset (regcache, &regs);
 }
 
-static void
-fetch_altivec_registers (struct regcache *regcache, int tid)
-{
-  int ret;
-  gdb_vrregset_t regs;
-  
-  ret = ptrace (PTRACE_GETVRREGS, tid, 0, &regs);
-  if (ret < 0)
-    {
-      if (errno == EIO)
-	{
-          have_ptrace_getvrregs = 0;
-	  return;
-	}
-      perror_with_name (_("Unable to fetch AltiVec registers"));
-    }
-  supply_vrregset (regcache, &regs);
-}
-
 /* This function actually issues the request to ptrace, telling
    it to get all general-purpose registers and put them into the
    specified regset.
@@ -847,7 +796,7 @@ fetch_ppc_registers (struct regcache *regcache, int tid)
     fetch_register (regcache, tid, tdep->ppc_fpscr_regnum);
   if (have_ptrace_getvrregs)
     if (tdep->ppc_vr0_regnum != -1 && tdep->ppc_vrsave_regnum != -1)
-      fetch_altivec_registers (regcache, tid);
+      fetch_altivec_registers (regcache, tid, -1);
   if (have_ptrace_getsetvsxregs)
     if (tdep->ppc_vsr0_upper_regnum != -1)
       fetch_vsx_registers (regcache, tid);
@@ -898,16 +847,14 @@ store_vsx_register (const struct regcache *regcache, int tid, int regno)
     perror_with_name (_("Unable to store VSX register"));
 }
 
-/* Store one register.  */
 static void
-store_altivec_register (const struct regcache *regcache, int tid, int regno)
+store_altivec_registers (const struct regcache *regcache, int tid,
+			 int regno)
 {
   int ret;
-  int offset = 0;
   gdb_vrregset_t regs;
   struct gdbarch *gdbarch = regcache->arch ();
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
-  int vrregsize = register_size (gdbarch, tdep->ppc_vr0_regnum);
+  const struct regset *vrregset = ppc_linux_vrregset (gdbarch);
 
   ret = ptrace (PTRACE_GETVRREGS, tid, 0, &regs);
   if (ret < 0)
@@ -917,21 +864,15 @@ store_altivec_register (const struct regcache *regcache, int tid, int regno)
           have_ptrace_getvrregs = 0;
           return;
         }
-      perror_with_name (_("Unable to fetch AltiVec register"));
+      perror_with_name (_("Unable to fetch AltiVec registers"));
     }
 
-  /* VSCR is fetched as a 16 bytes quantity, but it is really 4 bytes
-     long on the hardware.  */
-  if (regno == (tdep->ppc_vrsave_regnum - 1))
-    offset = vrregsize - register_size (gdbarch, tdep->ppc_vrsave_regnum);
-
-  regcache_raw_collect (regcache, regno,
-			regs + (regno
-				- tdep->ppc_vr0_regnum) * vrregsize + offset);
+  vrregset->collect_regset (vrregset, regcache, regno, &regs,
+			    PPC_LINUX_SIZEOF_VRREGSET);
 
   ret = ptrace (PTRACE_SETVRREGS, tid, 0, &regs);
   if (ret < 0)
-    perror_with_name (_("Unable to store AltiVec register"));
+    perror_with_name (_("Unable to store AltiVec registers"));
 }
 
 /* Assuming TID referrs to an SPE process, set the top halves of TID's
@@ -1034,7 +975,7 @@ store_register (const struct regcache *regcache, int tid, int regno)
 
   if (altivec_register_p (gdbarch, regno))
     {
-      store_altivec_register (regcache, tid, regno);
+      store_altivec_registers (regcache, tid, regno);
       return;
     }
   if (vsx_register_p (gdbarch, regno))
@@ -1111,29 +1052,6 @@ fill_vsxregset (const struct regcache *regcache, gdb_vsxregset_t *vsxregsetp)
 }
 
 static void
-fill_vrregset (const struct regcache *regcache, gdb_vrregset_t *vrregsetp)
-{
-  int i;
-  struct gdbarch *gdbarch = regcache->arch ();
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
-  int num_of_vrregs = tdep->ppc_vrsave_regnum - tdep->ppc_vr0_regnum + 1;
-  int vrregsize = register_size (gdbarch, tdep->ppc_vr0_regnum);
-  int offset = vrregsize - register_size (gdbarch, tdep->ppc_vrsave_regnum);
-
-  for (i = 0; i < num_of_vrregs; i++)
-    {
-      /* The last 2 registers of this set are only 32 bit long, not
-         128, but only VSCR is fetched as a 16 bytes quantity.  */
-      if (i == (num_of_vrregs - 2))
-        regcache_raw_collect (regcache, tdep->ppc_vr0_regnum + i,
-			      *vrregsetp + i * vrregsize + offset);
-      else
-        regcache_raw_collect (regcache, tdep->ppc_vr0_regnum + i,
-			      *vrregsetp + i * vrregsize);
-    }
-}
-
-static void
 store_vsx_registers (const struct regcache *regcache, int tid)
 {
   int ret;
@@ -1156,29 +1074,6 @@ store_vsx_registers (const struct regcache *regcache, int tid)
     perror_with_name (_("Couldn't write VSX registers"));
 }
 
-static void
-store_altivec_registers (const struct regcache *regcache, int tid)
-{
-  int ret;
-  gdb_vrregset_t regs;
-
-  ret = ptrace (PTRACE_GETVRREGS, tid, 0, &regs);
-  if (ret < 0)
-    {
-      if (errno == EIO)
-        {
-          have_ptrace_getvrregs = 0;
-          return;
-        }
-      perror_with_name (_("Couldn't get AltiVec registers"));
-    }
-
-  fill_vrregset (regcache, &regs);
-  
-  if (ptrace (PTRACE_SETVRREGS, tid, 0, &regs) < 0)
-    perror_with_name (_("Couldn't write AltiVec registers"));
-}
-
 /* This function actually issues the request to ptrace, telling
    it to store all general-purpose registers present in the specified
    regset.
@@ -1337,7 +1232,7 @@ store_ppc_registers (const struct regcache *regcache, int tid)
     }
   if (have_ptrace_getvrregs)
     if (tdep->ppc_vr0_regnum != -1 && tdep->ppc_vrsave_regnum != -1)
-      store_altivec_registers (regcache, tid);
+      store_altivec_registers (regcache, tid, -1);
   if (have_ptrace_getsetvsxregs)
     if (tdep->ppc_vsr0_upper_regnum != -1)
       store_vsx_registers (regcache, tid);
diff --git a/gdb/ppc-linux-tdep.c b/gdb/ppc-linux-tdep.c
index 344069d752e..7362c4bbe19 100644
--- a/gdb/ppc-linux-tdep.c
+++ b/gdb/ppc-linux-tdep.c
@@ -444,6 +444,24 @@ ppc_linux_collect_gregset (const struct regset *regset,
     }
 }
 
+static void
+ppc_linux_collect_vrregset (const struct regset *regset,
+			    const struct regcache *regcache,
+			    int regnum, void *buf, size_t len)
+{
+  gdb_byte *vrregs = (gdb_byte *) buf;
+
+  /* Zero-pad the unused bytes in the fields for vscr and vrsave
+     in case they get displayed somewhere (e.g. in core files).  */
+  if (regnum == PPC_VSCR_REGNUM || regnum == -1)
+    memset (&vrregs[32 * 16], 0, 16);
+
+  if (regnum == PPC_VRSAVE_REGNUM || regnum == -1)
+    memset (&vrregs[33 * 16], 0, 16);
+
+  regcache_collect_regset (regset, regcache, regnum, buf, len);
+}
+
 /* Regset descriptions.  */
 static const struct ppc_reg_offsets ppc32_linux_reg_offsets =
   {
@@ -462,12 +480,7 @@ static const struct ppc_reg_offsets ppc32_linux_reg_offsets =
     /* Floating-point registers.  */
     /* .f0_offset = */ 0,
     /* .fpscr_offset = */ 256,
-    /* .fpscr_size = */ 8,
-
-    /* AltiVec registers.  */
-    /* .vr0_offset = */ 0,
-    /* .vscr_offset = */ 512 + 12,
-    /* .vrsave_offset = */ 528
+    /* .fpscr_size = */ 8
   };
 
 static const struct ppc_reg_offsets ppc64_linux_reg_offsets =
@@ -487,12 +500,7 @@ static const struct ppc_reg_offsets ppc64_linux_reg_offsets =
     /* Floating-point registers.  */
     /* .f0_offset = */ 0,
     /* .fpscr_offset = */ 256,
-    /* .fpscr_size = */ 8,
-
-    /* AltiVec registers.  */
-    /* .vr0_offset = */ 0,
-    /* .vscr_offset = */ 512 + 12,
-    /* .vrsave_offset = */ 528
+    /* .fpscr_size = */ 8
   };
 
 static const struct regset ppc32_linux_gregset = {
@@ -513,10 +521,36 @@ static const struct regset ppc32_linux_fpregset = {
   ppc_collect_fpregset
 };
 
-static const struct regset ppc32_linux_vrregset = {
-  &ppc32_linux_reg_offsets,
-  ppc_supply_vrregset,
-  ppc_collect_vrregset
+static const struct regcache_map_entry ppc32_le_linux_vrregmap[] =
+  {
+      { 32, PPC_VR0_REGNUM, 16 },
+      { 1, PPC_VSCR_REGNUM, 4 },
+      { 1, REGCACHE_MAP_SKIP, 12 },
+      { 1, PPC_VRSAVE_REGNUM, 4 },
+      { 1, REGCACHE_MAP_SKIP, 12 },
+      { 0 }
+  };
+
+static const struct regcache_map_entry ppc32_be_linux_vrregmap[] =
+  {
+      { 32, PPC_VR0_REGNUM, 16 },
+      { 1, REGCACHE_MAP_SKIP, 12},
+      { 1, PPC_VSCR_REGNUM, 4 },
+      { 1, PPC_VRSAVE_REGNUM, 4 },
+      { 1, REGCACHE_MAP_SKIP, 12 },
+      { 0 }
+  };
+
+static const struct regset ppc32_le_linux_vrregset = {
+  ppc32_le_linux_vrregmap,
+  regcache_supply_regset,
+  ppc_linux_collect_vrregset
+};
+
+static const struct regset ppc32_be_linux_vrregset = {
+  ppc32_be_linux_vrregmap,
+  regcache_supply_regset,
+  ppc_linux_collect_vrregset
 };
 
 static const struct regset ppc32_linux_vsxregset = {
@@ -537,6 +571,15 @@ ppc_linux_fpregset (void)
   return &ppc32_linux_fpregset;
 }
 
+const struct regset *
+ppc_linux_vrregset (struct gdbarch *gdbarch)
+{
+  if (gdbarch_byte_order (gdbarch) == BFD_ENDIAN_BIG)
+    return &ppc32_be_linux_vrregset;
+  else
+    return &ppc32_le_linux_vrregset;
+}
+
 /* Iterate over supported core file register note sections. */
 
 static void
@@ -557,8 +600,11 @@ ppc_linux_iterate_over_regset_sections (struct gdbarch *gdbarch,
   cb (".reg2", 264, &ppc32_linux_fpregset, NULL, cb_data);
 
   if (have_altivec)
-    cb (".reg-ppc-vmx", PPC_LINUX_SIZEOF_VRREGSET, &ppc32_linux_vrregset,
-	"ppc Altivec", cb_data);
+    {
+      const struct regset *vrregset = ppc_linux_vrregset (gdbarch);
+      cb (".reg-ppc-vmx", PPC_LINUX_SIZEOF_VRREGSET, vrregset,
+	  "ppc Altivec", cb_data);
+    }
 
   if (have_vsx)
     cb (".reg-ppc-vsx", PPC_LINUX_SIZEOF_VSXREGSET,
diff --git a/gdb/ppc-linux-tdep.h b/gdb/ppc-linux-tdep.h
index 5e7c4be16ba..a8715bd4184 100644
--- a/gdb/ppc-linux-tdep.h
+++ b/gdb/ppc-linux-tdep.h
@@ -28,6 +28,9 @@ struct regset;
 const struct regset *ppc_linux_gregset (int);
 const struct regset *ppc_linux_fpregset (void);
 
+/* Get the vector regset that matches the target byte order.  */
+const struct regset *ppc_linux_vrregset (struct gdbarch *gdbarch);
+
 /* Extra register number constants.  The Linux kernel stores a
    "trap" code and the original value of r3 into special "registers";
    these need to be saved and restored when performing an inferior
diff --git a/gdb/ppc-nbsd-tdep.c b/gdb/ppc-nbsd-tdep.c
index 129ebc03426..c86aeb8a295 100644
--- a/gdb/ppc-nbsd-tdep.c
+++ b/gdb/ppc-nbsd-tdep.c
@@ -215,9 +215,5 @@ _initialize_ppcnbsd_tdep (void)
       ppcnbsd_reg_offsets.fpscr_offset = 256;
       ppcnbsd_reg_offsets.fpscr_size = 4;
 
-      /* AltiVec registers.  */
-      ppcnbsd_reg_offsets.vr0_offset = 0;
-      ppcnbsd_reg_offsets.vrsave_offset = 512;
-      ppcnbsd_reg_offsets.vscr_offset = 524;
     }
 }
diff --git a/gdb/ppc-obsd-nat.c b/gdb/ppc-obsd-nat.c
index 781b09c7fe4..4428dabd7b9 100644
--- a/gdb/ppc-obsd-nat.c
+++ b/gdb/ppc-obsd-nat.c
@@ -213,11 +213,6 @@ _initialize_ppcobsd_nat (void)
   ppcobsd_fpreg_offsets.fpscr_size = 4;
 #endif
 
-  /* AltiVec registers.  */
-  ppcobsd_reg_offsets.vr0_offset = offsetof (struct vreg, vreg);
-  ppcobsd_reg_offsets.vscr_offset = offsetof (struct vreg, vscr);
-  ppcobsd_reg_offsets.vrsave_offset = offsetof (struct vreg, vrsave);
-
   /* Support debugging kernel virtual memory images.  */
   bsd_kvm_add_target (ppcobsd_supply_pcb);
 }
diff --git a/gdb/ppc-obsd-tdep.c b/gdb/ppc-obsd-tdep.c
index 986ab041339..838783111a2 100644
--- a/gdb/ppc-obsd-tdep.c
+++ b/gdb/ppc-obsd-tdep.c
@@ -289,10 +289,6 @@ _initialize_ppcobsd_tdep (void)
       ppcobsd_reg_offsets.f0_offset = 128;
       ppcobsd_reg_offsets.fpscr_offset = -1;
 
-      /* AltiVec registers.  */
-      ppcobsd_reg_offsets.vr0_offset = 0;
-      ppcobsd_reg_offsets.vscr_offset = 512;
-      ppcobsd_reg_offsets.vrsave_offset = 520;
     }
 
   if (ppcobsd_fpreg_offsets.fpscr_offset == 0)
diff --git a/gdb/ppc-tdep.h b/gdb/ppc-tdep.h
index 156f82d39b4..c3571cbd51b 100644
--- a/gdb/ppc-tdep.h
+++ b/gdb/ppc-tdep.h
@@ -100,11 +100,6 @@ struct ppc_reg_offsets
   int f0_offset;
   int fpscr_offset;
   int fpscr_size;
-
-  /* AltiVec registers.  */
-  int vr0_offset;
-  int vscr_offset;
-  int vrsave_offset;
 };
 
 extern void ppc_supply_reg (struct regcache *regcache, int regnum,
diff --git a/gdb/rs6000-aix-tdep.c b/gdb/rs6000-aix-tdep.c
index e3e086c2102..ecf6191df01 100644
--- a/gdb/rs6000-aix-tdep.c
+++ b/gdb/rs6000-aix-tdep.c
@@ -70,12 +70,7 @@ static struct ppc_reg_offsets rs6000_aix32_reg_offsets =
   /* Floating-point registers.  */
   336, /* f0_offset */
   56, /* fpscr_offset */
-  4,  /* fpscr_size */
-
-  /* AltiVec registers.  */
-  -1, /* vr0_offset */
-  -1, /* vscr_offset */
-  -1 /* vrsave_offset */
+  4  /* fpscr_size */
 };
 
 static struct ppc_reg_offsets rs6000_aix64_reg_offsets =
@@ -95,12 +90,7 @@ static struct ppc_reg_offsets rs6000_aix64_reg_offsets =
   /* Floating-point registers.  */
   312, /* f0_offset */
   296, /* fpscr_offset */
-  4,  /* fpscr_size */
-
-  /* AltiVec registers.  */
-  -1, /* vr0_offset */
-  -1, /* vscr_offset */
-  -1 /* vrsave_offset */
+  4  /* fpscr_size */
 };
 
 
diff --git a/gdb/rs6000-tdep.c b/gdb/rs6000-tdep.c
index c5b49c5f465..4ef6f9e9805 100644
--- a/gdb/rs6000-tdep.c
+++ b/gdb/rs6000-tdep.c
@@ -485,24 +485,6 @@ ppc_fpreg_offset (struct gdbarch_tdep *tdep,
   return -1;
 }
 
-static int
-ppc_vrreg_offset (struct gdbarch_tdep *tdep,
-		  const struct ppc_reg_offsets *offsets,
-		  int regnum)
-{
-  if (regnum >= tdep->ppc_vr0_regnum
-      && regnum < tdep->ppc_vr0_regnum + ppc_num_vrs)
-    return offsets->vr0_offset + (regnum - tdep->ppc_vr0_regnum) * 16;
-
-  if (regnum == tdep->ppc_vrsave_regnum - 1)
-    return offsets->vscr_offset;
-
-  if (regnum == tdep->ppc_vrsave_regnum)
-    return offsets->vrsave_offset;
-
-  return -1;
-}
-
 /* Supply register REGNUM in the general-purpose register set REGSET
    from the buffer specified by GREGS and LEN to register cache
    REGCACHE.  If REGNUM is -1, do this for all registers in REGSET.  */
@@ -622,50 +604,6 @@ ppc_supply_vsxregset (const struct regset *regset, struct regcache *regcache,
     ppc_supply_reg (regcache, regnum, (const gdb_byte *) vsxregs, 0, 8);
 }
 
-/* Supply register REGNUM in the Altivec register set REGSET
-   from the buffer specified by VRREGS and LEN to register cache
-   REGCACHE.  If REGNUM is -1, do this for all registers in REGSET.  */
-
-void
-ppc_supply_vrregset (const struct regset *regset, struct regcache *regcache,
-		     int regnum, const void *vrregs, size_t len)
-{
-  struct gdbarch *gdbarch = regcache->arch ();
-  struct gdbarch_tdep *tdep;
-  const struct ppc_reg_offsets *offsets;
-  size_t offset;
-
-  if (!ppc_altivec_support_p (gdbarch))
-    return;
-
-  tdep = gdbarch_tdep (gdbarch);
-  offsets = (const struct ppc_reg_offsets *) regset->regmap;
-  if (regnum == -1)
-    {
-      int i;
-
-      for (i = tdep->ppc_vr0_regnum, offset = offsets->vr0_offset;
-	   i < tdep->ppc_vr0_regnum + ppc_num_vrs;
-	   i++, offset += 16)
-        ppc_supply_reg (regcache, i, (const gdb_byte *) vrregs, offset, 16);
-
-      ppc_supply_reg (regcache, (tdep->ppc_vrsave_regnum - 1),
-		      (const gdb_byte *) vrregs, offsets->vscr_offset, 4);
-
-      ppc_supply_reg (regcache, tdep->ppc_vrsave_regnum,
-		      (const gdb_byte *) vrregs, offsets->vrsave_offset, 4);
-      return;
-    }
-
-  offset = ppc_vrreg_offset (tdep, offsets, regnum);
-  if (regnum != tdep->ppc_vrsave_regnum
-      && regnum != tdep->ppc_vrsave_regnum - 1)
-    ppc_supply_reg (regcache, regnum, (const gdb_byte *) vrregs, offset, 16);
-  else
-    ppc_supply_reg (regcache, regnum,
-		    (const gdb_byte *) vrregs, offset, 4);
-}
-
 /* Collect register REGNUM in the general-purpose register set
    REGSET from register cache REGCACHE into the buffer specified by
    GREGS and LEN.  If REGNUM is -1, do this for all registers in
@@ -790,54 +728,6 @@ ppc_collect_vsxregset (const struct regset *regset,
     ppc_collect_reg (regcache, regnum, (gdb_byte *) vsxregs, 0, 8);
 }
 
-
-/* Collect register REGNUM in the Altivec register set
-   REGSET from register cache REGCACHE into the buffer specified by
-   VRREGS and LEN.  If REGNUM is -1, do this for all registers in
-   REGSET.  */
-
-void
-ppc_collect_vrregset (const struct regset *regset,
-		      const struct regcache *regcache,
-		      int regnum, void *vrregs, size_t len)
-{
-  struct gdbarch *gdbarch = regcache->arch ();
-  struct gdbarch_tdep *tdep;
-  const struct ppc_reg_offsets *offsets;
-  size_t offset;
-
-  if (!ppc_altivec_support_p (gdbarch))
-    return;
-
-  tdep = gdbarch_tdep (gdbarch);
-  offsets = (const struct ppc_reg_offsets *) regset->regmap;
-  if (regnum == -1)
-    {
-      int i;
-
-      for (i = tdep->ppc_vr0_regnum, offset = offsets->vr0_offset;
-	   i < tdep->ppc_vr0_regnum + ppc_num_vrs;
-	   i++, offset += 16)
-	ppc_collect_reg (regcache, i, (gdb_byte *) vrregs, offset, 16);
-
-      ppc_collect_reg (regcache, (tdep->ppc_vrsave_regnum - 1),
-		       (gdb_byte *) vrregs, offsets->vscr_offset, 4);
-
-      ppc_collect_reg (regcache, tdep->ppc_vrsave_regnum,
-		       (gdb_byte *) vrregs, offsets->vrsave_offset, 4);
-      return;
-    }
-
-  offset = ppc_vrreg_offset (tdep, offsets, regnum);
-  if (regnum != tdep->ppc_vrsave_regnum
-      && regnum != tdep->ppc_vrsave_regnum - 1)
-    ppc_collect_reg (regcache, regnum, (gdb_byte *) vrregs, offset, 16);
-  else
-    ppc_collect_reg (regcache, regnum,
-		    (gdb_byte *) vrregs, offset, 4);
-}
-
-
 static int
 insn_changes_sp_or_jumps (unsigned long insn)
 {