[PowerPC] Add support for PPR and DSCR

This patch adds gdb support for the Program Priorty Register and the
Data Stream Control Register, for the powerpc linux native and core
file targets, and for the powerpc linux server stub.

gdb/ChangeLog:
2018-10-26  Edjunior Barbosa Machado  <emachado@linux.vnet.ibm.com>
	    Pedro Franco de Carvalho  <pedromfc@linux.ibm.com>

	* arch/ppc-linux-tdesc.h (tdesc_powerpc_isa205_ppr_dscr_vsx32l)
	(tdesc_powerpc_isa205_ppr_dscr_vsx64l): Declare.
	* arch/ppc-linux-common.h (PPC_LINUX_SIZEOF_PPRREGSET)
	(PPC_LINUX_SIZEOF_DSCRREGSET): Define.
	(struct ppc_linux_features) <ppr_dscr>: New field.
	(ppc_linux_no_features): Add initializer for ppr_dscr field.
	* arch/ppc-linux-common.c (ppc_linux_match_description): Return
	new tdescs.
	* nat/ppc-linux.h (PPC_FEATURE2_DSCR, NT_PPC_PPR, NT_PPC_DSCR):
	Define if not already defined.
	* features/Makefile (WHICH): Add
	rs6000/powerpc-isa205-ppr-dscr-vsx32l and
	rs6000/powerpc-isa205-ppr-dscr-vsx64l.
	(XMLTOC): Add rs6000/powerpc-isa205-ppr-dscr-vsx32l.xml and
	rs6000/powerpc-isa205-ppr-dscr-vsx64l.xml.
	* features/rs6000/power-dscr.xml: New file.
	* features/rs6000/power-ppr.xml: New file.
	* features/rs6000/powerpc-isa205-ppr-dscr-vsx32l.xml: New file.
	* features/rs6000/powerpc-isa205-ppr-dscr-vsx64l.xml: New file.
	* features/rs6000/powerpc-isa205-ppr-dscr-vsx32l.c: Generate.
	* features/rs6000/powerpc-isa205-ppr-dscr-vsx64l.c: Generate.
	* regformats/rs6000/powerpc-isa205-ppr-dscr-vsx32l.dat: Generate.
	* regformats/rs6000/powerpc-isa205-ppr-dscr-vsx64l.dat: Generate.
	* ppc-linux-nat.c: Include <sys/uio.h>.
	(fetch_regset, store_regset, check_regset): New functions.
	(fetch_register, fetch_ppc_registers): Call fetch_regset with
	DSCR and PPR regsets.
	(store_register, store_ppc_registers): Call store_regset with
	DSCR and PPR regsets.
	(ppc_linux_get_hwcap2): New function.
	(ppc_linux_nat_target::read_description): Call
	ppc_linux_get_hwcap2 and check_regset, set ppr_dscr field in the
	features struct if needed.
	* ppc-linux-tdep.c: Include
	features/rs6000/powerpc-isa205-ppr-dscr-vsx32l.c and
	features/rs6000/powerpc-isa205-ppr-dscr-vsx64l.c.
	(ppc32_regmap_ppr, ppc32_regmap_dscr, ppc32_linux_pprregset)
	(ppc32_linux_dscrregset): New globals.
	(ppc_linux_iterate_over_regset_sections): Call back with the ppr
	and dscr regsets.
	(ppc_linux_core_read_description): Check if the ppr and dscr
	sections are present and set ppr_dscr in the features struct.
	(_initialize_ppc_linux_tdep): Call
	initialize_tdesc_powerpc_isa205_ppr_dscr_vsx32l and
	initialize_tdesc_powerpc_isa205_ppr_dscr_vsx64l.
	* ppc-linux-tdep.h (ppc32_linux_pprregset)
	(ppc32_linux_dscrregset): Declare.
	* ppc-tdep.h (struct gdbarch_tdep) <ppc_ppr_regnum>: New field.
	<ppc_dscr_regnum>: New field.
	(enum) <PPC_PPR_REGNUM, PPC_DSCR_REGNUM>: New enum values.
	* rs6000-tdep.c (rs6000_gdbarch_init): Look for and validate ppr
	and dscr features.
	(ppc_process_record_op31): Record changes to PPR and DSCR.

gdb/gdbserver/ChangeLog:
2018-10-26  Edjunior Barbosa Machado  <emachado@linux.vnet.ibm.com>
	    Pedro Franco de Carvalho  <pedromfc@linux.ibm.com>

	* configure.srv (ipa_ppc_linux_regobj): Add
	powerpc-isa205-ppr-dscr-vsx32l-ipa.o and
	powerpc-isa205-ppr-dscr-vsx64l-ipa.o.
	(powerpc*-*-linux*): Add powerpc-isa205-ppr-dscr-vsx32l.o and
	powerpc-isa205-ppr-dscr-vsx64l.o to srv_regobj, add
	rs6000/power-dscr.xml, rs6000/power-ppr.xml,
	rs6000/powerpc-isa205-ppr-dscr-vsx32l.xml and
	rs6000/powerpc-isa205-ppr-dscr-vsx64l.xml to srv_xmlfiles.
	* linux-ppc-tdesc-init.h (enum ppc_linux_tdesc)
	<PPC_TDESC_ISA205_PPR_DSCR_VSX>: New enum value.
	(init_registers_powerpc_isa205_ppr_dscr_vsx32l)
	(init_registers_powerpc_isa205_ppr_dscr_vsx64l): Declare.
	* linux-ppc-low.c: Include "elf/common.h" and <sys/uio.h>.
	(ppc_hwcap): Add comment.
	(ppc_hwcap2): New global.
	(ppc_check_regset, ppc_fill_pprregset, ppc_store_pprregset)
	(ppc_fill_dscrregset, ppc_store_dscrregset): New functions.
	(ppc_regsets): Add entries for the DSCR and PPR regsets.
	(ppc_arch_setup): Get AT_HWCAP2.  Set ppr_dscr in features struct
	when needed.  Set sizes for the the DSCR and PPR regsets.
	(ppc_get_ipa_tdesc_idx): Return PPC_TDESC_ISA205_PPR_DSCR_VSX.
	(initialize_low_arch): Call
	init_registers_powerpc_isa205_ppr_dscr_vsx32l and
	init_registers_powerpc_isa205_ppr_dscr_vsx64l.
	* linux-ppc-ipa.c (get_ipa_tdesc): Handle
	PPC_TDESC_ISA205_PPR_DSCR_VSX.
	(initialize_low_tracepoint): Call
	init_registers_powerpc_isa205_ppr_dscr_vsx32l and
	init_registers_powerpc_isa205_ppr_dscr_vsx64l.

gdb/testsuite/ChangeLog:
2018-10-26  Pedro Franco de Carvalho  <pedromfc@linux.ibm.com>

	* gdb.arch/powerpc-ppr-dscr.c: New file.
	* gdb.arch/powerpc-ppr-dscr.exp: New file.

gdb/doc/ChangeLog:
2018-10-26  Pedro Franco de Carvalho  <pedromfc@linux.ibm.com>

	* gdb.texinfo (PowerPC Features): Describe new features
	"org.gnu.gdb.power.ppr" and "org.gnu.gdb.power.dscr".

1 files changed, 97 insertions, 0 deletions

diff --git a/gdb/gdbserver/linux-ppc-low.c b/gdb/gdbserver/linux-ppc-low.c
index d1ab69f..e7eab37 100644
--- a/gdb/gdbserver/linux-ppc-low.c
+++ b/gdb/gdbserver/linux-ppc-low.c
@@ -20,6 +20,8 @@
 #include "server.h"
 #include "linux-low.h"
 
+#include "elf/common.h"
+#include <sys/uio.h>
 #include <elf.h>
 #include <asm/ptrace.h>
 
@@ -41,8 +43,14 @@
 #define PPC_LI(insn)	(PPC_SEXT (PPC_FIELD (insn, 6, 24), 24) << 2)
 #define PPC_BD(insn)	(PPC_SEXT (PPC_FIELD (insn, 16, 14), 14) << 2)
 
+/* Holds the AT_HWCAP auxv entry.  */
+
 static unsigned long ppc_hwcap;
 
+/* Holds the AT_HWCAP2 auxv entry.  */
+
+static unsigned long ppc_hwcap2;
+
 
 #define ppc_num_regs 73
 
@@ -116,6 +124,24 @@ static int ppc_regmap_e500[] =
  };
 #endif
 
+/* Check whether the kernel provides a register set with number
+   REGSET_ID of size REGSETSIZE for process/thread TID.  */
+
+static int
+ppc_check_regset (int tid, int regset_id, int regsetsize)
+{
+  void *buf = alloca (regsetsize);
+  struct iovec iov;
+
+  iov.iov_base = buf;
+  iov.iov_len = regsetsize;
+
+  if (ptrace (PTRACE_GETREGSET, tid, regset_id, &iov) >= 0
+      || errno == ENODATA)
+    return 1;
+  return 0;
+}
+
 static int
 ppc_cannot_store_register (int regno)
 {
@@ -459,6 +485,46 @@ static void ppc_fill_gregset (struct regcache *regcache, void *buf)
     ppc_collect_ptrace_register (regcache, i, (char *) buf + ppc_regmap[i]);
 }
 
+/* Program Priority Register regset fill function.  */
+
+static void
+ppc_fill_pprregset (struct regcache *regcache, void *buf)
+{
+  char *ppr = (char *) buf;
+
+  collect_register_by_name (regcache, "ppr", ppr);
+}
+
+/* Program Priority Register regset store function.  */
+
+static void
+ppc_store_pprregset (struct regcache *regcache, const void *buf)
+{
+  const char *ppr = (const char *) buf;
+
+  supply_register_by_name (regcache, "ppr", ppr);
+}
+
+/* Data Stream Control Register regset fill function.  */
+
+static void
+ppc_fill_dscrregset (struct regcache *regcache, void *buf)
+{
+  char *dscr = (char *) buf;
+
+  collect_register_by_name (regcache, "dscr", dscr);
+}
+
+/* Data Stream Control Register regset store function.  */
+
+static void
+ppc_store_dscrregset (struct regcache *regcache, const void *buf)
+{
+  const char *dscr = (const char *) buf;
+
+  supply_register_by_name (regcache, "dscr", dscr);
+}
+
 static void
 ppc_fill_vsxregset (struct regcache *regcache, void *buf)
 {
@@ -568,6 +634,10 @@ static struct regset_info ppc_regsets[] = {
      fetch them every time, but still fall back to PTRACE_PEEKUSER for the
      general registers.  Some kernels support these, but not the newer
      PPC_PTRACE_GETREGS.  */
+  { PTRACE_GETREGSET, PTRACE_SETREGSET, NT_PPC_PPR, 0, EXTENDED_REGS,
+    ppc_fill_pprregset, ppc_store_pprregset },
+  { PTRACE_GETREGSET, PTRACE_SETREGSET, NT_PPC_DSCR, 0, EXTENDED_REGS,
+    ppc_fill_dscrregset, ppc_store_dscrregset },
   { PTRACE_GETVSXREGS, PTRACE_SETVSXREGS, 0, 0, EXTENDED_REGS,
   ppc_fill_vsxregset, ppc_store_vsxregset },
   { PTRACE_GETVRREGS, PTRACE_SETVRREGS, 0, 0, EXTENDED_REGS,
@@ -625,6 +695,7 @@ ppc_arch_setup (void)
   /* The value of current_process ()->tdesc needs to be set for this
      call.  */
   ppc_get_auxv (AT_HWCAP, &ppc_hwcap);
+  ppc_get_auxv (AT_HWCAP2, &ppc_hwcap2);
 
   features.isa205 = ppc_linux_has_isa205 (ppc_hwcap);
 
@@ -634,6 +705,11 @@ ppc_arch_setup (void)
   if (ppc_hwcap & PPC_FEATURE_HAS_ALTIVEC)
     features.altivec = true;
 
+  if ((ppc_hwcap2 & PPC_FEATURE2_DSCR)
+      && ppc_check_regset (tid, NT_PPC_DSCR, PPC_LINUX_SIZEOF_DSCRREGSET)
+      && ppc_check_regset (tid, NT_PPC_PPR, PPC_LINUX_SIZEOF_PPRREGSET))
+    features.ppr_dscr = true;
+
   if (ppc_hwcap & PPC_FEATURE_CELL)
     features.cell = true;
 
@@ -678,6 +754,21 @@ ppc_arch_setup (void)
 	else
 	  regset->size = 0;
 	break;
+      case PTRACE_GETREGSET:
+	switch (regset->nt_type)
+	  {
+	  case NT_PPC_PPR:
+	    regset->size = (features.ppr_dscr ?
+			    PPC_LINUX_SIZEOF_PPRREGSET : 0);
+	    break;
+	  case NT_PPC_DSCR:
+	    regset->size = (features.ppr_dscr ?
+			    PPC_LINUX_SIZEOF_DSCRREGSET : 0);
+	    break;
+	  default:
+	    break;
+	  }
+	break;
       default:
 	break;
       }
@@ -3053,6 +3144,8 @@ ppc_get_ipa_tdesc_idx (void)
     return PPC_TDESC_ISA205_ALTIVEC;
   if (tdesc == tdesc_powerpc_isa205_vsx64l)
     return PPC_TDESC_ISA205_VSX;
+  if (tdesc == tdesc_powerpc_isa205_ppr_dscr_vsx64l)
+    return PPC_TDESC_ISA205_PPR_DSCR_VSX;
 #endif
 
   if (tdesc == tdesc_powerpc_32l)
@@ -3069,6 +3162,8 @@ ppc_get_ipa_tdesc_idx (void)
     return PPC_TDESC_ISA205_ALTIVEC;
   if (tdesc == tdesc_powerpc_isa205_vsx32l)
     return PPC_TDESC_ISA205_VSX;
+  if (tdesc == tdesc_powerpc_isa205_ppr_dscr_vsx32l)
+    return PPC_TDESC_ISA205_PPR_DSCR_VSX;
   if (tdesc == tdesc_powerpc_e500l)
     return PPC_TDESC_E500;
 
@@ -3127,6 +3222,7 @@ initialize_low_arch (void)
   init_registers_powerpc_isa205_32l ();
   init_registers_powerpc_isa205_altivec32l ();
   init_registers_powerpc_isa205_vsx32l ();
+  init_registers_powerpc_isa205_ppr_dscr_vsx32l ();
   init_registers_powerpc_e500l ();
 #if __powerpc64__
   init_registers_powerpc_64l ();
@@ -3136,6 +3232,7 @@ initialize_low_arch (void)
   init_registers_powerpc_isa205_64l ();
   init_registers_powerpc_isa205_altivec64l ();
   init_registers_powerpc_isa205_vsx64l ();
+  init_registers_powerpc_isa205_ppr_dscr_vsx64l ();
 #endif
 
   initialize_regsets_info (&ppc_regsets_info);