[PowerPC] Add support for PPR and DSCR

[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".