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[2/2] Detect 64-bit-ness in PowerPC Book III-E

Message ID 1420964846-18881-3-git-send-email-yao@codesourcery.com
State New
Headers show

Commit Message

Yao Qi Jan. 11, 2015, 8:27 a.m. UTC
This patch is to teach both GDB and GDBServer to detect 64-bit inferior
correctly.  We find a problem that GDBServer is unable to detect on a
e5500 core processor.  Current GDBServer assumes that MSR is a 64-bit
register, but MSR is a 32-bit register in Book III-E.  This patch is
to fix this problem by checking the right bit in MSR, in order to handle
both Book III-S and Book III-E.  In order to detect Book III-S and
Book III-E, we check the PPC_FEATURE_BOOKE from the host's HWCAP,
because it should an invariant on the same machine cross different
processes.

In order to share code, I add nat/ppc-linux.c for both GDB and
GDBserver side.  Note that this patch only adds ppc-linux.o to
NATDEPFILES in config/powerpc/ppc64-linux.mh, but doesn't add
ppc-linux.o to NATDEPFILES in config/powerpc/linux.mh, because
ppc-linux.o is only needed for ppc64-linux so far.  Once we add
functions for ppc32-linux target in ppc-linux.c in the future,
we can add ppc-linux.o to config/powerpc/linux.mh.

gdb:

2015-01-11  Yao Qi  <yao@codesourcery.com>

	* Makefile.in (ppc-linux.o): New rule.
	* config/powerpc/ppc64-linux.mh (NATDEPFILES): Add ppc-linux.o.
	* nat/ppc-linux.h [__powerpc64__] (ppc64_64bit_inferior_p):
	Declare.
	* nat/ppc-linux.c: New file.
	* ppc-linux-nat.c (ppc_linux_target_wordsize) [__powerpc64__]:
	Call ppc64_64bit_inferior_p.

gdb/gdbserver:

2015-01-11  Yao Qi  <yao@codesourcery.com>

	* Makefile.in (SFILES): Add nat/ppc-linux.c.
	(ppc-linux.o): New rule.
	* configure.srv (powerpc*-*-linux*): Add ppc-linux.o.
	* linux-ppc-low.c (ppc_arch_setup) [__powerpc64__]: Call
	ppc64_64bit_inferior_p
---
 gdb/Makefile.in                   |  4 +++
 gdb/config/powerpc/ppc64-linux.mh |  2 +-
 gdb/gdbserver/Makefile.in         |  5 ++-
 gdb/gdbserver/configure.srv       |  2 +-
 gdb/gdbserver/linux-ppc-low.c     |  4 +--
 gdb/nat/ppc-linux.c               | 69 +++++++++++++++++++++++++++++++++++++++
 gdb/nat/ppc-linux.h               |  6 ++++
 gdb/ppc-linux-nat.c               |  2 +-
 8 files changed, 87 insertions(+), 7 deletions(-)
 create mode 100644 gdb/nat/ppc-linux.c
diff mbox

Patch

diff --git a/gdb/Makefile.in b/gdb/Makefile.in
index f519f0a..fc1c7fa 100644
--- a/gdb/Makefile.in
+++ b/gdb/Makefile.in
@@ -2271,6 +2271,10 @@  mips-linux-watch.o: ${srcdir}/nat/mips-linux-watch.c
 	$(COMPILE) $(srcdir)/nat/mips-linux-watch.c
 	$(POSTCOMPILE)
 
+ppc-linux.o: ${srcdir}/nat/ppc-linux.c
+	$(COMPILE) $(srcdir)/nat/ppc-linux.c
+	$(POSTCOMPILE)
+
 #
 # gdb/tui/ dependencies
 #
diff --git a/gdb/config/powerpc/ppc64-linux.mh b/gdb/config/powerpc/ppc64-linux.mh
index 4b91408..1b3fbc7 100644
--- a/gdb/config/powerpc/ppc64-linux.mh
+++ b/gdb/config/powerpc/ppc64-linux.mh
@@ -6,7 +6,7 @@  NAT_FILE= config/nm-linux.h
 NATDEPFILES= inf-ptrace.o fork-child.o \
 	ppc-linux-nat.o proc-service.o linux-thread-db.o \
 	linux-nat.o linux-osdata.o linux-fork.o linux-procfs.o linux-ptrace.o \
-	linux-waitpid.o
+	linux-waitpid.o ppc-linux.o
 NAT_CDEPS = $(srcdir)/proc-service.list
 
 # The PowerPC has severe limitations on TOC size, and uses them even
diff --git a/gdb/gdbserver/Makefile.in b/gdb/gdbserver/Makefile.in
index 1ed2ec8..0e442fc 100644
--- a/gdb/gdbserver/Makefile.in
+++ b/gdb/gdbserver/Makefile.in
@@ -155,7 +155,7 @@  SFILES=	$(srcdir)/gdbreplay.c $(srcdir)/inferiors.c $(srcdir)/dll.c \
 	$(srcdir)/linux-m32r-low.c \
 	$(srcdir)/linux-m68k-low.c $(srcdir)/linux-mips-low.c \
 	$(srcdir)/linux-nios2-low.c \
-	$(srcdir)/linux-ppc-low.c \
+	$(srcdir)/linux-ppc-low.c $(srcdir)/nat/ppc-linux.c \
 	$(srcdir)/linux-s390-low.c \
 	$(srcdir)/linux-sh-low.c $(srcdir)/linux-sparc-low.c \
 	$(srcdir)/linux-x86-low.c \
@@ -581,6 +581,9 @@  linux-waitpid.o: ../nat/linux-waitpid.c
 mips-linux-watch.o: ../nat/mips-linux-watch.c
 	$(COMPILE) $<
 	$(POSTCOMPILE)
+ppc-linux.o: ../nat/ppc-linux.c
+	$(COMPILE) $<
+	$(POSTCOMPILE)
 
 aarch64.c : $(srcdir)/../regformats/aarch64.dat $(regdat_sh)
 	$(SHELL) $(regdat_sh) $(srcdir)/../regformats/aarch64.dat aarch64.c
diff --git a/gdb/gdbserver/configure.srv b/gdb/gdbserver/configure.srv
index 679fc9f..f52aee2 100644
--- a/gdb/gdbserver/configure.srv
+++ b/gdb/gdbserver/configure.srv
@@ -217,7 +217,7 @@  case "${target}" in
 			srv_regobj="${srv_regobj} powerpc-isa205-64l.o"
 			srv_regobj="${srv_regobj} powerpc-isa205-altivec64l.o"
 			srv_regobj="${srv_regobj} powerpc-isa205-vsx64l.o"
-			srv_tgtobj="$srv_linux_obj linux-ppc-low.o"
+			srv_tgtobj="$srv_linux_obj linux-ppc-low.o ppc-linux.o"
 			srv_xmlfiles="rs6000/powerpc-32l.xml"
 			srv_xmlfiles="${srv_xmlfiles} rs6000/powerpc-altivec32l.xml"
 			srv_xmlfiles="${srv_xmlfiles} rs6000/powerpc-cell32l.xml"
diff --git a/gdb/gdbserver/linux-ppc-low.c b/gdb/gdbserver/linux-ppc-low.c
index 6e880c1..188fac0 100644
--- a/gdb/gdbserver/linux-ppc-low.c
+++ b/gdb/gdbserver/linux-ppc-low.c
@@ -398,13 +398,11 @@  ppc_arch_setup (void)
   current_process ()->tdesc = tdesc;
   ppc_hwcap = 0;
 
-  /* Only if the high bit of the MSR is set, we actually have
-     a 64-bit inferior.  */
   regcache = new_register_cache (tdesc);
   fetch_inferior_registers (regcache, find_regno (tdesc, "msr"));
   collect_register_by_name (regcache, "msr", &msr);
   free_register_cache (regcache);
-  if (msr < 0)
+  if (ppc64_64bit_inferior_p (msr))
     {
       ppc_get_hwcap (&ppc_hwcap);
       if (ppc_hwcap & PPC_FEATURE_CELL)
diff --git a/gdb/nat/ppc-linux.c b/gdb/nat/ppc-linux.c
new file mode 100644
index 0000000..f6eaab2
--- /dev/null
+++ b/gdb/nat/ppc-linux.c
@@ -0,0 +1,69 @@ 
+/*Copyright (C) 2015 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include "common-defs.h"
+#include "ppc-linux.h"
+#include <elf.h>
+
+#ifdef __powerpc64__
+
+/* Get the HWCAP from the process of GDB or GDBserver.  If success,
+   save it in *VALP.   */
+
+static void
+ppc64_host_hwcap (unsigned long *valp)
+{
+  unsigned char data[2 * 8];
+  FILE *f = fopen ("/proc/self/auxv", "r");
+
+  if (f == NULL)
+    return;
+
+  while (fread (data, sizeof (data), 1, f) > 0)
+    {
+      unsigned long *data_p = (unsigned long *) data;
+
+      if (data_p[0] == AT_HWCAP)
+	{
+	  *valp = data_p[1];
+	  break;
+	}
+    }
+
+  fclose (f);
+}
+
+int
+ppc64_64bit_inferior_p (long msr)
+{
+  unsigned long ppc_host_hwcap = 0;
+
+  /* Get host's HWCAP to check whether the machine is Book E.  */
+  ppc64_host_hwcap (&ppc_host_hwcap);
+
+  /* We actually have a 64-bit inferior only if the certain bit of the
+     MSR is set.  The PowerISA Book III-S MSR is different from the
+     PowerISA Book III-E MSR.  The Book III-S MSR is 64 bits wide, and
+     its MSR[SF] is the bit 0 of a 64-bit value.  Book III-E MSR is 32
+     bits wide, and its MSR[CM] is the bit 0 of a 32-bit value.   */
+  if (ppc_host_hwcap & PPC_FEATURE_BOOKE)
+    return msr & 0x80000000;
+  else
+    return msr < 0;
+}
+
+#endif
diff --git a/gdb/nat/ppc-linux.h b/gdb/nat/ppc-linux.h
index 30d936f..0ff2223 100644
--- a/gdb/nat/ppc-linux.h
+++ b/gdb/nat/ppc-linux.h
@@ -82,4 +82,10 @@ 
 #define PTRACE_SETEVRREGS 21
 #endif
 
+#ifdef __powerpc64__
+/* Return whether the inferior is 64bit or not by checking certain bit
+   in MSR.  */
+int ppc64_64bit_inferior_p (long msr);
+#endif
+
 #endif
diff --git a/gdb/ppc-linux-nat.c b/gdb/ppc-linux-nat.c
index c5a286b..88ca49e 100644
--- a/gdb/ppc-linux-nat.c
+++ b/gdb/ppc-linux-nat.c
@@ -2367,7 +2367,7 @@  ppc_linux_target_wordsize (void)
 
   errno = 0;
   msr = (long) ptrace (PTRACE_PEEKUSER, tid, PT_MSR * 8, 0);
-  if (errno == 0 && msr < 0)
+  if (errno == 0 && ppc64_64bit_inferior_p (msr))
     wordsize = 8;
 #endif