32bit gdbserver-xen/libxc to debug 64bit guest

PATCH In review Mukesh Rathor 1 participant 1 message Nov 2, 2007

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Mukesh Rathor

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2007-11-02 02:15 UTC #0 lore raw

PATCH 1/2 32bit gdbserver-xen/libxc to debug 64bit guest

part 1 : files changed in gdbserver xen-sparse tree.

tools/debugger/gdb/gdb-6.2.1-xen-sparse/gdb/gdbserver/linux-xen-low.c +22 ~~-13~~

diff -uNpr xen-3.1.1-ovs.orig/tools/debugger/gdb/gdb-6.2.1-xen-sparse/gdb/gdbserver/linux-xen-low.c xen-3.1.1-ovs.new/tools/debugger/gdb/gdb-6.2.1-xen-sparse/gdb/gdbserver/linux-xen-low.c
@@ -22,6 +22,10 @@
 #include "server.h"
 #include "linux-low.h"
 
+#ifdef _GDB_CROSS_COMP
+#include "user.h"
+#endif
+
 #include <sys/wait.h>
 #include <stdio.h>
 #include <sys/param.h>

@@ -69,8 +73,13 @@ struct pending_signals
   struct pending_signals *prev;
 };
 
-#define PTRACE_ARG3_TYPE long
-#define PTRACE_XFER_TYPE long
+#ifdef _GDB_CROSS_COMP
+#define PTRACE_ARG3_TYPE unsigned long long
+#define PTRACE_XFER_TYPE unsigned long long
+#else
+#define PTRACE_ARG3_TYPE unsigned long 
+#define PTRACE_XFER_TYPE unsigned long
+#endif
 
 static int use_regsets_p = 1;

@@ -157,7 +166,8 @@ linux_attach (int domid)
     add_thread (0, new_process);
     new_process->stop_expected = 0;
 
-    if (xc_ptrace (xc_handle, PTRACE_ATTACH, domid, 0, isfile) != 0) {
+    if (xc_ptrace(xc_handle, PTRACE_ATTACH, domid, 0,(PTRACE_XFER_TYPE)isfile))
+    {
 	fprintf (stderr, "Cannot attach to domain %d: %s (%d)\n", domid,
 		 strerror (errno), errno);
 	fflush (stderr);

@@ -261,8 +271,7 @@ regsets_fetch_inferior_registers ()
 
       buf = malloc (regset->size);
       res = xc_ptrace (xc_handle, regset->get_request, 
-		      curvcpuid(),
-		      0, (PTRACE_XFER_TYPE)buf);
+		      curvcpuid(), 0, (PTRACE_XFER_TYPE)buf);
       if (res < 0)
 	{
 	  if (errno == EIO)

@@ -314,7 +323,8 @@ regsets_store_inferior_registers ()
 
       buf = malloc (regset->size);
       regset->fill_function (buf);
-      res = xc_ptrace (xc_handle, regset->set_request, curvcpuid(), 0, (PTRACE_XFER_TYPE)buf);
+      res = xc_ptrace (xc_handle, regset->set_request, curvcpuid(), 
+                       0, (PTRACE_XFER_TYPE)buf);
       if (res < 0)
 	{
 	  if (errno == EIO)

@@ -392,7 +402,8 @@ linux_read_memory (CORE_ADDR memaddr, ch
   for (i = 0; i < count; i++, addr += sizeof (PTRACE_XFER_TYPE))
     {
       errno = 0;
-      buffer[i] = xc_ptrace (xc_handle, PTRACE_PEEKTEXT, curvcpuid(), (PTRACE_ARG3_TYPE) addr, 0);
+      buffer[i] = xc_ptrace (xc_handle, PTRACE_PEEKTEXT, curvcpuid(), 
+                             (PTRACE_ARG3_TYPE)addr, 0);
       if (errno)
 	return errno;
     }

@@ -418,7 +429,7 @@ linux_write_memory (CORE_ADDR memaddr, c
   register int count
   = (((memaddr + len) - addr) + sizeof (PTRACE_XFER_TYPE) - 1) / sizeof (PTRACE_XFER_TYPE);
   /* Allocate buffer of that many longwords.  */
-  register PTRACE_XFER_TYPE *buffer = (PTRACE_XFER_TYPE *) alloca (count * sizeof (PTRACE_XFER_TYPE));
+  register PTRACE_XFER_TYPE *buffer = (PTRACE_XFER_TYPE*)alloca(count * sizeof(PTRACE_XFER_TYPE));
   extern int errno;
 
   TRACE_ENTER;

@@ -426,15 +437,13 @@ linux_write_memory (CORE_ADDR memaddr, c
   /* Fill start and end extra bytes of buffer with existing memory data.  */
 
   buffer[0] = xc_ptrace (xc_handle, PTRACE_PEEKTEXT, curvcpuid(),
-		      (PTRACE_ARG3_TYPE) addr, 0);
+		         (PTRACE_ARG3_TYPE)addr, 0);
 
   if (count > 1)
     {
       buffer[count - 1]
 	= xc_ptrace (xc_handle, PTRACE_PEEKTEXT, curvcpuid(),
-		  (PTRACE_ARG3_TYPE) (addr + (count - 1)
-				      * sizeof (PTRACE_XFER_TYPE)),
-		  0);
+		     (PTRACE_ARG3_TYPE)(addr + (count - 1) * sizeof(PTRACE_ARG3_TYPE)), 0);
     }
 
   /* Copy data to be written over corresponding part of buffer */

@@ -446,7 +455,7 @@ linux_write_memory (CORE_ADDR memaddr, c
     {
       errno = 0;
       xc_ptrace (xc_handle, PTRACE_POKETEXT, curvcpuid(), 
-		(PTRACE_ARG3_TYPE) addr, buffer[i]);
+		 (PTRACE_ARG3_TYPE) addr, buffer[i]);
       if (errno)
 	return errno;
     }

tools/debugger/gdb/gdb-6.2.1-xen-sparse/gdb/gdbserver/Makefile.in +9 -1

diff -uNpr xen-3.1.1-ovs.orig/tools/debugger/gdb/gdb-6.2.1-xen-sparse/gdb/gdbserver/Makefile.in xen-3.1.1-ovs.new/tools/debugger/gdb/gdb-6.2.1-xen-sparse/gdb/gdbserver/Makefile.in
@@ -135,6 +135,14 @@ OBS = inferiors.o regcache.o remote-util
 	$(DEPFILES)
 GDBSERVER_LIBS = @GDBSERVER_LIBS@
 
+# if cross compiling to get a 32binary on a 64bit system, we statically link
+# the xenctrl lib, so as not to break anything
+ifneq "$(findstring _GDB_CROSS_COMP, $(CFLAGS))" ""
+        STATIC_LNK=-Wl,-Bstatic
+        STATIC_UNLNK=-Wl,-Bdynamic
+endif
+
+
 # Prevent Sun make from putting in the machine type.  Setting
 # TARGET_ARCH to nothing works for SunOS 3, 4.0, but not for 4.1.
 .c.o:

@@ -172,7 +180,7 @@ clean-info:
 gdbserver-xen: $(OBS) ${ADD_DEPS} ${CDEPS}
 	rm -f gdbserver-xen
 	${CC-LD} $(GLOBAL_CFLAGS) $(LDFLAGS) -o gdbserver-xen $(OBS) \
-	  $(GDBSERVER_LIBS) $(XM_CLIBS)
+	  $(STATIC_LNK) $(GDBSERVER_LIBS) $(STATIC_UNLNK) $(XM_CLIBS)
 
 gdbreplay: gdbreplay.o
 	rm -f gdbreplay

tools/debugger/gdb/gdb-6.2.1-xen-sparse/mkbuildtree +1 -1

diff -uNpr xen-3.1.1-ovs.orig/tools/debugger/gdb/gdb-6.2.1-xen-sparse/mkbuildtree xen-3.1.1-ovs.new/tools/debugger/gdb/gdb-6.2.1-xen-sparse/mkbuildtree
@@ -66,7 +66,7 @@ relative_lndir ()
     (
     cd $i
     pref=`echo $i | sed -e 's#/[^/]*#../#g' -e 's#^\.##'`
-    for j in `find . -type f -o -type l -maxdepth 1`; do
+    for j in `find . -maxdepth 1 -type f -o -type l`; do
       ln -sf ${pref}${REAL_DIR}/$i/$j ${SYMLINK_DIR}/$i/$j
     done
     )

tools/debugger/gdb/gdbbuild +9 -2

diff -uNpr xen-3.1.1-ovs.orig/tools/debugger/gdb/gdbbuild xen-3.1.1-ovs.new/tools/debugger/gdb/gdbbuild
@@ -22,7 +22,14 @@ cd gdb-$GDB_VERSION-linux-i386-xen
 if [ "$MAKE" ]; then
     $MAKE
 elif which gmake ; then
-    gmake -j4
+    MAKE="gmake -j4"
 else
-    make -j4
+    MAKE="make -j4"
+fi
+
+if [[ $1 == _GDB_CROSS_COMP ]]
+then
+	$MAKE CFLAGS="-m32 -D_GDB_CROSS_COMP -D __x86_64__" LDFLAGS="-m32"
+else
+	$MAKE
 fi

tools/debugger/gdb/README +33 -5

diff -uNpr xen-3.1.1-ovs.orig/tools/debugger/gdb/README xen-3.1.1-ovs.new/tools/debugger/gdb/README
@@ -5,11 +5,37 @@ DomU & HVM GDB server for 32-bit (PAE an
 Lines marked below with [*] are optional, if you want full
 source-level debugging of your kernel image.
 
-To build the GDB server:
- 0. Build rest of the Xen first from the base directory
- 1. Run ./gdbbuild from within this directory.
- 2. Copy ./gdb-6.2.1-linux-i386-xen/gdb/gdbserver/gdbserver-xen
-    to your test machine.
+gdbserver can run on 32bit or 64bit dom0. It can attach to a 32 bit non-PAE,
+a 32bit PAE, or an x86_64 guest:
+
+            32 non-PAE        32 PAE        x86_64
+32 dom0:        Y               Y             Y
+64 dom0:        ?               ?             Y
+
+
+TO BUILD: Involves two steps, building libxc and gdbserver-xen. After building,
+          copy gdbserver-xen, and possibly libxc to dom0:
+
+32 non-PAE (build on 32bit box) or x86_64 (build on x86_64 box) :
+    1. Build libxc first by running >make
+    2. Build gdbserver-xen by running >gdbbuild
+    3. copy ./gdb-6.2.1-linux-i386-xen/gdb/gdbserver/gdbserver-xen to dom0
+
+32 PAE (build on 32bit box) :
+    1. Build libxc first by running 
+        >CFLAGS="-D_CROSS_COMP_PAE" make
+    2. Build gdbserver-xen by running 
+        >gdbbuild
+    3. copy gdbserver-xen  and libxenctrl.so.3.0.0 to dom0
+
+x86_64 (build on x86_64 box to run on 32 domU) :
+    1. Build libxc first by running 
+        >CFLAGS="-m32 -D_GDB_CROSS_COMP" make
+    2. Build gdbserver-xen by running 
+        >gdbbuild  _GDB_CROSS_COMP
+    3. copy gdbserver-xen to dom0 (libxenctrl is statically linked in this case)
+
+
 
 To build a debuggable guest domU kernel image:
  1. cd linux-2.6.xx-xenU

@@ -28,6 +54,8 @@ To debug a running guest:
     # target remote 127.0.0.1:9999
     # bt
     # disass
+ 5. gdb could be running on a different host, in which case:
+    # target remote 127.11.11.11:9999 where 127.11.11.11 is the xen host.
 
 To debug a crashed domU guest:
  1. Add '(enable-dump yes)' to /etc/xen/xend-config.sxp before

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