Re: [RFC] Add support for PPC Altivec registers in gcore

[Carlos Eduardo Seo <cseo@linux.vnet.ibm.com>]

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Ulrich Weigand wrote:
> Yes, exactly.  You'll have to update the list in gdbarch.sh,
> and run the script to regenerate gdbarch.c and gdbarch.h.
> 

Ok, here's my first shot at this new approach for writing core files. I 
had to add a new BFD function (binutils patch is attached as well - I'll 
submit this to the binutils mailing list later) and I didn't include the 
fill_register fallbacks in the new implementation.

I believe a similar loop could also be used in -tdep.c files to read the 
core files as well, right?

Only wrote the code for ppc, but this could be easily expanded to other 
archs, adding modifications similar to those I did in ppc-linux-tdep.c.

I think this first code is very raw, but I believe we can improve it and 
use this approach for all archs in the future.

Opinions / suggestions?

Regards,

-- 
Carlos Eduardo Seo
Software Engineer
IBM Linux Technology Center

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2008-02-08  Carlos Eduardo Seo  <cseo@linux.vnet.ibm.com>

	* gdbarch.c: Refreshed.
	* gdbarch.h: Refreshed.
	* gdbarch.sh: Added new gdbarch struct core_regset_sections.
	* regset.h (core_regset_section): Declare.
	* ppc-linux-tdep.c: (ppc_regset_sections): Declare.
	  (ppc_linux_init_abi): Initialized new gdbarch struct
	  core_regset_sections.
	* linux-nat.c (linux_nat_do_thread_registers): Added
	  support to the new gdbarch struct core_regset_sections.

Index: src/gdb/gdbarch.c
===================================================================
--- src.orig/gdb/gdbarch.c
+++ src/gdb/gdbarch.c
@@ -222,6 +222,7 @@ struct gdbarch
   gdbarch_register_reggroup_p_ftype *register_reggroup_p;
   gdbarch_fetch_pointer_argument_ftype *fetch_pointer_argument;
   gdbarch_regset_from_core_section_ftype *regset_from_core_section;
+  struct core_regset_section * core_regset_sections;
   gdbarch_core_xfer_shared_libraries_ftype *core_xfer_shared_libraries;
   int vtable_function_descriptors;
   int vbit_in_delta;
@@ -344,6 +345,7 @@ struct gdbarch startup_gdbarch =
   default_register_reggroup_p,  /* register_reggroup_p */
   0,  /* fetch_pointer_argument */
   0,  /* regset_from_core_section */
+  0,  /* core_regset_sections */
   0,  /* core_xfer_shared_libraries */
   0,  /* vtable_function_descriptors */
   0,  /* vbit_in_delta */
@@ -694,6 +696,9 @@ gdbarch_dump (struct gdbarch *gdbarch, s
                       "gdbarch_dump: core_read_description = <0x%lx>\n",
                       (long) gdbarch->core_read_description);
   fprintf_unfiltered (file,
+                      "gdbarch_dump: core_regset_sections = %s\n",
+                      (char *) gdbarch->core_regset_sections);
+  fprintf_unfiltered (file,
                       "gdbarch_dump: gdbarch_core_xfer_shared_libraries_p() = %d\n",
                       gdbarch_core_xfer_shared_libraries_p (gdbarch));
   fprintf_unfiltered (file,
@@ -2810,6 +2815,22 @@ set_gdbarch_regset_from_core_section (st
   gdbarch->regset_from_core_section = regset_from_core_section;
 }
 
+struct core_regset_section *
+gdbarch_core_regset_sections (struct gdbarch *gdbarch)
+{
+  gdb_assert (gdbarch != NULL);
+  if (gdbarch_debug >= 2)
+    fprintf_unfiltered (gdb_stdlog, "gdbarch_core_regset_sections called\n");
+  return gdbarch->core_regset_sections;
+}
+
+void
+set_gdbarch_core_regset_sections (struct gdbarch *gdbarch,
+                                  struct core_regset_section * core_regset_sections)
+{
+  gdbarch->core_regset_sections = core_regset_sections;
+}
+
 int
 gdbarch_core_xfer_shared_libraries_p (struct gdbarch *gdbarch)
 {
Index: src/gdb/gdbarch.h
===================================================================
--- src.orig/gdb/gdbarch.h
+++ src/gdb/gdbarch.h
@@ -50,6 +50,7 @@ struct target_ops;
 struct obstack;
 struct bp_target_info;
 struct target_desc;
+struct core_regset_section;
 
 extern struct gdbarch *current_gdbarch;
 
@@ -626,6 +627,11 @@ typedef const struct regset * (gdbarch_r
 extern const struct regset * gdbarch_regset_from_core_section (struct gdbarch *gdbarch, const char *sect_name, size_t sect_size);
 extern void set_gdbarch_regset_from_core_section (struct gdbarch *gdbarch, gdbarch_regset_from_core_section_ftype *regset_from_core_section);
 
+/* Supported register notes in core files */
+
+extern struct core_regset_section * gdbarch_core_regset_sections (struct gdbarch *gdbarch);
+extern void set_gdbarch_core_regset_sections (struct gdbarch *gdbarch, struct core_regset_section * core_regset_sections);
+
 /* Read offset OFFSET of TARGET_OBJECT_LIBRARIES formatted shared libraries list from
    core file into buffer READBUF with length LEN. */
 
Index: src/gdb/gdbarch.sh
===================================================================
--- src.orig/gdb/gdbarch.sh
+++ src/gdb/gdbarch.sh
@@ -594,6 +594,9 @@ F:CORE_ADDR:fetch_pointer_argument:struc
 # name SECT_NAME and size SECT_SIZE.
 M:const struct regset *:regset_from_core_section:const char *sect_name, size_t sect_size:sect_name, sect_size
 
+# Supported register notes in core files
+v:struct core_regset_section *:core_regset_sections:const char *name, int len::::::(char *) gdbarch->core_regset_sections
+
 # Read offset OFFSET of TARGET_OBJECT_LIBRARIES formatted shared libraries list from
 # core file into buffer READBUF with length LEN.
 M:LONGEST:core_xfer_shared_libraries:gdb_byte *readbuf, ULONGEST offset, LONGEST len:readbuf, offset, len
@@ -729,6 +732,7 @@ struct target_ops;
 struct obstack;
 struct bp_target_info;
 struct target_desc;
+struct core_regset_section;
 
 extern struct gdbarch *current_gdbarch;
 EOF
Index: src/gdb/regset.h
===================================================================
--- src.orig/gdb/regset.h
+++ src/gdb/regset.h
@@ -20,6 +20,12 @@
 #ifndef REGSET_H
 #define REGSET_H 1
 
+struct core_regset_section
+{
+  const char *sect_name;
+  int size;
+};
+
 struct gdbarch;
 struct regcache;
 
Index: src/gdb/ppc-linux-tdep.c
===================================================================
--- src.orig/gdb/ppc-linux-tdep.c
+++ src/gdb/ppc-linux-tdep.c
@@ -38,6 +38,13 @@
 #include "frame-unwind.h"
 #include "tramp-frame.h"
 
+static struct core_regset_section ppc_regset_sections[] =
+{
+  {".reg2", 264},
+  {".reg-ppc-vmx", 544},
+  {NULL, 0}
+};
+
 static CORE_ADDR
 ppc_linux_skip_trampoline_code (struct frame_info *frame, CORE_ADDR pc)
 {
@@ -945,6 +952,10 @@ ppc_linux_init_abi (struct gdbarch_info 
       tramp_frame_prepend_unwinder (gdbarch, &ppc64_linux_sigaction_tramp_frame);
       tramp_frame_prepend_unwinder (gdbarch, &ppc64_linux_sighandler_tramp_frame);
     }
+
+  /* Register sections.  */
+  set_gdbarch_core_regset_sections (gdbarch, ppc_regset_sections);
+
   set_gdbarch_regset_from_core_section (gdbarch, ppc_linux_regset_from_core_section);
 
   /* Enable TLS support.  */
Index: src/gdb/linux-nat.c
===================================================================
--- src.orig/gdb/linux-nat.c
+++ src/gdb/linux-nat.c
@@ -2631,6 +2631,9 @@ linux_nat_do_thread_registers (bfd *obfd
   const struct regset *regset;
   int core_regset_p;
   struct cleanup *old_chain;
+  struct core_regset_section *sect_list;
+  char *gdb_regset;
+  int i = 0;
 
   old_chain = save_inferior_ptid ();
   inferior_ptid = ptid;
@@ -2638,6 +2641,8 @@ linux_nat_do_thread_registers (bfd *obfd
   do_cleanups (old_chain);
 
   core_regset_p = gdbarch_regset_from_core_section_p (gdbarch);
+  sect_list = gdbarch_core_regset_sections (gdbarch);
+
   if (core_regset_p
       && (regset = gdbarch_regset_from_core_section (gdbarch, ".reg",
 						     sizeof (gregs))) != NULL
@@ -2653,35 +2658,69 @@ linux_nat_do_thread_registers (bfd *obfd
 					       lwp,
 					       stop_signal, &gregs);
 
-  if (core_regset_p
-      && (regset = gdbarch_regset_from_core_section (gdbarch, ".reg2",
-						     sizeof (fpregs))) != NULL
-      && regset->collect_regset != NULL)
-    regset->collect_regset (regset, regcache, -1,
-			    &fpregs, sizeof (fpregs));
+  /* The loop below uses the new struct core_regset_section, which stores
+     the supported section names and sizes for the core file. Note that
+     note PRSTATUS needs to be treated specially. But the other notes are
+     structurally the same, so they can benefit from the new struct.  */
+
+  if (core_regset_p && sect_list != NULL)
+    while ((sect_list + i)->sect_name != NULL)
+      {
+	if ((regset = gdbarch_regset_from_core_section (gdbarch,
+						     (sect_list + i)->sect_name,
+						     (*(sect_list + i)).size))
+	     != NULL && regset->collect_regset != NULL)
+	  {
+	    gdb_regset = xmalloc ((*(sect_list + i)).size);
+	    regset->collect_regset (regset, regcache, -1,
+				    gdb_regset, (*(sect_list + i)).size);
+	    note_data = (char *) elfcore_write_register_note (obfd,
+							   note_data,
+							   note_size,
+							   (sect_list + i)->sect_name,
+							   gdb_regset,
+							   (*(sect_list + i)).size);
+	    xfree (gdb_regset);
+	  }
+	  i++;
+      }
+
+  /* For architectures that does not have the struct core_regset_section implemented,
+     we use the old method. When all the architectures have the new support, the code
+     below should be deprecated.  */
+
   else
-    fill_fpregset (regcache, &fpregs, -1);
+    {
+      if (core_regset_p
+          && (regset = gdbarch_regset_from_core_section (gdbarch, ".reg2",
+							 sizeof (fpregs))) != NULL
+	  && regset->collect_regset != NULL)
+	regset->collect_regset (regset, regcache, -1,
+				&fpregs, sizeof (fpregs));
+      else
+	fill_fpregset (regcache, &fpregs, -1);
 
-  note_data = (char *) elfcore_write_prfpreg (obfd,
-					      note_data,
-					      note_size,
-					      &fpregs, sizeof (fpregs));
+      note_data = (char *) elfcore_write_prfpreg (obfd,
+						  note_data,
+						  note_size,
+						  &fpregs, sizeof (fpregs));
 
 #ifdef FILL_FPXREGSET
-  if (core_regset_p
-      && (regset = gdbarch_regset_from_core_section (gdbarch, ".reg-xfp",
-						     sizeof (fpxregs))) != NULL
-      && regset->collect_regset != NULL)
-    regset->collect_regset (regset, regcache, -1,
-			    &fpxregs, sizeof (fpxregs));
-  else
-    fill_fpxregset (regcache, &fpxregs, -1);
+      if (core_regset_p
+	  && (regset = gdbarch_regset_from_core_section (gdbarch, ".reg-xfp",
+							 sizeof (fpxregs))) != NULL
+	  && regset->collect_regset != NULL)
+	regset->collect_regset (regset, regcache, -1,
+				&fpxregs, sizeof (fpxregs));
+      else
+	fill_fpxregset (regcache, &fpxregs, -1);
 
-  note_data = (char *) elfcore_write_prxfpreg (obfd,
-					       note_data,
-					       note_size,
-					       &fpxregs, sizeof (fpxregs));
+      note_data = (char *) elfcore_write_prxfpreg (obfd,
+						   note_data,
+						   note_size,
+						   &fpxregs, sizeof (fpxregs));
 #endif
+    }
   return note_data;
 }
 

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2008-02-03  Carlos Eduardo Seo  <cseo@linux.vnet.ibm.com>

	* elf.c (elfcore_write_register_note): New function.
	* elf-bfd.h (elfcore_write_register_note): New prototype.

Index: src/bfd/elf.c
===================================================================
--- src.orig/bfd/elf.c
+++ src/bfd/elf.c
@@ -8438,6 +8438,23 @@ elfcore_write_ppc_vmx (bfd *abfd,
 			     note_name, NT_PPC_VMX, ppc_vmx, size);
 }
 
+char *
+elfcore_write_register_note (bfd *abfd,
+			     char *buf,
+			     int *bufsiz,
+			     const char *section,
+			     const void *data,
+			     int size)
+{
+  if (strcmp (section, ".reg2") == 0)
+    return elfcore_write_prfpreg (abfd, buf, bufsiz, data, size);
+  if (strcmp (section, ".reg-xfp") == 0)
+    return elfcore_write_prxfpreg (abfd, buf, bufsiz, data, size);
+  if (strcmp (section, ".reg-ppc-vmx") == 0)
+    return elfcore_write_ppc_vmx (abfd, buf, bufsiz, data, size);
+  return NULL;
+}
+
 static bfd_boolean
 elf_parse_notes (bfd *abfd, char *buf, size_t size, file_ptr offset)
 {
Index: src/bfd/elf-bfd.h
===================================================================
--- src.orig/bfd/elf-bfd.h
+++ src/bfd/elf-bfd.h
@@ -2109,6 +2109,8 @@ extern char *elfcore_write_ppc_vmx
   (bfd *, char *, int *, const void *, int);
 extern char *elfcore_write_lwpstatus
   (bfd *, char *, int *, long, int, const void *);
+extern char *elfcore_write_register_note
+  (bfd *, char *, int *, const char *, const void *, int);
 
 extern bfd *_bfd_elf32_bfd_from_remote_memory
   (bfd *templ, bfd_vma ehdr_vma, bfd_vma *loadbasep,