Re: [RFC] Add FR-V Linux core file support

[Kevin Buettner <kevinb at redhat dot com>]

I ended up committing the patch below.  I believe that this is largely
the same as the original patch.  The only difference is that I've revised
one of the comments in solib-frv.c.

Index: Makefile.in
===================================================================
RCS file: /cvs/src/src/gdb/Makefile.in,v
retrieving revision 1.792
diff -u -p -r1.792 Makefile.in
--- Makefile.in	15 Mar 2006 17:13:36 -0000	1.792
+++ Makefile.in	15 Mar 2006 23:37:43 -0000
@@ -1964,9 +1964,10 @@ frame.o: frame.c $(defs_h) $(frame_h) $(
 	$(command_h) $(gdbcmd_h) $(observer_h) $(objfiles_h) $(exceptions_h)
 frame-unwind.o: frame-unwind.c $(defs_h) $(frame_h) $(frame_unwind_h) \
 	$(gdb_assert_h) $(dummy_frame_h) $(gdb_obstack_h)
-frv-linux-tdep.o: frv-linux-tdep.c $(defs_h) $(target_h) $(frame_h) \
-	$(osabi_h) $(elf_bfd_h) $(elf_frv_h) $(frv_tdep_h) $(trad_frame_h) \
-	$(frame_unwind_h)
+frv-linux-tdep.o: frv-linux-tdep.c $(defs_h) $(gdbcore_h) $(target_h) \
+	$(frame_h) $(osabi_h) $(regcache_h) $(elf_bfd_h) $(elf_frv_h) \
+	$(frv_tdep_h) $(trad_frame_h) $(frame_unwind_h) $(regset_h) \
+	$(gdb_string_h)
 frv-tdep.o: frv-tdep.c $(defs_h) $(gdb_string_h) $(inferior_h) $(gdbcore_h) \
 	$(arch_utils_h) $(regcache_h) $(frame_h) $(frame_unwind_h) \
 	$(frame_base_h) $(trad_frame_h) $(dis_asm_h) $(gdb_assert_h) \
Index: frv-linux-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/frv-linux-tdep.c,v
retrieving revision 1.9
diff -u -p -r1.9 frv-linux-tdep.c
--- frv-linux-tdep.c	17 Dec 2005 22:33:59 -0000	1.9
+++ frv-linux-tdep.c	15 Mar 2006 23:37:43 -0000
@@ -20,14 +20,18 @@
    Boston, MA 02110-1301, USA.  */
 
 #include "defs.h"
+#include "gdbcore.h"
 #include "target.h"
 #include "frame.h"
 #include "osabi.h"
+#include "regcache.h"
 #include "elf-bfd.h"
 #include "elf/frv.h"
 #include "frv-tdep.h"
 #include "trad-frame.h"
 #include "frame-unwind.h"
+#include "regset.h"
+#include "gdb_string.h"
 
 /* Define the size (in bytes) of an FR-V instruction.  */
 static const int frv_instr_size = 4;
@@ -329,11 +333,162 @@ frv_linux_sigtramp_frame_sniffer (struct
   return NULL;
 }
 
+
+/* The FRV kernel defines ELF_NGREG as 46.  We add 2 in order to include
+   the loadmap addresses in the register set.  (See below for more info.)  */
+#define FRV_ELF_NGREG (46 + 2)
+typedef unsigned char frv_elf_greg_t[4];
+typedef struct { frv_elf_greg_t reg[FRV_ELF_NGREG]; } frv_elf_gregset_t;
+
+typedef unsigned char frv_elf_fpreg_t[4];
+typedef struct
+{
+  frv_elf_fpreg_t fr[64];
+  frv_elf_fpreg_t fner[2];
+  frv_elf_fpreg_t msr[2];
+  frv_elf_fpreg_t acc[8];
+  unsigned char accg[8];
+  frv_elf_fpreg_t fsr[1];
+} frv_elf_fpregset_t;
+
+/* Constants for accessing elements of frv_elf_gregset_t.  */
+
+#define FRV_PT_PSR 0
+#define	FRV_PT_ISR 1
+#define FRV_PT_CCR 2
+#define FRV_PT_CCCR 3
+#define FRV_PT_LR 4
+#define FRV_PT_LCR 5
+#define FRV_PT_PC 6
+#define FRV_PT_GNER0 10
+#define FRV_PT_GNER1 11
+#define FRV_PT_IACC0H 12
+#define FRV_PT_IACC0L 13
+
+/* Note: Only 32 of the GRs will be found in the corefile.  */
+#define FRV_PT_GR(j)	( 14 + (j))	/* GRj for 0<=j<=63. */
+
+#define FRV_PT_TBR FRV_PT_GR(0)		/* gr0 is always 0, so TBR is stuffed
+					   there.  */
+
+/* Technically, the loadmap addresses are not part of `pr_reg' as
+   found in the elf_prstatus struct.  The fields which communicate the
+   loadmap address appear (by design) immediately after `pr_reg'
+   though, and the BFD function elf32_frv_grok_prstatus() has been
+   implemented to include these fields in the register section that it
+   extracts from the core file.  So, for our purposes, they may be
+   viewed as registers.  */
+
+#define FRV_PT_EXEC_FDPIC_LOADMAP 46
+#define FRV_PT_INTERP_FDPIC_LOADMAP 47
+
+
+/* Unpack an frv_elf_gregset_t into GDB's register cache.  */
+
+static void 
+frv_linux_supply_gregset (const struct regset *regset,
+                          struct regcache *regcache,
+			  int regnum, const void *gregs, size_t len)
+{
+  int regi;
+  char zerobuf[MAX_REGISTER_SIZE];
+  const frv_elf_gregset_t *gregsetp = gregs;
+
+  memset (zerobuf, 0, MAX_REGISTER_SIZE);
+
+  /* gr0 always contains 0.  Also, the kernel passes the TBR value in
+     this slot.  */
+  regcache_raw_supply (regcache, first_gpr_regnum, zerobuf);
+
+  for (regi = first_gpr_regnum + 1; regi <= last_gpr_regnum; regi++)
+    {
+      if (regi >= first_gpr_regnum + 32)
+	regcache_raw_supply (regcache, regi, zerobuf);
+      else
+	regcache_raw_supply (regcache, regi,
+			     gregsetp->reg[FRV_PT_GR (regi - first_gpr_regnum)]);
+    }
+
+  regcache_raw_supply (regcache, pc_regnum, gregsetp->reg[FRV_PT_PC]);
+  regcache_raw_supply (regcache, psr_regnum, gregsetp->reg[FRV_PT_PSR]);
+  regcache_raw_supply (regcache, ccr_regnum, gregsetp->reg[FRV_PT_CCR]);
+  regcache_raw_supply (regcache, cccr_regnum, gregsetp->reg[FRV_PT_CCCR]);
+  regcache_raw_supply (regcache, lr_regnum, gregsetp->reg[FRV_PT_LR]);
+  regcache_raw_supply (regcache, lcr_regnum, gregsetp->reg[FRV_PT_LCR]);
+  regcache_raw_supply (regcache, gner0_regnum, gregsetp->reg[FRV_PT_GNER0]);
+  regcache_raw_supply (regcache, gner1_regnum, gregsetp->reg[FRV_PT_GNER1]);
+  regcache_raw_supply (regcache, tbr_regnum, gregsetp->reg[FRV_PT_TBR]);
+  regcache_raw_supply (regcache, fdpic_loadmap_exec_regnum,
+                       gregsetp->reg[FRV_PT_EXEC_FDPIC_LOADMAP]);
+  regcache_raw_supply (regcache, fdpic_loadmap_interp_regnum,
+                       gregsetp->reg[FRV_PT_INTERP_FDPIC_LOADMAP]);
+}
+
+/* Unpack an frv_elf_fpregset_t into GDB's register cache.  */
+
+static void
+frv_linux_supply_fpregset (const struct regset *regset,
+                           struct regcache *regcache,
+			   int regnum, const void *gregs, size_t len)
+{
+  int regi;
+  const frv_elf_fpregset_t *fpregsetp = gregs;
+
+  for (regi = first_fpr_regnum; regi <= last_fpr_regnum; regi++)
+    regcache_raw_supply (regcache, regi, fpregsetp->fr[regi - first_fpr_regnum]);
+
+  regcache_raw_supply (regcache, fner0_regnum, fpregsetp->fner[0]);
+  regcache_raw_supply (regcache, fner1_regnum, fpregsetp->fner[1]);
+
+  regcache_raw_supply (regcache, msr0_regnum, fpregsetp->msr[0]);
+  regcache_raw_supply (regcache, msr1_regnum, fpregsetp->msr[1]);
+
+  for (regi = acc0_regnum; regi <= acc7_regnum; regi++)
+    regcache_raw_supply (regcache, regi, fpregsetp->acc[regi - acc0_regnum]);
+
+  regcache_raw_supply (regcache, accg0123_regnum, fpregsetp->accg);
+  regcache_raw_supply (regcache, accg4567_regnum, fpregsetp->accg + 4);
+
+  regcache_raw_supply (regcache, fsr0_regnum, fpregsetp->fsr[0]);
+}
+
+/* FRV Linux register sets.  */
+
+static struct regset frv_linux_gregset =
+{
+  NULL,
+  frv_linux_supply_gregset
+};
+
+static struct regset frv_linux_fpregset =
+{
+  NULL,
+  frv_linux_supply_fpregset
+};
+
+static const struct regset *
+frv_linux_regset_from_core_section (struct gdbarch *gdbarch,
+				    const char *sect_name, size_t sect_size)
+{
+  if (strcmp (sect_name, ".reg") == 0 
+      && sect_size >= sizeof (frv_elf_gregset_t))
+    return &frv_linux_gregset;
+
+  if (strcmp (sect_name, ".reg2") == 0 
+      && sect_size >= sizeof (frv_elf_fpregset_t))
+    return &frv_linux_fpregset;
+
+  return NULL;
+}
+
+
 static void
 frv_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
   /* Set the sigtramp frame sniffer.  */
   frame_unwind_append_sniffer (gdbarch, frv_linux_sigtramp_frame_sniffer); 
+  set_gdbarch_regset_from_core_section (gdbarch,
+                                        frv_linux_regset_from_core_section);
 }
 
 static enum gdb_osabi
Index: solib-frv.c
===================================================================
RCS file: /cvs/src/src/gdb/solib-frv.c,v
retrieving revision 1.12
diff -u -p -r1.12 solib-frv.c
--- solib-frv.c	17 Dec 2005 22:34:02 -0000	1.12
+++ solib-frv.c	15 Mar 2006 23:37:43 -0000
@@ -421,6 +421,22 @@ frv_current_sos (void)
   struct so_list *sos_head = NULL;
   struct so_list **sos_next_ptr = &sos_head;
 
+  /* Make sure that the main executable has been relocated.  This is
+     required in order to find the address of the global offset table,
+     which in turn is used to find the link map info.  (See lm_base()
+     for details.)
+
+     Note that the relocation of the main executable is also performed
+     by SOLIB_CREATE_INFERIOR_HOOK(), however, in the case of core
+     files, this hook is called too late in order to be of benefit to
+     SOLIB_ADD.  SOLIB_ADD eventually calls this this function,
+     frv_current_sos, and also precedes the call to
+     SOLIB_CREATE_INFERIOR_HOOK().   (See post_create_inferior() in
+     infcmd.c.)  */
+  if (main_executable_lm_info == 0 && core_bfd != NULL)
+    frv_relocate_main_executable ();
+
+  /* Fetch the GOT corresponding to the main executable.  */
   mgot = main_got ();
 
   /* Locate the address of the first link map struct.  */
@@ -960,6 +976,14 @@ frv_clear_solib (void)
   enable_break1_done = 0;
   enable_break2_done = 0;
   main_lm_addr = 0;
+  if (main_executable_lm_info != 0)
+    {
+      xfree (main_executable_lm_info->map);
+      xfree (main_executable_lm_info->dyn_syms);
+      xfree (main_executable_lm_info->dyn_relocs);
+      xfree (main_executable_lm_info);
+      main_executable_lm_info = 0;
+    }
 }
 
 static void
Index: config/frv/frv.mt
===================================================================
RCS file: /cvs/src/src/gdb/config/frv/frv.mt,v
retrieving revision 1.5
diff -u -p -r1.5 frv.mt
--- config/frv/frv.mt	13 Sep 2004 20:55:39 -0000	1.5
+++ config/frv/frv.mt	15 Mar 2006 23:37:43 -0000
@@ -1,5 +1,5 @@
 # Target: Fujitsu FRV processor
-TDEPFILES= frv-tdep.o frv-linux-tdep.o solib.o solib-frv.o
+TDEPFILES= frv-tdep.o frv-linux-tdep.o solib.o solib-frv.o corelow.o
 DEPRECATED_TM_FILE= tm-frv.h
 SIM_OBS = remote-sim.o
 SIM = ../sim/frv/libsim.a