[commit] OpenBSD/ppc kernel debugging support

[Mark Kettenis <mark dot kettenis at xs4all dot nl>]

Just committed this bit.

Mark

Index: ChangeLog
from  Mark Kettenis  <kettenis@gnu.org>

	* ppcobsd-nat.c: Include "gdbcore.h", <sys/signal.h>,
	<machine/frame.h>, <machine/pcb.h> and "bsd-kvm.h".
	(ppcobsd_supply_pcb): New function.
	(_initialize_ppcobsd_nat): Enable libkvm interface.
	* Makefile.in (ppcobsd-nat.o): Update dependencies.

Index: ppcobsd-nat.c
===================================================================
RCS file: /cvs/src/src/gdb/ppcobsd-nat.c,v
retrieving revision 1.5
diff -u -p -r1.5 ppcobsd-nat.c
--- ppcobsd-nat.c 16 Apr 2005 22:12:08 -0000 1.5
+++ ppcobsd-nat.c 24 Jun 2005 21:01:20 -0000
@@ -20,17 +20,22 @@
    Boston, MA 02111-1307, USA.  */
 
 #include "defs.h"
+#include "gdbcore.h"
 #include "inferior.h"
 #include "regcache.h"
 
 #include <stddef.h>
 #include <sys/types.h>
 #include <sys/ptrace.h>
+#include <sys/signal.h>
+#include <machine/frame.h>
+#include <machine/pcb.h>
 #include <machine/reg.h>
 
 #include "ppc-tdep.h"
 #include "ppcobsd-tdep.h"
 #include "inf-ptrace.h"
+#include "bsd-kvm.h"
 
 /* OpenBSD/powerpc doesn't have PT_GETFPREGS/PT_SETFPREGS like
    NetBSD/powerpc and FreeBSD/powerpc.  */
@@ -72,6 +77,43 @@ ppcobsd_store_registers (int regnum)
 }
 
 
+static int
+ppcobsd_supply_pcb (struct regcache *regcache, struct pcb *pcb)
+{
+  struct gdbarch_tdep *tdep = gdbarch_tdep (get_regcache_arch (regcache));
+  struct switchframe sf;
+  struct callframe cf;
+  int i, regnum;
+
+  /* The following is true for OpenBSD 3.7:
+
+     The pcb contains %r1 (the stack pointer) at the point of the
+     context switch in cpu_switch().  At that point we have a stack
+     frame as described by `struct switchframe', and below that a call
+     frame as described by `struct callframe'.  From this information
+     we reconstruct the register state as it would look when we are in
+     cpu_switch().  */
+
+  /* The stack pointer shouldn't be zero.  */
+  if (pcb->pcb_sp == 0)
+    return 0;
+
+  read_memory (pcb->pcb_sp, (gdb_byte *)&sf, sizeof sf);
+  regcache_raw_supply (regcache, SP_REGNUM, &sf.sp);
+  regcache_raw_supply (regcache, tdep->ppc_cr_regnum, &sf.cr);
+  regcache_raw_supply (regcache, tdep->ppc_gp0_regnum + 2, &sf.fixreg2);
+  for (i = 0, regnum = tdep->ppc_gp0_regnum + 13; i < 19; i++, regnum++)
+    regcache_raw_supply (regcache, regnum, &sf.fixreg[i]);
+
+  read_memory (sf.sp, (gdb_byte *)&cf, sizeof cf);
+  regcache_raw_supply (regcache, PC_REGNUM, &cf.lr);
+  regcache_raw_supply (regcache, tdep->ppc_gp0_regnum + 30, &cf.r30);
+  regcache_raw_supply (regcache, tdep->ppc_gp0_regnum + 31, &cf.r31);
+
+  return 1;
+}
+
+
 /* Provide a prototype to silence -Wmissing-prototypes.  */
 void _initialize_ppcobsd_nat (void);
 
@@ -104,4 +146,7 @@ _initialize_ppcobsd_nat (void)
   ppcobsd_reg_offsets.vr0_offset = offsetof (struct vreg, vreg);
   ppcobsd_reg_offsets.vscr_offset = offsetof (struct vreg, vscr);
   ppcobsd_reg_offsets.vrsave_offset = offsetof (struct vreg, vrsave);
+
+  /* Support debugging kernel virtual memory images.  */
+  bsd_kvm_add_target (ppcobsd_supply_pcb);
 }