Re: gdb ignoring vCont supported commands

[Bill Morgan <arthurwilliammorgan at gmail dot com>]

On Tue, Oct 9, 2018 at 4:12 PM Pedro Alves <palves@redhat.com> wrote:

> On 10/09/2018 09:29 PM, Bill Morgan wrote:
> >
> > So it is now recognizing the vContSupported, but it is still sending
> > vCont;s
> >
>
> Argh, I forgot that this only really works on ARM GNU/Linux.
> What is your target?
>
> We're missing the small infrastructure change in GDB
> mentioned in the discussion I linked before.
>

I couldn't get the change on the other thread to work, but this has been
reported before and a patch submitted to fix it.

https://sourceware.org/bugzilla/show_bug.cgi?id=21272

I only needed this portion of the patch to get it working.

Any chance on getting it merged to master?

diff --git a/gdb/arm-tdep.c b/gdb/arm-tdep.c
index 53eee76926..721675266c 100644
--- a/gdb/arm-tdep.c
+++ b/gdb/arm-tdep.c
@@ -6221,7 +6221,24 @@ arm_get_next_pcs_addr_bits_remove (struct
arm_get_next_pcs *self,
 static CORE_ADDR
 arm_get_next_pcs_syscall_next_pc (struct arm_get_next_pcs *self)
 {
-  return 0;
+  CORE_ADDR next_pc = 0;
+  CORE_ADDR pc = regcache_read_pc (self->regcache);
+  int is_thumb = arm_is_thumb (self->regcache);
+
+  /* Without the knowledge of the OS (if any) we need to assume that the
next
+     user-mode instruction is executed */
+
+  if (is_thumb)
+    {
+      next_pc = pc + 2;
+    }
+
+  else
+    {
+      next_pc = pc + 4;
+    }
+
+  return next_pc;
 }

 /* Wrapper over arm_is_thumb for use in arm_get_next_pcs.  */
@@ -9384,6 +9401,7 @@ arm_gdbarch_init (struct gdbarch_info info, struct
gdbarch_list *arches)
   set_gdbarch_sw_breakpoint_from_kind (gdbarch,
arm_sw_breakpoint_from_kind);
   set_gdbarch_breakpoint_kind_from_current_state (gdbarch,
    arm_breakpoint_kind_from_current_state);
+  set_gdbarch_software_single_step( gdbarch, arm_software_single_step );

   /* Information about registers, etc.  */
   set_gdbarch_sp_regnum (gdbarch, ARM_SP_REGNUM);