Re: [Patch, microblaze]: Fix for remote G Packet message too long error for baremetal.

[Pedro Alves <palves@redhat.com>]

On 06/12/2014 09:56 AM, Ajit Kumar Agarwal wrote:
> Based on the feedbacks, all changes have been incorporated.
>  
> May I know who will committing this patch to the upstream ?
> 
> [Patch, microblaze]: Fix for remote G Packet message too long error for baremetal.
>     
>     Prior to version MicroBlaze v8.10.a,EDK 13.1, XMD's gdbserver stub returned 57
>     registers in response to GDB's G request.  Starting with version MicroBlaze
>     v8.10.a, EDK 13.1, XMD added the slr and shr register, for a count of 59
>     registers.This patch adds these registers to the expected G response. This
>     fixes the above problem for baremetal and also supports the backward compatibility.
>     
>     ChangeLog:
>     
>     2014-06-12 Ajit Agarwal <ajitkum@xilinx.com>
>     
>         * microblaze-tdep.c (microblaze_register_names): Add
>         the rshr and rslr register names.
>         (microblaze_gdbarch_init): Use of tdesc_has_registers.
>         Use of tdesc_find_feature. Use of tdesc_data_alloc.
>         Use of tdesc_numbered_register. Use of
>         microblaze_register_g_packet_guesses. Use of
>         tdesc_use_registers. Use of set_gdbarch_register_type.
>         (microblaze_register_g_packet_guesses): New.
>     
>         * microblaze-tdep.h (microblaze_reg_num): Add
>         field MICROBLAZE_SLR_REGNUM and MICROBLAZE_SHR_REGNUM
>         MICROBLAZE_NUM_REGS.
>         (microblaze_frame_cache): Use of MICROBLAZE_NUM_REGS.
>     
>         * features/microblaze-cpu.xml: New file.
>     
>         * features/microblaze-linux.c: New file.
>     
>         * features/microblaze-linux.xml: New file.
>     
>         * regformats/reg-microblaze.dat: New file.
> 
>         * features/Makefile (microblaze-linux): Add microblaze-linux
>         and microblaze-expedite.
>     
>     Signed-off-by:Ajit Agarwal ajitkum@xilinx.com
> 
> Thanks & Regards
> Ajit
> 
> 
> 0001-Patch-microblaze-Fix-for-remote-G-Packet-message-too.patch
> 
> 
> From ce1e6c1f1cd7d49df24727fc179df4c3f6f66bee Mon Sep 17 00:00:00 2001
> From: Ajit Kumar Agarwal <ajitkum@xhdspdgnu.(none)>
> Date: Thu, 12 Jun 2014 12:50:16 +0530
> Subject: [PATCH] [Patch, microblaze]: Fix for remote G Packet message too long error for baremetal.
> 
> Prior to version MicroBlaze v8.10.a,EDK 13.1, XMD's gdbserver stub returned 57
> registers in response to GDB's G request.  Starting with version MicroBlaze
> v8.10.a, EDK 13.1, XMD added the slr and shr register, for a count of 59
> registers.This patch adds these registers to the expected G response. This
> fixes the above problem for baremetal and also supports the backward compatibility.

Yet, you've named the xml files "linux", and, made the default description
assume GNU/Linux osabi.  That doesn't look right.

> 
> ChangeLog:
> 
> 2014-06-12 Ajit Agarwal <ajitkum@xilinx.com>
> 
> 	* microblaze-tdep.c (microblaze_register_names): Add
> 	the rshr and rslr register names.
> 	(microblaze_gdbarch_init): Use of tdesc_has_registers.
> 	Use of tdesc_find_feature. Use of tdesc_data_alloc.
> 	Use of tdesc_numbered_register. Use of
> 	microblaze_register_g_packet_guesses. Use of
> 	tdesc_use_registers. Use of set_gdbarch_register_type.
> 	(microblaze_register_g_packet_guesses): New.
> 
> 	* microblaze-tdep.h (microblaze_reg_num): Add
> 	field MICROBLAZE_SLR_REGNUM and MICROBLAZE_SHR_REGNUM
> 	MICROBLAZE_NUM_REGS.
> 	(microblaze_frame_cache): Use of MICROBLAZE_NUM_REGS.
> 
> 	* features/microblaze-cpu.xml: New file.
> 
> 	* features/microblaze-linux.c: New file.
> 
> 	* features/microblaze-linux.xml: New file.
> 
> 	* regformats/reg-microblaze.dat: New file.
> 
> 	* features/Makefile (microblaze-linux): Add microblaze-linux
> 	and microblaze-expedite.

No empty line between entries, please.

> 

> +++ b/gdb/features/microblaze-cpu.xml
> @@ -0,0 +1,69 @@
> +<?xml version="1.0"?>
> +<!-- Copyright (C) 2007-2014 Free Software Foundation, Inc.
> +
> +     Copying and distribution of this file, with or without modification,
> +     are permitted in any medium without royalty provided the copyright
> +     notice and this notice are preserved.  -->
> +
> +<!DOCTYPE feature SYSTEM "gdb-target.dtd">
> +<feature name="org.gnu.gdb.MicroBlaze.cpu">
> +  <reg name="r0" bitsize="32" regnum="0"/>
> +  <reg name="r1" bitsize="32"/>
> +  <reg name="r2" bitsize="32"/>
> +  <reg name="r3" bitsize="32"/>
> +  <reg name="r4" bitsize="32"/>
> +  <reg name="r5" bitsize="32"/>
> +  <reg name="r6" bitsize="32"/>
> +  <reg name="r7" bitsize="32"/>
> +  <reg name="r8" bitsize="32"/>
> +  <reg name="r9" bitsize="32"/>
> +  <reg name="r10" bitsize="32"/>
> +  <reg name="r11" bitsize="32"/>
> +  <reg name="r12" bitsize="32"/>
> +  <reg name="r13" bitsize="32"/>
> +  <reg name="r14" bitsize="32"/>
> +  <reg name="r15" bitsize="32"/>
> +  <reg name="r16" bitsize="32"/>
> +  <reg name="r17" bitsize="32"/>
> +  <reg name="r18" bitsize="32"/>
> +  <reg name="r19" bitsize="32"/>
> +  <reg name="r20" bitsize="32"/>
> +  <reg name="r21" bitsize="32"/>
> +  <reg name="r22" bitsize="32"/>
> +  <reg name="r23" bitsize="32"/>
> +  <reg name="r24" bitsize="32"/>
> +  <reg name="r25" bitsize="32"/>
> +  <reg name="r26" bitsize="32"/>
> +  <reg name="r27" bitsize="32"/>
> +  <reg name="r28" bitsize="32"/>
> +  <reg name="r29" bitsize="32"/>
> +  <reg name="r30" bitsize="32"/>
> +  <reg name="r31" bitsize="32"/>
> +  <reg name="rpc" bitsize="32"/>
> +  <reg name="rmsr" bitsize="32"/>
> +  <reg name="rear" bitsize="32"/>
> +  <reg name="resr" bitsize="32"/>
> +  <reg name="rfsr" bitsize="32"/>
> +  <reg name="rbtr" bitsize="32"/>
> +  <reg name="rpvr0" bitsize="32"/> 
> +  <reg name="rpvr1" bitsize="32"/> 
> +  <reg name="rpvr2" bitsize="32"/> 
> +  <reg name="rpvr3" bitsize="32"/> 
> +  <reg name="rpvr4" bitsize="32"/> 
> +  <reg name="rpvr5" bitsize="32"/> 
> +  <reg name="rpvr6" bitsize="32"/>
> +  <reg name="rpvr7" bitsize="32"/> 
> +  <reg name="rpvr8" bitsize="32"/> 
> +  <reg name="rpvr9" bitsize="32"/> 
> +  <reg name="rpvr10" bitsize="32"/> 
> +  <reg name="rpvr11" bitsize="32"/>
> +  <reg name="redr" bitsize="32"/> 
> +  <reg name="rpid" bitsize="32"/> 
> +  <reg name="rzpr" bitsize="32"/> 
> +  <reg name="rtlbx" bitsize="32"/> 
> +  <reg name="rtlbsx" bitsize="32"/> 
> +  <reg name="rtlblo" bitsize="32"/> 
> +  <reg name="rtlbhi" bitsize="32"/>
> +  <reg name="rslr" bitsize="32"/>
> +  <reg name="rshr" bitsize="32"/>
> +</feature>

I don't think this is right.  What you want to do, is create a
"core" feature, that includes only the set of generic purpose
registers that are always available in all microblaze
configurations.  As discussed, rslr and rshr aren't of that
kind.  Note that most ports call that feature "core":

 $ grep "org.gnu" * | grep cpu
 mips-tdep.c:                                "org.gnu.gdb.mips.cpu");
 nios2-tdep.c:      feature = tdesc_find_feature (tdesc, "org.gnu.gdb.nios2.cpu");

 $ grep "org.gnu" * | grep core
 aarch64-tdep.c:  feature = tdesc_find_feature (tdesc, "org.gnu.gdb.aarch64.core");
 arm-tdep.c:                                 "org.gnu.gdb.arm.core");
 i386-tdep.c:  feature_core = tdesc_find_feature (tdesc, "org.gnu.gdb.i386.core");
 m68k-tdep.c:                                "org.gnu.gdb.m68k.core");
 m68k-tdep.c:                                    "org.gnu.gdb.coldfire.core");
 m68k-tdep.c:                                    "org.gnu.gdb.fido.core");
 rs6000-tdep.c:                              "org.gnu.gdb.power.core");
 s390-linux-tdep.c:      feature = tdesc_find_feature (tdesc, "org.gnu.gdb.s390.core");
 tic6x-tdep.c:      feature = tdesc_find_feature (tdesc, "org.gnu.gdb.tic6x.core");

Btw, note how feature names are all lowercase, so

 "org.gnu.gdb.microblaze"

would be more standard.

Then, you'll want to create another xml description feature for the
C_USE_STACK_PROTECTION microblaze feature, like:

<!DOCTYPE feature SYSTEM "gdb-target.dtd">
<feature name="org.gnu.gdb.microblaze.stack-protect">
  <reg name="r0" bitsize="32" regnum="0"/>
  <reg name="rslr" bitsize="32"/>
  <reg name="rshr" bitsize="32"/>
</feature>

Finally, a machine that has the stack protection feature enabled
can report a description that makes use of xi:include, like:

<!DOCTYPE target SYSTEM "gdb-target.dtd">
<target>
  <xi:include href="microblaze-core.xml"/>
  <xi:include href="microblaze-stack-protect.xml"/>
</target>

There are several examples of this in the features/ directory.
E.g., see arm-with-vfpv2.xml.

> +static void
> +microblaze_register_g_packet_guesses (struct gdbarch *gdbarch)
> +{
> +      register_remote_g_packet_guess (gdbarch,
> +                                      MICROBLAZE_NUM_REGS, 
> +                                      tdesc_microblaze_linux);
>  
> +      register_remote_g_packet_guess (gdbarch,
> +                                      MICROBLAZE_NUM_REGS-2,
> +                                      tdesc_microblaze_linux);

Now here you'll want to guess different descriptions.  The second
case should guess a description that doesn't include rslr and
rshr at all.

Formatting isn't following the BTW, coding conventions.
Spaces around '-' missing and statements should indented with
2 spaces, not 6.

Thanks,
-- 
Pedro Alves