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

[Ajit Kumar Agarwal <ajit dot kumar dot agarwal at xilinx dot com>]

Based on the feedback incorporated the changes as mentioned below. Could you please 
review the patch and let me know if its okay.


   [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 patch
    fixes the above problem for baremetal and also supports the backward compatibility.
    
    ChangeLog:
    2014-06-18 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-core.xml: New file.
        * features/microblaze-stack-protect.xml: New file.
        * features/microblaze-with-stack-protect.c: New file.
        * features/microblaze-with-stack-protect.xml: New file.
        * features/Makefile (microblaze-linux): Add
        microblaze-linux and microblaze-expedite.
        * regformats/microblaze-with-stack-protect.dat: New file.
    
    Signed-off-by:Ajit Agarwal ajitkum@xilinx.com

Thanks & Regards
Ajit

-----Original Message-----
From: Pedro Alves [mailto:palves@redhat.com] 
Sent: Tuesday, June 17, 2014 4:47 PM
To: Ajit Kumar Agarwal
Cc: gdb-patches@sourceware.org; Michael Eager; Vinod Kathail; Vidhumouli Hunsigida; Nagaraju Mekala
Subject: Re: [Patch, microblaze]: Fix for remote G Packet message too long error for baremetal.

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

Attachment: 0001-Patch-microblaze-Fix-for-remote-G-Packet-message-too.patch
Description: 0001-Patch-microblaze-Fix-for-remote-G-Packet-message-too.patch