From patchwork Mon Sep 10 18:39:04 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: y@eu.adacore.com X-Patchwork-Id: 29297 Received: (qmail 85196 invoked by alias); 10 Sep 2018 18:39:16 -0000 Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org Delivered-To: mailing list gdb-patches@sourceware.org Received: (qmail 85179 invoked by uid 89); 10 Sep 2018 18:39:16 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-26.3 required=5.0 tests=BAYES_00, GIT_PATCH_0, GIT_PATCH_1, GIT_PATCH_2, GIT_PATCH_3, INVALID_MSGID, KAM_SHORT, RCVD_IN_DNSWL_NONE, SPF_PASS autolearn=ham version=3.3.2 spammy= X-HELO: smtp.eu.adacore.com Received: from mel.act-europe.fr (HELO smtp.eu.adacore.com) (194.98.77.210) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Mon, 10 Sep 2018 18:39:13 +0000 Received: from localhost (localhost [127.0.0.1]) by filtered-smtp.eu.adacore.com (Postfix) with ESMTP id 2D5BF814C6; Mon, 10 Sep 2018 20:39:08 +0200 (CEST) Received: from smtp.eu.adacore.com ([127.0.0.1]) by localhost (smtp.eu.adacore.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id Wia4Mw2nkFZB; Mon, 10 Sep 2018 20:39:08 +0200 (CEST) Received: from chelles.act-europe.fr (chelles.act-europe.fr [IPv6:2a02:2ab8:224:1:d6be:d9ff:fef8:4565]) by smtp.eu.adacore.com (Postfix) with ESMTP id 170A681398; Mon, 10 Sep 2018 20:39:08 +0200 (CEST) Received: by chelles.act-europe.fr (Postfix, from userid 507) id 141701EA0079; Mon, 10 Sep 2018 20:39:08 +0200 (CEST) From: y@eu.adacore.com To: gdb-patches@sourceware.org Cc: Jerome Guitton Subject: [RFA v2] arm-pikeos: software single step Date: Mon, 10 Sep 2018 20:39:04 +0200 Message-Id: <1536604744-3814-1-git-send-email-y> In-Reply-To: <20180910174345.GD3234@adacore.com> References: <20180910174345.GD3234@adacore.com> From: Jerome Guitton Hello, Below is the updated version following Tom's comments. The only changes are made are to fix the issues pointed out by Tom: - Missing function documentation; - Wrong casing in "PikeOS". Thank you! ---------------------------------------------------------------------- On ARM, PikeOS does not support hardware single step, causing various semi-random errors when trying to next/step over some user code. So this patch changes this target to use software-single-step instead. The challenge is that, up to now, the PikeOS target was in all respects identical to a baremetal target as far as GDB was concerned, meaning we were using the baremetal osabi for this target too. This is no longer possible, and we need to introduce a new OSABI variant. Unfortunately, there isn't anything in the object file that would allow us to differentiate between the two platforms. So we have to rely on a heuristic instead, where we look for some known symbols that are required in a PikeOS application (these symbols are expected to be defined by the default linker script, and correspond to routines used to allocate the application stack). gdb/ChangeLog: * arm-pikeos-tdep.c: New file. * configure.tgt: Add arm-pikeos-tdep.o to the case of ARM embedded system. * defs.h (enum gdb_osabi): Add GDB_OSABI_PIKEOS. * osabi.c (gdb_osabi_names): Add name for GDB_OSABI_PIKEOS. Tested on arm-pikeos and arm-elf using AdaCore's testsuite. We also evaluated it on armhf-linux as a cross platform. --- gdb/arm-pikeos-tdep.c | 102 +++++++++++++++++++++++++++++++++++++++++++++++++ gdb/configure.tgt | 1 + gdb/defs.h | 1 + gdb/osabi.c | 1 + 4 files changed, 105 insertions(+) create mode 100644 gdb/arm-pikeos-tdep.c diff --git a/gdb/arm-pikeos-tdep.c b/gdb/arm-pikeos-tdep.c new file mode 100644 index 0000000..9640f1f --- /dev/null +++ b/gdb/arm-pikeos-tdep.c @@ -0,0 +1,102 @@ +/* Copyright (C) 2016-2018 Free Software Foundation, Inc. + + This file is part of GDB. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . */ + +#include "defs.h" +#include "objfiles.h" +#include "arm-tdep.h" +#include "osabi.h" + +/* The gdbarch_register_osabi handler for ARM PikeOS; it performs + the gdbarch initialization for that platform. */ + +static void +arm_pikeos_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) +{ + /* Single stepping. */ + set_gdbarch_software_single_step (gdbarch, arm_software_single_step); +} + +/* The ARM PikeOS OSABI sniffer (see gdbarch_register_osabi_sniffer). + Returns GDB_OSABI_PIKEOS if the given BFD is a PikeOS binary, + GDB_OSABI_UNKNOWN otherwise. */ + +static enum gdb_osabi +arm_pikeos_osabi_sniffer (bfd *abfd) +{ + long storage_needed; + asymbol **symbol_table; + long number_of_symbols; + long i; + int pikeos_stack_found = 0; + int pikeos_stack_size_found = 0; + struct cleanup *old_chain = make_cleanup (null_cleanup, NULL); + + /* The BFD target of PikeOS is really just standard elf, so we + cannot use it to detect this variant. The only common thing that + may be found in PikeOS modules are symbols _vm_stack/__p4_stack and + _vm_stack_size/__p4_stack_end. They are used to specify the stack + location and size; and defined by the default linker script. + + OS ABI sniffers are called before the minimal symtabs are + created. So inspect the symbol table using BFD. */ + + storage_needed = bfd_get_symtab_upper_bound (abfd); + + if (storage_needed <= 0) + return GDB_OSABI_UNKNOWN; + + symbol_table = (asymbol **) xmalloc (storage_needed); + make_cleanup (xfree, symbol_table); + + number_of_symbols = bfd_canonicalize_symtab (abfd, symbol_table); + + if (number_of_symbols < 0) + { + do_cleanups (old_chain); + return GDB_OSABI_UNKNOWN; + } + + for (i = 0; i < number_of_symbols; i++) + { + const char *name = bfd_asymbol_name (symbol_table[i]); + + if (strcmp (name, "_vm_stack") == 0 + || strcmp (name, "__p4_stack") == 0) + pikeos_stack_found = 1; + + if (strcmp (name, "_vm_stack_size") == 0 + || strcmp (name, "__p4_stack_end") == 0) + pikeos_stack_size_found = 1; + } + + do_cleanups (old_chain); + + if (pikeos_stack_found && pikeos_stack_size_found) + return GDB_OSABI_PIKEOS; + else + return GDB_OSABI_UNKNOWN; +} + +void +_initialize_arm_pikeos_tdep (void) +{ + /* Register the sniffer for the PikeOS targets. */ + gdbarch_register_osabi_sniffer (bfd_arch_arm, bfd_target_elf_flavour, + arm_pikeos_osabi_sniffer); + gdbarch_register_osabi (bfd_arch_arm, 0, GDB_OSABI_PIKEOS, + arm_pikeos_init_abi); +} diff --git a/gdb/configure.tgt b/gdb/configure.tgt index 6d1a4df..a1f703f 100644 --- a/gdb/configure.tgt +++ b/gdb/configure.tgt @@ -180,6 +180,7 @@ arm*-*-symbianelf*) ;; arm*-*-*) # Target: ARM embedded system + gdb_target_obs="arm-pikeos-tdep.o" gdb_sim=../sim/arm/libsim.a ;; diff --git a/gdb/defs.h b/gdb/defs.h index fc42170..28f7a11 100644 --- a/gdb/defs.h +++ b/gdb/defs.h @@ -495,6 +495,7 @@ enum gdb_osabi GDB_OSABI_LYNXOS178, GDB_OSABI_NEWLIB, GDB_OSABI_SDE, + GDB_OSABI_PIKEOS, GDB_OSABI_INVALID /* keep this last */ }; diff --git a/gdb/osabi.c b/gdb/osabi.c index 7d0540b..68f4665 100644 --- a/gdb/osabi.c +++ b/gdb/osabi.c @@ -80,6 +80,7 @@ static const struct osabi_names gdb_osabi_names[] = { "LynxOS178", NULL }, { "Newlib", NULL }, { "SDE", NULL }, + { "PikeOS", NULL }, { "", NULL } };