From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp00.avonet.cz (smtp00.avonet.cz [217.112.162.55]) by sourceware.org (Postfix) with ESMTP id 5256E3858CDB for ; Mon, 28 Nov 2022 11:48:56 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 5256E3858CDB Authentication-Results: sourceware.org; dmarc=fail (p=none dis=none) header.from=fbl.cz Authentication-Results: sourceware.org; spf=fail smtp.mailfrom=fbl.cz Received: from ktus.lan (217-115-245-101.cust.avonet.cz [217.115.245.101]) by smtp00.avonet.cz (Postfix) with ESMTP id 4NLNzB4MRZz1xpv for ; Mon, 28 Nov 2022 12:48:54 +0100 (CET) Received: by ktus.lan (Postfix, from userid 209) id 762DD3144FC; Mon, 28 Nov 2022 12:48:54 +0100 (CET) X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org X-Spam-Level: X-Spam-Status: No, score=-12.9 required=5.0 tests=BAYES_00,GIT_PATCH_0,KAM_DMARC_NONE,KAM_DMARC_STATUS,SPF_HELO_NONE,TXREP,T_SPF_PERMERROR autolearn=ham autolearn_force=no version=3.4.6 Received: from [192.168.33.9] (217-115-245-101.cust.avonet.cz [217.115.245.101]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: vanekt) by ktus.lan (Postfix) with ESMTPSA id CAE3C3144FA for ; Mon, 28 Nov 2022 12:48:52 +0100 (CET) Message-ID: <7ce34c91-00ab-cf16-a13f-21fa8eada5a9@fbl.cz> Date: Mon, 28 Nov 2022 12:48:52 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.13.1 Subject: [PING] [PATCH v2] gdb: Modify until_break_command to act correctly on SIGTRAMP_FRAME Content-Language: cs To: gdb-patches@sourceware.org References: <1666353538-15846-1-git-send-email-vanekt@fbl.cz> From: Tomas Vanek In-Reply-To: <1666353538-15846-1-git-send-email-vanekt@fbl.cz> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit List-Id: On 21/10/2022 13:58, Tomas Vanek wrote: > This patch partially depends on > gdb/arm: Terminate frame unwinding in M-profile lockup state > (without it lockup state is unwound as if it were a normal > stack frame). > > The commands 'advance' and 'until' try to set a breakpoint > on the bogus return address derived from Arm M-profile magic > address (actually EXC_RETURN or a PC value indicating lockup). > > The offending breakpoint should be set at the return address in > the caller. The magic value 0xffffffff in LR indicates > there is no caller (return to this address would lock up the CPU). > > Similar behaviour of 'advance' and 'until' is observed in > an exception handler routine. In this case LR contains e.g. > 0xfffffff1 (EXC_RETURN) and GDB tries to set a breakpoint at > 0xfffffff0. It should use a return value stacked by the exception > instead. > > Testbench setup: > STM32G474, a Cortex-M4 device. Any Cortex-M device can be used. > A test application (an ordinary blink) with a standard startup > is loaded to the device flash. > > Steps to reproduce the problem: > > start GDB server > $ openocd -f interface/cmsis-dap.cfg -f target/stm32g4x.cfg > > start GDB in second terminal > $ arm-none-eabi-gdb blink.elf > > (gdb) target extended-remote localhost:3333 > > Reset the device and halt it: > (gdb) monitor reset halt > target halted due to debug-request, current mode: Thread > xPSR: 0x01000000 pc: 0x08000e14 msp: 0x20020000 > > Step by one instruction to re-read GDB register cache: > (gdb) stepi > > Check registers, LR should be 0xffffffff after reset: > (gdb) info registers > ... > sp 0x20020000 0x20020000 > lr 0xffffffff -1 > pc 0x8000e16 0x8000e16 > xPSR 0x1000000 16777216 > ... > > (gdb) set debug remote > > Issue 'advance' command: > (gdb) advance main > [remote] Sending packet: $mfffffffe,2#fa > [remote] Packet received: 0000 > [remote] Sending packet: $mfffffffe,2#fa > [remote] Packet received: 0000 > [remote] Sending packet: $m8000526,2#30 > [remote] Packet received: 2046 > [remote] Sending packet: $Z1,8000526,2#7a > [remote] Packet received: OK > [remote] packet_ok: Packet Z1 (hardware-breakpoint) is supported > [remote] Sending packet: $Z0,fffffffe,2#43 > [remote] Packet received: E0E > [remote] packet_ok: Packet Z0 (software-breakpoint) is supported > Warning: > Cannot insert breakpoint 0. > Cannot access memory at address 0xfffffffe > > Command aborted. > (gdb) > > Relevant messages from OpenOCD: > Error: Failed to read memory at 0xfffff000 > Error: can't add breakpoint: unknown reason > > This patch adds skipping over frames that are not suitable for > guarding with a breakpoint inspired by 'finish' command. > If no suitable frame is found, a momentary breakpoint is not set. > > v2: Comment fixes, bug reference. > > Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=28683 > Signed-off-by: Tomas Vanek > --- > gdb/breakpoint.c | 22 +++++++++++++++++----- > 1 file changed, 17 insertions(+), 5 deletions(-) > > diff --git a/gdb/breakpoint.c b/gdb/breakpoint.c > index f6591d4..bb85342 100644 > --- a/gdb/breakpoint.c > +++ b/gdb/breakpoint.c > @@ -10467,6 +10467,7 @@ enum async_reply_reason > until_break_command (const char *arg, int from_tty, int anywhere) > { > frame_info_ptr frame; > + frame_info_ptr caller_frame; > struct gdbarch *frame_gdbarch; > struct frame_id stack_frame_id; > struct frame_id caller_frame_id; > @@ -10505,7 +10506,17 @@ enum async_reply_reason > frame = get_selected_frame (NULL); > frame_gdbarch = get_frame_arch (frame); > stack_frame_id = get_stack_frame_id (frame); > - caller_frame_id = frame_unwind_caller_id (frame); > + > + caller_frame = get_prev_frame_always (frame); > + > + while (caller_frame) > + { > + if (get_frame_type (caller_frame) != TAILCALL_FRAME > + && gdbarch_code_of_frame_writable (get_frame_arch (caller_frame), caller_frame)) > + break; > + > + caller_frame = get_prev_frame_always (caller_frame); > + } > > /* Keep within the current frame, or in frames called by the current > one. */ > @@ -10514,14 +10525,15 @@ enum async_reply_reason > > gdb::optional lj_deleter; > > - if (frame_id_p (caller_frame_id)) > + if (caller_frame) > { > struct symtab_and_line sal2; > struct gdbarch *caller_gdbarch; > > - sal2 = find_pc_line (frame_unwind_caller_pc (frame), 0); > - sal2.pc = frame_unwind_caller_pc (frame); > - caller_gdbarch = frame_unwind_caller_arch (frame); > + sal2 = find_pc_line (get_frame_pc (caller_frame), 0); > + sal2.pc = get_frame_pc (caller_frame); > + caller_gdbarch = get_frame_arch (caller_frame); > + caller_frame_id = get_frame_id (caller_frame); > > breakpoint_up caller_breakpoint > = set_momentary_breakpoint (caller_gdbarch, sal2,