From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from simark.ca by simark.ca with LMTP id yX9DBbOZs19yfAAAWB0awg (envelope-from ) for ; Tue, 17 Nov 2020 04:36:51 -0500 Received: by simark.ca (Postfix, from userid 112) id 06D301F08B; Tue, 17 Nov 2020 04:36:51 -0500 (EST) X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on simark.ca X-Spam-Level: X-Spam-Status: No, score=-1.1 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,MAILING_LIST_MULTI,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.2 Received: from sourceware.org (server2.sourceware.org [8.43.85.97]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by simark.ca (Postfix) with ESMTPS id D7A581E58D for ; Tue, 17 Nov 2020 04:36:49 -0500 (EST) Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 6C5ED385800E; Tue, 17 Nov 2020 09:36:49 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 6C5ED385800E DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1605605809; bh=tjXoMVk7YyN+Ck51rKpqYWC8czFrjafdgtYrb7ZCZTs=; h=References:In-Reply-To:Date:Subject:To:List-Id:List-Unsubscribe: List-Archive:List-Post:List-Help:List-Subscribe:From:Reply-To:Cc: From; b=ibaQtRj1xZT+mlrFbumcvJS8qc5tUxIGiTafz0Th/9HeF2vYH0bkiC5hdhbIWVGIj 4qZC9st6r6sSbkF3e0LSzAvXYqvXpSpd7qFzR5aJDsZ2pefEgarllS2CtBbUxAnNuq e0irFNvPSosJznPY3hgOak9vMQ7sBa+Xq9AG5hso= Received: from mail-vk1-xa43.google.com (mail-vk1-xa43.google.com [IPv6:2607:f8b0:4864:20::a43]) by sourceware.org (Postfix) with ESMTPS id BEA4E385800D for ; Tue, 17 Nov 2020 09:36:46 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org BEA4E385800D Received: by mail-vk1-xa43.google.com with SMTP id d191so4376348vka.13 for ; Tue, 17 Nov 2020 01:36:46 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=tjXoMVk7YyN+Ck51rKpqYWC8czFrjafdgtYrb7ZCZTs=; b=jpvFCdqkYMhx2BOTTXUUHrXU677ks9ngqqiO1nLJo4u4y8WmKhTaXl7olxgtmFEmAD 1Emq/TcIQH3/kggLeG4/f56OMTxKiCzu4luX9wby77L0m2Zh4L9fC+nnpvGQueGKuv1G Kni5Radr2h8GH4LLAN8bFO1wthU+u7M6SpI8wZIK7q6UAnYyIB9cvvUI7l1GEvvQKxmU tA4V1fI/qA0UC//2g70SLxVTMx+00bsGyjUTK43eD/8G3cdYMUA3IMUn/TSDeD/x1nlX c+gVjF6zRub3n2/HOE7rHr4SGA3A4ixeznYfNAe3kNXzSq4vSszTSCr1xS5MsaeTxprH SSJw== X-Gm-Message-State: AOAM532wIt3EwMvOFoSq5cyA6OHU07X3toYWlr2+nOrt0IByCwdZhLmz eBSRvk04DZrFDlPSDKaOkmERKa/8lSDtPKkaeOBvAg== X-Google-Smtp-Source: ABdhPJwzKSGLVX1DeQdigtJejw/4WOKcfwVavAS/4ZD3F2+diX+yFBs3KXWIV1dW8NiHrjZyQAIXf0HJiQxNUN3xAoc= X-Received: by 2002:a05:6122:84f:: with SMTP id 15mr9895055vkk.25.1605605806327; Tue, 17 Nov 2020 01:36:46 -0800 (PST) MIME-Version: 1.0 References: <20201109170435.15766-1-luis.machado@linaro.org> <20201109170435.15766-17-luis.machado@linaro.org> In-Reply-To: Date: Tue, 17 Nov 2020 09:36:34 +0000 Message-ID: Subject: Re: [PATCH v3 16/24] AArch64: Report tag violation error information To: Luis Machado Content-Type: text/plain; charset="UTF-8" X-BeenThere: gdb-patches@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gdb-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: David Spickett via Gdb-patches Reply-To: David Spickett Cc: gdb-patches@sourceware.org Errors-To: gdb-patches-bounces@sourceware.org Sender: "Gdb-patches" > This is a GDB-ism. The hook itself is named like that. I don't like the name, but I thought I'd leave it the same just to keep it standard. Fair enough. > We could print it without leading zeroes. That may make things a bit more compact. Would that work? Sounds good to me. On Mon, 16 Nov 2020 at 16:46, Luis Machado wrote: > > On 11/16/20 12:43 PM, David Spickett wrote: > >> +aarch64_linux_report_signal_info (struct gdbarch *gdbarch, > >> + struct ui_out *uiout, > >> + enum gdb_signal siggnal) > > > > siggnal -> signal > > > > This is a GDB-ism. The hook itself is named like that. I don't like the > name, but I thought I'd leave it the same just to keep it standard. > > > Also a nit about the formatting. > > > > Copying from 20/24 of v3: > >> +Memory tag violation while accessing address 0x0000fffff7ff8000 > >> +Allocation tag 0x0000000000000001. > > > > (I'm guessing the code to print the "Allocation tag" line lives here > > in some part) > > > > Would it make more sense to either not align the tag value to > > anything, or to align it to the size of the architecture's tag? Which > > would be 4 bits in this case so the same either way. > > We could print it without leading zeroes. That may make things a bit > more compact. Would that work? > > > > > On Mon, 9 Nov 2020 at 17:05, Luis Machado wrote: > >> > >> Whenever a memory tag violation occurs, we get a SIGSEGV. Additional > >> information can be obtained through the siginfo data structure. > >> > >> For AArch64 the Linux kernel may expose the fault address and tag > >> information, if we have a synchronous event. Otherwise there is > >> no fault address available. > >> > >> gdb/ChangeLog: > >> > >> YYYY-MM-DD Luis Machado > >> > >> * aarch64-linux-tdep.c > >> (aarch64_linux_report_signal_info): New function. > >> (aarch64_linux_init_abi): Register > >> aarch64_linux_report_signal_info as the report_signal_info hook. > >> * arch/aarch64-linux.h (SEGV_MTEAERR): Define. > >> (SEGV_MTESERR): Define. > >> --- > >> gdb/aarch64-linux-tdep.c | 64 ++++++++++++++++++++++++++++++++++++ > >> gdb/arch/aarch64-mte-linux.h | 6 ++++ > >> 2 files changed, 70 insertions(+) > >> > >> diff --git a/gdb/aarch64-linux-tdep.c b/gdb/aarch64-linux-tdep.c > >> index 39b1790263..70e180e1cb 100644 > >> --- a/gdb/aarch64-linux-tdep.c > >> +++ b/gdb/aarch64-linux-tdep.c > >> @@ -1626,6 +1626,67 @@ aarch64_linux_memtag_to_string (struct gdbarch *gdbarch, > >> return string_printf ("0x%s", phex_nz (tag, sizeof (tag))); > >> } > >> > >> +/* AArch64 Linux implementation of the report_signal_info gdbarch > >> + hook. Displays information about possible memory tag violations. */ > >> + > >> +static void > >> +aarch64_linux_report_signal_info (struct gdbarch *gdbarch, > >> + struct ui_out *uiout, > >> + enum gdb_signal siggnal) > >> +{ > >> + struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); > >> + > >> + if (!tdep->has_mte () || siggnal != GDB_SIGNAL_SEGV) > >> + return; > >> + > >> + CORE_ADDR fault_addr = 0; > >> + long si_code = 0; > >> + > >> + try > >> + { > >> + /* Sigcode tells us if the segfault is actually a memory tag > >> + violation. */ > >> + si_code = parse_and_eval_long ("$_siginfo.si_code\n"); > >> + > >> + fault_addr > >> + = parse_and_eval_long ("$_siginfo._sifields._sigfault.si_addr"); > >> + } > >> + catch (const gdb_exception &exception) > >> + { > >> + return; > >> + } > >> + > >> + /* If this is not a memory tag violation, just return. */ > >> + if (si_code != SEGV_MTEAERR && si_code != SEGV_MTESERR) > >> + return; > >> + > >> + uiout->text ("\n"); > >> + > >> + uiout->field_string ("sigcode-meaning", _("Memory tag violation")); > >> + > >> + /* For synchronous faults, show additional information. */ > >> + if (si_code == SEGV_MTESERR) > >> + { > >> + uiout->text (_(" while accessing address ")); > >> + uiout->field_core_addr ("fault-addr", gdbarch, fault_addr); > >> + uiout->text ("\n"); > >> + > >> + CORE_ADDR atag; > >> + if (aarch64_linux_get_atag (fault_addr, &atag) != 0) > >> + uiout->text (_("Allocation tag unavailable")); > >> + else > >> + { > >> + uiout->text (_("Allocation tag ")); > >> + uiout->field_core_addr ("allocation-tag", gdbarch, atag); > >> + } > >> + } > >> + else > >> + { > >> + uiout->text ("\n"); > >> + uiout->text (_("Fault address unavailable")); > >> + } > >> +} > >> + > >> static void > >> aarch64_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) > >> { > >> @@ -1706,6 +1767,9 @@ aarch64_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) > >> > >> /* Register a hook for converting a memory tag to a string. */ > >> set_gdbarch_memtag_to_string (gdbarch, aarch64_linux_memtag_to_string); > >> + > >> + set_gdbarch_report_signal_info (gdbarch, > >> + aarch64_linux_report_signal_info); > >> } > >> > >> /* Initialize the aarch64_linux_record_tdep. */ > >> diff --git a/gdb/arch/aarch64-mte-linux.h b/gdb/arch/aarch64-mte-linux.h > >> index 5c5783f28b..a5a980ed49 100644 > >> --- a/gdb/arch/aarch64-mte-linux.h > >> +++ b/gdb/arch/aarch64-mte-linux.h > >> @@ -35,6 +35,12 @@ > >> #define MTE_LOGICAL_TAG_START_BIT 56 > >> #define MTE_LOGICAL_MAX_VALUE 0xf > >> > >> +/* Memory tagging definitions. */ > >> +#ifndef SEGV_MTEAERR > >> +# define SEGV_MTEAERR 8 > >> +# define SEGV_MTESERR 9 > >> +#endif > >> + > >> /* Return the number of tag granules in the memory range > >> [ADDR, ADDR + LEN) given GRANULE_SIZE. */ > >> extern size_t get_tag_granules (CORE_ADDR addr, size_t len, > >> -- > >> 2.17.1 > >>