From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qt1-x843.google.com (mail-qt1-x843.google.com [IPv6:2607:f8b0:4864:20::843]) by sourceware.org (Postfix) with ESMTPS id 2C23D383F861 for ; Wed, 15 Jul 2020 19:50:07 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 2C23D383F861 Received: by mail-qt1-x843.google.com with SMTP id d27so2752407qtg.4 for ; Wed, 15 Jul 2020 12:50:07 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=XSzBclHRFcLjWPlxpR19Q8RPTu0GQYJwUZxR7Y9ntoA=; b=f6afsdcBATFOHROb762KHslMoQAstVp4N4pmalKWkbnPz3DFMEHk/YxBqrkzJ3vfSI KuVcvaJGYUlaBo9EGH72VaQfvP1NX5s/7wiJKLJBql1Fei0BVavfF9ohVgGYSC2gKgHm ppbJ1fSke00Nv7bWrPYZRRcC57Y6aI3VkLpJ/FQ0a0I24T2WE0aisrTOC61tSxCzQuYo rvVqcwJW74zPph+5FGWg8/8WDqo2LCKMphRYZhsiWHdFR54yJnenm8ZFJ9Q5vTBI3wkj l2P+MWUMWhMHni41Qzi1GhtTtArCubvrGLU8emjHgaUWygVBJtnz1COuwwQx/DxDAk5X Q6SQ== X-Gm-Message-State: AOAM530aMTwqP8p+kPk2pkevb1IzUWFM90+RgRhktrpJp4qxkLFM6jlm /7zdVO9IOkPBGcCj2rWdgs6aFsk2c+q3CA== X-Google-Smtp-Source: ABdhPJxcJy+dcwDK13NEq8nH58qNEEqrVpvhUi5If6LQiit30KYMcOP/F+eEGfTD1TraIRf1Uc6xnw== X-Received: by 2002:ac8:408c:: with SMTP id p12mr1495151qtl.332.1594842606509; Wed, 15 Jul 2020 12:50:06 -0700 (PDT) Received: from localhost.localdomain ([2804:7f0:8283:82c3:9daa:7611:ebe6:931]) by smtp.gmail.com with ESMTPSA id z18sm4340537qta.51.2020.07.15.12.49.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 15 Jul 2020 12:50:06 -0700 (PDT) From: Luis Machado To: gdb-patches@sourceware.org, Alan.Hayward@arm.com Cc: omair.javaid@linaro.org, catalin.marinas@arm.com, david.spickett@linaro.org, jose.marchesi@oracle.com Subject: [PATCH 21/23] Document new "x" and "print" memory tagging extensions Date: Wed, 15 Jul 2020 16:45:11 -0300 Message-Id: <20200715194513.16641-22-luis.machado@linaro.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200715194513.16641-1-luis.machado@linaro.org> References: <20200715194513.16641-1-luis.machado@linaro.org> X-Spam-Status: No, score=-10.8 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org 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: , X-List-Received-Date: Wed, 15 Jul 2020 19:50:08 -0000 Document the changes to the "print" and "x" commands to support memory tagging. gdb/doc/ChangeLog: YYYY-MM-DD Luis Machado * gdb.texinfo (Data): Document memory tagging changes to the "print" command. (Examining Memory): Document memory tagging changes to the "x" command. (Memory Tagging): Update with more information on changes to the "x" and "print" commands. --- gdb/doc/gdb.texinfo | 34 +++++++++++++++++++++++++++++++--- 1 file changed, 31 insertions(+), 3 deletions(-) diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo index 4156d1d70a..a341ac4752 100644 --- a/gdb/doc/gdb.texinfo +++ b/gdb/doc/gdb.texinfo @@ -9893,6 +9893,10 @@ If you omit @var{expr}, @value{GDBN} displays the last value again (from the conveniently inspect the same value in an alternative format. @end table +If the architecture supports memory tagging, the @code{print} command will +display pointer/memory tag mismatches if what is being printed is a pointer +or reference type. + A more low-level way of examining data is with the @code{x} command. It examines data in memory at a specified address and prints it in a specified format. @xref{Memory, ,Examining Memory}. @@ -10660,7 +10664,8 @@ number is specified, memory is examined backward from @var{addr}. @item @var{f}, the display format The display format is one of the formats used by @code{print} (@samp{x}, @samp{d}, @samp{u}, @samp{o}, @samp{t}, @samp{a}, @samp{c}, -@samp{f}, @samp{s}), and in addition @samp{i} (for machine instructions). +@samp{f}, @samp{s}), @samp{i} (for machine instructions) and +@samp{m} (for displaying memory tags). The default is @samp{x} (hexadecimal) initially. The default changes each time you use either @code{x} or @code{print}. @@ -10755,6 +10760,20 @@ counter is shown with a @code{=>} marker. For example: 0x804838c : call 0x80482d4 @end smallexample +If the architecture supports memory tagging, the tags can be displayed by +using @samp{m}. The information will be displayed once per granule size +(the amount of bytes a particular memory tag covers). For example, AArch64 +has a granule size of 16 bytes, so it will display a tag every 16 bytes. + +Due to the way @value{GDBN} prints information with the @code{x} command (not +aligned to a particular boundary), the tag information will refer to the +initial address displayed on a particular line. If a memory tag boundary +is crossed in the middle of a line displayed by the @code{x} command, it +will be displayed in the next line. + +The @samp{m} format doesn't affect any other specified formats that were +passed to the @code{x} command. + @cindex @code{$_}, @code{$__}, and value history The addresses and contents printed by the @code{x} command are not saved in the value history because there is often too much of them and they @@ -10821,8 +10840,17 @@ If the underlying architecture supports memory tagging, like AArch64, @value{GDBN} can make use of it to validate addresses and pointers against memory allocation tags. -A command prefix of @code{mtag} gives access to the various memory tagging -commands. +The @code{print} and @code{x} commands will display tag information when +appropriate, and a command prefix of @code{mtag} gives access to the +various memory tagging commands. + +The @code{print} command will automatically attempt to validate the logical +tag against the allocation tag for pointers and addresses, and will display +a message in case of failure. + +The @code{x} command has a @code{m} modifier. When present, this modifier +will make the @code{x} command output allocation tag information for a given +memory region that is being examined. The @code{mtag} commands are the following: -- 2.17.1