From: Luis Machado <luis.machado@linaro.org>
To: gdb-patches@sourceware.org
Subject: [PATCH v6 23/25] Document new "x" and "print" memory tagging extensions
Date: Mon, 22 Mar 2021 10:21:17 -0300 [thread overview]
Message-ID: <20210322132120.1202230-24-luis.machado@linaro.org> (raw)
In-Reply-To: <20210322132120.1202230-1-luis.machado@linaro.org>
Updates on v6
- Document the new memory-tag-violation print option.
--
Document the changes to the "print" and "x" commands to support memory
tagging.
gdb/doc/ChangeLog:
YYYY-MM-DD Luis Machado <luis.machado@linaro.org>
* 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 | 42 +++++++++++++++++++++++++++++++++++++++---
1 file changed, 39 insertions(+), 3 deletions(-)
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index d976325e695..dbf878cdbc3 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -9951,6 +9951,10 @@ 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. @xref{Memory Tagging}.
+
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}.
@@ -10718,7 +10722,8 @@ 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}.
@@ -10813,6 +10818,22 @@ counter is shown with a @code{=>} marker. For example:
0x804838c <main+24>: call 0x80482d4 <puts@@plt>
@end smallexample
+If the architecture supports memory tagging, the tags can be displayed by
+using @samp{m}. @xref{Memory Tagging}.
+
+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 on 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
@@ -10890,8 +10911,9 @@ If the underlying architecture supports memory tagging, like AArch64 MTE
or SPARC ADI do, @value{GDBN} can make use of it to validate pointers
against memory allocation tags.
-A command prefix of @code{memory-tag} gives access to the various memory tagging
-commands.
+The @code{print} (@pxref{Data}) and @code{x} (@pxref{Memory}) commands will
+display tag information when appropriate, and a command prefix of
+@code{memory-tag} gives access to the various memory tagging commands.
The @code{memory-tag} commands are the following:
@@ -11527,6 +11549,20 @@ language, for most languages @code{@{...@}} is used, but Fortran uses
Display the current threshold after which nested structures are
replaces with ellipsis.
+@anchor{set print memory-tag-violations}
+@cindex printing memory tag violation information
+@item set print memory-tag-violations
+@itemx set print memory-tag-violations on
+Cause @value{GDBN} to display additional information about memory tag violations
+when printing pointers and addresses.
+
+@item set print memory-tag-violations off
+Stop printing memory tag violation information.
+
+@item show print memory-tag-violations
+Show whether memory tag violation information is displayed when printing
+pointers and addresses.
+
@anchor{set print null-stop}
@item set print null-stop
@cindex @sc{null} elements in arrays
--
2.25.1
next prev parent reply other threads:[~2021-03-22 13:22 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-22 13:20 [PATCH v6 00/25] Memory Tagging Support + AArch64 Linux implementation Luis Machado
2021-03-22 13:20 ` [PATCH v6 01/25] New target methods for memory tagging support Luis Machado
2021-03-23 21:22 ` Simon Marchi
2021-03-22 13:20 ` [PATCH v6 02/25] New gdbarch memory tagging hooks Luis Machado
2021-03-22 13:20 ` [PATCH v6 03/25] Add GDB-side remote target support for memory tagging Luis Machado
2021-03-22 13:20 ` [PATCH v6 04/25] Unit testing for GDB-side remote memory tagging handling Luis Machado
2021-03-22 13:20 ` [PATCH v6 05/25] GDBserver remote packet support for memory tagging Luis Machado
2021-03-22 13:21 ` [PATCH v6 06/25] Unit tests for gdbserver memory tagging remote packets Luis Machado
2021-03-22 13:21 ` [PATCH v6 07/25] Documentation for " Luis Machado
2021-03-22 17:47 ` Eli Zaretskii
2021-03-22 13:21 ` [PATCH v6 08/25] AArch64: Add MTE CPU feature check support Luis Machado
2021-03-22 13:21 ` [PATCH v6 09/25] AArch64: Add target description/feature for MTE registers Luis Machado
2021-03-22 13:21 ` [PATCH v6 10/25] AArch64: Add MTE register set support for GDB and gdbserver Luis Machado
2021-03-22 13:21 ` [PATCH v6 11/25] AArch64: Add MTE ptrace requests Luis Machado
2021-03-22 13:21 ` [PATCH v6 12/25] AArch64: Implement memory tagging target methods for AArch64 Luis Machado
2021-03-22 13:21 ` [PATCH v6 13/25] Convert char array to std::string in linux_find_memory_regions_full Luis Machado
2021-03-22 13:21 ` [PATCH v6 14/25] Refactor parsing of /proc/<pid>/smaps Luis Machado
2021-03-23 21:28 ` Simon Marchi
2021-03-22 13:21 ` [PATCH v6 15/25] AArch64: Implement the memory tagging gdbarch hooks Luis Machado
2021-03-23 21:32 ` Simon Marchi
2021-03-22 13:21 ` [PATCH v6 16/25] AArch64: Add unit testing for logical tag set/get operations Luis Machado
2022-01-31 14:34 ` Simon Marchi
2021-03-22 13:21 ` [PATCH v6 17/25] AArch64: Report tag violation error information Luis Machado
2021-03-22 13:21 ` [PATCH v6 18/25] AArch64: Add gdbserver MTE support Luis Machado
2021-03-22 13:21 ` [PATCH v6 19/25] AArch64: Add MTE register set support for core files Luis Machado
2021-03-22 13:21 ` [PATCH v6 20/25] New memory-tag commands Luis Machado
2021-03-22 13:21 ` [PATCH v6 21/25] Documentation for the new mtag commands Luis Machado
2021-03-22 17:49 ` Eli Zaretskii
2021-03-22 13:21 ` [PATCH v6 22/25] Extend "x" and "print" commands to support memory tagging Luis Machado
2021-03-22 13:21 ` Luis Machado [this message]
2021-03-22 17:51 ` [PATCH v6 23/25] Document new "x" and "print" memory tagging extensions Eli Zaretskii
2021-03-22 13:21 ` [PATCH v6 24/25] Add NEWS entry Luis Machado
2021-03-22 17:51 ` Eli Zaretskii
2021-03-22 17:52 ` Luis Machado
2021-03-22 13:21 ` [PATCH v6 25/25] Add memory tagging testcases Luis Machado
2021-03-23 22:50 ` [PATCH v6 00/25] Memory Tagging Support + AArch64 Linux implementation Simon Marchi
2021-03-24 18:18 ` Luis Machado
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