From: Luis Machado <luis.machado@linaro.org>
To: gdb-patches@sourceware.org
Cc: alan.hayward@arm.com, jhb@FreeBSD.org, david.spickett@linaro.org
Subject: [PATCH v2 22/24] Document new "x" and "print" memory tagging extensions
Date: Thu, 22 Oct 2020 17:00:12 -0300 [thread overview]
Message-ID: <20201022200014.5189-23-luis.machado@linaro.org> (raw)
In-Reply-To: <20201022200014.5189-1-luis.machado@linaro.org>
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 | 28 +++++++++++++++++++++++++---
1 file changed, 25 insertions(+), 3 deletions(-)
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 5056a021a5..5821210f55 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -9897,6 +9897,10 @@ 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}.
@@ -10664,7 +10668,8 @@ 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}.
@@ -10759,6 +10764,22 @@ 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
@@ -10826,8 +10847,9 @@ If the underlying architecture supports memory tagging, like AArch64 MTE
or SPARC ADI do, @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} (@pxref{Data}) and @code{x} (@pxref{Memory}) commands will
+display tag information when appropriate, and a command prefix of @code{mtag}
+gives access to the various memory tagging commands.
The @code{mtag} commands are the following:
--
2.17.1
next prev parent reply other threads:[~2020-10-22 20:01 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-22 19:59 [PATCH v2 00/24] Memory Tagging Support + AArch64 Linux implementation Luis Machado
2020-10-22 19:59 ` [PATCH v2 01/24] New target methods for memory tagging support Luis Machado
2020-10-27 13:22 ` Simon Marchi
2020-10-27 13:43 ` Luis Machado
2020-10-27 13:50 ` Simon Marchi
2020-10-22 19:59 ` [PATCH v2 02/24] New gdbarch memory tagging hooks Luis Machado
2020-10-22 19:59 ` [PATCH v2 03/24] Add GDB-side remote target support for memory tagging Luis Machado
2020-10-29 14:22 ` Alan Hayward
2020-10-29 14:41 ` Luis Machado
2020-10-22 19:59 ` [PATCH v2 04/24] Unit testing for GDB-side remote memory tagging handling Luis Machado
2020-10-22 19:59 ` [PATCH v2 05/24] GDBserver remote packet support for memory tagging Luis Machado
2020-10-22 19:59 ` [PATCH v2 06/24] Unit tests for gdbserver memory tagging remote packets Luis Machado
2020-10-22 19:59 ` [PATCH v2 07/24] Documentation for " Luis Machado
2020-10-23 6:25 ` Eli Zaretskii
2020-10-23 14:07 ` Luis Machado
2020-10-23 14:33 ` Eli Zaretskii
2020-10-23 14:39 ` Luis Machado
2020-10-22 19:59 ` [PATCH v2 08/24] AArch64: Add MTE CPU feature check support Luis Machado
2020-10-22 19:59 ` [PATCH v2 09/24] AArch64: Add target description/feature for MTE registers Luis Machado
2020-10-22 20:00 ` [PATCH v2 10/24] AArch64: Add MTE register set support for GDB and gdbserver Luis Machado
2020-10-22 20:00 ` [PATCH v2 11/24] AArch64: Add MTE ptrace requests Luis Machado
2020-10-22 20:00 ` [PATCH v2 12/24] AArch64: Implement memory tagging target methods for AArch64 Luis Machado
2020-10-29 14:21 ` Alan Hayward
2020-10-29 14:39 ` Luis Machado
2020-10-29 14:45 ` Luis Machado
2020-10-29 17:32 ` Alan Hayward
2020-10-22 20:00 ` [PATCH v2 13/24] Refactor parsing of /proc/<pid>/smaps Luis Machado
2020-10-22 20:00 ` [PATCH v2 14/24] AArch64: Implement the memory tagging gdbarch hooks Luis Machado
2020-10-22 20:00 ` [PATCH v2 15/24] AArch64: Add unit testing for logical tag set/get operations Luis Machado
2020-10-22 20:00 ` [PATCH v2 16/24] AArch64: Report tag violation error information Luis Machado
2020-10-22 20:00 ` [PATCH v2 17/24] AArch64: Add gdbserver MTE support Luis Machado
2020-10-22 20:00 ` [PATCH v2 18/24] AArch64: Add MTE register set support for core files Luis Machado
2020-10-22 20:00 ` [PATCH v2 19/24] New mtag commands Luis Machado
2020-10-22 20:00 ` [PATCH v2 20/24] Documentation for the new " Luis Machado
2020-10-23 6:35 ` Eli Zaretskii
2020-10-23 14:33 ` Luis Machado
2020-10-23 17:52 ` Eli Zaretskii
2020-10-23 19:04 ` Luis Machado
2020-10-23 19:34 ` Eli Zaretskii
2020-10-26 14:59 ` Luis Machado
2020-10-26 15:35 ` Eli Zaretskii
2020-10-26 16:57 ` Luis Machado
2020-10-22 20:00 ` [PATCH v2 21/24] Extend "x" and "print" commands to support memory tagging Luis Machado
2020-10-22 20:00 ` Luis Machado [this message]
2020-10-23 6:37 ` [PATCH v2 22/24] Document new "x" and "print" memory tagging extensions Eli Zaretskii
2020-10-22 20:00 ` [PATCH v2 23/24] Add NEWS entry Luis Machado
2020-10-23 6:38 ` Eli Zaretskii
2020-10-22 20:00 ` [PATCH v2 24/24] Add memory tagging testcases Luis Machado
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