binutils-gdb/gdb/memtag.c
Luis Machado 68cffbbd44 [AArch64] MTE corefile support
Teach GDB how to dump memory tags for AArch64 when using the gcore command
and how to read memory tag data back from a core file generated by GDB
(via gcore) or by the Linux kernel.

The format is documented in the Linux Kernel documentation [1].

Each tagged memory range (listed in /proc/<pid>/smaps) gets dumped to its
own PT_AARCH64_MEMTAG_MTE segment. A section named ".memtag" is created for each
of those segments when reading the core file back.

To save a little bit of space, given MTE tags only take 4 bits, the memory tags
are stored packed as 2 tags per byte.

When reading the data back, the tags are unpacked.

I've added a new testcase to exercise the feature.

Build-tested with --enable-targets=all and regression tested on aarch64-linux
Ubuntu 20.04.

[1] Documentation/arm64/memory-tagging-extension.rst (Core Dump Support)
2022-07-19 15:24:31 +01:00

69 lines
2.2 KiB
C

/* GDB generic memory tagging functions.
Copyright (C) 2022 Free Software Foundation, Inc.
This file is part of GDB.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include "defs.h"
#include "memtag.h"
#include "bfd.h"
/* See memtag.h */
bool
get_next_core_memtag_section (bfd *abfd, asection *section,
CORE_ADDR address, memtag_section_info &info)
{
/* If the caller provided no SECTION to start from, search from the
beginning. */
if (section == nullptr)
section = bfd_get_section_by_name (abfd, "memtag");
/* Go through all the memtag sections and figure out if ADDRESS
falls within one of the memory ranges that contain tags. */
while (section != nullptr)
{
size_t memtag_range_size = section->rawsize;
size_t tags_size = bfd_section_size (section);
/* Empty memory range or empty tag dump should not happen. Warn about
it but keep going through the sections. */
if (memtag_range_size == 0 || tags_size == 0)
{
warning (_("Found memtag section with empty memory "
"range or empty tag dump"));
continue;
}
else
{
CORE_ADDR start_address = bfd_section_vma (section);
CORE_ADDR end_address = start_address + memtag_range_size;
/* Is the address within [start_address, end_address)? */
if (address >= start_address
&& address < end_address)
{
info.start_address = start_address;
info.end_address = end_address;
info.memtag_section = section;
return true;
}
}
section = bfd_get_next_section_by_name (abfd, section);
}
return false;
}