Commit Graph

5 Commits

Author SHA1 Message Date
David Spickett
31f9960c38 [lldb][AArch64] Add "memory tag read" command
This new command looks much like "memory read"
and mirrors its basic behaviour.

(lldb) memory tag read new_buf_ptr new_buf_ptr+32
Logical tag: 0x9
Allocation tags:
[0x900fffff7ffa000, 0x900fffff7ffa010): 0x9
[0x900fffff7ffa010, 0x900fffff7ffa020): 0x0

Important proprties:
* The end address is optional and defaults to reading
  1 tag if ommitted
* It is an error to try to read tags if the architecture
  or process doesn't support it, or if the range asked
  for is not tagged.
* It is an error to read an inverted range (end < begin)
  (logical tags are removed for this check so you can
  pass tagged addresses here)
* The range will be expanded to fit the tagging granule,
  so you can get more tags than simply (end-begin)/granule size.
  Whatever you get back will always cover the original range.

Reviewed By: omjavaid

Differential Revision: https://reviews.llvm.org/D97285
2021-06-24 17:35:45 +01:00
David Spickett
f31e390453 [lldb][AArch64] Don't check for VmFlags in smaps files
AArch64 kernel builds default to having /smaps and
the "VmFlags" line was added in 3.8. Long before MTE
was supported.

So we can assume that if you're AArch64 with MTE,
you can run this test.

The previous method of checking had a race condition
where the process we read smaps for, could finish before
we get to read the file.

I explored some alternatives but in the end I think
it's fine to just assume we have what we need.

Reviewed By: omjavaid

Differential Revision: https://reviews.llvm.org/D100493
2021-04-29 09:30:14 +01:00
David Spickett
6cdc2239db [lldb][AArch64] Simplify MTE memory region test
By checking for cpu and toolchain features ahead
of time we don't need the custom return codes.

Reviewed By: omjavaid

Differential Revision: https://reviews.llvm.org/D97684
2021-04-14 11:50:45 +01:00
David Spickett
29a4d7813c [lldb][AArch64] Only run MTE memory region test if we have MTE
This test is flakey because it tries to read the proc/smaps
file of the first lldb-server process it finds. This process
can finish before we finish doing that.

http://lab.llvm.org:8011/#/builders/96/builds/6634/steps/6/logs/stdio

For now limit this to MTE targets which basically means
QEMU via lldb-dotest, which doesn't have this issue.

I'll fix the race condition shortly.
2021-04-13 15:40:38 +01:00
David Spickett
32541685b2 [lldb][AArch64/Linux] Show memory tagged memory regions
This extends the "memory region" command to
show tagged regions on AArch64 Linux when the MTE
extension is enabled.

(lldb) memory region the_page
[0x0000fffff7ff8000-0x0000fffff7ff9000) rw-
memory tagging: enabled

This is done by adding an optional "flags" field to
the qMemoryRegion packet. The only supported flag is
"mt" but this can be extended.

This "mt" flag is read from /proc/{pid}/smaps on Linux,
other platforms will leave out the "flags" field.

Where this "mt" flag is received "memory region" will
show that it is enabled. If it is not or the target
doesn't support memory tagging, the line is not shown.
(since majority of the time tagging will not be enabled)

Testing is added for the existing /proc/{pid}/maps
parsing and the new smaps parsing.
Minidump parsing has been updated where needed,
though it only uses maps not smaps.

Target specific tests can be run with QEMU and I have
added MTE flags to the existing helper scripts.

Reviewed By: labath

Differential Revision: https://reviews.llvm.org/D87442
2020-11-20 11:21:59 +00:00