Commit Graph

13 Commits

Author SHA1 Message Date
Jakub Jelinek
7adcbafe45 Update copyright years. 2022-01-03 10:42:10 +01:00
Jakub Jelinek
99dee82307 Update copyright years. 2021-01-04 10:26:59 +01:00
Szabolcs Nagy
ab240ab509 aarch64: add PAC-RET protection to libitm sjlj.S
_ITM_beginTransaction is a 'returns_twice' function that saves x30
on the stack as part of gtm_jmpbuf (that is passed down to
GTM_begin_transaction), but the saved x30 is also used for return.

The return path should be protected so we don't leave an
  ldp x29, x30, [sp]
  ret
gadget in the code, so x30 is signed on function entry. This
exposes the signed address in the gtm_jmpbuf too. The jmpbuf does
not need a signed address since GTM_longjmp uses
  ldp x29, x30, [x1]
  br x30
and with BTI there is a BTI j at the _ITM_beginTransaction call site
where this jump returns. Using PAC does not hurt: the gtm_jmpbuf is
internal to libitm and its layout is only used by sjlj.S so the
signed address does not escape. Saving signed x30 into gtm_jmpbuf
provides a bit of extra protection, but more importantly it allows
adding the PAC-RET support without changing the existing code much.

In theory bti and pac-ret protection can be added unconditionally
since the instructions are in the nop space, in practice they
can cause trouble if some tooling does not understand the gnu
property note (e.g. old binutils) or some unwinder or debugger
does not understand the new dwarf op code used for pac-ret (e.g
old gdb). So the code is written to only support branch-protection
according to the code generation options.

libitm/ChangeLog:

	* config/aarch64/sjlj.S: Add conditional pac-ret protection.
2020-07-24 11:44:53 +01:00
Szabolcs Nagy
319078dad6 aarch64: Fix BTI support in libitm
sjlj.S did not have the GNU property note markup and the BTI c
instructions that are necessary when it is built with branch
protection.

The notes are only added when libitm is built with branch
protection, because old linkers mishandle the note (merge
them incorrectly or emit warnings), the BTI instructions
are added unconditionally.

2020-07-09  Szabolcs Nagy  <szabolcs.nagy@arm.com>

libitm/ChangeLog:

	* config/aarch64/sjlj.S: Add BTI marking and related definitions,
	and add BTI c to function entries.
2020-07-09 09:50:25 +01:00
Szabolcs Nagy
463ba375f7 aarch64: Fix noexecstack note in libitm
sjlj.S only had the note on Linux, but it is supposed
to have it on FreeBSD too.

2020-07-09  Szabolcs Nagy  <szabolcs.nagy@arm.com>

libitm/ChangeLog:

	* config/aarch64/sjlj.S: Add stack note if __FreeBSD__ is defined.
2020-07-09 09:50:25 +01:00
Jakub Jelinek
8d9254fc8a Update copyright years.
From-SVN: r279813
2020-01-01 12:51:42 +01:00
Jakub Jelinek
a554497024 Update copyright years.
From-SVN: r267494
2019-01-01 13:31:55 +01:00
Jakub Jelinek
85ec4feb11 Update copyright years.
From-SVN: r256169
2018-01-03 11:03:58 +01:00
Jakub Jelinek
cbe34bb5ed Update copyright years.
From-SVN: r243994
2017-01-01 13:07:43 +01:00
Jakub Jelinek
818ab71a41 Update copyright years.
From-SVN: r232055
2016-01-04 15:30:50 +01:00
Jakub Jelinek
5624e564d2 Update copyright years.
From-SVN: r219188
2015-01-05 13:33:28 +01:00
Richard Henderson
b6334cf4bb libitm: Improve aarch64 _ITM_beginTransaction
* config/aarch64/sjlj.S (_ITM_beginTransaction): Use post-inc
        addressing mode in epilogue.

From-SVN: r213035
2014-07-24 19:58:06 -07:00
Richard Henderson
b17f08ddf9 libitm: Enable aarch64
From-SVN: r210615
2014-05-19 07:41:18 -07:00