> This patch adds MSVC's "/guard:signret" flag to the C/C++ compilation
> flags so that the VM code includes signing and authentication
> instructions to ensure that the return address is not tampered by any
> callee. Specifically, MSVC chooses signing using the B key, so every
> non-leaf function starts with the `pacibsp` instruction (for signining
> the return address) and ends with the `autibsp` instruction (for
> authenticating the return address). Both `pacibsp` and `autibsp`
> instructions are in the NOP space, so older AArch64 processors that do
> not support these instructions shouldn't be impacted by these
> instructions.
>
> As a matter of slight detail, this patch adds the "/guard:signret" flag
> only when the OpenJDK build is passed the "--enable-branch-protection"
> flag, which is off by default. Consequently, this change will not
> impact ordinary builds of OpenJDK.
>
> I've validated this patch by running the test/jdk:tier{1,2,3},
> test/hotspot/jtreg:tier{1,2,3}, test/langtools:tier{1,2,3}, and
> test/lib-test:tier1 tests with branch protection enabled. This patch
> does not introduce any new failures.
>
> ---------
> - [x] I confirm that I make this contribution in accordance with the [OpenJDK
> Interim AI Policy](https://openjdk.org/legal/ai).
Ashay Rane has updated the pull request incrementally with one additional
commit since the last revision:
Clarify that Branch Protection is not fully supported
-------------
Changes:
- all: https://git.openjdk.org/jdk/pull/31795/files
- new: https://git.openjdk.org/jdk/pull/31795/files/93170e60..3d5608c6
Webrevs:
- full: https://webrevs.openjdk.org/?repo=jdk&pr=31795&range=03
- incr: https://webrevs.openjdk.org/?repo=jdk&pr=31795&range=02-03
Stats: 5 lines in 2 files changed: 1 ins; 0 del; 4 mod
Patch: https://git.openjdk.org/jdk/pull/31795.diff
Fetch: git fetch https://git.openjdk.org/jdk.git pull/31795/head:pull/31795
PR: https://git.openjdk.org/jdk/pull/31795
