[PATCH v8 0/6] arm64: add Armv8.3 pointer authentication enhancements

Amit Daniel Kachhap
2020-09-14T08:38:32Z

These patch series adds support for Armv8.3 pointer authentication
enhanced features mandatory for Armv8.6 and optional for Armv8.3.
These features are,

* Enhanced PAC generation algorithm (ARMv8.3-pauth2).
* Generate fault when authenticate instruction fails (ARMV8.3-FPAC).

More details can be found here [1].

Changes since v7 [2]:
* Cleaned-up trivial checks as pointed by Catalin.

Changes since v6 [3]:
* Clubbed Ptrauth combined branch instructions as suggested by Will.

Changes since v5 [4]:
* Few Comments modified as suggested by Dave and Suzuki.
* Added Reviewed-by's.

Changes since v4 [5]:
* New patch "arm64: kprobe: add checks for ARMv8.3-PAuth combined instructions".
This fixes uprobe crash with ARMv8.3-PAuth combined instructions.
* New patch "arm64: traps: Allow force_signal_inject to pass esr error code".
This is preparatory patch for ARMV8.3-FPAC fault exception handling.
* Removed caching of bootcpu address authentication cpufeature levels in
static variables. This was suggested by Dave and Suzuki.
* Use existing force_signal_inject function to invoke ptrauth fault
signal as suggested by Dave.
* Commit log changes.

Changes since v3 [6]:
* Added a new patch "arm64: kprobe: clarify the comment of steppable hint instructions"
as suggested in the last iteration.
* Removed the ptrauth fault handler from el0 compat handler as pointed
by Dave.
* Mentioned the new feature name clearly as ARMV8.3-FPAC and ARMv8.3-pauth2
as per ARMv8-A reference manual.
* Commit logs cleanup.

Changes since v2 [7]:
* Dropped the patch "arm64: cpufeature: Fix the handler for address authentication"
* Added new matching function for address authentication as generic
matching function has_cpuid_feature is specific for LOWER_SAFE
features. This was suggested by Suzuki [3].
* Disabled probe of Authenticate ptrauth instructions as per Mark
Brown's merged changes of whitelisting of hint instructions.

This series is based on kernel version v5.9-rc5.

Regards,
Amit

[1]: https://community.arm.com/developer/ip-products/processors/b/processors-ip-blog/posts/arm-architecture-developments-armv8-6-a
[2]: http://lists.infradead.org/pipermail/linux-arm-kernel/2020-September/599573.html
[3]: http://lists.infradead.org/pipermail/linux-arm-kernel/2020-September/598163.html
[4]: https://lore.kernel.org/linux-arm-kernel/1597734671-23407-1-git-send-email-amit.kachhap@arm.com/
[5]: http://lists.infradead.org/pipermail/linux-arm-kernel/2020-July/584393.html
[6]: https://lore.kernel.org/linux-arm-kernel/1592457029-18547-1-git-send-email-amit.kachhap@arm.com/
[7]: http://lists.infradead.org/pipermail/linux-arm-kernel/2020-April/723751.html

Amit Daniel Kachhap (6):
arm64: kprobe: add checks for ARMv8.3-PAuth combined instructions
arm64: traps: Allow force_signal_inject to pass esr error code
arm64: ptrauth: Introduce Armv8.3 pointer authentication enhancements
arm64: cpufeature: Modify address authentication cpufeature to exact
arm64: kprobe: disable probe of fault prone ptrauth instruction
arm64: kprobe: clarify the comment of steppable hint instructions

arch/arm64/include/asm/esr.h | 4 ++-
arch/arm64/include/asm/exception.h | 1 +
arch/arm64/include/asm/insn.h | 4 +++
arch/arm64/include/asm/sysreg.h | 24 +++++++++-----
arch/arm64/include/asm/traps.h | 2 +-
arch/arm64/kernel/cpufeature.c | 44 ++++++++++++++++++++------
arch/arm64/kernel/entry-common.c | 21 ++++++++++++
arch/arm64/kernel/fpsimd.c | 4 +--
arch/arm64/kernel/insn.c | 11 +++----
arch/arm64/kernel/probes/decode-insn.c | 9 ++++--
arch/arm64/kernel/traps.c | 26 +++++++++++----
11 files changed, 112 insertions(+), 38 deletions(-)