Add the BTI instructions and the associated note to make the AArch64 asm
objects compatible with BTI enforcement.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Leif Lindholm <quic_llindhol@quicinc.com>
Reviewed-by: Oliver Smith-Denny <osd@smith-denny.com>
Currently, the AArch64 implementation of LongJump() avoids using the RET
instruction to perform the jump, even though the target address is held
in the link register X30, as the nature of a long jump implies that the
ordinary return address prediction machinery will not be able to make a
correct prediction.
However, LongJump() is rarely used, and the return stack will be out of
sync in any case, so this optimization has little value in practice, and
given that indirect calls other than function returns require a BTI
landing pad at the call site, this optimization is not compatible with
BTI. So let's just use RET instead.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Leif Lindholm <quic_llindhol@quicinc.com>
Reviewed-by: Oliver Smith-Denny <osd@smith-denny.com>
Correct the memory offsets used in REG_ONE/REG_PAIR macros to
synchronize them with definition of the BASE_LIBRARY_JUMP_BUFFER
structure on AArch64.
The REG_ONE macro declares only a single 64-bit register be
read/written; however, the subsequent offset is 16 bytes larger,
creating an unused memory gap in the middle of the structure and
causing SetJump/LongJump functions to read/write 8 bytes of memory
past the end of the jump buffer struct.
Signed-off-by: Jan Bobek <jbobek@nvidia.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@arm.com>
Acked-by: Michael D Kinney <michael.d.kinney@intel.com>
Acked-by: Liming Gao <gaoliming@byosoft.com.cn>
