Commit 5b1944b4ce4b03e28a5843d36812756168d66b08
2023-11-29T00:38:13
aarch64: Write the BTI instructions as "hint" instructions (#810) GNU binutils refuses to assemble the direct BTI instructions unless the target architecture explicitly supports BTI, ending up with errors such as ../src/aarch64/sysv.S: Assembler messages: ../src/aarch64/sysv.S:87: Error: selected processor does not support `bti c' ../src/aarch64/sysv.S:156: Error: selected processor does not support `bti j' Building with -march=armv8.5-a fixes building this. However, the BTI instructions assemble into hint instructions, that are ignored by processors that don't implement them. Therefore it is possible to assemble them for the baseline armv8.0-a target as well, by replacing "bti j" with "hint #36", "bti c" with "hint #34" and "bti jc" with "hint #38"; this assembles into the same instruction bits.