SIGILL on rdcycle, which becomes a privileged instruction since linux 6.6

[kxxt]

All rdcycle usage should be replaced/removed from the codebase.

• ./../../third_party/abseil-cpp/absl/base/internal/unscaledcycleclock.cc:128: unscaledcycleclock: remove RISC-V support abseil/abseil-cpp#1644
• Clang might generate this instruction. I am not sure about this. (Not found in v29.4.5 binary)
• There are some rdcycle instructions in v8. Not sure if they are really used.

[kxxt]

For abseil-cpp, it's already fixed in main branch of chromium's vendored copy: https://chromium.googlesource.com/chromium/src/+/refs/heads/main/third_party/abseil-cpp/absl/base/internal/unscaledcycleclock.cc by 03b48d871136a25321821618e5b2544ee8dec4b0 https://chromium-review.googlesource.com/c/chromium/src/+/5404980

It's introduced into chromium in 115290d7e28203c9275c89cc301271ba56157e48 https://chromium-review.googlesource.com/c/chromium/src/+/3161995

I still need to determine which electron versions are affected.

[kxxt]

chromium [96.0.4644.0, 125.0.6395.0) is affected, which corresponds to electron [18, 30].

electron 31 is not affected.

electron 29 and 30 will be fixed.

If anyone need support for EOL electron versions(26, 27, 28), please leave a comment here.

[kxxt]

./../../third_party/abseil-cpp/absl/base/internal/unscaledcycleclock.cc:128 is fixed in

• Binary releases of v30.2.0.riscv2, v29.4.5.riscv2, v29.4.0.riscv3
• Source branch v30.2.0-riscv, v29.4.5-riscv, v29.4.0-riscv, v28.3.3-riscv

[kxxt]

Closing as the absl one is the only real world usage found.