On Thu, Jun 19, 2025 at 03:55:35PM -0700, Eric Biggers wrote:
The MIPS32r2 ChaCha code has never been buildable with the clang assembler. First, clang doesn't support the 'rotl' pseudo-instruction:
error: unknown instruction, did you mean: rol, rotr?Second, clang requires that both operands of the 'wsbh' instruction be explicitly given:
error: too few operands for instructionTo fix this, align the code with the real instruction set by (1) using the real instruction 'rotr' instead of the nonstandard pseudo- instruction 'rotl', and (2) explicitly giving both operands to 'wsbh'.
To make removing the use of 'rotl' a bit easier, also remove the unnecessary special-casing for big endian CPUs at .Lchacha_mips_xor_bytes. The tail handling is actually endian-independent since it processes one byte at a time. On big endian CPUs the old code byte-swapped SAVED_X, then iterated through it in reverse order. But the byteswap and reverse iteration canceled out.
Tested with chacha20poly1305-selftest in QEMU using "-M malta" with both little endian and big endian mips32r2 kernels.
Fixes: 49aa7c00eddf ("crypto: mips/chacha - import 32r2 ChaCha code from Zinc") Cc: stable@vger.kernel.org Reported-by: kernel test robot lkp@intel.com Closes: https://lore.kernel.org/oe-kbuild-all/202505080409.EujEBwA0-lkp@intel.com/ Signed-off-by: Eric Biggers ebiggers@kernel.org
This applies on top of other pending lib/crypto patches and can be retrieved from git at:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/ebiggers/linux.git mips-chacha-fixlib/crypto/mips/chacha-core.S | 20 +++++++------------- 1 file changed, 7 insertions(+), 13 deletions(-)
Applied to https://git.kernel.org/pub/scm/linux/kernel/git/ebiggers/linux.git/log/?h=li...
- Eric