[PATCH v1 0/9] Add dynamic DEXCR support

[Michael Ellerman]

On Wed, 17 Apr 2024 21:23:16 +1000, Benjamin Gray wrote:
> Adds support for a process to change its DEXCR value. The implementation is
> somewhat conservative; SBHE (speculative branch hint enable) is not exposed
> as an editable aspect because its effects can bleed over to other threads.
> 
> As explained in the third patch, this series changes the reset/inherit
> behaviour on exec. Previously there was a bitmask that tracked which aspects
> to copy from the current state vs resetting to a fixed default. This
> allows unprivileged processes to disable ROP protection for setuid binaries
> though, and is generally a weird interface to work with. The actual intent
> (and new implementation) tracks the exec value as an independent value that
> doesn't use the parent's DEXCR at all. The parent can control this reset value
> separately to its own DEXCR value.
> 
> [...]

Applied to powerpc/next.

[1/9] selftests/powerpc/dexcr: Add -no-pie to hashchk tests
      https://git.kernel.org/powerpc/c/d7228a58d9438d6f219dc7f33eab0d1980b3bd2f
[2/9] powerpc/dexcr: Track the DEXCR per-process
      https://git.kernel.org/powerpc/c/75171f06c4507c3b6b5a69d793879fb20d108bb1
[3/9] powerpc/dexcr: Reset DEXCR value across exec
      https://git.kernel.org/powerpc/c/bbd99922d0f4518518282217159666c679c6a0d1
[4/9] powerpc/dexcr: Add DEXCR prctl interface
      https://git.kernel.org/powerpc/c/628d701f2de5b9a16d1dd82bea68fd895f56f1a1
[5/9] selftests/powerpc/dexcr: Add DEXCR prctl interface test
      https://git.kernel.org/powerpc/c/5bfa66bf86d792bbcc76bc09cf99a2ae9d6e0eec
[6/9] selftests/powerpc/dexcr: Attempt to enable NPHIE in hashchk selftest
      https://git.kernel.org/powerpc/c/9930fba02a1c587849aea1e6c5688168013c065f
[7/9] selftests/powerpc/dexcr: Add DEXCR config details to lsdexcr
      https://git.kernel.org/powerpc/c/9c4866b209ad31cae7c832d45c6137ce6a993ca0
[8/9] selftests/powerpc/dexcr: Add chdexcr utility
      https://git.kernel.org/powerpc/c/f88723a609787254f7645eb6ac261b8363e8a5bc
[9/9] Documentation: Document PowerPC kernel dynamic DEXCR interface
      https://git.kernel.org/powerpc/c/9248edf31ab28723fb00900ecb8bacdb05eeefff

cheers