Re: [patch 28/38] mips: Select ARCH_HAS_RANDOM_ENTROPY

"Maciej W. Rozycki" <[email protected]> Mon, 13 Apr 2026 06:47:45 +0100 (BST)
Newsgroups gmane.comp.file-systems.ext4,gmane.linux.kernel,gmane.linux.network,gmane.linux.kernel.wireless.general,gmane.linux.kernel.cryptoapi,gmane.linux.kernel.mm,gmane.linux.hams,gmane.linux.ports.alpha,gmane.linux.ports.arm.kernel,gmane.linux.ports.parisc,gmane.linux.ports.ppc64.devel,gmane.linux.ports.riscv,gmane.linux.ports.sparc
Message-ID <[email protected]>
On Fri, 10 Apr 2026, Thomas Gleixner wrote:

> The only solution for now is to uninline random_get_entropy().  Fix up all
> other dependencies on the content of asm/timex.h in those files which
> really depend on it.

 Oh dear!  I'd yet have to fully evaluate the consequences, but offhand 
this has clearly turned what compiles to a single CPU instruction on the 
vast majority of MIPS platforms into an expensive function call, possibly 
also changing the caller from a leaf to a nested function with all the 
associated execution penalty.  Is there no other way?

 Cf. commit 06947aaaf9bf ("MIPS: Implement random_get_entropy with CP0 
Random").

  Maciej