On Wed, Apr 17, 2024 at 2:15 AM Sean Christopherson <seanjc@xxxxxxxxxx> wrote: > Add a generic Kconfig, CPU_MITIGATIONS, to control whether or not CPU > mitigations are enabled by default, and force it on for all architectures > except x86. A recent commit to turn mitigations off by default if > SPECULATION_MITIGATIONS=n kinda sorta missed that "cpu_mitigations" is > completely generic, where as SPECULATION_MITIGATIONS is x86 specific. > > Alternatively, SPECULATION_MITIGATIONS could simply be defined in common > code, but that creates weirdness for x86 because SPECULATION_MITIGATIONS > ends up being defined twice, and the default behavior would likely depend > on the arbitrary include order (if the two definitions diverged). > > Ideally, CPU_MITIGATIONS would be unconditionally on by default for all > architectures, and manually turned off, but there is no way to unselect a > Kconfig. > > Reported-by: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx> > Reported-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx> > Reported-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> > Closes: https://lkml.kernel.org/r/20240413115324.53303a68%40canb.auug.org.au > Fixes: f337a6a21e2f ("x86/cpu: Actually turn off mitigations by default for SPECULATION_MITIGATIONS=n") > Cc: stable@xxxxxxxxxxxxxxx > Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx> Tested-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx> Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
