On Tue, Jan 09, 2018 at 01:56:20PM +0100, Willy Tarreau wrote: > - use pti_disable instead of task flag > --- > arch/x86/entry/calling.h | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/arch/x86/entry/calling.h b/arch/x86/entry/calling.h > index 2c0d3b5..5361a10 100644 > --- a/arch/x86/entry/calling.h > +++ b/arch/x86/entry/calling.h > @@ -229,6 +229,11 @@ > > .macro SWITCH_TO_USER_CR3_NOSTACK scratch_reg:req scratch_reg2:req > ALTERNATIVE "jmp .Lend_\@", "", X86_FEATURE_PTI > + > + /* The "pti_disable" mm attribute is mirrored into this per-cpu var */ > + cmpb $0, PER_CPU_VAR(pti_disable) > + jne .Lend_\@ > + > mov %cr3, \scratch_reg
So could you switch back to a task flag for this? That word is already cache-hot on the exit path while your new variable is not.
