On Wed, 1 Nov 2017, Dave Hansen wrote: > On 11/01/2017 02:25 PM, Thomas Gleixner wrote: > >> cr4 = this_cpu_read(cpu_tlbstate.cr4); > >> - /* clear PGE */ > >> - native_write_cr4(cr4 & ~X86_CR4_PGE); > >> - /* write old PGE again and flush TLBs */ > >> + /* > >> + * This function is only called on systems that support X86_CR4_PGE > >> + * and where always set X86_CR4_PGE. Warn if we are called without > >> + * PGE set. > >> + */ > >> + WARN_ON_ONCE(!(cr4 & X86_CR4_PGE)); > > Because if CR4_PGE is not set, this warning triggers. So this defeats the > > toggle mode you are implementing. > > The warning is there because there is probably plenty of *other* stuff > that breaks if we have X86_FEATURE_PGE=1, but CR4.PGE=0. > > The point of this was to make this function do the right thing no matter > what, but warn if it gets called in an unexpected way. Fair enough. Can you please reflect that in the changelog ? Thanks, tglx -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
