On Fri, Sep 23, 2022 at 03:15:15PM -0700, Dave Hansen wrote: > On 9/23/22 14:19, Kees Cook wrote: > >> But currently, PAE is not even enabled in the i386_defconfig, and > >> defaults to off. This means people that are unaware of this won't > >> enable it, and will be running without NX support. > > And they all make me cry. ;) > > It's been like that for a long time, presumably because the defconfig > should *boot* in as many cases as possible. It wouldn't be hard to > change. It also wouldn't be hard to default to HIGHMEM4G (non-PAE) on > targeted builds for CPUs that don't support it. Patch attached to do > that, if anyone else has an opinion. > > We should probably just leave i386 alone, but it breaks my heart to see > Kees in tears. *dabs his eyes with tissue* > diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig > index f9920f1341c8..fad978c7b7c5 100644 > --- a/arch/x86/Kconfig > +++ b/arch/x86/Kconfig > @@ -1363,9 +1363,14 @@ config X86_CPUID > with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to > /dev/cpu/31/cpuid. > > +config CPU_HAS_PAE > + def_bool y > + depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !MWINCHIP3D && !MK6 > + > choice > prompt "High Memory Support" > default HIGHMEM4G > + default HIGHMEM64G if CPU_HAS_PAE > depends on X86_32 > > config NOHIGHMEM > @@ -1412,7 +1417,7 @@ config HIGHMEM4G > > config HIGHMEM64G > bool "64GB" > - depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !MWINCHIP3D && !MK6 > + depends on CPU_HAS_PAE > select X86_PAE > help > Select this if you have a 32-bit processor and more than 4 I feel happy now! :) -- Kees Cook
