Messages in this thread | | | Date | Wed, 11 May 2011 23:06:37 -0700 | From | "H. Peter Anvin" <> | Subject | Re: [PATCH 3/3] x86, cpu: Enable/disable SMEP |
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On 05/11/2011 03:36 PM, Andi Kleen wrote: > "Fenghua Yu"<fenghua.yu@intel.com> writes: > >> +static int disable_smep; > > If you add a __initdata here the whole thing will completely disappear > after boot. > >> @@ -867,6 +886,8 @@ static void __cpuinit identify_cpu(struct cpuinfo_x86 *c) >> /* Init Machine Check Exception if available. */ >> mcheck_cpu_init(c); >> >> + setup_smep(c); > > My feeling is you're setting this too late. In theory there could be > early overflows. Better use a early_param and set it as early > as possible, directly after the cpuid flags are set up in early > initialization. > > -Andi
SMEP only matters if we can into userspace code, so I *think* the above should be okay. However, the most logical place would be to enable it in the same place(s) where we enable NX.
-hpa
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