On 7/11/2017 12:56 AM, Borislav Petkov wrote:
On Tue, Jul 11, 2017 at 01:07:46AM -0400, Brian Gerst wrote:
If I make the scattered feature support conditional on CONFIG_X86_64
(based on comment below) then cpu_has() will always be false unless
CONFIG_X86_64 is enabled. So this won't need to be wrapped by the
#ifdef.
If you change it to use cpu_feature_enabled(), gcc will see that it is
disabled and eliminate the dead code at compile time.
Just do this:
if (cpu_has(c, X86_FEATURE_SME)) {
if (IS_ENABLED(CONFIG_X86_32)) {
clear_cpu_cap(c, X86_FEATURE_SME);
} else {
u64 msr;
/* Check if SME is enabled */
rdmsrl(MSR_K8_SYSCFG, msr);
if (!(msr & MSR_K8_SYSCFG_MEM_ENCRYPT))
clear_cpu_cap(c, X86_FEATURE_SME);
}
}
so that it is explicit that we disable it on 32-bit and we can save us
the ifdeffery elsewhere.
I'll use this method for the change and avoid the #ifdefs.
Thanks,
Tom
Thanks.
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