Processors which have self-snooping capability can handle conflicting memory type across CPUs by snooping its own cache. However, there exists CPU models in which having conflicting memory types still leads to unpredictable behavior, machine check errors, or hangs. Clear this feature to prevent its use.
Cc: Tony Luck <[email protected]> Cc: "H. Peter Anvin" <[email protected]> Cc: Andy Shevchenko <[email protected]> Cc: Andi Kleen <[email protected]> Cc: Hans de Goede <[email protected]> Cc: Peter Feiner <[email protected]> Cc: "Rafael J. Wysocki" <[email protected]> Cc: Greg Kroah-Hartman <[email protected]> Cc: Jordan Borgner <[email protected]> Cc: "Ravi V. Shankar" <[email protected]> Cc: [email protected] Cc: [email protected] Suggested-by: Alan Cox <[email protected]> Signed-off-by: Ricardo Neri <[email protected]> --- arch/x86/kernel/cpu/intel.c | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c index f17c1a714779..62e366ec0812 100644 --- a/arch/x86/kernel/cpu/intel.c +++ b/arch/x86/kernel/cpu/intel.c @@ -66,6 +66,32 @@ void check_mpx_erratum(struct cpuinfo_x86 *c) } } +/* + * Processors which have self-snooping capability can handle conflicting + * memory type across CPUs by snooping its own cache. However, there exists + * CPU models in which having conflicting memory types still leads to + * unpredictable behavior, machine check errors, or hangs. Clear this feature + * to prevent its use. + */ +static void check_memory_type_self_snoop_errata(struct cpuinfo_x86 *c) +{ + switch (c->x86_model) { + case INTEL_FAM6_CORE_YONAH: + case INTEL_FAM6_CORE2_MEROM: + case INTEL_FAM6_CORE2_MEROM_L: + case INTEL_FAM6_CORE2_PENRYN: + case INTEL_FAM6_CORE2_DUNNINGTON: + case INTEL_FAM6_NEHALEM: + case INTEL_FAM6_NEHALEM_G: + case INTEL_FAM6_NEHALEM_EP: + case INTEL_FAM6_NEHALEM_EX: + case INTEL_FAM6_WESTMERE: + case INTEL_FAM6_WESTMERE_EP: + case INTEL_FAM6_SANDYBRIDGE: + setup_clear_cpu_cap(X86_FEATURE_SELFSNOOP); + } +} + static bool ring3mwait_disabled __read_mostly; static int __init ring3mwait_disable(char *__unused) @@ -304,6 +330,7 @@ static void early_init_intel(struct cpuinfo_x86 *c) } check_mpx_erratum(c); + check_memory_type_self_snoop_errata(c); /* * Get the number of SMT siblings early from the extended topology -- 2.17.1
