commit
9b040453d4440659f33dc6f0aa26af418ebfe70b upstream.
stop_this_cpu() tests CPUID leaf 0x8000001f::EAX unconditionally. Intel
CPUs return the content of the highest supported leaf when a non-existing
leaf is read, while AMD CPUs return all zeros for unsupported leafs.
So the result of the test on Intel CPUs is lottery.
While harmless it's incorrect and causes the conditional wbinvd() to be
issued where not required.
Check whether the leaf is supported before reading it.
[ tglx: Adjusted changelog ]
Fixes:
08f253ec3767 ("x86/cpu: Clear SME feature flag when not in use")
Signed-off-by: Tony Battersby <tonyb@cybernetics.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Reviewed-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/3817d810-e0f1-8ef8-0bbd-663b919ca49b@cybernetics.com
Link: https://lore.kernel.org/r/20230615193330.322186388@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
void __noreturn stop_this_cpu(void *dummy)
{
+ struct cpuinfo_x86 *c = this_cpu_ptr(&cpu_info);
unsigned int cpu = smp_processor_id();
local_irq_disable();
*/
set_cpu_online(cpu, false);
disable_local_APIC();
- mcheck_cpu_clear(this_cpu_ptr(&cpu_info));
+ mcheck_cpu_clear(c);
/*
* Use wbinvd on processors that support SME. This provides support
* Test the CPUID bit directly because the machine might've cleared
* X86_FEATURE_SME due to cmdline options.
*/
- if (cpuid_eax(0x8000001f) & BIT(0))
+ if (c->extended_cpuid_level >= 0x8000001f && (cpuid_eax(0x8000001f) & BIT(0)))
native_wbinvd();
/*