280 lines
8.1 KiB
C
280 lines
8.1 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
|
|
/*
|
|
* Intel SMP support routines.
|
|
*
|
|
* (c) 1995 Alan Cox, Building #3 <alan@lxorguk.ukuu.org.uk>
|
|
* (c) 1998-99, 2000, 2009 Ingo Molnar <mingo@redhat.com>
|
|
* (c) 2002,2003 Andi Kleen, SuSE Labs.
|
|
*
|
|
* i386 and x86_64 integration by Glauber Costa <gcosta@redhat.com>
|
|
*/
|
|
|
|
#include <linux/init.h>
|
|
|
|
#include <linux/mm.h>
|
|
#include <linux/delay.h>
|
|
#include <linux/spinlock.h>
|
|
#include <linux/export.h>
|
|
#include <linux/kernel_stat.h>
|
|
#include <linux/mc146818rtc.h>
|
|
#include <linux/cache.h>
|
|
#include <linux/interrupt.h>
|
|
#include <linux/cpu.h>
|
|
#include <linux/gfp.h>
|
|
|
|
#include <asm/mtrr.h>
|
|
#include <asm/tlbflush.h>
|
|
#include <asm/mmu_context.h>
|
|
#include <asm/proto.h>
|
|
#include <asm/apic.h>
|
|
#include <asm/idtentry.h>
|
|
#include <asm/nmi.h>
|
|
#include <asm/mce.h>
|
|
#include <asm/trace/irq_vectors.h>
|
|
#include <asm/kexec.h>
|
|
#include <asm/virtext.h>
|
|
|
|
/*
|
|
* Some notes on x86 processor bugs affecting SMP operation:
|
|
*
|
|
* Pentium, Pentium Pro, II, III (and all CPUs) have bugs.
|
|
* The Linux implications for SMP are handled as follows:
|
|
*
|
|
* Pentium III / [Xeon]
|
|
* None of the E1AP-E3AP errata are visible to the user.
|
|
*
|
|
* E1AP. see PII A1AP
|
|
* E2AP. see PII A2AP
|
|
* E3AP. see PII A3AP
|
|
*
|
|
* Pentium II / [Xeon]
|
|
* None of the A1AP-A3AP errata are visible to the user.
|
|
*
|
|
* A1AP. see PPro 1AP
|
|
* A2AP. see PPro 2AP
|
|
* A3AP. see PPro 7AP
|
|
*
|
|
* Pentium Pro
|
|
* None of 1AP-9AP errata are visible to the normal user,
|
|
* except occasional delivery of 'spurious interrupt' as trap #15.
|
|
* This is very rare and a non-problem.
|
|
*
|
|
* 1AP. Linux maps APIC as non-cacheable
|
|
* 2AP. worked around in hardware
|
|
* 3AP. fixed in C0 and above steppings microcode update.
|
|
* Linux does not use excessive STARTUP_IPIs.
|
|
* 4AP. worked around in hardware
|
|
* 5AP. symmetric IO mode (normal Linux operation) not affected.
|
|
* 'noapic' mode has vector 0xf filled out properly.
|
|
* 6AP. 'noapic' mode might be affected - fixed in later steppings
|
|
* 7AP. We do not assume writes to the LVT deassering IRQs
|
|
* 8AP. We do not enable low power mode (deep sleep) during MP bootup
|
|
* 9AP. We do not use mixed mode
|
|
*
|
|
* Pentium
|
|
* There is a marginal case where REP MOVS on 100MHz SMP
|
|
* machines with B stepping processors can fail. XXX should provide
|
|
* an L1cache=Writethrough or L1cache=off option.
|
|
*
|
|
* B stepping CPUs may hang. There are hardware work arounds
|
|
* for this. We warn about it in case your board doesn't have the work
|
|
* arounds. Basically that's so I can tell anyone with a B stepping
|
|
* CPU and SMP problems "tough".
|
|
*
|
|
* Specific items [From Pentium Processor Specification Update]
|
|
*
|
|
* 1AP. Linux doesn't use remote read
|
|
* 2AP. Linux doesn't trust APIC errors
|
|
* 3AP. We work around this
|
|
* 4AP. Linux never generated 3 interrupts of the same priority
|
|
* to cause a lost local interrupt.
|
|
* 5AP. Remote read is never used
|
|
* 6AP. not affected - worked around in hardware
|
|
* 7AP. not affected - worked around in hardware
|
|
* 8AP. worked around in hardware - we get explicit CS errors if not
|
|
* 9AP. only 'noapic' mode affected. Might generate spurious
|
|
* interrupts, we log only the first one and count the
|
|
* rest silently.
|
|
* 10AP. not affected - worked around in hardware
|
|
* 11AP. Linux reads the APIC between writes to avoid this, as per
|
|
* the documentation. Make sure you preserve this as it affects
|
|
* the C stepping chips too.
|
|
* 12AP. not affected - worked around in hardware
|
|
* 13AP. not affected - worked around in hardware
|
|
* 14AP. we always deassert INIT during bootup
|
|
* 15AP. not affected - worked around in hardware
|
|
* 16AP. not affected - worked around in hardware
|
|
* 17AP. not affected - worked around in hardware
|
|
* 18AP. not affected - worked around in hardware
|
|
* 19AP. not affected - worked around in BIOS
|
|
*
|
|
* If this sounds worrying believe me these bugs are either ___RARE___,
|
|
* or are signal timing bugs worked around in hardware and there's
|
|
* about nothing of note with C stepping upwards.
|
|
*/
|
|
|
|
static atomic_t stopping_cpu = ATOMIC_INIT(-1);
|
|
static bool smp_no_nmi_ipi = false;
|
|
|
|
static int smp_stop_nmi_callback(unsigned int val, struct pt_regs *regs)
|
|
{
|
|
/* We are registered on stopping cpu too, avoid spurious NMI */
|
|
if (raw_smp_processor_id() == atomic_read(&stopping_cpu))
|
|
return NMI_HANDLED;
|
|
|
|
cpu_emergency_vmxoff();
|
|
stop_this_cpu(NULL);
|
|
|
|
return NMI_HANDLED;
|
|
}
|
|
|
|
/*
|
|
* this function calls the 'stop' function on all other CPUs in the system.
|
|
*/
|
|
DEFINE_IDTENTRY_SYSVEC(sysvec_reboot)
|
|
{
|
|
ack_APIC_irq();
|
|
cpu_emergency_vmxoff();
|
|
stop_this_cpu(NULL);
|
|
}
|
|
|
|
static int register_stop_handler(void)
|
|
{
|
|
return register_nmi_handler(NMI_LOCAL, smp_stop_nmi_callback,
|
|
NMI_FLAG_FIRST, "smp_stop");
|
|
}
|
|
|
|
static void native_stop_other_cpus(int wait)
|
|
{
|
|
unsigned long flags;
|
|
unsigned long timeout;
|
|
|
|
if (reboot_force)
|
|
return;
|
|
|
|
/*
|
|
* Use an own vector here because smp_call_function
|
|
* does lots of things not suitable in a panic situation.
|
|
*/
|
|
|
|
/*
|
|
* We start by using the REBOOT_VECTOR irq.
|
|
* The irq is treated as a sync point to allow critical
|
|
* regions of code on other cpus to release their spin locks
|
|
* and re-enable irqs. Jumping straight to an NMI might
|
|
* accidentally cause deadlocks with further shutdown/panic
|
|
* code. By syncing, we give the cpus up to one second to
|
|
* finish their work before we force them off with the NMI.
|
|
*/
|
|
if (num_online_cpus() > 1) {
|
|
/* did someone beat us here? */
|
|
if (atomic_cmpxchg(&stopping_cpu, -1, safe_smp_processor_id()) != -1)
|
|
return;
|
|
|
|
/* sync above data before sending IRQ */
|
|
wmb();
|
|
|
|
apic_send_IPI_allbutself(REBOOT_VECTOR);
|
|
|
|
/*
|
|
* Don't wait longer than a second for IPI completion. The
|
|
* wait request is not checked here because that would
|
|
* prevent an NMI shutdown attempt in case that not all
|
|
* CPUs reach shutdown state.
|
|
*/
|
|
timeout = USEC_PER_SEC;
|
|
while (num_online_cpus() > 1 && timeout--)
|
|
udelay(1);
|
|
}
|
|
|
|
/* if the REBOOT_VECTOR didn't work, try with the NMI */
|
|
if (num_online_cpus() > 1) {
|
|
/*
|
|
* If NMI IPI is enabled, try to register the stop handler
|
|
* and send the IPI. In any case try to wait for the other
|
|
* CPUs to stop.
|
|
*/
|
|
if (!smp_no_nmi_ipi && !register_stop_handler()) {
|
|
/* Sync above data before sending IRQ */
|
|
wmb();
|
|
|
|
pr_emerg("Shutting down cpus with NMI\n");
|
|
|
|
apic_send_IPI_allbutself(NMI_VECTOR);
|
|
}
|
|
/*
|
|
* Don't wait longer than 10 ms if the caller didn't
|
|
* reqeust it. If wait is true, the machine hangs here if
|
|
* one or more CPUs do not reach shutdown state.
|
|
*/
|
|
timeout = USEC_PER_MSEC * 10;
|
|
while (num_online_cpus() > 1 && (wait || timeout--))
|
|
udelay(1);
|
|
}
|
|
|
|
local_irq_save(flags);
|
|
disable_local_APIC();
|
|
mcheck_cpu_clear(this_cpu_ptr(&cpu_info));
|
|
local_irq_restore(flags);
|
|
}
|
|
|
|
/*
|
|
* Reschedule call back. KVM uses this interrupt to force a cpu out of
|
|
* guest mode.
|
|
*/
|
|
DEFINE_IDTENTRY_SYSVEC_SIMPLE(sysvec_reschedule_ipi)
|
|
{
|
|
ack_APIC_irq();
|
|
trace_reschedule_entry(RESCHEDULE_VECTOR);
|
|
inc_irq_stat(irq_resched_count);
|
|
scheduler_ipi();
|
|
trace_reschedule_exit(RESCHEDULE_VECTOR);
|
|
}
|
|
|
|
DEFINE_IDTENTRY_SYSVEC(sysvec_call_function)
|
|
{
|
|
ack_APIC_irq();
|
|
trace_call_function_entry(CALL_FUNCTION_VECTOR);
|
|
inc_irq_stat(irq_call_count);
|
|
generic_smp_call_function_interrupt();
|
|
trace_call_function_exit(CALL_FUNCTION_VECTOR);
|
|
}
|
|
|
|
DEFINE_IDTENTRY_SYSVEC(sysvec_call_function_single)
|
|
{
|
|
ack_APIC_irq();
|
|
trace_call_function_single_entry(CALL_FUNCTION_SINGLE_VECTOR);
|
|
inc_irq_stat(irq_call_count);
|
|
generic_smp_call_function_single_interrupt();
|
|
trace_call_function_single_exit(CALL_FUNCTION_SINGLE_VECTOR);
|
|
}
|
|
|
|
static int __init nonmi_ipi_setup(char *str)
|
|
{
|
|
smp_no_nmi_ipi = true;
|
|
return 1;
|
|
}
|
|
|
|
__setup("nonmi_ipi", nonmi_ipi_setup);
|
|
|
|
struct smp_ops smp_ops = {
|
|
.smp_prepare_boot_cpu = native_smp_prepare_boot_cpu,
|
|
.smp_prepare_cpus = native_smp_prepare_cpus,
|
|
.smp_cpus_done = native_smp_cpus_done,
|
|
|
|
.stop_other_cpus = native_stop_other_cpus,
|
|
#if defined(CONFIG_KEXEC_CORE)
|
|
.crash_stop_other_cpus = kdump_nmi_shootdown_cpus,
|
|
#endif
|
|
.smp_send_reschedule = native_smp_send_reschedule,
|
|
|
|
.cpu_up = native_cpu_up,
|
|
.cpu_die = native_cpu_die,
|
|
.cpu_disable = native_cpu_disable,
|
|
.play_dead = native_play_dead,
|
|
|
|
.send_call_func_ipi = native_send_call_func_ipi,
|
|
.send_call_func_single_ipi = native_send_call_func_single_ipi,
|
|
};
|
|
EXPORT_SYMBOL_GPL(smp_ops);
|