736 lines
18 KiB
C
736 lines
18 KiB
C
/*
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* Intel SMP support routines.
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*
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* (c) 1995 Alan Cox, Building #3 <alan@redhat.com>
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* (c) 1998-99, 2000 Ingo Molnar <mingo@redhat.com>
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*
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* This code is released under the GNU General Public License version 2 or
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* later.
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*/
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#include <linux/init.h>
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#include <linux/mm.h>
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#include <linux/delay.h>
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#include <linux/spinlock.h>
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#include <linux/smp_lock.h>
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#include <linux/kernel_stat.h>
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#include <linux/mc146818rtc.h>
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#include <linux/cache.h>
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#include <linux/interrupt.h>
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#include <linux/cpu.h>
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#include <linux/module.h>
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#include <asm/mtrr.h>
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#include <asm/tlbflush.h>
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#include <mach_apic.h>
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/*
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* Some notes on x86 processor bugs affecting SMP operation:
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*
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* Pentium, Pentium Pro, II, III (and all CPUs) have bugs.
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* The Linux implications for SMP are handled as follows:
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*
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* Pentium III / [Xeon]
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* None of the E1AP-E3AP errata are visible to the user.
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*
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* E1AP. see PII A1AP
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* E2AP. see PII A2AP
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* E3AP. see PII A3AP
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*
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* Pentium II / [Xeon]
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* None of the A1AP-A3AP errata are visible to the user.
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*
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* A1AP. see PPro 1AP
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* A2AP. see PPro 2AP
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* A3AP. see PPro 7AP
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*
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* Pentium Pro
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* None of 1AP-9AP errata are visible to the normal user,
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* except occasional delivery of 'spurious interrupt' as trap #15.
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* This is very rare and a non-problem.
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*
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* 1AP. Linux maps APIC as non-cacheable
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* 2AP. worked around in hardware
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* 3AP. fixed in C0 and above steppings microcode update.
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* Linux does not use excessive STARTUP_IPIs.
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* 4AP. worked around in hardware
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* 5AP. symmetric IO mode (normal Linux operation) not affected.
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* 'noapic' mode has vector 0xf filled out properly.
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* 6AP. 'noapic' mode might be affected - fixed in later steppings
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* 7AP. We do not assume writes to the LVT deassering IRQs
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* 8AP. We do not enable low power mode (deep sleep) during MP bootup
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* 9AP. We do not use mixed mode
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*
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* Pentium
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* There is a marginal case where REP MOVS on 100MHz SMP
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* machines with B stepping processors can fail. XXX should provide
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* an L1cache=Writethrough or L1cache=off option.
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*
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* B stepping CPUs may hang. There are hardware work arounds
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* for this. We warn about it in case your board doesn't have the work
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* arounds. Basically thats so I can tell anyone with a B stepping
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* CPU and SMP problems "tough".
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*
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* Specific items [From Pentium Processor Specification Update]
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*
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* 1AP. Linux doesn't use remote read
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* 2AP. Linux doesn't trust APIC errors
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* 3AP. We work around this
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* 4AP. Linux never generated 3 interrupts of the same priority
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* to cause a lost local interrupt.
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* 5AP. Remote read is never used
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* 6AP. not affected - worked around in hardware
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* 7AP. not affected - worked around in hardware
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* 8AP. worked around in hardware - we get explicit CS errors if not
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* 9AP. only 'noapic' mode affected. Might generate spurious
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* interrupts, we log only the first one and count the
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* rest silently.
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* 10AP. not affected - worked around in hardware
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* 11AP. Linux reads the APIC between writes to avoid this, as per
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* the documentation. Make sure you preserve this as it affects
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* the C stepping chips too.
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* 12AP. not affected - worked around in hardware
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* 13AP. not affected - worked around in hardware
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* 14AP. we always deassert INIT during bootup
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* 15AP. not affected - worked around in hardware
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* 16AP. not affected - worked around in hardware
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* 17AP. not affected - worked around in hardware
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* 18AP. not affected - worked around in hardware
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* 19AP. not affected - worked around in BIOS
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*
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* If this sounds worrying believe me these bugs are either ___RARE___,
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* or are signal timing bugs worked around in hardware and there's
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* about nothing of note with C stepping upwards.
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*/
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DEFINE_PER_CPU(struct tlb_state, cpu_tlbstate) ____cacheline_aligned = { &init_mm, 0, };
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/*
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* the following functions deal with sending IPIs between CPUs.
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*
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* We use 'broadcast', CPU->CPU IPIs and self-IPIs too.
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*/
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static inline int __prepare_ICR (unsigned int shortcut, int vector)
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{
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unsigned int icr = shortcut | APIC_DEST_LOGICAL;
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switch (vector) {
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default:
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icr |= APIC_DM_FIXED | vector;
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break;
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case NMI_VECTOR:
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icr |= APIC_DM_NMI;
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break;
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}
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return icr;
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}
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static inline int __prepare_ICR2 (unsigned int mask)
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{
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return SET_APIC_DEST_FIELD(mask);
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}
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void __send_IPI_shortcut(unsigned int shortcut, int vector)
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{
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/*
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* Subtle. In the case of the 'never do double writes' workaround
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* we have to lock out interrupts to be safe. As we don't care
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* of the value read we use an atomic rmw access to avoid costly
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* cli/sti. Otherwise we use an even cheaper single atomic write
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* to the APIC.
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*/
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unsigned int cfg;
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/*
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* Wait for idle.
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*/
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apic_wait_icr_idle();
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/*
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* No need to touch the target chip field
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*/
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cfg = __prepare_ICR(shortcut, vector);
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/*
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* Send the IPI. The write to APIC_ICR fires this off.
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*/
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apic_write_around(APIC_ICR, cfg);
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}
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void fastcall send_IPI_self(int vector)
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{
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__send_IPI_shortcut(APIC_DEST_SELF, vector);
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}
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/*
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* This is only used on smaller machines.
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*/
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void send_IPI_mask_bitmask(cpumask_t cpumask, int vector)
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{
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unsigned long mask = cpus_addr(cpumask)[0];
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unsigned long cfg;
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unsigned long flags;
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local_irq_save(flags);
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WARN_ON(mask & ~cpus_addr(cpu_online_map)[0]);
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/*
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* Wait for idle.
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*/
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apic_wait_icr_idle();
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/*
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* prepare target chip field
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*/
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cfg = __prepare_ICR2(mask);
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apic_write_around(APIC_ICR2, cfg);
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/*
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* program the ICR
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*/
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cfg = __prepare_ICR(0, vector);
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/*
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* Send the IPI. The write to APIC_ICR fires this off.
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*/
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apic_write_around(APIC_ICR, cfg);
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local_irq_restore(flags);
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}
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void send_IPI_mask_sequence(cpumask_t mask, int vector)
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{
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unsigned long cfg, flags;
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unsigned int query_cpu;
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/*
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* Hack. The clustered APIC addressing mode doesn't allow us to send
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* to an arbitrary mask, so I do a unicasts to each CPU instead. This
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* should be modified to do 1 message per cluster ID - mbligh
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*/
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local_irq_save(flags);
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for (query_cpu = 0; query_cpu < NR_CPUS; ++query_cpu) {
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if (cpu_isset(query_cpu, mask)) {
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/*
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* Wait for idle.
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*/
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apic_wait_icr_idle();
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/*
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* prepare target chip field
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*/
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cfg = __prepare_ICR2(cpu_to_logical_apicid(query_cpu));
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apic_write_around(APIC_ICR2, cfg);
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/*
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* program the ICR
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*/
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cfg = __prepare_ICR(0, vector);
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/*
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* Send the IPI. The write to APIC_ICR fires this off.
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*/
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apic_write_around(APIC_ICR, cfg);
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}
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}
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local_irq_restore(flags);
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}
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#include <mach_ipi.h> /* must come after the send_IPI functions above for inlining */
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/*
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* Smarter SMP flushing macros.
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* c/o Linus Torvalds.
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*
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* These mean you can really definitely utterly forget about
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* writing to user space from interrupts. (Its not allowed anyway).
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*
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* Optimizations Manfred Spraul <manfred@colorfullife.com>
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*/
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static cpumask_t flush_cpumask;
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static struct mm_struct * flush_mm;
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static unsigned long flush_va;
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static DEFINE_SPINLOCK(tlbstate_lock);
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#define FLUSH_ALL 0xffffffff
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/*
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* We cannot call mmdrop() because we are in interrupt context,
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* instead update mm->cpu_vm_mask.
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*
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* We need to reload %cr3 since the page tables may be going
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* away from under us..
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*/
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static inline void leave_mm (unsigned long cpu)
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{
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if (per_cpu(cpu_tlbstate, cpu).state == TLBSTATE_OK)
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BUG();
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cpu_clear(cpu, per_cpu(cpu_tlbstate, cpu).active_mm->cpu_vm_mask);
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load_cr3(swapper_pg_dir);
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}
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/*
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*
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* The flush IPI assumes that a thread switch happens in this order:
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* [cpu0: the cpu that switches]
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* 1) switch_mm() either 1a) or 1b)
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* 1a) thread switch to a different mm
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* 1a1) cpu_clear(cpu, old_mm->cpu_vm_mask);
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* Stop ipi delivery for the old mm. This is not synchronized with
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* the other cpus, but smp_invalidate_interrupt ignore flush ipis
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* for the wrong mm, and in the worst case we perform a superflous
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* tlb flush.
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* 1a2) set cpu_tlbstate to TLBSTATE_OK
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* Now the smp_invalidate_interrupt won't call leave_mm if cpu0
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* was in lazy tlb mode.
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* 1a3) update cpu_tlbstate[].active_mm
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* Now cpu0 accepts tlb flushes for the new mm.
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* 1a4) cpu_set(cpu, new_mm->cpu_vm_mask);
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* Now the other cpus will send tlb flush ipis.
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* 1a4) change cr3.
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* 1b) thread switch without mm change
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* cpu_tlbstate[].active_mm is correct, cpu0 already handles
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* flush ipis.
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* 1b1) set cpu_tlbstate to TLBSTATE_OK
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* 1b2) test_and_set the cpu bit in cpu_vm_mask.
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* Atomically set the bit [other cpus will start sending flush ipis],
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* and test the bit.
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* 1b3) if the bit was 0: leave_mm was called, flush the tlb.
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* 2) switch %%esp, ie current
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*
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* The interrupt must handle 2 special cases:
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* - cr3 is changed before %%esp, ie. it cannot use current->{active_,}mm.
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* - the cpu performs speculative tlb reads, i.e. even if the cpu only
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* runs in kernel space, the cpu could load tlb entries for user space
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* pages.
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*
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* The good news is that cpu_tlbstate is local to each cpu, no
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* write/read ordering problems.
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*/
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/*
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* TLB flush IPI:
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*
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* 1) Flush the tlb entries if the cpu uses the mm that's being flushed.
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* 2) Leave the mm if we are in the lazy tlb mode.
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*/
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fastcall void smp_invalidate_interrupt(struct pt_regs *regs)
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{
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struct pt_regs *old_regs = set_irq_regs(regs);
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unsigned long cpu;
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cpu = get_cpu();
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if (!cpu_isset(cpu, flush_cpumask))
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goto out;
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/*
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* This was a BUG() but until someone can quote me the
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* line from the intel manual that guarantees an IPI to
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* multiple CPUs is retried _only_ on the erroring CPUs
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* its staying as a return
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*
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* BUG();
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*/
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if (flush_mm == per_cpu(cpu_tlbstate, cpu).active_mm) {
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if (per_cpu(cpu_tlbstate, cpu).state == TLBSTATE_OK) {
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if (flush_va == FLUSH_ALL)
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local_flush_tlb();
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else
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__flush_tlb_one(flush_va);
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} else
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leave_mm(cpu);
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}
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ack_APIC_irq();
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smp_mb__before_clear_bit();
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cpu_clear(cpu, flush_cpumask);
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smp_mb__after_clear_bit();
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out:
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put_cpu_no_resched();
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set_irq_regs(old_regs);
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}
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static void flush_tlb_others(cpumask_t cpumask, struct mm_struct *mm,
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unsigned long va)
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{
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/*
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* A couple of (to be removed) sanity checks:
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*
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* - current CPU must not be in mask
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* - mask must exist :)
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*/
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BUG_ON(cpus_empty(cpumask));
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BUG_ON(cpu_isset(smp_processor_id(), cpumask));
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BUG_ON(!mm);
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/* If a CPU which we ran on has gone down, OK. */
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cpus_and(cpumask, cpumask, cpu_online_map);
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if (cpus_empty(cpumask))
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return;
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/*
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* i'm not happy about this global shared spinlock in the
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* MM hot path, but we'll see how contended it is.
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* Temporarily this turns IRQs off, so that lockups are
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* detected by the NMI watchdog.
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*/
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spin_lock(&tlbstate_lock);
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flush_mm = mm;
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flush_va = va;
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#if NR_CPUS <= BITS_PER_LONG
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atomic_set_mask(cpumask, &flush_cpumask);
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#else
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{
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int k;
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unsigned long *flush_mask = (unsigned long *)&flush_cpumask;
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unsigned long *cpu_mask = (unsigned long *)&cpumask;
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for (k = 0; k < BITS_TO_LONGS(NR_CPUS); ++k)
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atomic_set_mask(cpu_mask[k], &flush_mask[k]);
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}
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#endif
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/*
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* We have to send the IPI only to
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* CPUs affected.
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*/
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send_IPI_mask(cpumask, INVALIDATE_TLB_VECTOR);
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while (!cpus_empty(flush_cpumask))
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/* nothing. lockup detection does not belong here */
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mb();
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flush_mm = NULL;
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flush_va = 0;
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spin_unlock(&tlbstate_lock);
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}
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void flush_tlb_current_task(void)
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{
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struct mm_struct *mm = current->mm;
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cpumask_t cpu_mask;
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preempt_disable();
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cpu_mask = mm->cpu_vm_mask;
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cpu_clear(smp_processor_id(), cpu_mask);
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local_flush_tlb();
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if (!cpus_empty(cpu_mask))
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flush_tlb_others(cpu_mask, mm, FLUSH_ALL);
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preempt_enable();
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}
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void flush_tlb_mm (struct mm_struct * mm)
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{
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cpumask_t cpu_mask;
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preempt_disable();
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cpu_mask = mm->cpu_vm_mask;
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cpu_clear(smp_processor_id(), cpu_mask);
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if (current->active_mm == mm) {
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if (current->mm)
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local_flush_tlb();
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else
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leave_mm(smp_processor_id());
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}
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if (!cpus_empty(cpu_mask))
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flush_tlb_others(cpu_mask, mm, FLUSH_ALL);
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preempt_enable();
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}
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void flush_tlb_page(struct vm_area_struct * vma, unsigned long va)
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{
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struct mm_struct *mm = vma->vm_mm;
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cpumask_t cpu_mask;
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preempt_disable();
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cpu_mask = mm->cpu_vm_mask;
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cpu_clear(smp_processor_id(), cpu_mask);
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if (current->active_mm == mm) {
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if(current->mm)
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__flush_tlb_one(va);
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else
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leave_mm(smp_processor_id());
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}
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if (!cpus_empty(cpu_mask))
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flush_tlb_others(cpu_mask, mm, va);
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preempt_enable();
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}
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EXPORT_SYMBOL(flush_tlb_page);
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static void do_flush_tlb_all(void* info)
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{
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unsigned long cpu = smp_processor_id();
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__flush_tlb_all();
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if (per_cpu(cpu_tlbstate, cpu).state == TLBSTATE_LAZY)
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leave_mm(cpu);
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}
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void flush_tlb_all(void)
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{
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on_each_cpu(do_flush_tlb_all, NULL, 1, 1);
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}
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|
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/*
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* this function sends a 'reschedule' IPI to another CPU.
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* it goes straight through and wastes no time serializing
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* anything. Worst case is that we lose a reschedule ...
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*/
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void smp_send_reschedule(int cpu)
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{
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WARN_ON(cpu_is_offline(cpu));
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send_IPI_mask(cpumask_of_cpu(cpu), RESCHEDULE_VECTOR);
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}
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|
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/*
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* Structure and data for smp_call_function(). This is designed to minimise
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* static memory requirements. It also looks cleaner.
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*/
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static DEFINE_SPINLOCK(call_lock);
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struct call_data_struct {
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void (*func) (void *info);
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void *info;
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atomic_t started;
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atomic_t finished;
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int wait;
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};
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|
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void lock_ipi_call_lock(void)
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{
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spin_lock_irq(&call_lock);
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}
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|
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void unlock_ipi_call_lock(void)
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{
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spin_unlock_irq(&call_lock);
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}
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|
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static struct call_data_struct *call_data;
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/**
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* smp_call_function(): Run a function on all other CPUs.
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* @func: The function to run. This must be fast and non-blocking.
|
|
* @info: An arbitrary pointer to pass to the function.
|
|
* @nonatomic: currently unused.
|
|
* @wait: If true, wait (atomically) until function has completed on other CPUs.
|
|
*
|
|
* Returns 0 on success, else a negative status code. Does not return until
|
|
* remote CPUs are nearly ready to execute <<func>> or are or have executed.
|
|
*
|
|
* You must not call this function with disabled interrupts or from a
|
|
* hardware interrupt handler or from a bottom half handler.
|
|
*/
|
|
int smp_call_function (void (*func) (void *info), void *info, int nonatomic,
|
|
int wait)
|
|
{
|
|
struct call_data_struct data;
|
|
int cpus;
|
|
|
|
/* Holding any lock stops cpus from going down. */
|
|
spin_lock(&call_lock);
|
|
cpus = num_online_cpus() - 1;
|
|
if (!cpus) {
|
|
spin_unlock(&call_lock);
|
|
return 0;
|
|
}
|
|
|
|
/* Can deadlock when called with interrupts disabled */
|
|
WARN_ON(irqs_disabled());
|
|
|
|
data.func = func;
|
|
data.info = info;
|
|
atomic_set(&data.started, 0);
|
|
data.wait = wait;
|
|
if (wait)
|
|
atomic_set(&data.finished, 0);
|
|
|
|
call_data = &data;
|
|
mb();
|
|
|
|
/* Send a message to all other CPUs and wait for them to respond */
|
|
send_IPI_allbutself(CALL_FUNCTION_VECTOR);
|
|
|
|
/* Wait for response */
|
|
while (atomic_read(&data.started) != cpus)
|
|
cpu_relax();
|
|
|
|
if (wait)
|
|
while (atomic_read(&data.finished) != cpus)
|
|
cpu_relax();
|
|
spin_unlock(&call_lock);
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(smp_call_function);
|
|
|
|
static void stop_this_cpu (void * dummy)
|
|
{
|
|
/*
|
|
* Remove this CPU:
|
|
*/
|
|
cpu_clear(smp_processor_id(), cpu_online_map);
|
|
local_irq_disable();
|
|
disable_local_APIC();
|
|
if (cpu_data[smp_processor_id()].hlt_works_ok)
|
|
for(;;) halt();
|
|
for (;;);
|
|
}
|
|
|
|
/*
|
|
* this function calls the 'stop' function on all other CPUs in the system.
|
|
*/
|
|
|
|
void smp_send_stop(void)
|
|
{
|
|
smp_call_function(stop_this_cpu, NULL, 1, 0);
|
|
|
|
local_irq_disable();
|
|
disable_local_APIC();
|
|
local_irq_enable();
|
|
}
|
|
|
|
/*
|
|
* Reschedule call back. Nothing to do,
|
|
* all the work is done automatically when
|
|
* we return from the interrupt.
|
|
*/
|
|
fastcall void smp_reschedule_interrupt(struct pt_regs *regs)
|
|
{
|
|
struct pt_regs *old_regs = set_irq_regs(regs);
|
|
ack_APIC_irq();
|
|
set_irq_regs(old_regs);
|
|
}
|
|
|
|
fastcall void smp_call_function_interrupt(struct pt_regs *regs)
|
|
{
|
|
struct pt_regs *old_regs = set_irq_regs(regs);
|
|
void (*func) (void *info) = call_data->func;
|
|
void *info = call_data->info;
|
|
int wait = call_data->wait;
|
|
|
|
ack_APIC_irq();
|
|
/*
|
|
* Notify initiating CPU that I've grabbed the data and am
|
|
* about to execute the function
|
|
*/
|
|
mb();
|
|
atomic_inc(&call_data->started);
|
|
/*
|
|
* At this point the info structure may be out of scope unless wait==1
|
|
*/
|
|
irq_enter();
|
|
(*func)(info);
|
|
irq_exit();
|
|
|
|
if (wait) {
|
|
mb();
|
|
atomic_inc(&call_data->finished);
|
|
}
|
|
set_irq_regs(old_regs);
|
|
}
|
|
|
|
/*
|
|
* this function sends a 'generic call function' IPI to one other CPU
|
|
* in the system.
|
|
*
|
|
* cpu is a standard Linux logical CPU number.
|
|
*/
|
|
static void
|
|
__smp_call_function_single(int cpu, void (*func) (void *info), void *info,
|
|
int nonatomic, int wait)
|
|
{
|
|
struct call_data_struct data;
|
|
int cpus = 1;
|
|
|
|
data.func = func;
|
|
data.info = info;
|
|
atomic_set(&data.started, 0);
|
|
data.wait = wait;
|
|
if (wait)
|
|
atomic_set(&data.finished, 0);
|
|
|
|
call_data = &data;
|
|
wmb();
|
|
/* Send a message to all other CPUs and wait for them to respond */
|
|
send_IPI_mask(cpumask_of_cpu(cpu), CALL_FUNCTION_VECTOR);
|
|
|
|
/* Wait for response */
|
|
while (atomic_read(&data.started) != cpus)
|
|
cpu_relax();
|
|
|
|
if (!wait)
|
|
return;
|
|
|
|
while (atomic_read(&data.finished) != cpus)
|
|
cpu_relax();
|
|
}
|
|
|
|
/*
|
|
* smp_call_function_single - Run a function on another CPU
|
|
* @func: The function to run. This must be fast and non-blocking.
|
|
* @info: An arbitrary pointer to pass to the function.
|
|
* @nonatomic: Currently unused.
|
|
* @wait: If true, wait until function has completed on other CPUs.
|
|
*
|
|
* Retrurns 0 on success, else a negative status code.
|
|
*
|
|
* Does not return until the remote CPU is nearly ready to execute <func>
|
|
* or is or has executed.
|
|
*/
|
|
|
|
int smp_call_function_single(int cpu, void (*func) (void *info), void *info,
|
|
int nonatomic, int wait)
|
|
{
|
|
/* prevent preemption and reschedule on another processor */
|
|
int me = get_cpu();
|
|
if (cpu == me) {
|
|
WARN_ON(1);
|
|
put_cpu();
|
|
return -EBUSY;
|
|
}
|
|
spin_lock_bh(&call_lock);
|
|
__smp_call_function_single(cpu, func, info, nonatomic, wait);
|
|
spin_unlock_bh(&call_lock);
|
|
put_cpu();
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(smp_call_function_single);
|
|
|
|
static int convert_apicid_to_cpu(int apic_id)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < NR_CPUS; i++) {
|
|
if (x86_cpu_to_apicid[i] == apic_id)
|
|
return i;
|
|
}
|
|
return -1;
|
|
}
|
|
|
|
int safe_smp_processor_id(void)
|
|
{
|
|
int apicid, cpuid;
|
|
|
|
if (!boot_cpu_has(X86_FEATURE_APIC))
|
|
return 0;
|
|
|
|
apicid = hard_smp_processor_id();
|
|
if (apicid == BAD_APICID)
|
|
return 0;
|
|
|
|
cpuid = convert_apicid_to_cpu(apicid);
|
|
|
|
return cpuid >= 0 ? cpuid : 0;
|
|
}
|