a68db763af
There's another problem shown up by Ingo's recent patch to make smp_processor_id() complain if it's called with preemption enabled. local_finish_flush_tlb_mm() calls activate_context() in a situation where it could be rescheduled to another processor. This patch disables preemption around the call. Signed-off-by: Peter Chubb <peterc@gelato.unsw.edu.au> Signed-off-by: Tony Luck <tony.luck@intel.com>
379 lines
8.6 KiB
C
379 lines
8.6 KiB
C
/*
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* SMP Support
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*
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* Copyright (C) 1999 Walt Drummond <drummond@valinux.com>
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* Copyright (C) 1999, 2001, 2003 David Mosberger-Tang <davidm@hpl.hp.com>
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*
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* Lots of stuff stolen from arch/alpha/kernel/smp.c
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*
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* 01/05/16 Rohit Seth <rohit.seth@intel.com> IA64-SMP functions. Reorganized
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* the existing code (on the lines of x86 port).
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* 00/09/11 David Mosberger <davidm@hpl.hp.com> Do loops_per_jiffy
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* calibration on each CPU.
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* 00/08/23 Asit Mallick <asit.k.mallick@intel.com> fixed logical processor id
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* 00/03/31 Rohit Seth <rohit.seth@intel.com> Fixes for Bootstrap Processor
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* & cpu_online_map now gets done here (instead of setup.c)
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* 99/10/05 davidm Update to bring it in sync with new command-line processing
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* scheme.
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* 10/13/00 Goutham Rao <goutham.rao@intel.com> Updated smp_call_function and
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* smp_call_function_single to resend IPI on timeouts
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*/
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/init.h>
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#include <linux/interrupt.h>
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#include <linux/smp.h>
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#include <linux/kernel_stat.h>
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#include <linux/mm.h>
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#include <linux/cache.h>
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#include <linux/delay.h>
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#include <linux/efi.h>
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#include <linux/bitops.h>
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#include <asm/atomic.h>
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#include <asm/current.h>
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#include <asm/delay.h>
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#include <asm/machvec.h>
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#include <asm/io.h>
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#include <asm/irq.h>
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#include <asm/page.h>
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#include <asm/pgalloc.h>
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#include <asm/pgtable.h>
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#include <asm/processor.h>
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#include <asm/ptrace.h>
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#include <asm/sal.h>
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#include <asm/system.h>
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#include <asm/tlbflush.h>
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#include <asm/unistd.h>
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#include <asm/mca.h>
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/*
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* Structure and data for smp_call_function(). This is designed to minimise static memory
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* requirements. It also looks cleaner.
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*/
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static __cacheline_aligned 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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long wait;
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atomic_t started;
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atomic_t finished;
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};
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static volatile struct call_data_struct *call_data;
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#define IPI_CALL_FUNC 0
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#define IPI_CPU_STOP 1
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/* This needs to be cacheline aligned because it is written to by *other* CPUs. */
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static DEFINE_PER_CPU(u64, ipi_operation) ____cacheline_aligned;
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extern void cpu_halt (void);
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void
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lock_ipi_calllock(void)
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{
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spin_lock_irq(&call_lock);
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}
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void
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unlock_ipi_calllock(void)
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{
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spin_unlock_irq(&call_lock);
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}
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static void
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stop_this_cpu (void)
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{
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/*
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* Remove this CPU:
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*/
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cpu_clear(smp_processor_id(), cpu_online_map);
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max_xtp();
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local_irq_disable();
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cpu_halt();
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}
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void
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cpu_die(void)
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{
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max_xtp();
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local_irq_disable();
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cpu_halt();
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/* Should never be here */
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BUG();
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for (;;);
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}
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irqreturn_t
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handle_IPI (int irq, void *dev_id, struct pt_regs *regs)
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{
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int this_cpu = get_cpu();
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unsigned long *pending_ipis = &__ia64_per_cpu_var(ipi_operation);
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unsigned long ops;
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mb(); /* Order interrupt and bit testing. */
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while ((ops = xchg(pending_ipis, 0)) != 0) {
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mb(); /* Order bit clearing and data access. */
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do {
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unsigned long which;
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which = ffz(~ops);
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ops &= ~(1 << which);
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switch (which) {
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case IPI_CALL_FUNC:
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{
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struct call_data_struct *data;
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void (*func)(void *info);
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void *info;
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int wait;
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/* release the 'pointer lock' */
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data = (struct call_data_struct *) call_data;
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func = data->func;
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info = data->info;
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wait = data->wait;
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mb();
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atomic_inc(&data->started);
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/*
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* At this point the structure may be gone unless
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* wait is true.
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*/
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(*func)(info);
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/* Notify the sending CPU that the task is done. */
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mb();
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if (wait)
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atomic_inc(&data->finished);
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}
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break;
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case IPI_CPU_STOP:
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stop_this_cpu();
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break;
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default:
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printk(KERN_CRIT "Unknown IPI on CPU %d: %lu\n", this_cpu, which);
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break;
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}
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} while (ops);
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mb(); /* Order data access and bit testing. */
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}
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put_cpu();
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return IRQ_HANDLED;
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}
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/*
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* Called with preeemption disabled.
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*/
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static inline void
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send_IPI_single (int dest_cpu, int op)
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{
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set_bit(op, &per_cpu(ipi_operation, dest_cpu));
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platform_send_ipi(dest_cpu, IA64_IPI_VECTOR, IA64_IPI_DM_INT, 0);
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}
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/*
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* Called with preeemption disabled.
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*/
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static inline void
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send_IPI_allbutself (int op)
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{
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unsigned int i;
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for (i = 0; i < NR_CPUS; i++) {
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if (cpu_online(i) && i != smp_processor_id())
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send_IPI_single(i, op);
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}
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}
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/*
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* Called with preeemption disabled.
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*/
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static inline void
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send_IPI_all (int op)
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{
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int i;
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for (i = 0; i < NR_CPUS; i++)
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if (cpu_online(i))
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send_IPI_single(i, op);
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}
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/*
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* Called with preeemption disabled.
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*/
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static inline void
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send_IPI_self (int op)
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{
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send_IPI_single(smp_processor_id(), op);
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}
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/*
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* Called with preeemption disabled.
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*/
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void
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smp_send_reschedule (int cpu)
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{
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platform_send_ipi(cpu, IA64_IPI_RESCHEDULE, IA64_IPI_DM_INT, 0);
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}
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void
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smp_flush_tlb_all (void)
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{
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on_each_cpu((void (*)(void *))local_flush_tlb_all, NULL, 1, 1);
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}
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void
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smp_flush_tlb_mm (struct mm_struct *mm)
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{
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preempt_disable();
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/* this happens for the common case of a single-threaded fork(): */
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if (likely(mm == current->active_mm && atomic_read(&mm->mm_users) == 1))
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{
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local_finish_flush_tlb_mm(mm);
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preempt_enable();
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return;
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}
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preempt_enable();
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/*
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* We could optimize this further by using mm->cpu_vm_mask to track which CPUs
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* have been running in the address space. It's not clear that this is worth the
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* trouble though: to avoid races, we have to raise the IPI on the target CPU
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* anyhow, and once a CPU is interrupted, the cost of local_flush_tlb_all() is
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* rather trivial.
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*/
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on_each_cpu((void (*)(void *))local_finish_flush_tlb_mm, mm, 1, 1);
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}
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/*
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* Run a function on another CPU
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* <func> The function to run. This must be fast and non-blocking.
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* <info> An arbitrary pointer to pass to the function.
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* <nonatomic> Currently unused.
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* <wait> If true, wait until function has completed on other CPUs.
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* [RETURNS] 0 on success, else a negative status code.
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*
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* Does not return until the remote CPU is nearly ready to execute <func>
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* or is or has executed.
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*/
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int
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smp_call_function_single (int cpuid, void (*func) (void *info), void *info, int nonatomic,
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int wait)
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{
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struct call_data_struct data;
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int cpus = 1;
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int me = get_cpu(); /* prevent preemption and reschedule on another processor */
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if (cpuid == me) {
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printk(KERN_INFO "%s: trying to call self\n", __FUNCTION__);
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put_cpu();
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return -EBUSY;
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}
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data.func = func;
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data.info = info;
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atomic_set(&data.started, 0);
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data.wait = wait;
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if (wait)
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atomic_set(&data.finished, 0);
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spin_lock_bh(&call_lock);
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call_data = &data;
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mb(); /* ensure store to call_data precedes setting of IPI_CALL_FUNC */
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send_IPI_single(cpuid, IPI_CALL_FUNC);
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/* Wait for response */
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while (atomic_read(&data.started) != cpus)
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cpu_relax();
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if (wait)
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while (atomic_read(&data.finished) != cpus)
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cpu_relax();
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call_data = NULL;
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spin_unlock_bh(&call_lock);
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put_cpu();
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return 0;
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}
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EXPORT_SYMBOL(smp_call_function_single);
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/*
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* this function sends a 'generic call function' IPI to all other CPUs
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* in the system.
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*/
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/*
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* [SUMMARY] Run a function on all other CPUs.
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* <func> The function to run. This must be fast and non-blocking.
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* <info> An arbitrary pointer to pass to the function.
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* <nonatomic> currently unused.
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* <wait> If true, wait (atomically) until function has completed on other CPUs.
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* [RETURNS] 0 on success, else a negative status code.
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*
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* Does not return until remote CPUs are nearly ready to execute <func> or are or have
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* executed.
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*
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* You must not call this function with disabled interrupts or from a
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* hardware interrupt handler or from a bottom half handler.
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*/
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int
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smp_call_function (void (*func) (void *info), void *info, int nonatomic, int wait)
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{
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struct call_data_struct data;
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int cpus = num_online_cpus()-1;
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if (!cpus)
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return 0;
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/* Can deadlock when called with interrupts disabled */
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WARN_ON(irqs_disabled());
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data.func = func;
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data.info = info;
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atomic_set(&data.started, 0);
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data.wait = wait;
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if (wait)
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atomic_set(&data.finished, 0);
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spin_lock(&call_lock);
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call_data = &data;
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mb(); /* ensure store to call_data precedes setting of IPI_CALL_FUNC */
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send_IPI_allbutself(IPI_CALL_FUNC);
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/* Wait for response */
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while (atomic_read(&data.started) != cpus)
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cpu_relax();
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if (wait)
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while (atomic_read(&data.finished) != cpus)
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cpu_relax();
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call_data = NULL;
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spin_unlock(&call_lock);
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return 0;
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}
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EXPORT_SYMBOL(smp_call_function);
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/*
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* this function calls the 'stop' function on all other CPUs in the system.
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*/
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void
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smp_send_stop (void)
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{
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send_IPI_allbutself(IPI_CPU_STOP);
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}
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int __init
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setup_profiling_timer (unsigned int multiplier)
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{
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return -EINVAL;
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}
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