linux/arch/tile/kernel/smp.c
Linus Torvalds 0429fbc0bd Merge branch 'for-3.18-consistent-ops' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu
Pull percpu consistent-ops changes from Tejun Heo:
 "Way back, before the current percpu allocator was implemented, static
  and dynamic percpu memory areas were allocated and handled separately
  and had their own accessors.  The distinction has been gone for many
  years now; however, the now duplicate two sets of accessors remained
  with the pointer based ones - this_cpu_*() - evolving various other
  operations over time.  During the process, we also accumulated other
  inconsistent operations.

  This pull request contains Christoph's patches to clean up the
  duplicate accessor situation.  __get_cpu_var() uses are replaced with
  with this_cpu_ptr() and __this_cpu_ptr() with raw_cpu_ptr().

  Unfortunately, the former sometimes is tricky thanks to C being a bit
  messy with the distinction between lvalues and pointers, which led to
  a rather ugly solution for cpumask_var_t involving the introduction of
  this_cpu_cpumask_var_ptr().

  This converts most of the uses but not all.  Christoph will follow up
  with the remaining conversions in this merge window and hopefully
  remove the obsolete accessors"

* 'for-3.18-consistent-ops' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: (38 commits)
  irqchip: Properly fetch the per cpu offset
  percpu: Resolve ambiguities in __get_cpu_var/cpumask_var_t -fix
  ia64: sn_nodepda cannot be assigned to after this_cpu conversion. Use __this_cpu_write.
  percpu: Resolve ambiguities in __get_cpu_var/cpumask_var_t
  Revert "powerpc: Replace __get_cpu_var uses"
  percpu: Remove __this_cpu_ptr
  clocksource: Replace __this_cpu_ptr with raw_cpu_ptr
  sparc: Replace __get_cpu_var uses
  avr32: Replace __get_cpu_var with __this_cpu_write
  blackfin: Replace __get_cpu_var uses
  tile: Use this_cpu_ptr() for hardware counters
  tile: Replace __get_cpu_var uses
  powerpc: Replace __get_cpu_var uses
  alpha: Replace __get_cpu_var
  ia64: Replace __get_cpu_var uses
  s390: cio driver &__get_cpu_var replacements
  s390: Replace __get_cpu_var uses
  mips: Replace __get_cpu_var uses
  MIPS: Replace __get_cpu_var uses in FPU emulator.
  arm: Replace __this_cpu_ptr with raw_cpu_ptr
  ...
2014-10-15 07:48:18 +02:00

258 lines
5.8 KiB
C

/*
* Copyright 2010 Tilera Corporation. All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, version 2.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
* NON INFRINGEMENT. See the GNU General Public License for
* more details.
*
* TILE SMP support routines.
*/
#include <linux/smp.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/module.h>
#include <asm/cacheflush.h>
#include <asm/homecache.h>
/*
* We write to width and height with a single store in head_NN.S,
* so make the variable aligned to "long".
*/
HV_Topology smp_topology __write_once __aligned(sizeof(long));
EXPORT_SYMBOL(smp_topology);
#if CHIP_HAS_IPI()
static unsigned long __iomem *ipi_mappings[NR_CPUS];
#endif
/*
* Top-level send_IPI*() functions to send messages to other cpus.
*/
/* Set by smp_send_stop() to avoid recursive panics. */
static int stopping_cpus;
static void __send_IPI_many(HV_Recipient *recip, int nrecip, int tag)
{
int sent = 0;
while (sent < nrecip) {
int rc = hv_send_message(recip, nrecip,
(HV_VirtAddr)&tag, sizeof(tag));
if (rc < 0) {
if (!stopping_cpus) /* avoid recursive panic */
panic("hv_send_message returned %d", rc);
break;
}
WARN_ONCE(rc == 0, "hv_send_message() returned zero\n");
sent += rc;
}
}
void send_IPI_single(int cpu, int tag)
{
HV_Recipient recip = {
.y = cpu / smp_width,
.x = cpu % smp_width,
.state = HV_TO_BE_SENT
};
__send_IPI_many(&recip, 1, tag);
}
void send_IPI_many(const struct cpumask *mask, int tag)
{
HV_Recipient recip[NR_CPUS];
int cpu;
int nrecip = 0;
int my_cpu = smp_processor_id();
for_each_cpu(cpu, mask) {
HV_Recipient *r;
BUG_ON(cpu == my_cpu);
r = &recip[nrecip++];
r->y = cpu / smp_width;
r->x = cpu % smp_width;
r->state = HV_TO_BE_SENT;
}
__send_IPI_many(recip, nrecip, tag);
}
void send_IPI_allbutself(int tag)
{
struct cpumask mask;
cpumask_copy(&mask, cpu_online_mask);
cpumask_clear_cpu(smp_processor_id(), &mask);
send_IPI_many(&mask, tag);
}
/*
* Functions related to starting/stopping cpus.
*/
/* Handler to start the current cpu. */
static void smp_start_cpu_interrupt(void)
{
get_irq_regs()->pc = start_cpu_function_addr;
}
/* Handler to stop the current cpu. */
static void smp_stop_cpu_interrupt(void)
{
arch_local_irq_disable_all();
set_cpu_online(smp_processor_id(), 0);
for (;;)
asm("nap; nop");
}
/* This function calls the 'stop' function on all other CPUs in the system. */
void smp_send_stop(void)
{
stopping_cpus = 1;
send_IPI_allbutself(MSG_TAG_STOP_CPU);
}
/* On panic, just wait; we may get an smp_send_stop() later on. */
void panic_smp_self_stop(void)
{
while (1)
asm("nap; nop");
}
/*
* Dispatch code called from hv_message_intr() for HV_MSG_TILE hv messages.
*/
void evaluate_message(int tag)
{
switch (tag) {
case MSG_TAG_START_CPU: /* Start up a cpu */
smp_start_cpu_interrupt();
break;
case MSG_TAG_STOP_CPU: /* Sent to shut down slave CPU's */
smp_stop_cpu_interrupt();
break;
case MSG_TAG_CALL_FUNCTION_MANY: /* Call function on cpumask */
generic_smp_call_function_interrupt();
break;
case MSG_TAG_CALL_FUNCTION_SINGLE: /* Call function on one other CPU */
generic_smp_call_function_single_interrupt();
break;
default:
panic("Unknown IPI message tag %d", tag);
break;
}
}
/*
* flush_icache_range() code uses smp_call_function().
*/
struct ipi_flush {
unsigned long start;
unsigned long end;
};
static void ipi_flush_icache_range(void *info)
{
struct ipi_flush *flush = (struct ipi_flush *) info;
__flush_icache_range(flush->start, flush->end);
}
void flush_icache_range(unsigned long start, unsigned long end)
{
struct ipi_flush flush = { start, end };
/* If invoked with irqs disabled, we can not issue IPIs. */
if (irqs_disabled())
flush_remote(0, HV_FLUSH_EVICT_L1I, NULL, 0, 0, 0,
NULL, NULL, 0);
else {
preempt_disable();
on_each_cpu(ipi_flush_icache_range, &flush, 1);
preempt_enable();
}
}
EXPORT_SYMBOL(flush_icache_range);
/* Called when smp_send_reschedule() triggers IRQ_RESCHEDULE. */
static irqreturn_t handle_reschedule_ipi(int irq, void *token)
{
__this_cpu_inc(irq_stat.irq_resched_count);
scheduler_ipi();
return IRQ_HANDLED;
}
static struct irqaction resched_action = {
.handler = handle_reschedule_ipi,
.name = "resched",
.dev_id = handle_reschedule_ipi /* unique token */,
};
void __init ipi_init(void)
{
#if CHIP_HAS_IPI()
int cpu;
/* Map IPI trigger MMIO addresses. */
for_each_possible_cpu(cpu) {
HV_Coord tile;
HV_PTE pte;
unsigned long offset;
tile.x = cpu_x(cpu);
tile.y = cpu_y(cpu);
if (hv_get_ipi_pte(tile, KERNEL_PL, &pte) != 0)
panic("Failed to initialize IPI for cpu %d\n", cpu);
offset = PFN_PHYS(pte_pfn(pte));
ipi_mappings[cpu] = ioremap_prot(offset, PAGE_SIZE, pte);
}
#endif
/* Bind handle_reschedule_ipi() to IRQ_RESCHEDULE. */
tile_irq_activate(IRQ_RESCHEDULE, TILE_IRQ_PERCPU);
BUG_ON(setup_irq(IRQ_RESCHEDULE, &resched_action));
}
#if CHIP_HAS_IPI()
void smp_send_reschedule(int cpu)
{
WARN_ON(cpu_is_offline(cpu));
/*
* We just want to do an MMIO store. The traditional writeq()
* functions aren't really correct here, since they're always
* directed at the PCI shim. For now, just do a raw store,
* casting away the __iomem attribute.
*/
((unsigned long __force *)ipi_mappings[cpu])[IRQ_RESCHEDULE] = 0;
}
#else
void smp_send_reschedule(int cpu)
{
HV_Coord coord;
WARN_ON(cpu_is_offline(cpu));
coord.y = cpu_y(cpu);
coord.x = cpu_x(cpu);
hv_trigger_ipi(coord, IRQ_RESCHEDULE);
}
#endif /* CHIP_HAS_IPI() */