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android_kernel_motorola_sm6225/arch/sparc/kernel/leon_smp.c
Christoph Lameter 494fc42170 sparc: Replace __get_cpu_var uses 
__get_cpu_var() is used for multiple purposes in the kernel source. One of
them is address calculation via the form &__get_cpu_var(x).  This calculates
the address for the instance of the percpu variable of the current processor
based on an offset.

Other use cases are for storing and retrieving data from the current
processors percpu area.  __get_cpu_var() can be used as an lvalue when
writing data or on the right side of an assignment.

__get_cpu_var() is defined as :

#define __get_cpu_var(var) (*this_cpu_ptr(&(var)))

__get_cpu_var() always only does an address determination. However, store
and retrieve operations could use a segment prefix (or global register on
other platforms) to avoid the address calculation.

this_cpu_write() and this_cpu_read() can directly take an offset into a
percpu area and use optimized assembly code to read and write per cpu
variables.

This patch converts __get_cpu_var into either an explicit address
calculation using this_cpu_ptr() or into a use of this_cpu operations that
use the offset.  Thereby address calculations are avoided and less registers
are used when code is generated.

At the end of the patch set all uses of __get_cpu_var have been removed so
the macro is removed too.

The patch set includes passes over all arches as well. Once these operations
are used throughout then specialized macros can be defined in non -x86
arches as well in order to optimize per cpu access by f.e.  using a global
register that may be set to the per cpu base.

Transformations done to __get_cpu_var()

1. Determine the address of the percpu instance of the current processor.

	DEFINE_PER_CPU(int, y);
	int *x = &__get_cpu_var(y);

    Converts to

	int *x = this_cpu_ptr(&y);

2. Same as #1 but this time an array structure is involved.

	DEFINE_PER_CPU(int, y[20]);
	int *x = __get_cpu_var(y);

    Converts to

	int *x = this_cpu_ptr(y);

3. Retrieve the content of the current processors instance of a per cpu
variable.

	DEFINE_PER_CPU(int, y);
	int x = __get_cpu_var(y)

   Converts to

	int x = __this_cpu_read(y);

4. Retrieve the content of a percpu struct

	DEFINE_PER_CPU(struct mystruct, y);
	struct mystruct x = __get_cpu_var(y);

   Converts to

	memcpy(&x, this_cpu_ptr(&y), sizeof(x));

5. Assignment to a per cpu variable

	DEFINE_PER_CPU(int, y)
	__get_cpu_var(y) = x;

   Converts to

	__this_cpu_write(y, x);

6. Increment/Decrement etc of a per cpu variable

	DEFINE_PER_CPU(int, y);
	__get_cpu_var(y)++

   Converts to

	__this_cpu_inc(y)

Cc: sparclinux@vger.kernel.org
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2014-08-26 13:45:55 -04:00

469 lines
11 KiB
C
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/* leon_smp.c: Sparc-Leon SMP support.
*
* based on sun4m_smp.c
* Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
* Copyright (C) 2009 Daniel Hellstrom (daniel@gaisler.com) Aeroflex Gaisler AB
* Copyright (C) 2009 Konrad Eisele (konrad@gaisler.com) Aeroflex Gaisler AB
*/
#include <asm/head.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/threads.h>
#include <linux/smp.h>
#include <linux/interrupt.h>
#include <linux/kernel_stat.h>
#include <linux/of.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/profile.h>
#include <linux/pm.h>
#include <linux/delay.h>
#include <linux/gfp.h>
#include <linux/cpu.h>
#include <linux/clockchips.h>
#include <asm/cacheflush.h>
#include <asm/tlbflush.h>
#include <asm/ptrace.h>
#include <linux/atomic.h>
#include <asm/irq_regs.h>
#include <asm/traps.h>
#include <asm/delay.h>
#include <asm/irq.h>
#include <asm/page.h>
#include <asm/pgalloc.h>
#include <asm/pgtable.h>
#include <asm/oplib.h>
#include <asm/cpudata.h>
#include <asm/asi.h>
#include <asm/leon.h>
#include <asm/leon_amba.h>
#include <asm/timer.h>
#include "kernel.h"
#include "irq.h"
extern ctxd_t *srmmu_ctx_table_phys;
static int smp_processors_ready;
extern volatile unsigned long cpu_callin_map[NR_CPUS];
extern cpumask_t smp_commenced_mask;
void leon_configure_cache_smp(void);
static void leon_ipi_init(void);
/* IRQ number of LEON IPIs */
int leon_ipi_irq = LEON3_IRQ_IPI_DEFAULT;
static inline unsigned long do_swap(volatile unsigned long *ptr,
unsigned long val)
{
__asm__ __volatile__("swapa [%2] %3, %0\n\t" : "=&r"(val)
: "0"(val), "r"(ptr), "i"(ASI_LEON_DCACHE_MISS)
: "memory");
return val;
}
void leon_cpu_pre_starting(void *arg)
{
leon_configure_cache_smp();
}
void leon_cpu_pre_online(void *arg)
{
int cpuid = hard_smp_processor_id();
/* Allow master to continue. The master will then give us the
* go-ahead by setting the smp_commenced_mask and will wait without
* timeouts until our setup is completed fully (signified by
* our bit being set in the cpu_online_mask).
*/
do_swap(&cpu_callin_map[cpuid], 1);
local_ops->cache_all();
local_ops->tlb_all();
/* Fix idle thread fields. */
__asm__ __volatile__("ld [%0], %%g6\n\t" : : "r"(&current_set[cpuid])
: "memory" /* paranoid */);
/* Attach to the address space of init_task. */
atomic_inc(&init_mm.mm_count);
current->active_mm = &init_mm;
while (!cpumask_test_cpu(cpuid, &smp_commenced_mask))
mb();
}
/*
* Cycle through the processors asking the PROM to start each one.
*/
extern struct linux_prom_registers smp_penguin_ctable;
void leon_configure_cache_smp(void)
{
unsigned long cfg = sparc_leon3_get_dcachecfg();
int me = smp_processor_id();
if (ASI_LEON3_SYSCTRL_CFG_SSIZE(cfg) > 4) {
printk(KERN_INFO "Note: SMP with snooping only works on 4k cache, found %dk(0x%x) on cpu %d, disabling caches\n",
(unsigned int)ASI_LEON3_SYSCTRL_CFG_SSIZE(cfg),
(unsigned int)cfg, (unsigned int)me);
sparc_leon3_disable_cache();
} else {
if (cfg & ASI_LEON3_SYSCTRL_CFG_SNOOPING) {
sparc_leon3_enable_snooping();
} else {
printk(KERN_INFO "Note: You have to enable snooping in the vhdl model cpu %d, disabling caches\n",
me);
sparc_leon3_disable_cache();
}
}
local_ops->cache_all();
local_ops->tlb_all();
}
static void leon_smp_setbroadcast(unsigned int mask)
{
int broadcast =
((LEON3_BYPASS_LOAD_PA(&(leon3_irqctrl_regs->mpstatus)) >>
LEON3_IRQMPSTATUS_BROADCAST) & 1);
if (!broadcast) {
prom_printf("######## !!!! The irqmp-ctrl must have broadcast enabled, smp wont work !!!!! ####### nr cpus: %d\n",
leon_smp_nrcpus());
if (leon_smp_nrcpus() > 1) {
BUG();
} else {
prom_printf("continue anyway\n");
return;
}
}
LEON_BYPASS_STORE_PA(&(leon3_irqctrl_regs->mpbroadcast), mask);
}
int leon_smp_nrcpus(void)
{
int nrcpu =
((LEON3_BYPASS_LOAD_PA(&(leon3_irqctrl_regs->mpstatus)) >>
LEON3_IRQMPSTATUS_CPUNR) & 0xf) + 1;
return nrcpu;
}
void __init leon_boot_cpus(void)
{
int nrcpu = leon_smp_nrcpus();
int me = smp_processor_id();
/* Setup IPI */
leon_ipi_init();
printk(KERN_INFO "%d:(%d:%d) cpus mpirq at 0x%x\n", (unsigned int)me,
(unsigned int)nrcpu, (unsigned int)NR_CPUS,
(unsigned int)&(leon3_irqctrl_regs->mpstatus));
leon_enable_irq_cpu(LEON3_IRQ_CROSS_CALL, me);
leon_enable_irq_cpu(LEON3_IRQ_TICKER, me);
leon_enable_irq_cpu(leon_ipi_irq, me);
leon_smp_setbroadcast(1 << LEON3_IRQ_TICKER);
leon_configure_cache_smp();
local_ops->cache_all();
}
int leon_boot_one_cpu(int i, struct task_struct *idle)
{
int timeout;
current_set[i] = task_thread_info(idle);
/* See trampoline.S:leon_smp_cpu_startup for details...
* Initialize the contexts table
* Since the call to prom_startcpu() trashes the structure,
* we need to re-initialize it for each cpu
*/
smp_penguin_ctable.which_io = 0;
smp_penguin_ctable.phys_addr = (unsigned int)srmmu_ctx_table_phys;
smp_penguin_ctable.reg_size = 0;
/* whirrr, whirrr, whirrrrrrrrr... */
printk(KERN_INFO "Starting CPU %d : (irqmp: 0x%x)\n", (unsigned int)i,
(unsigned int)&leon3_irqctrl_regs->mpstatus);
local_ops->cache_all();
/* Make sure all IRQs are of from the start for this new CPU */
LEON_BYPASS_STORE_PA(&leon3_irqctrl_regs->mask[i], 0);
/* Wake one CPU */
LEON_BYPASS_STORE_PA(&(leon3_irqctrl_regs->mpstatus), 1 << i);
/* wheee... it's going... */
for (timeout = 0; timeout < 10000; timeout++) {
if (cpu_callin_map[i])
break;
udelay(200);
}
printk(KERN_INFO "Started CPU %d\n", (unsigned int)i);
if (!(cpu_callin_map[i])) {
printk(KERN_ERR "Processor %d is stuck.\n", i);
return -ENODEV;
} else {
leon_enable_irq_cpu(LEON3_IRQ_CROSS_CALL, i);
leon_enable_irq_cpu(LEON3_IRQ_TICKER, i);
leon_enable_irq_cpu(leon_ipi_irq, i);
}
local_ops->cache_all();
return 0;
}
void __init leon_smp_done(void)
{
int i, first;
int *prev;
/* setup cpu list for irq rotation */
first = 0;
prev = &first;
for (i = 0; i < NR_CPUS; i++) {
if (cpu_online(i)) {
*prev = i;
prev = &cpu_data(i).next;
}
}
*prev = first;
local_ops->cache_all();
/* Free unneeded trap tables */
if (!cpu_present(1)) {
free_reserved_page(virt_to_page(&trapbase_cpu1));
}
if (!cpu_present(2)) {
free_reserved_page(virt_to_page(&trapbase_cpu2));
}
if (!cpu_present(3)) {
free_reserved_page(virt_to_page(&trapbase_cpu3));
}
/* Ok, they are spinning and ready to go. */
smp_processors_ready = 1;
}
struct leon_ipi_work {
int single;
int msk;
int resched;
};
static DEFINE_PER_CPU_SHARED_ALIGNED(struct leon_ipi_work, leon_ipi_work);
/* Initialize IPIs on the LEON, in order to save IRQ resources only one IRQ
* is used for all three types of IPIs.
*/
static void __init leon_ipi_init(void)
{
int cpu, len;
struct leon_ipi_work *work;
struct property *pp;
struct device_node *rootnp;
struct tt_entry *trap_table;
unsigned long flags;
/* Find IPI IRQ or stick with default value */
rootnp = of_find_node_by_path("/ambapp0");
if (rootnp) {
pp = of_find_property(rootnp, "ipi_num", &len);
if (pp && (*(int *)pp->value))
leon_ipi_irq = *(int *)pp->value;
}
printk(KERN_INFO "leon: SMP IPIs at IRQ %d\n", leon_ipi_irq);
/* Adjust so that we jump directly to smpleon_ipi */
local_irq_save(flags);
trap_table = &sparc_ttable[SP_TRAP_IRQ1 + (leon_ipi_irq - 1)];
trap_table->inst_three += smpleon_ipi - real_irq_entry;
local_ops->cache_all();
local_irq_restore(flags);
for_each_possible_cpu(cpu) {
work = &per_cpu(leon_ipi_work, cpu);
work->single = work->msk = work->resched = 0;
}
}
static void leon_send_ipi(int cpu, int level)
{
unsigned long mask;
mask = leon_get_irqmask(level);
LEON3_BYPASS_STORE_PA(&leon3_irqctrl_regs->force[cpu], mask);
}
static void leon_ipi_single(int cpu)
{
struct leon_ipi_work *work = &per_cpu(leon_ipi_work, cpu);
/* Mark work */
work->single = 1;
/* Generate IRQ on the CPU */
leon_send_ipi(cpu, leon_ipi_irq);
}
static void leon_ipi_mask_one(int cpu)
{
struct leon_ipi_work *work = &per_cpu(leon_ipi_work, cpu);
/* Mark work */
work->msk = 1;
/* Generate IRQ on the CPU */
leon_send_ipi(cpu, leon_ipi_irq);
}
static void leon_ipi_resched(int cpu)
{
struct leon_ipi_work *work = &per_cpu(leon_ipi_work, cpu);
/* Mark work */
work->resched = 1;
/* Generate IRQ on the CPU (any IRQ will cause resched) */
leon_send_ipi(cpu, leon_ipi_irq);
}
void leonsmp_ipi_interrupt(void)
{
struct leon_ipi_work *work = this_cpu_ptr(&leon_ipi_work);
if (work->single) {
work->single = 0;
smp_call_function_single_interrupt();
}
if (work->msk) {
work->msk = 0;
smp_call_function_interrupt();
}
if (work->resched) {
work->resched = 0;
smp_resched_interrupt();
}
}
static struct smp_funcall {
smpfunc_t func;
unsigned long arg1;
unsigned long arg2;
unsigned long arg3;
unsigned long arg4;
unsigned long arg5;
unsigned long processors_in[NR_CPUS]; /* Set when ipi entered. */
unsigned long processors_out[NR_CPUS]; /* Set when ipi exited. */
} ccall_info;
static DEFINE_SPINLOCK(cross_call_lock);
/* Cross calls must be serialized, at least currently. */
static void leon_cross_call(smpfunc_t func, cpumask_t mask, unsigned long arg1,
unsigned long arg2, unsigned long arg3,
unsigned long arg4)
{
if (smp_processors_ready) {
register int high = NR_CPUS - 1;
unsigned long flags;
spin_lock_irqsave(&cross_call_lock, flags);
{
/* If you make changes here, make sure gcc generates proper code... */
register smpfunc_t f asm("i0") = func;
register unsigned long a1 asm("i1") = arg1;
register unsigned long a2 asm("i2") = arg2;
register unsigned long a3 asm("i3") = arg3;
register unsigned long a4 asm("i4") = arg4;
register unsigned long a5 asm("i5") = 0;
__asm__ __volatile__("std %0, [%6]\n\t"
"std %2, [%6 + 8]\n\t"
"std %4, [%6 + 16]\n\t" : :
"r"(f), "r"(a1), "r"(a2), "r"(a3),
"r"(a4), "r"(a5),
"r"(&ccall_info.func));
}
/* Init receive/complete mapping, plus fire the IPI's off. */
{
register int i;
cpumask_clear_cpu(smp_processor_id(), &mask);
cpumask_and(&mask, cpu_online_mask, &mask);
for (i = 0; i <= high; i++) {
if (cpumask_test_cpu(i, &mask)) {
ccall_info.processors_in[i] = 0;
ccall_info.processors_out[i] = 0;
leon_send_ipi(i, LEON3_IRQ_CROSS_CALL);
}
}
}
{
register int i;
i = 0;
do {
if (!cpumask_test_cpu(i, &mask))
continue;
while (!ccall_info.processors_in[i])
barrier();
} while (++i <= high);
i = 0;
do {
if (!cpumask_test_cpu(i, &mask))
continue;
while (!ccall_info.processors_out[i])
barrier();
} while (++i <= high);
}
spin_unlock_irqrestore(&cross_call_lock, flags);
}
}
/* Running cross calls. */
void leon_cross_call_irq(void)
{
int i = smp_processor_id();
ccall_info.processors_in[i] = 1;
ccall_info.func(ccall_info.arg1, ccall_info.arg2, ccall_info.arg3,
ccall_info.arg4, ccall_info.arg5);
ccall_info.processors_out[i] = 1;
}
static const struct sparc32_ipi_ops leon_ipi_ops = {
.cross_call = leon_cross_call,
.resched = leon_ipi_resched,
.single = leon_ipi_single,
.mask_one = leon_ipi_mask_one,
};
void __init leon_init_smp(void)
{
/* Patch ipi15 trap table */
t_nmi[1] = t_nmi[1] + (linux_trap_ipi15_leon - linux_trap_ipi15_sun4m);
sparc32_ipi_ops = &leon_ipi_ops;
}
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