linux_dsm_epyc7002/arch/microblaze/kernel/process.c
Frederic Weisbecker 1268fbc746 nohz: Remove tick_nohz_idle_enter_norcu() / tick_nohz_idle_exit_norcu()
Those two APIs were provided to optimize the calls of
tick_nohz_idle_enter() and rcu_idle_enter() into a single
irq disabled section. This way no interrupt happening in-between would
needlessly process any RCU job.

Now we are talking about an optimization for which benefits
have yet to be measured. Let's start simple and completely decouple
idle rcu and dyntick idle logics to simplify.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2011-12-11 10:31:57 -08:00

261 lines
6.8 KiB
C

/*
* Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu>
* Copyright (C) 2008-2009 PetaLogix
* Copyright (C) 2006 Atmark Techno, Inc.
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*/
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/pm.h>
#include <linux/tick.h>
#include <linux/bitops.h>
#include <asm/system.h>
#include <asm/pgalloc.h>
#include <asm/uaccess.h> /* for USER_DS macros */
#include <asm/cacheflush.h>
void show_regs(struct pt_regs *regs)
{
printk(KERN_INFO " Registers dump: mode=%X\r\n", regs->pt_mode);
printk(KERN_INFO " r1=%08lX, r2=%08lX, r3=%08lX, r4=%08lX\n",
regs->r1, regs->r2, regs->r3, regs->r4);
printk(KERN_INFO " r5=%08lX, r6=%08lX, r7=%08lX, r8=%08lX\n",
regs->r5, regs->r6, regs->r7, regs->r8);
printk(KERN_INFO " r9=%08lX, r10=%08lX, r11=%08lX, r12=%08lX\n",
regs->r9, regs->r10, regs->r11, regs->r12);
printk(KERN_INFO " r13=%08lX, r14=%08lX, r15=%08lX, r16=%08lX\n",
regs->r13, regs->r14, regs->r15, regs->r16);
printk(KERN_INFO " r17=%08lX, r18=%08lX, r19=%08lX, r20=%08lX\n",
regs->r17, regs->r18, regs->r19, regs->r20);
printk(KERN_INFO " r21=%08lX, r22=%08lX, r23=%08lX, r24=%08lX\n",
regs->r21, regs->r22, regs->r23, regs->r24);
printk(KERN_INFO " r25=%08lX, r26=%08lX, r27=%08lX, r28=%08lX\n",
regs->r25, regs->r26, regs->r27, regs->r28);
printk(KERN_INFO " r29=%08lX, r30=%08lX, r31=%08lX, rPC=%08lX\n",
regs->r29, regs->r30, regs->r31, regs->pc);
printk(KERN_INFO " msr=%08lX, ear=%08lX, esr=%08lX, fsr=%08lX\n",
regs->msr, regs->ear, regs->esr, regs->fsr);
}
void (*pm_idle)(void);
void (*pm_power_off)(void) = NULL;
EXPORT_SYMBOL(pm_power_off);
static int hlt_counter = 1;
void disable_hlt(void)
{
hlt_counter++;
}
EXPORT_SYMBOL(disable_hlt);
void enable_hlt(void)
{
hlt_counter--;
}
EXPORT_SYMBOL(enable_hlt);
static int __init nohlt_setup(char *__unused)
{
hlt_counter = 1;
return 1;
}
__setup("nohlt", nohlt_setup);
static int __init hlt_setup(char *__unused)
{
hlt_counter = 0;
return 1;
}
__setup("hlt", hlt_setup);
void default_idle(void)
{
if (likely(hlt_counter)) {
local_irq_disable();
stop_critical_timings();
cpu_relax();
start_critical_timings();
local_irq_enable();
} else {
clear_thread_flag(TIF_POLLING_NRFLAG);
smp_mb__after_clear_bit();
local_irq_disable();
while (!need_resched())
cpu_sleep();
local_irq_enable();
set_thread_flag(TIF_POLLING_NRFLAG);
}
}
void cpu_idle(void)
{
set_thread_flag(TIF_POLLING_NRFLAG);
/* endless idle loop with no priority at all */
while (1) {
void (*idle)(void) = pm_idle;
if (!idle)
idle = default_idle;
tick_nohz_idle_enter();
rcu_idle_enter();
while (!need_resched())
idle();
rcu_idle_exit();
tick_nohz_idle_exit();
preempt_enable_no_resched();
schedule();
preempt_disable();
check_pgt_cache();
}
}
void flush_thread(void)
{
}
int copy_thread(unsigned long clone_flags, unsigned long usp,
unsigned long unused,
struct task_struct *p, struct pt_regs *regs)
{
struct pt_regs *childregs = task_pt_regs(p);
struct thread_info *ti = task_thread_info(p);
*childregs = *regs;
if (user_mode(regs))
childregs->r1 = usp;
else
childregs->r1 = ((unsigned long) ti) + THREAD_SIZE;
#ifndef CONFIG_MMU
memset(&ti->cpu_context, 0, sizeof(struct cpu_context));
ti->cpu_context.r1 = (unsigned long)childregs;
ti->cpu_context.msr = (unsigned long)childregs->msr;
#else
/* if creating a kernel thread then update the current reg (we don't
* want to use the parent's value when restoring by POP_STATE) */
if (kernel_mode(regs))
/* save new current on stack to use POP_STATE */
childregs->CURRENT_TASK = (unsigned long)p;
/* if returning to user then use the parent's value of this register */
/* if we're creating a new kernel thread then just zeroing all
* the registers. That's OK for a brand new thread.*/
/* Pls. note that some of them will be restored in POP_STATE */
if (kernel_mode(regs))
memset(&ti->cpu_context, 0, sizeof(struct cpu_context));
/* if this thread is created for fork/vfork/clone, then we want to
* restore all the parent's context */
/* in addition to the registers which will be restored by POP_STATE */
else {
ti->cpu_context = *(struct cpu_context *)regs;
childregs->msr |= MSR_UMS;
}
/* FIXME STATE_SAVE_PT_OFFSET; */
ti->cpu_context.r1 = (unsigned long)childregs;
/* we should consider the fact that childregs is a copy of the parent
* regs which were saved immediately after entering the kernel state
* before enabling VM. This MSR will be restored in switch_to and
* RETURN() and we want to have the right machine state there
* specifically this state must have INTs disabled before and enabled
* after performing rtbd
* compose the right MSR for RETURN(). It will work for switch_to also
* excepting for VM and UMS
* don't touch UMS , CARRY and cache bits
* right now MSR is a copy of parent one */
childregs->msr |= MSR_BIP;
childregs->msr &= ~MSR_EIP;
childregs->msr |= MSR_IE;
childregs->msr &= ~MSR_VM;
childregs->msr |= MSR_VMS;
childregs->msr |= MSR_EE; /* exceptions will be enabled*/
ti->cpu_context.msr = (childregs->msr|MSR_VM);
ti->cpu_context.msr &= ~MSR_UMS; /* switch_to to kernel mode */
ti->cpu_context.msr &= ~MSR_IE;
#endif
ti->cpu_context.r15 = (unsigned long)ret_from_fork - 8;
if (clone_flags & CLONE_SETTLS)
;
return 0;
}
#ifndef CONFIG_MMU
/*
* Return saved PC of a blocked thread.
*/
unsigned long thread_saved_pc(struct task_struct *tsk)
{
struct cpu_context *ctx =
&(((struct thread_info *)(tsk->stack))->cpu_context);
/* Check whether the thread is blocked in resume() */
if (in_sched_functions(ctx->r15))
return (unsigned long)ctx->r15;
else
return ctx->r14;
}
#endif
static void kernel_thread_helper(int (*fn)(void *), void *arg)
{
fn(arg);
do_exit(-1);
}
int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
{
struct pt_regs regs;
memset(&regs, 0, sizeof(regs));
/* store them in non-volatile registers */
regs.r5 = (unsigned long)fn;
regs.r6 = (unsigned long)arg;
local_save_flags(regs.msr);
regs.pc = (unsigned long)kernel_thread_helper;
regs.pt_mode = 1;
return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0,
&regs, 0, NULL, NULL);
}
EXPORT_SYMBOL_GPL(kernel_thread);
unsigned long get_wchan(struct task_struct *p)
{
/* TBD (used by procfs) */
return 0;
}
/* Set up a thread for executing a new program */
void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long usp)
{
regs->pc = pc;
regs->r1 = usp;
regs->pt_mode = 0;
#ifdef CONFIG_MMU
regs->msr |= MSR_UMS;
#endif
}
#ifdef CONFIG_MMU
#include <linux/elfcore.h>
/*
* Set up a thread for executing a new program
*/
int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpregs)
{
return 0; /* MicroBlaze has no separate FPU registers */
}
#endif /* CONFIG_MMU */