mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-24 09:50:04 +00:00
f64c6013a2
The x86/mtrr code does horrific things because hardware. It uses stop_machine_from_inactive_cpu(), which does a wakeup (of the stopper thread on another CPU), which uses RCU, all before the CPU is onlined. RCU complains about this, because wakeups use RCU and RCU does (rightfully) not consider offline CPUs for grace-periods. Fix this by initializing RCU way early in the MTRR case. Tested-by: Mike Galbraith <efault@gmx.de> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> [ paulmck: Add !SMP support, per 0day Test Robot report. ]
137 lines
3.6 KiB
C
137 lines
3.6 KiB
C
/*
|
|
* Read-Copy Update mechanism for mutual exclusion, the Bloatwatch edition.
|
|
*
|
|
* 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; either version 2 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* 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. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program; if not, you can access it online at
|
|
* http://www.gnu.org/licenses/gpl-2.0.html.
|
|
*
|
|
* Copyright IBM Corporation, 2008
|
|
*
|
|
* Author: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
|
|
*
|
|
* For detailed explanation of Read-Copy Update mechanism see -
|
|
* Documentation/RCU
|
|
*/
|
|
#ifndef __LINUX_TINY_H
|
|
#define __LINUX_TINY_H
|
|
|
|
#include <linux/ktime.h>
|
|
|
|
struct rcu_dynticks;
|
|
static inline int rcu_dynticks_snap(struct rcu_dynticks *rdtp)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
/* Never flag non-existent other CPUs! */
|
|
static inline bool rcu_eqs_special_set(int cpu) { return false; }
|
|
|
|
static inline unsigned long get_state_synchronize_rcu(void)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
static inline void cond_synchronize_rcu(unsigned long oldstate)
|
|
{
|
|
might_sleep();
|
|
}
|
|
|
|
static inline unsigned long get_state_synchronize_sched(void)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
static inline void cond_synchronize_sched(unsigned long oldstate)
|
|
{
|
|
might_sleep();
|
|
}
|
|
|
|
extern void rcu_barrier_bh(void);
|
|
extern void rcu_barrier_sched(void);
|
|
|
|
static inline void synchronize_rcu_expedited(void)
|
|
{
|
|
synchronize_sched(); /* Only one CPU, so pretty fast anyway!!! */
|
|
}
|
|
|
|
static inline void rcu_barrier(void)
|
|
{
|
|
rcu_barrier_sched(); /* Only one CPU, so only one list of callbacks! */
|
|
}
|
|
|
|
static inline void synchronize_rcu_bh(void)
|
|
{
|
|
synchronize_sched();
|
|
}
|
|
|
|
static inline void synchronize_rcu_bh_expedited(void)
|
|
{
|
|
synchronize_sched();
|
|
}
|
|
|
|
static inline void synchronize_sched_expedited(void)
|
|
{
|
|
synchronize_sched();
|
|
}
|
|
|
|
static inline void kfree_call_rcu(struct rcu_head *head,
|
|
rcu_callback_t func)
|
|
{
|
|
call_rcu(head, func);
|
|
}
|
|
|
|
#define rcu_note_context_switch(preempt) \
|
|
do { \
|
|
rcu_sched_qs(); \
|
|
rcu_note_voluntary_context_switch_lite(current); \
|
|
} while (0)
|
|
|
|
static inline int rcu_needs_cpu(u64 basemono, u64 *nextevt)
|
|
{
|
|
*nextevt = KTIME_MAX;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Take advantage of the fact that there is only one CPU, which
|
|
* allows us to ignore virtualization-based context switches.
|
|
*/
|
|
static inline void rcu_virt_note_context_switch(int cpu) { }
|
|
static inline void rcu_cpu_stall_reset(void) { }
|
|
static inline void rcu_idle_enter(void) { }
|
|
static inline void rcu_idle_exit(void) { }
|
|
static inline void rcu_irq_enter(void) { }
|
|
static inline void rcu_irq_exit_irqson(void) { }
|
|
static inline void rcu_irq_enter_irqson(void) { }
|
|
static inline void rcu_irq_exit(void) { }
|
|
static inline void exit_rcu(void) { }
|
|
#ifdef CONFIG_SRCU
|
|
void rcu_scheduler_starting(void);
|
|
#else /* #ifndef CONFIG_SRCU */
|
|
static inline void rcu_scheduler_starting(void) { }
|
|
#endif /* #else #ifndef CONFIG_SRCU */
|
|
static inline void rcu_end_inkernel_boot(void) { }
|
|
static inline bool rcu_is_watching(void) { return true; }
|
|
|
|
/* Avoid RCU read-side critical sections leaking across. */
|
|
static inline void rcu_all_qs(void) { barrier(); }
|
|
|
|
/* RCUtree hotplug events */
|
|
#define rcutree_prepare_cpu NULL
|
|
#define rcutree_online_cpu NULL
|
|
#define rcutree_offline_cpu NULL
|
|
#define rcutree_dead_cpu NULL
|
|
#define rcutree_dying_cpu NULL
|
|
static inline void rcu_cpu_starting(unsigned int cpu) { }
|
|
|
|
#endif /* __LINUX_RCUTINY_H */
|