linux_dsm_epyc7002/include/linux/smp.h
David Daney f21afc25f9 smp.h: Use local_irq_{save,restore}() in !SMP version of on_each_cpu().
Thanks to commit f91eb62f71 ("init: scream bloody murder if interrupts
are enabled too early"), "bloody murder" is now being screamed.

With a MIPS OCTEON config, we use on_each_cpu() in our
irq_chip.irq_bus_sync_unlock() function.  This gets called in early as a
result of the time_init() call.  Because the !SMP version of
on_each_cpu() unconditionally enables irqs, we get:

    WARNING: at init/main.c:560 start_kernel+0x250/0x410()
    Interrupts were enabled early
    CPU: 0 PID: 0 Comm: swapper Not tainted 3.10.0-rc5-Cavium-Octeon+ #801
    Call Trace:
      show_stack+0x68/0x80
      warn_slowpath_common+0x78/0xb0
      warn_slowpath_fmt+0x38/0x48
      start_kernel+0x250/0x410

Suggested fix: Do what we already do in the SMP version of
on_each_cpu(), and use local_irq_save/local_irq_restore.  Because we
need a flags variable, make it a static inline to avoid name space
issues.

[ Change from v1: Convert on_each_cpu to a static inline function, add
  #include <linux/irqflags.h> to avoid build breakage on some files.

  on_each_cpu_mask() and on_each_cpu_cond() suffer the same problem as
  on_each_cpu(), but they are not causing !SMP bugs for me, so I will
  defer changing them to a less urgent patch. ]

Signed-off-by: David Daney <david.daney@cavium.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-06-14 19:24:42 -10:00

235 lines
5.8 KiB
C

#ifndef __LINUX_SMP_H
#define __LINUX_SMP_H
/*
* Generic SMP support
* Alan Cox. <alan@redhat.com>
*/
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/list.h>
#include <linux/cpumask.h>
#include <linux/init.h>
#include <linux/irqflags.h>
extern void cpu_idle(void);
typedef void (*smp_call_func_t)(void *info);
struct call_single_data {
struct list_head list;
smp_call_func_t func;
void *info;
u16 flags;
};
/* total number of cpus in this system (may exceed NR_CPUS) */
extern unsigned int total_cpus;
int smp_call_function_single(int cpuid, smp_call_func_t func, void *info,
int wait);
#ifdef CONFIG_SMP
#include <linux/preempt.h>
#include <linux/kernel.h>
#include <linux/compiler.h>
#include <linux/thread_info.h>
#include <asm/smp.h>
/*
* main cross-CPU interfaces, handles INIT, TLB flush, STOP, etc.
* (defined in asm header):
*/
/*
* stops all CPUs but the current one:
*/
extern void smp_send_stop(void);
/*
* sends a 'reschedule' event to another CPU:
*/
extern void smp_send_reschedule(int cpu);
/*
* Prepare machine for booting other CPUs.
*/
extern void smp_prepare_cpus(unsigned int max_cpus);
/*
* Bring a CPU up
*/
extern int __cpu_up(unsigned int cpunum, struct task_struct *tidle);
/*
* Final polishing of CPUs
*/
extern void smp_cpus_done(unsigned int max_cpus);
/*
* Call a function on all other processors
*/
int smp_call_function(smp_call_func_t func, void *info, int wait);
void smp_call_function_many(const struct cpumask *mask,
smp_call_func_t func, void *info, bool wait);
void __smp_call_function_single(int cpuid, struct call_single_data *data,
int wait);
int smp_call_function_any(const struct cpumask *mask,
smp_call_func_t func, void *info, int wait);
void kick_all_cpus_sync(void);
/*
* Generic and arch helpers
*/
#ifdef CONFIG_USE_GENERIC_SMP_HELPERS
void __init call_function_init(void);
void generic_smp_call_function_single_interrupt(void);
#define generic_smp_call_function_interrupt \
generic_smp_call_function_single_interrupt
#else
static inline void call_function_init(void) { }
#endif
/*
* Call a function on all processors
*/
int on_each_cpu(smp_call_func_t func, void *info, int wait);
/*
* Call a function on processors specified by mask, which might include
* the local one.
*/
void on_each_cpu_mask(const struct cpumask *mask, smp_call_func_t func,
void *info, bool wait);
/*
* Call a function on each processor for which the supplied function
* cond_func returns a positive value. This may include the local
* processor.
*/
void on_each_cpu_cond(bool (*cond_func)(int cpu, void *info),
smp_call_func_t func, void *info, bool wait,
gfp_t gfp_flags);
/*
* Mark the boot cpu "online" so that it can call console drivers in
* printk() and can access its per-cpu storage.
*/
void smp_prepare_boot_cpu(void);
extern unsigned int setup_max_cpus;
extern void __init setup_nr_cpu_ids(void);
extern void __init smp_init(void);
#else /* !SMP */
static inline void smp_send_stop(void) { }
/*
* These macros fold the SMP functionality into a single CPU system
*/
#define raw_smp_processor_id() 0
static inline int up_smp_call_function(smp_call_func_t func, void *info)
{
return 0;
}
#define smp_call_function(func, info, wait) \
(up_smp_call_function(func, info))
static inline int on_each_cpu(smp_call_func_t func, void *info, int wait)
{
unsigned long flags;
local_irq_save(flags);
func(info);
local_irq_restore(flags);
return 0;
}
/*
* Note we still need to test the mask even for UP
* because we actually can get an empty mask from
* code that on SMP might call us without the local
* CPU in the mask.
*/
#define on_each_cpu_mask(mask, func, info, wait) \
do { \
if (cpumask_test_cpu(0, (mask))) { \
local_irq_disable(); \
(func)(info); \
local_irq_enable(); \
} \
} while (0)
/*
* Preemption is disabled here to make sure the cond_func is called under the
* same condtions in UP and SMP.
*/
#define on_each_cpu_cond(cond_func, func, info, wait, gfp_flags)\
do { \
void *__info = (info); \
preempt_disable(); \
if ((cond_func)(0, __info)) { \
local_irq_disable(); \
(func)(__info); \
local_irq_enable(); \
} \
preempt_enable(); \
} while (0)
static inline void smp_send_reschedule(int cpu) { }
#define smp_prepare_boot_cpu() do {} while (0)
#define smp_call_function_many(mask, func, info, wait) \
(up_smp_call_function(func, info))
static inline void call_function_init(void) { }
static inline int
smp_call_function_any(const struct cpumask *mask, smp_call_func_t func,
void *info, int wait)
{
return smp_call_function_single(0, func, info, wait);
}
static inline void kick_all_cpus_sync(void) { }
#endif /* !SMP */
/*
* smp_processor_id(): get the current CPU ID.
*
* if DEBUG_PREEMPT is enabled then we check whether it is
* used in a preemption-safe way. (smp_processor_id() is safe
* if it's used in a preemption-off critical section, or in
* a thread that is bound to the current CPU.)
*
* NOTE: raw_smp_processor_id() is for internal use only
* (smp_processor_id() is the preferred variant), but in rare
* instances it might also be used to turn off false positives
* (i.e. smp_processor_id() use that the debugging code reports but
* which use for some reason is legal). Don't use this to hack around
* the warning message, as your code might not work under PREEMPT.
*/
#ifdef CONFIG_DEBUG_PREEMPT
extern unsigned int debug_smp_processor_id(void);
# define smp_processor_id() debug_smp_processor_id()
#else
# define smp_processor_id() raw_smp_processor_id()
#endif
#define get_cpu() ({ preempt_disable(); smp_processor_id(); })
#define put_cpu() preempt_enable()
/*
* Callback to arch code if there's nosmp or maxcpus=0 on the
* boot command line:
*/
extern void arch_disable_smp_support(void);
void smp_setup_processor_id(void);
#endif /* __LINUX_SMP_H */