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linux-next/include/linux/thread_info.h
Heiko Carstens c8061485a0 sched/core, x86: Make struct thread_info arch specific again
The following commit:

  c65eacbe29 ("sched/core: Allow putting thread_info into task_struct")

... made 'struct thread_info' a generic struct with only a
single ::flags member, if CONFIG_THREAD_INFO_IN_TASK_STRUCT=y is
selected.

This change however seems to be quite x86 centric, since at least the
generic preemption code (asm-generic/preempt.h) assumes that struct
thread_info also has a preempt_count member, which apparently was not
true for x86.

We could add a bit more #ifdefs to solve this problem too, but it seems
to be much simpler to make struct thread_info arch specific
again. This also makes the conversion to THREAD_INFO_IN_TASK_STRUCT a
bit easier for architectures that have a couple of arch specific stuff
in their thread_info definition.

The arch specific stuff _could_ be moved to thread_struct. However
keeping them in thread_info makes it easier: accessing thread_info
members is simple, since it is at the beginning of the task_struct,
while the thread_struct is at the end. At least on s390 the offsets
needed to access members of the thread_struct (with task_struct as
base) are too large for various asm instructions.  This is not a
problem when keeping these members within thread_info.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: keescook@chromium.org
Cc: linux-arch@vger.kernel.org
Link: http://lkml.kernel.org/r/1476901693-8492-2-git-send-email-mark.rutland@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-10-20 13:27:47 +02:00

140 lines
3.3 KiB
C

/* thread_info.h: common low-level thread information accessors
*
* Copyright (C) 2002 David Howells (dhowells@redhat.com)
* - Incorporating suggestions made by Linus Torvalds
*/
#ifndef _LINUX_THREAD_INFO_H
#define _LINUX_THREAD_INFO_H
#include <linux/types.h>
#include <linux/bug.h>
struct timespec;
struct compat_timespec;
#ifdef CONFIG_THREAD_INFO_IN_TASK
#define current_thread_info() ((struct thread_info *)current)
#endif
/*
* System call restart block.
*/
struct restart_block {
long (*fn)(struct restart_block *);
union {
/* For futex_wait and futex_wait_requeue_pi */
struct {
u32 __user *uaddr;
u32 val;
u32 flags;
u32 bitset;
u64 time;
u32 __user *uaddr2;
} futex;
/* For nanosleep */
struct {
clockid_t clockid;
struct timespec __user *rmtp;
#ifdef CONFIG_COMPAT
struct compat_timespec __user *compat_rmtp;
#endif
u64 expires;
} nanosleep;
/* For poll */
struct {
struct pollfd __user *ufds;
int nfds;
int has_timeout;
unsigned long tv_sec;
unsigned long tv_nsec;
} poll;
};
};
extern long do_no_restart_syscall(struct restart_block *parm);
#include <linux/bitops.h>
#include <asm/thread_info.h>
#ifdef __KERNEL__
#ifdef CONFIG_DEBUG_STACK_USAGE
# define THREADINFO_GFP (GFP_KERNEL_ACCOUNT | __GFP_NOTRACK | \
__GFP_ZERO)
#else
# define THREADINFO_GFP (GFP_KERNEL_ACCOUNT | __GFP_NOTRACK)
#endif
/*
* flag set/clear/test wrappers
* - pass TIF_xxxx constants to these functions
*/
static inline void set_ti_thread_flag(struct thread_info *ti, int flag)
{
set_bit(flag, (unsigned long *)&ti->flags);
}
static inline void clear_ti_thread_flag(struct thread_info *ti, int flag)
{
clear_bit(flag, (unsigned long *)&ti->flags);
}
static inline int test_and_set_ti_thread_flag(struct thread_info *ti, int flag)
{
return test_and_set_bit(flag, (unsigned long *)&ti->flags);
}
static inline int test_and_clear_ti_thread_flag(struct thread_info *ti, int flag)
{
return test_and_clear_bit(flag, (unsigned long *)&ti->flags);
}
static inline int test_ti_thread_flag(struct thread_info *ti, int flag)
{
return test_bit(flag, (unsigned long *)&ti->flags);
}
#define set_thread_flag(flag) \
set_ti_thread_flag(current_thread_info(), flag)
#define clear_thread_flag(flag) \
clear_ti_thread_flag(current_thread_info(), flag)
#define test_and_set_thread_flag(flag) \
test_and_set_ti_thread_flag(current_thread_info(), flag)
#define test_and_clear_thread_flag(flag) \
test_and_clear_ti_thread_flag(current_thread_info(), flag)
#define test_thread_flag(flag) \
test_ti_thread_flag(current_thread_info(), flag)
#define tif_need_resched() test_thread_flag(TIF_NEED_RESCHED)
#ifndef CONFIG_HAVE_ARCH_WITHIN_STACK_FRAMES
static inline int arch_within_stack_frames(const void * const stack,
const void * const stackend,
const void *obj, unsigned long len)
{
return 0;
}
#endif
#ifdef CONFIG_HARDENED_USERCOPY
extern void __check_object_size(const void *ptr, unsigned long n,
bool to_user);
static __always_inline void check_object_size(const void *ptr, unsigned long n,
bool to_user)
{
if (!__builtin_constant_p(n))
__check_object_size(ptr, n, to_user);
}
#else
static inline void check_object_size(const void *ptr, unsigned long n,
bool to_user)
{ }
#endif /* CONFIG_HARDENED_USERCOPY */
#endif /* __KERNEL__ */
#endif /* _LINUX_THREAD_INFO_H */