![Mark Rutland](/assets/img/avatar_default.png)
The generic THREAD_INFO_IN_TASK definition of thread_info::flags is a
u32, matching x86 prior to the introduction of THREAD_INFO_IN_TASK.
However, common helpers like test_ti_thread_flag() implicitly assume
that thread_info::flags has at least the size and alignment of unsigned
long, and relying on padding and alignment provided by other elements of
task_struct is somewhat fragile. Additionally, some architectures use
more that 32 bits for thread_info::flags, and others may need to in
future.
With THREAD_INFO_IN_TASK, task struct follows thread_info with a long
field, and thus we no longer save any space as we did back in commit:
affa219b60
("x86: change thread_info's flag field back to 32 bits")
Given all this, it makes more sense for the generic thread_info::flags
to be an unsigned long.
In fact given <linux/thread_info.h> contains/uses the helpers mentioned
above, BE arches *must* use unsigned long (or something of the same size)
today, or they wouldn't work.
Make it so.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1474651447-30447-1-git-send-email-mark.rutland@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
151 lines
3.5 KiB
C
151 lines
3.5 KiB
C
/* thread_info.h: common low-level thread information accessors
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*
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* Copyright (C) 2002 David Howells (dhowells@redhat.com)
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* - Incorporating suggestions made by Linus Torvalds
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*/
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#ifndef _LINUX_THREAD_INFO_H
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#define _LINUX_THREAD_INFO_H
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#include <linux/types.h>
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#include <linux/bug.h>
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struct timespec;
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struct compat_timespec;
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#ifdef CONFIG_THREAD_INFO_IN_TASK
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struct thread_info {
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unsigned long flags; /* low level flags */
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};
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#define INIT_THREAD_INFO(tsk) \
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{ \
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.flags = 0, \
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}
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#endif
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#ifdef CONFIG_THREAD_INFO_IN_TASK
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#define current_thread_info() ((struct thread_info *)current)
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#endif
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/*
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* System call restart block.
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*/
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struct restart_block {
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long (*fn)(struct restart_block *);
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union {
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/* For futex_wait and futex_wait_requeue_pi */
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struct {
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u32 __user *uaddr;
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u32 val;
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u32 flags;
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u32 bitset;
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u64 time;
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u32 __user *uaddr2;
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} futex;
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/* For nanosleep */
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struct {
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clockid_t clockid;
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struct timespec __user *rmtp;
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#ifdef CONFIG_COMPAT
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struct compat_timespec __user *compat_rmtp;
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#endif
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u64 expires;
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} nanosleep;
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/* For poll */
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struct {
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struct pollfd __user *ufds;
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int nfds;
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int has_timeout;
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unsigned long tv_sec;
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unsigned long tv_nsec;
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} poll;
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};
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};
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extern long do_no_restart_syscall(struct restart_block *parm);
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#include <linux/bitops.h>
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#include <asm/thread_info.h>
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#ifdef __KERNEL__
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#ifdef CONFIG_DEBUG_STACK_USAGE
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# define THREADINFO_GFP (GFP_KERNEL_ACCOUNT | __GFP_NOTRACK | \
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__GFP_ZERO)
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#else
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# define THREADINFO_GFP (GFP_KERNEL_ACCOUNT | __GFP_NOTRACK)
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#endif
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/*
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* flag set/clear/test wrappers
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* - pass TIF_xxxx constants to these functions
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*/
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static inline void set_ti_thread_flag(struct thread_info *ti, int flag)
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{
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set_bit(flag, (unsigned long *)&ti->flags);
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}
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static inline void clear_ti_thread_flag(struct thread_info *ti, int flag)
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{
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clear_bit(flag, (unsigned long *)&ti->flags);
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}
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static inline int test_and_set_ti_thread_flag(struct thread_info *ti, int flag)
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{
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return test_and_set_bit(flag, (unsigned long *)&ti->flags);
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}
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static inline int test_and_clear_ti_thread_flag(struct thread_info *ti, int flag)
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{
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return test_and_clear_bit(flag, (unsigned long *)&ti->flags);
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}
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static inline int test_ti_thread_flag(struct thread_info *ti, int flag)
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{
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return test_bit(flag, (unsigned long *)&ti->flags);
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}
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#define set_thread_flag(flag) \
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set_ti_thread_flag(current_thread_info(), flag)
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#define clear_thread_flag(flag) \
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clear_ti_thread_flag(current_thread_info(), flag)
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#define test_and_set_thread_flag(flag) \
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test_and_set_ti_thread_flag(current_thread_info(), flag)
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#define test_and_clear_thread_flag(flag) \
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test_and_clear_ti_thread_flag(current_thread_info(), flag)
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#define test_thread_flag(flag) \
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test_ti_thread_flag(current_thread_info(), flag)
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#define tif_need_resched() test_thread_flag(TIF_NEED_RESCHED)
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#ifndef CONFIG_HAVE_ARCH_WITHIN_STACK_FRAMES
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static inline int arch_within_stack_frames(const void * const stack,
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const void * const stackend,
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const void *obj, unsigned long len)
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{
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return 0;
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}
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#endif
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#ifdef CONFIG_HARDENED_USERCOPY
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extern void __check_object_size(const void *ptr, unsigned long n,
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bool to_user);
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static __always_inline void check_object_size(const void *ptr, unsigned long n,
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bool to_user)
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{
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if (!__builtin_constant_p(n))
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__check_object_size(ptr, n, to_user);
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}
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#else
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static inline void check_object_size(const void *ptr, unsigned long n,
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bool to_user)
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{ }
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#endif /* CONFIG_HARDENED_USERCOPY */
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#endif /* __KERNEL__ */
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#endif /* _LINUX_THREAD_INFO_H */
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