2de0db992d
sys_futex() is a wrapper to do_futex() which does not modify any values here: - uaddr, val and val3 are kept the same - op is masked with FUTEX_CMD_MASK, but is always set to FUTEX_WAKE. Therefore, val2 is always 0. - as utime is set to NULL, *timeout is NULL This patch is part of a series which removes in-kernel calls to syscalls. On this basis, the syscall entry path can be streamlined. For details, see http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Darren Hart <dvhart@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
85 lines
2.1 KiB
C
85 lines
2.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_FUTEX_H
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#define _LINUX_FUTEX_H
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#include <linux/ktime.h>
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#include <uapi/linux/futex.h>
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struct inode;
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struct mm_struct;
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struct task_struct;
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extern int
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handle_futex_death(u32 __user *uaddr, struct task_struct *curr, int pi);
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/*
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* Futexes are matched on equal values of this key.
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* The key type depends on whether it's a shared or private mapping.
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* Don't rearrange members without looking at hash_futex().
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*
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* offset is aligned to a multiple of sizeof(u32) (== 4) by definition.
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* We use the two low order bits of offset to tell what is the kind of key :
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* 00 : Private process futex (PTHREAD_PROCESS_PRIVATE)
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* (no reference on an inode or mm)
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* 01 : Shared futex (PTHREAD_PROCESS_SHARED)
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* mapped on a file (reference on the underlying inode)
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* 10 : Shared futex (PTHREAD_PROCESS_SHARED)
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* (but private mapping on an mm, and reference taken on it)
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*/
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#define FUT_OFF_INODE 1 /* We set bit 0 if key has a reference on inode */
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#define FUT_OFF_MMSHARED 2 /* We set bit 1 if key has a reference on mm */
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union futex_key {
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struct {
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unsigned long pgoff;
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struct inode *inode;
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int offset;
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} shared;
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struct {
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unsigned long address;
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struct mm_struct *mm;
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int offset;
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} private;
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struct {
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unsigned long word;
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void *ptr;
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int offset;
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} both;
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};
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#define FUTEX_KEY_INIT (union futex_key) { .both = { .ptr = NULL } }
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#ifdef CONFIG_FUTEX
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extern void exit_robust_list(struct task_struct *curr);
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long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
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u32 __user *uaddr2, u32 val2, u32 val3);
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#ifdef CONFIG_HAVE_FUTEX_CMPXCHG
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#define futex_cmpxchg_enabled 1
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#else
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extern int futex_cmpxchg_enabled;
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#endif
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#else
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static inline void exit_robust_list(struct task_struct *curr)
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{
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}
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static inline long do_futex(u32 __user *uaddr, int op, u32 val,
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ktime_t *timeout, u32 __user *uaddr2,
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u32 val2, u32 val3)
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{
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return -EINVAL;
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}
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#endif
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#ifdef CONFIG_FUTEX_PI
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extern void exit_pi_state_list(struct task_struct *curr);
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#else
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static inline void exit_pi_state_list(struct task_struct *curr)
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{
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}
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#endif
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#endif
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