3bb4987878
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> Signed-off-by: Danny Lin <danny@kdrag0n.dev> Signed-off-by: Park Ju Hyung <qkrwngud825@gmail.com> Signed-off-by: UtsavBalar1231 <utsavbalar1231@gmail.com>
101 lines
2.7 KiB
C
101 lines
2.7 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/sched.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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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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/*
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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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u64 i_seq;
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unsigned long pgoff;
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unsigned int offset;
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} shared;
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struct {
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union {
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struct mm_struct *mm;
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u64 __tmp;
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};
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unsigned long address;
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unsigned int offset;
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} private;
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struct {
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u64 ptr;
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unsigned long word;
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unsigned int offset;
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} both;
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};
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#define FUTEX_KEY_INIT (union futex_key) { .both = { .ptr = 0ULL } }
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#ifdef CONFIG_FUTEX
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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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enum {
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FUTEX_STATE_OK,
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FUTEX_STATE_EXITING,
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FUTEX_STATE_DEAD,
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};
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static inline void futex_init_task(struct task_struct *tsk)
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{
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tsk->robust_list = NULL;
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#ifdef CONFIG_COMPAT
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tsk->compat_robust_list = NULL;
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#endif
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INIT_LIST_HEAD(&tsk->pi_state_list);
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tsk->pi_state_cache = NULL;
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tsk->futex_state = FUTEX_STATE_OK;
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mutex_init(&tsk->futex_exit_mutex);
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}
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void futex_exit_recursive(struct task_struct *tsk);
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void futex_exit_release(struct task_struct *tsk);
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void futex_exec_release(struct task_struct *tsk);
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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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#else
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static inline void futex_init_task(struct task_struct *tsk) { }
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static inline void futex_exit_recursive(struct task_struct *tsk) { }
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static inline void futex_exit_release(struct task_struct *tsk) { }
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static inline void futex_exec_release(struct task_struct *tsk) { }
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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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#endif
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