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From: Al Viro <viro@zeniv.linux.org.uk>
To: linux-alpha@vger.kernel.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Subject: [PATCHES] alpha asm glue cleanups and fixes
Date: Sat, 25 Sep 2021 02:54:13 +0000	[thread overview]
Message-ID: <YU6PVepETVUJF28v@zeniv-ca.linux.org.uk> (raw)

	Fallout from asm glue review on alpha:

1) TIF_NOTIFY_SIGNAL support is broken; do_work_pending() handles
it, but the logics *calling* do_work_pending() ignores that flag
completely.  If it's called for other reasons - fine, but
TIF_NOTIFY_SIGNAL alone will not suffice for that.  Bug from the
last cycle.  5.11 bug.

2) _TIF_ALLWORK_MASK is junk - never had been used.

3) !AUDIT_SYSCALL configs have buggered logics for going into
straced syscall path.  Any thread flag (including TIF_SIGNAL_PENDING)
will suffice to send us there.  3.14 bug.

4) on straced syscalls we have force_successful_syscall_return() broken -
it ends up with a3 *not* set to 0.

5) on non-straced syscalls force_successful_syscall_return() handling is
suboptimal - it duplicates code from the normal syscall return path for
no good reason; instead of branching to the copy, it might branch to the
original just fine.

6) ret_from_fork could just as well go to ret_from_user - it's not going
to be hit when returning to kernel mode.

Patchset lives in git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs.git
#work.alpha; individual patches in followups.

             reply	other threads:[~2021-09-25  2:54 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-25  2:54 Al Viro [this message]
2021-09-25  2:55 ` [PATCH 1/6] alpha: fix TIF_NOTIFY_SIGNAL handling Al Viro
2021-09-25  2:55   ` [PATCH 2/6] alpha: _TIF_ALLWORK_MASK is unused Al Viro
2021-09-25  2:55   ` [PATCH 3/6] alpha: fix syscall entry in !AUDUT_SYSCALL case Al Viro
2021-09-25  2:55   ` [PATCH 4/6] alpha: fix handling of a3 on straced syscalls Al Viro
2021-09-25  2:55   ` [PATCH 5/6] alpha: syscall exit cleanup Al Viro
2021-09-25  2:55   ` [PATCH 6/6] alpha: ret_from_fork can go straight to ret_to_user Al Viro
2021-09-25  2:55   ` [PATCH 7/7] alpha: lazy FPU switching Al Viro
2021-09-25 19:07     ` Linus Torvalds
2021-09-25 20:43       ` Al Viro
2021-09-25 23:18         ` Linus Torvalds
2021-09-26  0:31           ` Al Viro
2021-10-30 20:46         ` Al Viro
2021-10-30 20:46           ` Al Viro
2021-10-30 21:25           ` Maciej W. Rozycki
2021-10-30 22:13             ` Al Viro
2021-09-26  9:08       ` John Paul Adrian Glaubitz
2021-09-25  2:59 ` [PATCHES] alpha asm glue cleanups and fixes Al Viro
2022-09-02  1:48 ` Al Viro
2022-09-02  1:50   ` [PATCH v2 1/7] alpha: fix TIF_NOTIFY_SIGNAL handling Al Viro
2022-09-02  1:50     ` [PATCH v2 2/7] alpha: _TIF_ALLWORK_MASK is unused Al Viro
2022-09-02  1:50     ` [PATCH v2 3/7] alpha: fix syscall entry in !AUDUT_SYSCALL case Al Viro
2022-09-02  1:50     ` [PATCH v2 4/7] alpha: fix handling of a3 on straced syscalls Al Viro
2022-09-02  1:50     ` [PATCH v2 5/7] alpha: syscall exit cleanup Al Viro
2022-09-02  1:50     ` [PATCH v2 6/7] alpha: ret_from_fork can go straight to ret_to_user Al Viro
2022-09-02  1:50     ` [PATCH v2 7/7] alpha: lazy FPU switching Al Viro
2022-09-02  4:24       ` Linus Torvalds
2022-09-02  5:07         ` Al Viro
2022-09-02  5:14           ` Al Viro

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