54 lines
2.1 KiB
Diff
54 lines
2.1 KiB
Diff
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Will Deacon <will.deacon@arm.com>
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Date: Tue, 24 Oct 2017 11:22:47 +0100
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Subject: [PATCH] locking/barriers: Add implicit smp_read_barrier_depends() to
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READ_ONCE()
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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CVE-2017-5754
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[ Note, this is a Git cherry-pick of the following commit:
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76ebbe78f739 ("locking/barriers: Add implicit smp_read_barrier_depends() to READ_ONCE()")
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... for easier x86 PTI code testing and back-porting. ]
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In preparation for the removal of lockless_dereference(), which is the
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same as READ_ONCE() on all architectures other than Alpha, add an
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implicit smp_read_barrier_depends() to READ_ONCE() so that it can be
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used to head dependency chains on all architectures.
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Signed-off-by: Will Deacon <will.deacon@arm.com>
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Cc: Linus Torvalds <torvalds@linux-foundation.org>
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Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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Cc: Peter Zijlstra <peterz@infradead.org>
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Cc: Thomas Gleixner <tglx@linutronix.de>
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Link: http://lkml.kernel.org/r/1508840570-22169-3-git-send-email-will.deacon@arm.com
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Signed-off-by: Ingo Molnar <mingo@kernel.org>
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(cherry picked from commit c2bc66082e1048c7573d72e62f597bdc5ce13fea)
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Signed-off-by: Andy Whitcroft <apw@canonical.com>
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Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
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(cherry picked from commit 6ef3d843f8f1a8b72ca83d4b1d457c2896278ccd)
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Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
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---
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include/linux/compiler.h | 1 +
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1 file changed, 1 insertion(+)
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diff --git a/include/linux/compiler.h b/include/linux/compiler.h
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index 043b60de041e..8af8814ebe7a 100644
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--- a/include/linux/compiler.h
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+++ b/include/linux/compiler.h
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@@ -314,6 +314,7 @@ static __always_inline void __write_once_size(volatile void *p, void *res, int s
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__read_once_size(&(x), __u.__c, sizeof(x)); \
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else \
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__read_once_size_nocheck(&(x), __u.__c, sizeof(x)); \
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+ smp_read_barrier_depends(); /* Enforce dependency ordering from x */ \
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__u.__val; \
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})
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#define READ_ONCE(x) __READ_ONCE(x, 1)
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--
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2.14.2
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