Commit-ID:  3d44d51bd339766f0178f0cf2e8d048b4a4872aa
Gitweb:     http://git.kernel.org/tip/3d44d51bd339766f0178f0cf2e8d048b4a4872aa
Author:     Andy Lutomirski <[email protected]>
AuthorDate: Wed, 24 Feb 2016 12:18:49 -0800
Committer:  Ingo Molnar <[email protected]>
CommitDate: Thu, 25 Feb 2016 08:31:20 +0100

x86/entry/compat: Add missing CLAC to entry_INT80_32

This doesn't seem to fix a regression -- I don't think the CLAC was
ever there.

I double-checked in a debugger: entries through the int80 gate do
not automatically clear AC.

Stable maintainers: I can provide a backport to 4.3 and earlier if
needed.  This needs to be backported all the way to 3.10.

Reported-by: Brian Gerst <[email protected]>
Signed-off-by: Andy Lutomirski <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Denys Vlasenko <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: <[email protected]> # v3.10 and later
Fixes: 63bcff2a307b ("x86, smap: Add STAC and CLAC instructions to control user 
space access")
Link: 
http://lkml.kernel.org/r/b02b7e71ae54074be01fc171cbd4b72517055c0e.1456345086.git.l...@kernel.org
Signed-off-by: Ingo Molnar <[email protected]>
---
 arch/x86/entry/entry_64_compat.S | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/x86/entry/entry_64_compat.S b/arch/x86/entry/entry_64_compat.S
index ff1c6d6..3c990ee 100644
--- a/arch/x86/entry/entry_64_compat.S
+++ b/arch/x86/entry/entry_64_compat.S
@@ -261,6 +261,7 @@ ENTRY(entry_INT80_compat)
         * Interrupts are off on entry.
         */
        PARAVIRT_ADJUST_EXCEPTION_FRAME
+       ASM_CLAC                        /* Do this early to minimize exposure */
        SWAPGS
 
        /*

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