Commit-ID: 2e57ae0515124af45dd889bfbd4840fd40fcc07d
Gitweb: http://git.kernel.org/tip/2e57ae0515124af45dd889bfbd4840fd40fcc07d
Author: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
AuthorDate: Mon, 7 Nov 2011 16:33:41 -0800
Committer: Ingo Molnar <mingo@xxxxxxx>
CommitDate: Mon, 5 Dec 2011 12:17:29 +0100
x86: Default to vsyscall=emulate
This essentially reverts:
2b666859ec32: x86: Default to vsyscall=native for now
The ABI breakage should now be fixed by:
commit 48c4206f5b02f28c4c78a1f5b491d3772fb64fb9
Author: Andy Lutomirski <luto@xxxxxxx>
Date: Thu Oct 20 08:48:19 2011 -0700
x86-64: Set siginfo and context on vsyscall emulation faults
Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Cc: richard -rw- weinberger <richard.weinberger@xxxxxxxxx>
Cc: Adrian Bunk <bunk@xxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/93154af3b2b6d208906ae02d80d92cf60c6fa94f.1320712291.git.luto@xxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
---
Documentation/kernel-parameters.txt | 7 +++----
arch/x86/kernel/vsyscall_64.c | 2 +-
2 files changed, 4 insertions(+), 5 deletions(-)
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index a0c5c5f..ce7fc8b 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -2750,11 +2750,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
functions are at fixed addresses, they make nice
targets for exploits that can control RIP.
- emulate Vsyscalls turn into traps and are emulated
- reasonably safely.
+ emulate [default] Vsyscalls turn into traps and are
+ emulated reasonably safely.
- native [default] Vsyscalls are native syscall
- instructions.
+ native Vsyscalls are native syscall instructions.
This is a little bit faster than trapping
and makes a few dynamic recompilers work
better than they would in emulation mode.
diff --git a/arch/x86/kernel/vsyscall_64.c b/arch/x86/kernel/vsyscall_64.c
index 8084bec..b07ba93 100644
--- a/arch/x86/kernel/vsyscall_64.c
+++ b/arch/x86/kernel/vsyscall_64.c
@@ -57,7 +57,7 @@ DEFINE_VVAR(struct vsyscall_gtod_data, vsyscall_gtod_data) =
.lock = __SEQLOCK_UNLOCKED(__vsyscall_gtod_data.lock),
};
-static enum { EMULATE, NATIVE, NONE } vsyscall_mode = NATIVE;
+static enum { EMULATE, NATIVE, NONE } vsyscall_mode = EMULATE;
static int __init vsyscall_setup(char *str)
{
--
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