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authorAndi Kleen <ak@suse.de>2006-09-26 10:52:41 +0200
committerAndi Kleen <andi@basil.nowhere.org>2006-09-26 10:52:41 +0200
commit658fdbef66e5e9be79b457edc2cbbb3add840aa9 (patch)
tree931fa9bac154671ab96762fee73b3641b1191bb8 /arch/x86_64/kernel
parentadf1423698f00d00b267f7dca8231340ce7d65ef (diff)
[PATCH] Don't leak NT bit into next task
SYSENTER can cause a NT to be set which might cause crashes on the IRET in the next task. Following similar i386 patch from Linus. Signed-off-by: Andi Kleen <ak@suse.de>
Diffstat (limited to 'arch/x86_64/kernel')
-rw-r--r--arch/x86_64/kernel/entry.S4
-rw-r--r--arch/x86_64/kernel/setup64.c4
2 files changed, 8 insertions, 0 deletions
diff --git a/arch/x86_64/kernel/entry.S b/arch/x86_64/kernel/entry.S
index 4cbc65290ae..2802524104f 100644
--- a/arch/x86_64/kernel/entry.S
+++ b/arch/x86_64/kernel/entry.S
@@ -155,6 +155,10 @@
/* rdi: prev */
ENTRY(ret_from_fork)
CFI_DEFAULT_STACK
+ push kernel_eflags(%rip)
+ CFI_ADJUST_CFA_OFFSET 4
+ popf # reset kernel eflags
+ CFI_ADJUST_CFA_OFFSET -4
call schedule_tail
GET_THREAD_INFO(%rcx)
testl $(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT),threadinfo_flags(%rcx)
diff --git a/arch/x86_64/kernel/setup64.c b/arch/x86_64/kernel/setup64.c
index 9332d2361e0..8c4b80fe71a 100644
--- a/arch/x86_64/kernel/setup64.c
+++ b/arch/x86_64/kernel/setup64.c
@@ -180,6 +180,8 @@ void __cpuinit check_efer(void)
}
}
+unsigned long kernel_eflags;
+
/*
* cpu_init() initializes state that is per-CPU. Some data is already
* initialized (naturally) in the bootstrap process, such as the GDT
@@ -281,4 +283,6 @@ void __cpuinit cpu_init (void)
set_debugreg(0UL, 7);
fpu_init();
+
+ raw_local_save_flags(kernel_eflags);
}