From 658fdbef66e5e9be79b457edc2cbbb3add840aa9 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Tue, 26 Sep 2006 10:52:41 +0200 Subject: [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 --- arch/x86_64/kernel/entry.S | 4 ++++ arch/x86_64/kernel/setup64.c | 4 ++++ 2 files changed, 8 insertions(+) (limited to 'arch/x86_64/kernel') 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); } -- cgit v1.2.3