diff options
| author | Michael Ellerman <mpe@ellerman.id.au> | 2014-06-10 16:46:21 +1000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-07-06 18:59:11 -0700 |
| commit | feb6334d1c3b1678a6eaa5a6f93ba0cc6bd8d953 (patch) | |
| tree | 9b9e0dfce4a34987412b8adddb885ef15331ea44 | |
| parent | 8ae1bea30532b765c1fb340d6531bf1772de5ee2 (diff) | |
powerpc/perf: Ensure all EBB register state is cleared on fork()
commit 3df48c981d5a9610e02e9270b1bc4274fb536710 upstream.
In commit 330a1eb "Core EBB support for 64-bit book3s" I messed up
clear_task_ebb(). It clears some but not all of the task's Event Based
Branch (EBB) registers when we duplicate a task struct.
That allows a child task to observe the EBBHR & EBBRR of its parent,
which it should not be able to do.
Fix it by clearing EBBHR & EBBRR.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | arch/powerpc/include/asm/switch_to.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/switch_to.h b/arch/powerpc/include/asm/switch_to.h index 0e83e7d8c73f..b5fad8afe837 100644 --- a/arch/powerpc/include/asm/switch_to.h +++ b/arch/powerpc/include/asm/switch_to.h @@ -84,6 +84,8 @@ static inline void clear_task_ebb(struct task_struct *t) { #ifdef CONFIG_PPC_BOOK3S_64 /* EBB perf events are not inherited, so clear all EBB state. */ + t->thread.ebbrr = 0; + t->thread.ebbhr = 0; t->thread.bescr = 0; t->thread.mmcr2 = 0; t->thread.mmcr0 = 0; |