powerpc/fsl: Flush the branch predictor at each kernel entry (64bit)
commit 10c5e83afd4a3f01712d97d3bb1ae34d5b74a185 upstream. In order to protect against speculation attacks on indirect branches, the branch predictor is flushed at kernel entry to protect for the following situations: - userspace process attacking another userspace process - userspace process attacking the kernel Basically when the privillege level change (i.e. the kernel is entered), the branch predictor state is flushed. Signed-off-by: NDiana Craciun <diana.craciun@nxp.com> Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au> Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
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