Linux kernel stable tree (mirror) https://git.radix-linux.su/kernel/linux.git/atom?h=linux-4.16.y 2013-07-08T21:08:51+00:00 2013-07-08T21:08:51+00:00 Ard Biesheuvel ard.biesheuvel@linaro.org 2013-05-16T09:41:48+00:00 urn:sha1:73c132c15da504789b924871e2491479a18e4f6a In order to safely support the use of NEON instructions in kernel mode, some precautions need to be taken: - the userland context that may be present in the registers (even if the NEON/VFP is currently disabled) must be stored under the correct task (which may not be 'current' in the UP case), - to avoid having to keep track of additional vfpstates for the kernel side, disallow the use of NEON in interrupt context and run with preemption disabled, - after use, re-enable preemption and re-enable the lazy restore machinery by disabling the NEON/VFP unit. This patch adds the functions kernel_neon_begin() and kernel_neon_end() which take care of the above. It also adds the Kconfig symbol KERNEL_MODE_NEON to enable it. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Acked-by: Nicolas Pitre <nico@linaro.org>