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| author | Ard Biesheuvel | 2013-05-16 11:41:48 +0200 |
|---|---|---|
| committer | Ard Biesheuvel | 2013-07-08 23:08:51 +0200 |
| commit | 73c132c15da504789b924871e2491479a18e4f6a (patch) | |
| tree | e5aab4cb0d9263419677a4aa9aea392ffad76053 /arch/arm/Kconfig | |
| parent | ARM: be strict about FP exceptions in kernel mode (diff) | |
| download | kernel-qcow2-linux-73c132c15da504789b924871e2491479a18e4f6a.tar.gz kernel-qcow2-linux-73c132c15da504789b924871e2491479a18e4f6a.tar.xz kernel-qcow2-linux-73c132c15da504789b924871e2491479a18e4f6a.zip | |
ARM: add support for kernel mode NEON
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>
Diffstat (limited to 'arch/arm/Kconfig')
| -rw-r--r-- | arch/arm/Kconfig | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 136f263ed47b..d6068b435151 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -2197,6 +2197,13 @@ config NEON Say Y to include support code for NEON, the ARMv7 Advanced SIMD Extension. +config KERNEL_MODE_NEON + bool "Support for NEON in kernel mode" + default n + depends on NEON + help + Say Y to include support for NEON in kernel mode. + endmenu menu "Userspace binary formats" |