Thread (53 messages) 53 messages, 4 authors, 2018-06-20

[PATCHv3 06/19] arm64: move sve_user_{enable, disable} to <asm/fpsimd.h>

From: catalin.marinas@arm.com (Catalin Marinas)
Date: 2018-06-19 12:00:31
Also in: linux-fsdevel

On Mon, Jun 18, 2018 at 01:02:57PM +0100, Mark Rutland wrote:
In subsequent patches, we'll want to make use of sve_user_enable() and
sve_user_disable() outside of kernel/fpsimd.c. Let's move these to
<asm/fpsimd.h> where we can make use of them.

To avoid ifdeffery in sequences like:

if (system_supports_sve() && some_condition
	sve_user_disable();

... empty stubs are provided when support for SVE is not enabled. Note
that system_supports_sve() contains as IS_ENABLED(CONFIG_ARM64_SVE), so
the sve_user_disable() call should be optimized away entirely when
CONFIG_ARM64_SVE is not selected.

To ensure that this is the case, the stub definitions contain a
BUILD_BUG(), as we do for other stubs for which calls should always be
optimized away when the relevant config option is not selected.

At the same time, the include list of <asm/fpsimd.h> is sorted while
adding <asm/sysreg.h>.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Martin <dave.martin@arm.com>
Cc: Will Deacon <redacted>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
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