linux/arch/arm64
Dave Martin 0cff8e776f arm64/sve: Refactor user SVE trap maintenance for external use
In preparation for optimising the way KVM manages switching the
guest and host FPSIMD state, it is necessary to provide a means for
code outside arch/arm64/kernel/fpsimd.c to restore the user trap
configuration for SVE correctly for the current task.

Rather than requiring external code to duplicate the maintenance
explicitly, this patch moves the trap maintenenace to
fpsimd_bind_to_cpu(), since it is logically part of the work of
associating the current task with the cpu.

Because fpsimd_bind_to_cpu() is rather a cryptic name to publish
alongside fpsimd_bind_state_to_cpu(), the former function is
renamed to fpsimd_bind_task_to_cpu() to make its purpose more
explicit.

This patch makes appropriate changes to ensure that
fpsimd_bind_task_to_cpu() is always called alongside
task_fpsimd_load(), so that the trap maintenance continues to be
done in every situation where it was done prior to this patch.

As a side-effect, the metadata updates done by
fpsimd_bind_task_to_cpu() now change from conditional to
unconditional in the "already bound" case of sigreturn.  This is
harmless, and a couple of extra stores on this slow path will not
impact performance.  I consider this a reasonable price to pay for
a slightly cleaner interface.

Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2018-05-25 12:27:56 +01:00
..
boot This pull request contains Broadcom ARM64-based SoCs Device Tree fixes 2018-04-27 10:21:18 +02:00
configs arm64: defconfig: add CONFIG_UNIPHIER_THERMAL and CONFIG_SNI_AVE 2018-03-27 15:31:19 +02:00
crypto kbuild: mark $(targets) as .SECONDARY and remove .PRECIOUS markers 2018-04-07 19:04:02 +09:00
include arm64: fpsimd: Eliminate task->mm checks 2018-05-25 12:27:55 +01:00
kernel arm64/sve: Refactor user SVE trap maintenance for external use 2018-05-25 12:27:56 +01:00
kvm KVM: arm64: Convert lazy FPSIMD context switch trap to C 2018-05-25 12:27:54 +01:00
lib arm64: avoid instrumenting atomic_ll_sc.o 2018-04-27 12:14:44 +01:00
mm arm64: mm: drop addr parameter from sync icache and dcache 2018-04-24 09:23:00 +01:00
net bpf, arm64: fix out of bounds access in tail call 2018-02-22 16:06:28 -08:00
xen arm64: mm: Add additional parameter to uaccess_ttbr0_disable 2018-01-17 13:57:49 +01:00
Kconfig ARM: 2018-04-09 11:42:31 -07:00
Kconfig.debug arm64: relocation testing module 2017-04-04 17:03:32 +01:00
Kconfig.platforms arm64: add Renesas R8A77965 support 2018-03-13 19:05:58 +01:00
Makefile arm64: support __int128 with clang 2018-04-24 19:07:55 +01:00