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@xxxxxxx>
> Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
> Cc: Dave Martin <dave.martin@xxxxxxx>
> Cc: Will Deacon <will.deacon@xxxxxxx>
Reviewed-by: Dave Martin <Dave.Martin@xxxxxxx>
> ---
> arch/arm64/include/asm/fpsimd.h | 17 ++++++++++++++++-
> arch/arm64/kernel/fpsimd.c | 10 ----------
> 2 files changed, 16 insertions(+), 11 deletions(-)
>
> diff --git a/arch/arm64/include/asm/fpsimd.h b/arch/arm64/include/asm/fpsimd.h
> index fa92747a49c8..dd1ad3950ef5 100644
> --- a/arch/arm64/include/asm/fpsimd.h
> +++ b/arch/arm64/include/asm/fpsimd.h
> @@ -16,13 +16,15 @@
> #ifndef __ASM_FP_H
> #define __ASM_FP_H
>
> -#include <asm/ptrace.h>
> #include <asm/errno.h>
> +#include <asm/ptrace.h>
> #include <asm/processor.h>
> #include <asm/sigcontext.h>
> +#include <asm/sysreg.h>
>
> #ifndef __ASSEMBLY__
>
> +#include <linux/build_bug.h>
> #include <linux/cache.h>
> #include <linux/init.h>
> #include <linux/stddef.h>
> @@ -102,6 +104,16 @@ extern int sve_set_vector_length(struct task_struct *task,
> extern int sve_set_current_vl(unsigned long arg);
> extern int sve_get_current_vl(void);
>
> +static inline void sve_user_disable(void)
> +{
> + sysreg_clear_set(cpacr_el1, CPACR_EL1_ZEN_EL0EN, 0);
> +}
> +
> +static inline void sve_user_enable(void)
> +{
> + sysreg_clear_set(cpacr_el1, 0, CPACR_EL1_ZEN_EL0EN);
> +}
> +
> /*
> * Probing and setup functions.
> * Calls to these functions must be serialised with one another.
> @@ -128,6 +140,9 @@ static inline int sve_get_current_vl(void)
> return -EINVAL;
> }
>
> +static inline void sve_user_disable(void) { BUILD_BUG(); }
> +static inline void sve_user_enable(void) { BUILD_BUG(); }
> +
> static inline void sve_init_vq_map(void) { }
> static inline void sve_update_vq_map(void) { }
> static inline int sve_verify_vq_map(void) { return 0; }
> diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c
> index a98a7f96aff1..58c53bc96928 100644
> --- a/arch/arm64/kernel/fpsimd.c
> +++ b/arch/arm64/kernel/fpsimd.c
> @@ -159,16 +159,6 @@ static void sve_free(struct task_struct *task)
> __sve_free(task);
> }
>
> -static void sve_user_disable(void)
> -{
> - sysreg_clear_set(cpacr_el1, CPACR_EL1_ZEN_EL0EN, 0);
> -}
> -
> -static void sve_user_enable(void)
> -{
> - sysreg_clear_set(cpacr_el1, 0, CPACR_EL1_ZEN_EL0EN);
> -}
> -
> /*
> * TIF_SVE controls whether a task can use SVE without trapping while
> * in userspace, and also the way a task's FPSIMD/SVE state is stored
> --
> 2.11.0
>
>
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