| Message ID | 20190613161656.20765-7-julien.grall@arm.com (mailing list archive) |
|---|---|
| State | RFC |
| Headers | show |
| Series | arm64/sve: First steps towards optimizing syscalls | expand |
On Thu, Jun 13, 2019 at 05:16:54PM +0100, Julien Grall wrote: > In a follow-up patch, we may save the FPSIMD rather than the full SVE > state when the state has to be zeroed on return to userspace (e.g > during a syscall). > > Introduce an helper to load SVE vectors from FPSIMD state and zero the rest > of SVE registers. > > Signed-off-by: Julien Grall <julien.grall@arm.com> > --- > arch/arm64/include/asm/fpsimd.h | 3 +++ > arch/arm64/kernel/entry-fpsimd.S | 17 +++++++++++++++++ > 2 files changed, 20 insertions(+) > > diff --git a/arch/arm64/include/asm/fpsimd.h b/arch/arm64/include/asm/fpsimd.h > index fda3544c9606..f07a88552588 100644 > --- a/arch/arm64/include/asm/fpsimd.h > +++ b/arch/arm64/include/asm/fpsimd.h > @@ -86,6 +86,9 @@ extern void sve_load_state(void const *state, u32 const *pfpsr, > > extern void sve_flush_live(void); > > +extern void sve_load_from_fpsimd_state(struct user_fpsimd_state const *state, > + unsigned long vq_minus_1); > + Lose the extra blank line? > extern unsigned int sve_get_vl(void); > > struct arm64_cpu_capabilities; > diff --git a/arch/arm64/kernel/entry-fpsimd.S b/arch/arm64/kernel/entry-fpsimd.S > index 17121a51c41f..35c21a707730 100644 > --- a/arch/arm64/kernel/entry-fpsimd.S > +++ b/arch/arm64/kernel/entry-fpsimd.S > @@ -58,6 +58,23 @@ ENTRY(sve_get_vl) > ret > ENDPROC(sve_get_vl) > > +/* > + * Load SVE state from FPSIMD state. > + * > + * x0 = pointer to struct fpsimd_state > + * x1 = VQ - 1 > + * > + * Each SVE vector will be loaded with the first 128-bits taken from FPSIMD > + * and the rest zeroed. All the other SVE registers will be zeroed. > + */ > +ENTRY(sve_load_from_fpsimd_state) > + sve_load_vq x1, x2, x3 > + fpsimd_restore x0, 8 > + _for n, 0, 15, _sve_pfalse \n > + _sve_wrffr 0 > + ret > +ENDPROC(sve_load_from_fpsimd_state) > + > /* Zero all SVE registers but the first 128-bits of each vector */ > ENTRY(sve_flush_live) > sve_flush With the extra blank line in fpsimd.h gone (if you agree): Reviewed-by: Dave Martin <Dave.Martin@arm.com>
Hi Dave, On 6/21/19 4:33 PM, Dave Martin wrote: > On Thu, Jun 13, 2019 at 05:16:54PM +0100, Julien Grall wrote: >> In a follow-up patch, we may save the FPSIMD rather than the full SVE >> state when the state has to be zeroed on return to userspace (e.g >> during a syscall). >> >> Introduce an helper to load SVE vectors from FPSIMD state and zero the rest >> of SVE registers. >> >> Signed-off-by: Julien Grall <julien.grall@arm.com> >> --- >> arch/arm64/include/asm/fpsimd.h | 3 +++ >> arch/arm64/kernel/entry-fpsimd.S | 17 +++++++++++++++++ >> 2 files changed, 20 insertions(+) >> >> diff --git a/arch/arm64/include/asm/fpsimd.h b/arch/arm64/include/asm/fpsimd.h >> index fda3544c9606..f07a88552588 100644 >> --- a/arch/arm64/include/asm/fpsimd.h >> +++ b/arch/arm64/include/asm/fpsimd.h >> @@ -86,6 +86,9 @@ extern void sve_load_state(void const *state, u32 const *pfpsr, >> >> extern void sve_flush_live(void); >> >> +extern void sve_load_from_fpsimd_state(struct user_fpsimd_state const *state, >> + unsigned long vq_minus_1); >> + > > Lose the extra blank line? > >> extern unsigned int sve_get_vl(void); >> >> struct arm64_cpu_capabilities; >> diff --git a/arch/arm64/kernel/entry-fpsimd.S b/arch/arm64/kernel/entry-fpsimd.S >> index 17121a51c41f..35c21a707730 100644 >> --- a/arch/arm64/kernel/entry-fpsimd.S >> +++ b/arch/arm64/kernel/entry-fpsimd.S >> @@ -58,6 +58,23 @@ ENTRY(sve_get_vl) >> ret >> ENDPROC(sve_get_vl) >> >> +/* >> + * Load SVE state from FPSIMD state. >> + * >> + * x0 = pointer to struct fpsimd_state >> + * x1 = VQ - 1 >> + * >> + * Each SVE vector will be loaded with the first 128-bits taken from FPSIMD >> + * and the rest zeroed. All the other SVE registers will be zeroed. >> + */ >> +ENTRY(sve_load_from_fpsimd_state) >> + sve_load_vq x1, x2, x3 >> + fpsimd_restore x0, 8 >> + _for n, 0, 15, _sve_pfalse \n >> + _sve_wrffr 0 >> + ret >> +ENDPROC(sve_load_from_fpsimd_state) >> + >> /* Zero all SVE registers but the first 128-bits of each vector */ >> ENTRY(sve_flush_live) >> sve_flush > > With the extra blank line in fpsimd.h gone (if you agree): I don't particularly care of the newline :). > > Reviewed-by: Dave Martin <Dave.Martin@arm.com> > Thank you! Cheers,
diff --git a/arch/arm64/include/asm/fpsimd.h b/arch/arm64/include/asm/fpsimd.h index fda3544c9606..f07a88552588 100644 --- a/arch/arm64/include/asm/fpsimd.h +++ b/arch/arm64/include/asm/fpsimd.h @@ -86,6 +86,9 @@ extern void sve_load_state(void const *state, u32 const *pfpsr, extern void sve_flush_live(void); +extern void sve_load_from_fpsimd_state(struct user_fpsimd_state const *state, + unsigned long vq_minus_1); + extern unsigned int sve_get_vl(void); struct arm64_cpu_capabilities; diff --git a/arch/arm64/kernel/entry-fpsimd.S b/arch/arm64/kernel/entry-fpsimd.S index 17121a51c41f..35c21a707730 100644 --- a/arch/arm64/kernel/entry-fpsimd.S +++ b/arch/arm64/kernel/entry-fpsimd.S @@ -58,6 +58,23 @@ ENTRY(sve_get_vl) ret ENDPROC(sve_get_vl) +/* + * Load SVE state from FPSIMD state. + * + * x0 = pointer to struct fpsimd_state + * x1 = VQ - 1 + * + * Each SVE vector will be loaded with the first 128-bits taken from FPSIMD + * and the rest zeroed. All the other SVE registers will be zeroed. + */ +ENTRY(sve_load_from_fpsimd_state) + sve_load_vq x1, x2, x3 + fpsimd_restore x0, 8 + _for n, 0, 15, _sve_pfalse \n + _sve_wrffr 0 + ret +ENDPROC(sve_load_from_fpsimd_state) + /* Zero all SVE registers but the first 128-bits of each vector */ ENTRY(sve_flush_live) sve_flush
In a follow-up patch, we may save the FPSIMD rather than the full SVE state when the state has to be zeroed on return to userspace (e.g during a syscall). Introduce an helper to load SVE vectors from FPSIMD state and zero the rest of SVE registers. Signed-off-by: Julien Grall <julien.grall@arm.com> --- arch/arm64/include/asm/fpsimd.h | 3 +++ arch/arm64/kernel/entry-fpsimd.S | 17 +++++++++++++++++ 2 files changed, 20 insertions(+)