| Message ID | 20240930161051.3777828-6-kristina.martsenko@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | arm64: Use memory copy instructions in kernel routines | expand |
On Mon, Sep 30, 2024 at 05:10:51PM +0100, Kristina Martsenko wrote: > Similarly to what was done to the memcpy() routines, make copy_page() > and clear_page() also use the Armv8.8 FEAT_MOPS instructions. > > Note: For copy_page() this uses the CPY* instructions instead of CPYF* > as CPYF* doesn't allow src and dst to be equal. It's not clear if > copy_page() needs to allow equal src and dst but it has worked so far > with the current implementation and there is no documentation forbidding > it. When we get real hardware, if CPYF* is faster we should switch to these instructions. I wouldn't expect source and destination to be the same but we can add a check. > SYM_FUNC_START(__pi_copy_page) > +#ifdef CONFIG_AS_HAS_MOPS > + .arch_extension mops > +alternative_if_not ARM64_HAS_MOPS > + b .Lno_mops > +alternative_else_nop_endif Same comment as on the previous patch w.r.t. the branch.
diff --git a/arch/arm64/lib/clear_page.S b/arch/arm64/lib/clear_page.S index ebde40e7fa2b..bd6f7d5eb6eb 100644 --- a/arch/arm64/lib/clear_page.S +++ b/arch/arm64/lib/clear_page.S @@ -15,6 +15,19 @@ * x0 - dest */ SYM_FUNC_START(__pi_clear_page) +#ifdef CONFIG_AS_HAS_MOPS + .arch_extension mops +alternative_if_not ARM64_HAS_MOPS + b .Lno_mops +alternative_else_nop_endif + + mov x1, #PAGE_SIZE + setpn [x0]!, x1!, xzr + setmn [x0]!, x1!, xzr + seten [x0]!, x1!, xzr + ret +.Lno_mops: +#endif mrs x1, dczid_el0 tbnz x1, #4, 2f /* Branch if DC ZVA is prohibited */ and w1, w1, #0xf diff --git a/arch/arm64/lib/copy_page.S b/arch/arm64/lib/copy_page.S index 6a56d7cf309d..e6374e7e5511 100644 --- a/arch/arm64/lib/copy_page.S +++ b/arch/arm64/lib/copy_page.S @@ -18,6 +18,19 @@ * x1 - src */ SYM_FUNC_START(__pi_copy_page) +#ifdef CONFIG_AS_HAS_MOPS + .arch_extension mops +alternative_if_not ARM64_HAS_MOPS + b .Lno_mops +alternative_else_nop_endif + + mov x2, #PAGE_SIZE + cpypwn [x0]!, [x1]!, x2! + cpymwn [x0]!, [x1]!, x2! + cpyewn [x0]!, [x1]!, x2! + ret +.Lno_mops: +#endif ldp x2, x3, [x1] ldp x4, x5, [x1, #16] ldp x6, x7, [x1, #32]
Similarly to what was done to the memcpy() routines, make copy_page() and clear_page() also use the Armv8.8 FEAT_MOPS instructions. Note: For copy_page() this uses the CPY* instructions instead of CPYF* as CPYF* doesn't allow src and dst to be equal. It's not clear if copy_page() needs to allow equal src and dst but it has worked so far with the current implementation and there is no documentation forbidding it. Note, the unoptimized version of copy_page() in assembler.h is left as it is. Signed-off-by: Kristina Martsenko <kristina.martsenko@arm.com> --- arch/arm64/lib/clear_page.S | 13 +++++++++++++ arch/arm64/lib/copy_page.S | 13 +++++++++++++ 2 files changed, 26 insertions(+)