Avoid excessive scheduling delays under a preemptible kernel by
conditionally yielding the NEON after every block of input.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
---
arch/arm64/crypto/sha512-ce-core.S | 27 +++++++++++++++-----
1 file changed, 21 insertions(+), 6 deletions(-)
diff --git a/arch/arm64/crypto/sha512-ce-core.S b/arch/arm64/crypto/sha512-ce-core.S
index 7f3bca5c59a2..ce65e3abe4f2 100644
--- a/arch/arm64/crypto/sha512-ce-core.S
+++ b/arch/arm64/crypto/sha512-ce-core.S
@@ -107,17 +107,23 @@
*/
.text
ENTRY(sha512_ce_transform)
+ frame_push 3
+
+ mov x19, x0
+ mov x20, x1
+ mov x21, x2
+
/* load state */
- ld1 {v8.2d-v11.2d}, [x0]
+0: ld1 {v8.2d-v11.2d}, [x19]
/* load first 4 round constants */
adr_l x3, .Lsha512_rcon
ld1 {v20.2d-v23.2d}, [x3], #64
/* load input */
-0: ld1 {v12.2d-v15.2d}, [x1], #64
- ld1 {v16.2d-v19.2d}, [x1], #64
- sub w2, w2, #1
+1: ld1 {v12.2d-v15.2d}, [x20], #64
+ ld1 {v16.2d-v19.2d}, [x20], #64
+ sub w21, w21, #1
CPU_LE( rev64 v12.16b, v12.16b )
CPU_LE( rev64 v13.16b, v13.16b )
@@ -196,9 +202,18 @@ CPU_LE( rev64 v19.16b, v19.16b )
add v11.2d, v11.2d, v3.2d
/* handled all input blocks? */
- cbnz w2, 0b
+ cbz w21, 3f
+
+ if_will_cond_yield_neon
+ st1 {v8.2d-v11.2d}, [x19]
+ do_cond_yield_neon
+ b 0b
+ endif_yield_neon
+
+ b 1b
/* store new state */
-3: st1 {v8.2d-v11.2d}, [x0]
+3: st1 {v8.2d-v11.2d}, [x19]
+ frame_pop
ret
ENDPROC(sha512_ce_transform)
--
2.15.1
