Avoid excessive scheduling delays under a preemptible kernel by
yielding the NEON every 8 blocks of input.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
---
arch/arm64/crypto/sha2-ce-core.S | 40 ++++++++++++++------
1 file changed, 29 insertions(+), 11 deletions(-)
diff --git a/arch/arm64/crypto/sha2-ce-core.S b/arch/arm64/crypto/sha2-ce-core.S
index 679c6c002f4f..d156b3ae967c 100644
--- a/arch/arm64/crypto/sha2-ce-core.S
+++ b/arch/arm64/crypto/sha2-ce-core.S
@@ -77,30 +77,39 @@
* int blocks)
*/
ENTRY(sha2_ce_transform)
+ stp x29, x30, [sp, #-48]!
+ mov x29, sp
+ stp x19, x20, [sp, #16]
+ str x21, [sp, #32]
+
+ mov x19, x0
+ mov x20, x1
+ mov x21, x2
+
/* load round constants */
- adr x8, .Lsha2_rcon
+0: adr x8, .Lsha2_rcon
ld1 { v0.4s- v3.4s}, [x8], #64
ld1 { v4.4s- v7.4s}, [x8], #64
ld1 { v8.4s-v11.4s}, [x8], #64
ld1 {v12.4s-v15.4s}, [x8]
/* load state */
- ld1 {dgav.4s, dgbv.4s}, [x0]
+ ld1 {dgav.4s, dgbv.4s}, [x19]
/* load sha256_ce_state::finalize */
ldr_l w4, sha256_ce_offsetof_finalize, x4
- ldr w4, [x0, x4]
+ ldr w4, [x19, x4]
/* load input */
-0: ld1 {v16.4s-v19.4s}, [x1], #64
- sub w2, w2, #1
+1: ld1 {v16.4s-v19.4s}, [x20], #64
+ sub w21, w21, #1
CPU_LE( rev32 v16.16b, v16.16b )
CPU_LE( rev32 v17.16b, v17.16b )
CPU_LE( rev32 v18.16b, v18.16b )
CPU_LE( rev32 v19.16b, v19.16b )
-1: add t0.4s, v16.4s, v0.4s
+2: add t0.4s, v16.4s, v0.4s
mov dg0v.16b, dgav.16b
mov dg1v.16b, dgbv.16b
@@ -129,16 +138,22 @@ CPU_LE( rev32 v19.16b, v19.16b )
add dgbv.4s, dgbv.4s, dg1v.4s
/* handled all input blocks? */
- cbnz w2, 0b
+ cbz w21, 3f
+
+ yield_neon_pre w21, 3, 1, 1b // yield every 8 blocks
+ st1 {dgav.4s, dgbv.4s}, [x19]
+ yield_neon_post 0b
+
+ b 1b
/*
* Final block: add padding and total bit count.
* Skip if the input size was not a round multiple of the block size,
* the padding is handled by the C code in that case.
*/
- cbz x4, 3f
+3: cbz x4, 4f
ldr_l w4, sha256_ce_offsetof_count, x4
- ldr x4, [x0, x4]
+ ldr x4, [x19, x4]
movi v17.2d, #0
mov x8, #0x80000000
movi v18.2d, #0
@@ -147,9 +162,12 @@ CPU_LE( rev32 v19.16b, v19.16b )
mov x4, #0
mov v19.d[0], xzr
mov v19.d[1], x7
- b 1b
+ b 2b
/* store new state */
-3: st1 {dgav.4s, dgbv.4s}, [x0]
+4: st1 {dgav.4s, dgbv.4s}, [x19]
+ ldp x19, x20, [sp, #16]
+ ldr x21, [sp, #32]
+ ldp x29, x30, [sp], #48
ret
ENDPROC(sha2_ce_transform)
--
2.11.0
