As done by the ECB and CBC helpers in arch/x86/crypt/ecb_cbc_helpers.h,
limit the number of bytes processed between kernel_fpu_begin() and
kernel_fpu_end() calls.
Those functions call preempt_disable() and preempt_enable(), so
the CPU core is unavailable for scheduling while running, causing:
rcu: INFO: rcu_preempt detected expedited stalls on CPUs/tasks: ...
Fixes: 930ab34d906d ("crypto: x86/sm3 - add AVX assembly implementation")
Suggested-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Robert Elliott <elliott@xxxxxxx>
---
arch/x86/crypto/sm3_avx_glue.c | 29 ++++++++++++++++++++++++-----
1 file changed, 24 insertions(+), 5 deletions(-)
diff --git a/arch/x86/crypto/sm3_avx_glue.c b/arch/x86/crypto/sm3_avx_glue.c
index 661b6f22ffcd..ffb6d2f409ef 100644
--- a/arch/x86/crypto/sm3_avx_glue.c
+++ b/arch/x86/crypto/sm3_avx_glue.c
@@ -17,6 +17,8 @@
#include <crypto/sm3_base.h>
#include <asm/simd.h>
+#define FPU_BYTES 4096U /* avoid kernel_fpu_begin/end scheduler/rcu stalls */
+
asmlinkage void sm3_transform_avx(struct sm3_state *state,
const u8 *data, int nblocks);
@@ -37,9 +39,16 @@ static int sm3_avx_update(struct shash_desc *desc, const u8 *data,
*/
BUILD_BUG_ON(offsetof(struct sm3_state, state) != 0);
- kernel_fpu_begin();
- sm3_base_do_update(desc, data, len, sm3_transform_avx);
- kernel_fpu_end();
+ do {
+ unsigned int chunk = min(len, FPU_BYTES);
+
+ kernel_fpu_begin();
+ sm3_base_do_update(desc, data, chunk, sm3_transform_avx);
+ kernel_fpu_end();
+
+ len -= chunk;
+ data += chunk;
+ } while (len);
return 0;
}
@@ -57,9 +66,19 @@ static int sm3_avx_finup(struct shash_desc *desc, const u8 *data,
return 0;
}
+ do {
+ unsigned int chunk = min(len, FPU_BYTES);
+
+ if (chunk) {
+ kernel_fpu_begin();
+ sm3_base_do_update(desc, data, chunk, sm3_transform_avx);
+ kernel_fpu_end();
+ }
+
+ len -= chunk;
+ data += chunk;
+ } while (len);
kernel_fpu_begin();
- if (len)
- sm3_base_do_update(desc, data, len, sm3_transform_avx);
sm3_base_do_finalize(desc, sm3_transform_avx);
kernel_fpu_end();
--
2.37.3
