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 <[email protected]>
Signed-off-by: Robert Elliott <[email protected]>
---
v3 use while loop, static int
---
arch/x86/crypto/sm3_avx_glue.c | 35 ++++++++++++++++++++++++++++------
1 file changed, 29 insertions(+), 6 deletions(-)
diff --git a/arch/x86/crypto/sm3_avx_glue.c b/arch/x86/crypto/sm3_avx_glue.c
index 661b6f22ffcd..483aaed996ba 100644
--- a/arch/x86/crypto/sm3_avx_glue.c
+++ b/arch/x86/crypto/sm3_avx_glue.c
@@ -17,6 +17,9 @@
#include <crypto/sm3_base.h>
#include <asm/simd.h>
+/* avoid kernel_fpu_begin/end scheduler/rcu stalls */
+static const unsigned int bytes_per_fpu = 11 * 1024;
+
asmlinkage void sm3_transform_avx(struct sm3_state *state,
const u8 *data, int nblocks);
@@ -25,8 +28,10 @@ static int sm3_avx_update(struct shash_desc *desc, const u8 *data,
{
struct sm3_state *sctx = shash_desc_ctx(desc);
+ BUILD_BUG_ON(bytes_per_fpu == 0);
+
if (!crypto_simd_usable() ||
- (sctx->count % SM3_BLOCK_SIZE) + len < SM3_BLOCK_SIZE) {
+ (sctx->count % SM3_BLOCK_SIZE) + len < SM3_BLOCK_SIZE) {
sm3_update(sctx, data, len);
return 0;
}
@@ -37,9 +42,16 @@ 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();
+ while (len) {
+ unsigned int chunk = min(len, bytes_per_fpu);
+
+ kernel_fpu_begin();
+ sm3_base_do_update(desc, data, chunk, sm3_transform_avx);
+ kernel_fpu_end();
+
+ len -= chunk;
+ data += chunk;
+ }
return 0;
}
@@ -47,6 +59,8 @@ static int sm3_avx_update(struct shash_desc *desc, const u8 *data,
static int sm3_avx_finup(struct shash_desc *desc, const u8 *data,
unsigned int len, u8 *out)
{
+ BUILD_BUG_ON(bytes_per_fpu == 0);
+
if (!crypto_simd_usable()) {
struct sm3_state *sctx = shash_desc_ctx(desc);
@@ -57,9 +71,18 @@ static int sm3_avx_finup(struct shash_desc *desc, const u8 *data,
return 0;
}
+ while (len) {
+ unsigned int chunk = min(len, bytes_per_fpu);
+
+ kernel_fpu_begin();
+ sm3_base_do_update(desc, data, chunk, sm3_transform_avx);
+ kernel_fpu_end();
+
+ len -= chunk;
+ data += chunk;
+ }
+
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