| Message ID | 20200127165646.19806-7-andrew.smirnov@gmail.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | Herbert Xu |
| Headers | show |
| Series | enable CAAM's HWRNG as default | expand |
On 1/27/2020 6:57 PM, Andrey Smirnov wrote: > @@ -60,12 +65,12 @@ static struct caam_rng_ctx *to_caam_rng_ctx(struct hwrng *r) > static void caam_rng_done(struct device *jrdev, u32 *desc, u32 err, > void *context) > { > - struct completion *done = context; > + struct caam_rng_job_ctx *jctx = context; > > if (err) > - caam_jr_strstatus(jrdev, err); > + *jctx->err = caam_jr_strstatus(jrdev, err); > > - complete(done); > + complete(jctx->done); > } > > static u32 *caam_init_desc(u32 *desc, dma_addr_t dst_dma, int len) > @@ -89,6 +94,10 @@ static int caam_rng_read_one(struct device *jrdev, > { > dma_addr_t dst_dma; > int err; > + struct caam_rng_job_ctx jctx = { > + .done = done, > + .err = &err, > + }; > > len = min_t(int, len, CAAM_RNG_MAX_FIFO_STORE_SIZE); > > @@ -101,7 +110,7 @@ static int caam_rng_read_one(struct device *jrdev, > init_completion(done); > err = caam_jr_enqueue(jrdev, > caam_init_desc(desc, dst_dma, len), > - caam_rng_done, done); > + caam_rng_done, &jctx); AFAICT there's a race condition b/w caam_jr_enqueue() and caam_rng_done(), both writing to "err": caam_jr_enqueue() -> JR interrupt -> caam_jr_interrupt() -> tasklet_schedule()... -> spin_unlock_bh() -> caam_jr_dequeue() -> caam_rng_done() -> write err -> return 0 -> write err Horia
On Wed, Feb 12, 2020 at 2:41 AM Horia Geanta <horia.geanta@nxp.com> wrote: > > On 1/27/2020 6:57 PM, Andrey Smirnov wrote: > > @@ -60,12 +65,12 @@ static struct caam_rng_ctx *to_caam_rng_ctx(struct hwrng *r) > > static void caam_rng_done(struct device *jrdev, u32 *desc, u32 err, > > void *context) > > { > > - struct completion *done = context; > > + struct caam_rng_job_ctx *jctx = context; > > > > if (err) > > - caam_jr_strstatus(jrdev, err); > > + *jctx->err = caam_jr_strstatus(jrdev, err); > > > > - complete(done); > > + complete(jctx->done); > > } > > > > static u32 *caam_init_desc(u32 *desc, dma_addr_t dst_dma, int len) > > @@ -89,6 +94,10 @@ static int caam_rng_read_one(struct device *jrdev, > > { > > dma_addr_t dst_dma; > > int err; > > + struct caam_rng_job_ctx jctx = { > > + .done = done, > > + .err = &err, > > + }; > > > > len = min_t(int, len, CAAM_RNG_MAX_FIFO_STORE_SIZE); > > > > @@ -101,7 +110,7 @@ static int caam_rng_read_one(struct device *jrdev, > > init_completion(done); > > err = caam_jr_enqueue(jrdev, > > caam_init_desc(desc, dst_dma, len), > > - caam_rng_done, done); > > + caam_rng_done, &jctx); > AFAICT there's a race condition b/w caam_jr_enqueue() and caam_rng_done(), > both writing to "err": > caam_jr_enqueue() > -> JR interrupt -> caam_jr_interrupt() -> tasklet_schedule()... > -> spin_unlock_bh() > -> caam_jr_dequeue() -> caam_rng_done() -> write err > -> return 0 -> write err > Yes, I thought it didn't really matter for calling wait_for_completion(done), but now that I think on it again, it can return wrong result code from vcaam_rng_read_one(). Will fix in v8. Thanks, Andrey Smirnov
diff --git a/drivers/crypto/caam/caamrng.c b/drivers/crypto/caam/caamrng.c index cb498186b9b9..790624ae83c6 100644 --- a/drivers/crypto/caam/caamrng.c +++ b/drivers/crypto/caam/caamrng.c @@ -52,6 +52,11 @@ struct caam_rng_ctx { struct kfifo fifo; }; +struct caam_rng_job_ctx { + struct completion *done; + int *err; +}; + static struct caam_rng_ctx *to_caam_rng_ctx(struct hwrng *r) { return container_of(r, struct caam_rng_ctx, rng); @@ -60,12 +65,12 @@ static struct caam_rng_ctx *to_caam_rng_ctx(struct hwrng *r) static void caam_rng_done(struct device *jrdev, u32 *desc, u32 err, void *context) { - struct completion *done = context; + struct caam_rng_job_ctx *jctx = context; if (err) - caam_jr_strstatus(jrdev, err); + *jctx->err = caam_jr_strstatus(jrdev, err); - complete(done); + complete(jctx->done); } static u32 *caam_init_desc(u32 *desc, dma_addr_t dst_dma, int len) @@ -89,6 +94,10 @@ static int caam_rng_read_one(struct device *jrdev, { dma_addr_t dst_dma; int err; + struct caam_rng_job_ctx jctx = { + .done = done, + .err = &err, + }; len = min_t(int, len, CAAM_RNG_MAX_FIFO_STORE_SIZE); @@ -101,7 +110,7 @@ static int caam_rng_read_one(struct device *jrdev, init_completion(done); err = caam_jr_enqueue(jrdev, caam_init_desc(desc, dst_dma, len), - caam_rng_done, done); + caam_rng_done, &jctx); if (!err) wait_for_completion(done);
We shouldn't stay silent if RNG job fails. Add appropriate code to check for that case and propagate error code up appropriately. Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com> Cc: Chris Healy <cphealy@gmail.com> Cc: Lucas Stach <l.stach@pengutronix.de> Cc: Horia Geantă <horia.geanta@nxp.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Iuliana Prodan <iuliana.prodan@nxp.com> Cc: linux-crypto@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: linux-imx@nxp.com --- drivers/crypto/caam/caamrng.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-)