From: PrasannaKumar Muralidharan Subject: [PATCH] hw_random: Make explicit that max >= 32 always Date: Fri, 18 Nov 2016 23:00:10 +0530 Message-ID: <20161118173010.5448-1-prasannatsmkumar@gmail.com> Cc: PrasannaKumar Muralidharan To: mpm@selenic.com, herbert@gondor.apana.org.au, daniel.thompson@linaro.org, linux-crypto@vger.kernel.org Return-path: Received: from mail-pg0-f67.google.com ([74.125.83.67]:33802 "EHLO mail-pg0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752057AbcKRRaj (ORCPT ); Fri, 18 Nov 2016 12:30:39 -0500 Received: by mail-pg0-f67.google.com with SMTP id e9so20819927pgc.1 for ; Fri, 18 Nov 2016 09:30:39 -0800 (PST) Sender: linux-crypto-owner@vger.kernel.org List-ID: As hw_random core calls ->read with max > 32 or more, make it explicit. Also remove checks involving 'max' being less than 8. Signed-off-by: PrasannaKumar Muralidharan --- drivers/char/hw_random/msm-rng.c | 4 ---- drivers/char/hw_random/pic32-rng.c | 3 --- drivers/char/hw_random/pseries-rng.c | 5 ++--- include/linux/hw_random.h | 3 +-- 4 files changed, 3 insertions(+), 12 deletions(-) diff --git a/drivers/char/hw_random/msm-rng.c b/drivers/char/hw_random/msm-rng.c index 96fb986..841fee8 100644 --- a/drivers/char/hw_random/msm-rng.c +++ b/drivers/char/hw_random/msm-rng.c @@ -90,10 +90,6 @@ static int msm_rng_read(struct hwrng *hwrng, void *data, size_t max, bool wait) /* calculate max size bytes to transfer back to caller */ maxsize = min_t(size_t, MAX_HW_FIFO_SIZE, max); - /* no room for word data */ - if (maxsize < WORD_SZ) - return 0; - ret = clk_prepare_enable(rng->clk); if (ret) return ret; diff --git a/drivers/char/hw_random/pic32-rng.c b/drivers/char/hw_random/pic32-rng.c index 11dc9b7..9b5e68a 100644 --- a/drivers/char/hw_random/pic32-rng.c +++ b/drivers/char/hw_random/pic32-rng.c @@ -62,9 +62,6 @@ static int pic32_rng_read(struct hwrng *rng, void *buf, size_t max, u32 t; unsigned int timeout = RNG_TIMEOUT; - if (max < 8) - return 0; - do { t = readl(priv->base + RNGRCNT) & RCNT_MASK; if (t == 64) { diff --git a/drivers/char/hw_random/pseries-rng.c b/drivers/char/hw_random/pseries-rng.c index 63ce51d..d9f46b4 100644 --- a/drivers/char/hw_random/pseries-rng.c +++ b/drivers/char/hw_random/pseries-rng.c @@ -28,7 +28,6 @@ static int pseries_rng_read(struct hwrng *rng, void *data, size_t max, bool wait) { u64 buffer[PLPAR_HCALL_BUFSIZE]; - size_t size = max < 8 ? max : 8; int rc; rc = plpar_hcall(H_RANDOM, (unsigned long *)buffer); @@ -36,10 +35,10 @@ static int pseries_rng_read(struct hwrng *rng, void *data, size_t max, bool wait pr_err_ratelimited("H_RANDOM call failed %d\n", rc); return -EIO; } - memcpy(data, buffer, size); + memcpy(data, buffer, 8); /* The hypervisor interface returns 64 bits */ - return size; + return 8; } /** diff --git a/include/linux/hw_random.h b/include/linux/hw_random.h index 34a0dc1..bee0827 100644 --- a/include/linux/hw_random.h +++ b/include/linux/hw_random.h @@ -30,8 +30,7 @@ * Must not be NULL. *OBSOLETE* * @read: New API. drivers can fill up to max bytes of data * into the buffer. The buffer is aligned for any type - * and max is guaranteed to be >= to that alignment - * (either 4 or 8 depending on architecture). + * and max is a multiple of 4 and >= 32 bytes. * @priv: Private data, for use by the RNG driver. * @quality: Estimation of true entropy in RNG's bitstream * (per mill). -- 2.9.3