From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>,
Florian Fainelli <f.fainelli@gmail.com>,
Herbert Xu <herbert@gondor.apana.org.au>,
Sasha Levin <sashal@kernel.org>,
olivia@selenic.com, rjui@broadcom.com, sbranden@broadcom.com,
linux-crypto@vger.kernel.org,
linux-rpi-kernel@lists.infradead.org,
linux-arm-kernel@lists.infradead.org
Subject: [PATCH AUTOSEL 5.10 10/14] hwrng: bcm2835 - use hwrng_msleep() instead of cpu_relax()
Date: Tue, 1 Nov 2022 07:30:06 -0400 [thread overview]
Message-ID: <20221101113012.800271-10-sashal@kernel.org> (raw)
In-Reply-To: <20221101113012.800271-1-sashal@kernel.org>
From: "Jason A. Donenfeld" <Jason@zx2c4.com>
[ Upstream commit 96cb9d0554457086664d3bd10630b11193d863f1 ]
Rather than busy looping, yield back to the scheduler and sleep for a
bit in the event that there's no data. This should hopefully prevent the
stalls that Mark reported:
<6>[ 3.362859] Freeing initrd memory: 16196K
<3>[ 23.160131] rcu: INFO: rcu_sched self-detected stall on CPU
<3>[ 23.166057] rcu: 0-....: (2099 ticks this GP) idle=03b4/1/0x40000002 softirq=28/28 fqs=1050
<4>[ 23.174895] (t=2101 jiffies g=-1147 q=2353 ncpus=4)
<4>[ 23.180203] CPU: 0 PID: 49 Comm: hwrng Not tainted 6.0.0 #1
<4>[ 23.186125] Hardware name: BCM2835
<4>[ 23.189837] PC is at bcm2835_rng_read+0x30/0x6c
<4>[ 23.194709] LR is at hwrng_fillfn+0x71/0xf4
<4>[ 23.199218] pc : [<c07ccdc8>] lr : [<c07cb841>] psr: 40000033
<4>[ 23.205840] sp : f093df70 ip : 00000000 fp : 00000000
<4>[ 23.211404] r10: c3c7e800 r9 : 00000000 r8 : c17e6b20
<4>[ 23.216968] r7 : c17e6b64 r6 : c18b0a74 r5 : c07ccd99 r4 : c3f171c0
<4>[ 23.223855] r3 : 000fffff r2 : 00000040 r1 : c3c7e800 r0 : c3f171c0
<4>[ 23.230743] Flags: nZcv IRQs on FIQs on Mode SVC_32 ISA Thumb Segment none
<4>[ 23.238426] Control: 50c5387d Table: 0020406a DAC: 00000051
<4>[ 23.244519] CPU: 0 PID: 49 Comm: hwrng Not tainted 6.0.0 #1
Link: https://lore.kernel.org/all/Y0QJLauamRnCDUef@sirena.org.uk/
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/char/hw_random/bcm2835-rng.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/char/hw_random/bcm2835-rng.c b/drivers/char/hw_random/bcm2835-rng.c
index 1a7c43b43c6b..8e10a4d753f7 100644
--- a/drivers/char/hw_random/bcm2835-rng.c
+++ b/drivers/char/hw_random/bcm2835-rng.c
@@ -69,7 +69,7 @@ static int bcm2835_rng_read(struct hwrng *rng, void *buf, size_t max,
while ((rng_readl(priv, RNG_STATUS) >> 24) == 0) {
if (!wait)
return 0;
- cpu_relax();
+ hwrng_msleep(rng, 1000);
}
num_words = rng_readl(priv, RNG_STATUS) >> 24;
--
2.35.1
next prev parent reply other threads:[~2022-11-01 11:36 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-01 11:29 [PATCH AUTOSEL 5.10 01/14] media: rkisp1: Initialize color space on resizer sink and source pads Sasha Levin
2022-11-01 11:29 ` [PATCH AUTOSEL 5.10 02/14] media: rkisp1: Zero v4l2_subdev_format fields in when validating links Sasha Levin
2022-11-01 11:29 ` [PATCH AUTOSEL 5.10 03/14] media: s5p_cec: limit msg.len to CEC_MAX_MSG_SIZE Sasha Levin
2022-11-01 11:30 ` [PATCH AUTOSEL 5.10 04/14] media: cros-ec-cec: " Sasha Levin
2022-11-01 11:30 ` [PATCH AUTOSEL 5.10 05/14] media: dvb-frontends/drxk: initialize err to 0 Sasha Levin
2022-11-01 11:30 ` [PATCH AUTOSEL 5.10 06/14] media: meson: vdec: fix possible refcount leak in vdec_probe() Sasha Levin
2022-11-01 11:30 ` [PATCH AUTOSEL 5.10 07/14] media: atomisp: Ensure that USERPTR pointers are page aligned Sasha Levin
2022-11-01 11:30 ` [PATCH AUTOSEL 5.10 08/14] media: atomisp: Fix v4l2_fh resource leak on open errors Sasha Levin
2022-11-01 11:30 ` [PATCH AUTOSEL 5.10 09/14] ACPI: APEI: Fix integer overflow in ghes_estatus_pool_init() Sasha Levin
2022-11-01 11:30 ` Sasha Levin [this message]
2022-11-01 11:30 ` [PATCH AUTOSEL 5.10 11/14] scsi: core: Restrict legal sdev_state transitions via sysfs Sasha Levin
2022-11-01 11:30 ` [PATCH AUTOSEL 5.10 12/14] HID: saitek: add madcatz variant of MMO7 mouse device ID Sasha Levin
2022-11-01 11:30 ` [PATCH AUTOSEL 5.10 13/14] drm/amdgpu: set vm_update_mode=0 as default for Sienna Cichlid in SRIOV case Sasha Levin
2022-11-01 11:30 ` [PATCH AUTOSEL 5.10 14/14] i2c: xiic: Add platform module alias Sasha Levin
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20221101113012.800271-10-sashal@kernel.org \
--to=sashal@kernel.org \
--cc=Jason@zx2c4.com \
--cc=f.fainelli@gmail.com \
--cc=herbert@gondor.apana.org.au \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-crypto@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-rpi-kernel@lists.infradead.org \
--cc=olivia@selenic.com \
--cc=rjui@broadcom.com \
--cc=sbranden@broadcom.com \
--cc=stable@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox