linux-kernel - [PATCH 6/6] pwm: Do stricter return value checking for .round_waveform

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID:  <dfb824ae37f99df068c752d48cbd163c044a74fb.1743844730.git.u.kleine-koenig@baylibre.com>
Date: Sat,  5 Apr 2025 11:27:17 +0200
From: Uwe Kleine-König <u.kleine-koenig@...libre.com>
To: linux-pwm@...r.kernel.org
Cc: linux-kernel@...r.kernel.org
Subject: [PATCH 6/6] pwm: Do stricter return value checking for .round_waveform_tohw()

The .round_waveform_tohw() is supposed to return 0 if the request could
be rounded down to match the hardware capabilities and return 1 if
rounding down wasn't possible.

Expand the PWM_DEBUG check to not only assert proper downrounding if 0
was returned but also check that it was actually rounded up when the
callback signalled uprounding.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@...libre.com>
---
 drivers/pwm/core.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index 0387bd838487..1a9d497f5cfe 100644
--- a/drivers/pwm/core.c
+++ b/drivers/pwm/core.c
@@ -270,10 +270,10 @@ int pwm_round_waveform_might_sleep(struct pwm_device *pwm, struct pwm_waveform *
 			wf_req.duty_length_ns, wf_req.period_length_ns, wf_req.duty_offset_ns, ret_tohw);
 
 	if (IS_ENABLED(CONFIG_PWM_DEBUG) &&
-	    ret_tohw == 0 && !pwm_check_rounding(&wf_req, wf))
-		dev_err(&chip->dev, "Wrong rounding: requested %llu/%llu [+%llu], result %llu/%llu [+%llu]\n",
+	    (ret_tohw == 0) != pwm_check_rounding(&wf_req, wf))
+		dev_err(&chip->dev, "Wrong rounding: requested %llu/%llu [+%llu], result %llu/%llu [+%llu], ret: %d\n",
 			wf_req.duty_length_ns, wf_req.period_length_ns, wf_req.duty_offset_ns,
-			wf->duty_length_ns, wf->period_length_ns, wf->duty_offset_ns);
+			wf->duty_length_ns, wf->period_length_ns, wf->duty_offset_ns, ret_tohw);
 
 	return ret_tohw;
 }
@@ -341,10 +341,10 @@ static int __pwm_set_waveform(struct pwm_device *pwm,
 		if (err)
 			return err;
 
-		if (IS_ENABLED(CONFIG_PWM_DEBUG) && ret_tohw == 0 && !pwm_check_rounding(wf, &wf_rounded))
-			dev_err(&chip->dev, "Wrong rounding: requested %llu/%llu [+%llu], result %llu/%llu [+%llu]\n",
+		if (IS_ENABLED(CONFIG_PWM_DEBUG) && (ret_tohw == 0) != pwm_check_rounding(wf, &wf_rounded))
+			dev_err(&chip->dev, "Wrong rounding: requested %llu/%llu [+%llu], result %llu/%llu [+%llu], ret: %d\n",
 				wf->duty_length_ns, wf->period_length_ns, wf->duty_offset_ns,
-				wf_rounded.duty_length_ns, wf_rounded.period_length_ns, wf_rounded.duty_offset_ns);
+				wf_rounded.duty_length_ns, wf_rounded.period_length_ns, wf_rounded.duty_offset_ns, ret_tohw);
 
 		if (exact && pwmwfcmp(wf, &wf_rounded)) {
 			dev_dbg(&chip->dev, "Requested no rounding, but %llu/%llu [+%llu] -> %llu/%llu [+%llu]\n",
-- 
2.47.2