linux-kernel-mentees.lists.linuxfoundation.org archive mirror
 help / color / mirror / Atom feed
From: shobhitkukreti at gmail.com (shobhitkukreti at gmail.com)
Subject: [Linux-kernel-mentees] [PATCH v2] video: atmel_lcdc: Fix Shifting signed 32 bit value by 31 bits problem
Date: Sat,  6 Jul 2019 11:28:31 -0700	[thread overview]
Message-ID: <1562437711-30079-1-git-send-email-shobhitkukreti@gmail.com> (raw)
In-Reply-To: <20190706174059.GA14822@t-1000>

From: Shobhit Kukreti <shobhitkukreti at gmail.com>

Fix ATMEL_LCDC_MEMOR and ATMEL_LCDC_MEMOR_LITTLE defines to use "U"
cast to avoid shifting signed 32 bit values by 31 bit problem. This
is not a problem for gcc built kernel.

However, this may be a problem since the header is part of public API
which could be included for builds using compilers which do not handle
this condition safely resulting in undefined behavior

Signed-off-by: Shobhit Kukreti <shobhitkukreti at gmail.com>
---
Changes in v2:
	Fixed spelling typo

 include/video/atmel_lcdc.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/video/atmel_lcdc.h b/include/video/atmel_lcdc.h
index 43e497c..ac96b4f 100644
--- a/include/video/atmel_lcdc.h
+++ b/include/video/atmel_lcdc.h
@@ -103,9 +103,9 @@ struct atmel_lcdfb_pdata {
 #define	ATMEL_LCDC_CLKMOD	(1 << 15)
 #define		ATMEL_LCDC_CLKMOD_ACTIVEDISPLAY	(0 << 15)
 #define		ATMEL_LCDC_CLKMOD_ALWAYSACTIVE	(1 << 15)
-#define	ATMEL_LCDC_MEMOR	(1 << 31)
+#define	ATMEL_LCDC_MEMOR	(1U << 31)
 #define		ATMEL_LCDC_MEMOR_BIG		(0 << 31)
-#define		ATMEL_LCDC_MEMOR_LITTLE		(1 << 31)
+#define		ATMEL_LCDC_MEMOR_LITTLE		(1U << 31)
 
 #define ATMEL_LCDC_TIM1		0x0808
 #define	ATMEL_LCDC_VFP		(0xffU <<  0)
-- 
2.7.4

WARNING: multiple messages have this Message-ID (diff)
From: shobhitkukreti at gmail.com (shobhitkukreti@gmail.com)
Subject: [Linux-kernel-mentees] [PATCH v2] video: atmel_lcdc: Fix Shifting signed 32 bit value by 31 bits problem
Date: Sat,  6 Jul 2019 11:28:31 -0700	[thread overview]
Message-ID: <1562437711-30079-1-git-send-email-shobhitkukreti@gmail.com> (raw)
Message-ID: <20190706182831.aziu6m03NhLc13EFmB3DHChcgM9yRVfBBCrALKGj-Dw@z> (raw)
In-Reply-To: <20190706174059.GA14822@t-1000>

From: Shobhit Kukreti <shobhitkukreti@gmail.com>

Fix ATMEL_LCDC_MEMOR and ATMEL_LCDC_MEMOR_LITTLE defines to use "U"
cast to avoid shifting signed 32 bit values by 31 bit problem. This
is not a problem for gcc built kernel.

However, this may be a problem since the header is part of public API
which could be included for builds using compilers which do not handle
this condition safely resulting in undefined behavior

Signed-off-by: Shobhit Kukreti <shobhitkukreti at gmail.com>
---
Changes in v2:
	Fixed spelling typo

 include/video/atmel_lcdc.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/video/atmel_lcdc.h b/include/video/atmel_lcdc.h
index 43e497c..ac96b4f 100644
--- a/include/video/atmel_lcdc.h
+++ b/include/video/atmel_lcdc.h
@@ -103,9 +103,9 @@ struct atmel_lcdfb_pdata {
 #define	ATMEL_LCDC_CLKMOD	(1 << 15)
 #define		ATMEL_LCDC_CLKMOD_ACTIVEDISPLAY	(0 << 15)
 #define		ATMEL_LCDC_CLKMOD_ALWAYSACTIVE	(1 << 15)
-#define	ATMEL_LCDC_MEMOR	(1 << 31)
+#define	ATMEL_LCDC_MEMOR	(1U << 31)
 #define		ATMEL_LCDC_MEMOR_BIG		(0 << 31)
-#define		ATMEL_LCDC_MEMOR_LITTLE		(1 << 31)
+#define		ATMEL_LCDC_MEMOR_LITTLE		(1U << 31)
 
 #define ATMEL_LCDC_TIM1		0x0808
 #define	ATMEL_LCDC_VFP		(0xffU <<  0)
-- 
2.7.4

  parent reply	other threads:[~2019-07-06 18:28 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-06 17:41 [Linux-kernel-mentees] [PATCH] video: atmel_lcdc: Fix Shifting signed 32 bit value by 31 bits problem shobhitkukreti
2019-07-06 17:41 ` Shobhit Kukreti
2019-07-06 18:28 ` shobhitkukreti [this message]
2019-07-06 18:28   ` [Linux-kernel-mentees] [PATCH v2] " shobhitkukreti
2019-07-15 11:33   ` b.zolnierkie
2019-07-15 11:33     ` Bartlomiej Zolnierkiewicz
2019-07-22  0:42     ` [Linux-kernel-mentees] [PATCH v3] " shobhitkukreti
2019-07-22  0:42       ` Shobhit Kukreti
2019-08-19 14:29       ` b.zolnierkie
2019-08-19 14:29         ` Bartlomiej Zolnierkiewicz
2020-01-08 13:08       ` Nicolas.Ferre

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=1562437711-30079-1-git-send-email-shobhitkukreti@gmail.com \
    --to=linux-kernel-mentees@lists.linux-foundation.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;
as well as URLs for NNTP newsgroup(s).