linux-kernel - [PATCH v7 1/3] phy: mediatek: remove temporary variable @mask

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-next>] [day] [month] [year] [list]

Message-ID: <20230118084343.26913-1-chunfeng.yun@mediatek.com>
Date:   Wed, 18 Jan 2023 16:43:41 +0800
From:   Chunfeng Yun <chunfeng.yun@...iatek.com>
To:     Vinod Koul <vkoul@...nel.org>
CC:     Chunfeng Yun <chunfeng.yun@...iatek.com>,
        Kishon Vijay Abraham I <kishon@...nel.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Nathan Chancellor <nathan@...nel.org>,
        Nick Desaulniers <ndesaulniers@...gle.com>,
        Tom Rix <trix@...hat.com>,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-mediatek@...ts.infradead.org>,
        <linux-phy@...ts.infradead.org>, <linux-kernel@...r.kernel.org>,
        <llvm@...ts.linux.dev>, Eddie Hung <eddie.hung@...iatek.com>,
        kernel test robot <lkp@...el.com>
Subject: [PATCH v7 1/3] phy: mediatek: remove temporary variable @mask_

Remove the temporary @mask_, this may cause build warning when use clang
compiler for powerpc, but can't reproduce it when compile for arm64.
the build warning is caused by:

"warning: result of comparison of constant 18446744073709551615 with
expression of type (aka 'unsigned long') is always false
[-Wtautological-constant-out-of-range-compare]"

More information provided in below lore link.

After removing @mask_, there is a "CHECK:MACRO_ARG_REUSE" when run
checkpatch.pl, but due to @mask is constant, no reuse problem will happen.

Link: https://lore.kernel.org/lkml/202212160357.jJuesD8n-lkp@intel.com/t/
Fixes: 84513eccd678 ("phy: mediatek: fix build warning of FIELD_PREP()")
Reported-by: kernel test robot <lkp@...el.com>
Signed-off-by: Chunfeng Yun <chunfeng.yun@...iatek.com>
---
v7: modify title suggested by Vinod,
    modify commit message and add link tag suggested by Nick

v6: modify the title
v5: no changes
v4 new patch, I'm not sure it can fix build warning, due to I don't cross compile
    it for powerpc using clang in office.
---
 drivers/phy/mediatek/phy-mtk-io.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/phy/mediatek/phy-mtk-io.h b/drivers/phy/mediatek/phy-mtk-io.h
index d20ad5e5be81..58f06db822cb 100644
--- a/drivers/phy/mediatek/phy-mtk-io.h
+++ b/drivers/phy/mediatek/phy-mtk-io.h
@@ -39,8 +39,8 @@ static inline void mtk_phy_update_bits(void __iomem *reg, u32 mask, u32 val)
 /* field @mask shall be constant and continuous */
 #define mtk_phy_update_field(reg, mask, val) \
 ({ \
-	typeof(mask) mask_ = (mask);	\
-	mtk_phy_update_bits(reg, mask_, FIELD_PREP(mask_, val)); \
+	BUILD_BUG_ON_MSG(!__builtin_constant_p(mask), "mask is not constant"); \
+	mtk_phy_update_bits(reg, mask, FIELD_PREP(mask, val)); \
 })
 
 #endif
-- 
2.18.0