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[60.250.204.170]) by smtp.googlemail.com with ESMTPSA id 17sm50927847wma.3.2020.11.22.23.38.22 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Sun, 22 Nov 2020 23:38:25 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=sKnvipRdH5O5nwcZGT41u1DCEbXND0993nykFgKds7Y=; b=smrn5v9zKwc7LpQiiXvRkqe4V4Xyo+HcNnQfIYBjcjZxl8xKleGocb/Dw0+JucTxl0 gxQvqP/MpdMJlRV26CVCy/SJ2AcVpTLt99cqNxGb634lBSI0yaa06VsU0RIpc1PNV9B2 USJUf+z6LxdBBxOQEVYDTvkfQmRouuPJkvz5niDZI9/IAFuBvKhiyCJf7i3FlSXlHqMS +ekzryEGGiDuUjaltP2PZHoT6qlajd5DcBNhcsTILlV9wfjhUJiRbLYBZiXSSwqoYPPW /BnY6F2MeKVCVJlJEv7htF1Zbtqj9S23U2Z88XxTzAkbKxALjrAVhrxuVYEEwknCfApz 5+jw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=sKnvipRdH5O5nwcZGT41u1DCEbXND0993nykFgKds7Y=; b=rG8XV83NiAIL7PHIRz7veVTV5rJiEB4JTSFN2sHLWX0z9vn7Nn+h9IoOUFYq9dRhpX NvH/6PiJ5utdoLCP6gZ4p8mnxzl1ulYfXANqDFYBCNMJknoi9XZkMVyGP1ZJhWjz0yCW Kf9AsxpJLlo8ZOpNlQUqHcgQlruH568UhSiKbt9t6C3P65eR9M4DEhJBGPArq1QExNac rwI+xANTwAs6VqKnyQYB6NLdfwyj9aMpT1hMNLHuO85YwbM4QfU959cnbqrThztcsOtF fcJL/IjKqebLNJwIHsHychBNXMgfwVxLmEXEc0eNPK4okqcdITGgWQgxCfFEz+ahIi8I 8fAw== X-Gm-Message-State: AOAM533MOMPkF9IzFWAn42D4H2Eu7Lg1kdH///DDm3MYIXB8qEtoNXf8 MjwO/INBIXxyHt02fDlN0TE= X-Google-Smtp-Source: ABdhPJwtvwR4tEbGdt64452+NtS6ThnxMs/sNtsxvROMuyckjORrFOrYWPoMYP+r428ViukTUJSJ7w== X-Received: by 2002:a1c:3d05:: with SMTP id k5mr23507181wma.151.1606117106354; Sun, 22 Nov 2020 23:38:26 -0800 (PST) From: Antony Yu Cc: swpenim@gmail.com, Russell King , Nathan Chancellor , Nick Desaulniers , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com Subject: [RESEND,PATCH] ARM: fix __div64_32() error when compiling with clang Date: Mon, 23 Nov 2020 15:36:32 +0800 Message-Id: <20201123073634.6854-1-swpenim@gmail.com> X-Mailer: git-send-email 2.29.0 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable To: unlisted-recipients:; (no To-header on input) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-ZohoMail-DKIM: fail (Header signature does not verify) Content-Type: text/plain; charset="utf-8" __do_div64 clobbers the input register r0 in little endian system. According to the inline assembly document, if an input operand is modified, it should be tied to a output operand. This patch can prevent compilers from reusing r0 register after asm statements. Signed-off-by: Antony Yu --- arch/arm/include/asm/div64.h | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/arm/include/asm/div64.h b/arch/arm/include/asm/div64.h index 898e9c78a7e7..809efc51e90f 100644 --- a/arch/arm/include/asm/div64.h +++ b/arch/arm/include/asm/div64.h @@ -39,9 +39,10 @@ static inline uint32_t __div64_32(uint64_t *n, uint32_t = base) asm( __asmeq("%0", __xh) __asmeq("%1", "r2") __asmeq("%2", "r0") - __asmeq("%3", "r4") + __asmeq("%3", "r0") + __asmeq("%4", "r4") "bl __do_div64" - : "=3Dr" (__rem), "=3Dr" (__res) + : "=3Dr" (__rem), "=3Dr" (__res), "=3Dr" (__n) : "r" (__n), "r" (__base) : "ip", "lr", "cc"); *n =3D __res; --=20 2.23.0