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From: Akira Tsukamoto <akira.tsukamoto@gmail.com>
To: Paul Walmsley <paul.walmsley@sifive.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Guenter Roeck <linux@roeck-us.net>,
	Geert Uytterhoeven <geert@linux-m68k.org>,
	Albert Ou <aou@eecs.berkeley.edu>,
	linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: [PATCH 2/4] riscv: __asm_copy_to-from_user: Fix: fail on RV32
Date: Tue, 20 Jul 2021 17:51:45 +0900	[thread overview]
Message-ID: <93a6ae3b-3271-5edb-0a1b-260ba789f3f1@gmail.com> (raw)
In-Reply-To: <37097718-c472-025a-2058-55667badc5b9@gmail.com>


Had a bug when converting bytes to bits when the cpu was rv32.

The a3 contains the number of bytes and multiple of 8
would be the bits. The LGREG is holding 2 for RV32 and 3 for
RV32, so to achieve multiple of 8 it must always be constant 3.
The 2 was mistakenly used for rv32.

Signed-off-by: Akira Tsukamoto <akira.tsukamoto@gmail.com>
---
 arch/riscv/lib/uaccess.S | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/riscv/lib/uaccess.S b/arch/riscv/lib/uaccess.S
index 8bbeca89a93f..279876821969 100644
--- a/arch/riscv/lib/uaccess.S
+++ b/arch/riscv/lib/uaccess.S
@@ -125,7 +125,7 @@ ENTRY(__asm_copy_from_user)
 	 * t3 - prev shift
 	 * t4 - current shift
 	 */
-	slli	t3, a3, LGREG
+	slli	t3, a3, 3 /* converting bytes in a3 to bits */
 	li	a5, SZREG*8
 	sub	t4, a5, t3
 
-- 
2.17.1



  parent reply	other threads:[~2021-07-20  8:57 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-20  8:49 [PATCH 0/4] __asm_copy_to-from_user: Fixes Akira Tsukamoto
2021-07-20  8:50 ` [PATCH 1/4] riscv: __asm_copy_to-from_user: Fix: overrun copy Akira Tsukamoto
2021-07-20  8:51 ` Akira Tsukamoto [this message]
2021-07-20  9:49   ` [PATCH 2/4] riscv: __asm_copy_to-from_user: Fix: fail on RV32 Geert Uytterhoeven
2021-07-20 10:18     ` Akira Tsukamoto
2021-07-20  8:52 ` [PATCH 3/4] riscv: __asm_copy_to-from_user: Remove unnecessary size check Akira Tsukamoto
2021-07-20  8:53 ` [PATCH 4/4] riscv: __asm_copy_to-from_user: Fix: Typos in comments Akira Tsukamoto
2021-07-20  9:31 ` [PATCH 0/4] __asm_copy_to-from_user: Fixes Geert Uytterhoeven
2021-07-20 14:19 ` Guenter Roeck
2021-07-24  0:58 ` Palmer Dabbelt

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