From nobody Wed Dec 17 19:16:28 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 63EC813D608 for ; Tue, 25 Jun 2024 04:19:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719289150; cv=none; b=MuoKAElP+la67R70ygaFUJhCDovuJPxnWfBZNI3q+pDI45TMIhnBI4iytTVxmd9k1IvWfy/Rcm5SQmOSYCl1EyJZxWbNnosGXPPLNwjZG7h9X1D2f9I5onQIfheJqgjF2vyEW8UCCUz01UiDYWtBdumGqPxxphHeMBqaGUQqNCc= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719289150; c=relaxed/simple; bh=ZzlEc7s3uYpxeTkZStcoK6OMbfxXl2VXk7KZNHt3OpE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=aBCfXnwbd+PENfHd63aOWcxbpohqAJPOdnpZ14bQ/6vaX7k0X9KkeiOQNAY8m+pRxN5FWuo8Cpg0K5M0BI+vBgJoR4pxN5trjK+vqKppKeBw2lhIGlxuhq34DSyry2pcVtuvm70yNHlij4B2ganIT8ZibCU7YVWA0t38kEUilzU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=AhGk98Mv; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="AhGk98Mv" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2927FC32782; Tue, 25 Jun 2024 04:19:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1719289149; bh=ZzlEc7s3uYpxeTkZStcoK6OMbfxXl2VXk7KZNHt3OpE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=AhGk98Mv6hs+xLaijlXJ/I4OLbsJW/jkS3axHL7EefamGHEOtW1ZtoJvCEg85A6XL ItftEQ4YK4kTtKWFpCYEXezDscYbWPD3IzrXXzr5tKOecVnYIBSK/ojBHSr+B2y7C4 NfeS1uaz7Ayl1voJExBvwc+qq9qNvjMpiTJ8oDytePSBOTK4a5EFOuwdrvWoZqqZhN JAkk4oz1BgQGcHR9zrfBIfqdrdAxPG8hJFdKN6nV42e8vOOKfEXjCIIlcUYIIpsK45 DGqRJScKzZV08XVnqphuA+74tE+WeSgl+r5K/FQmbw87cuDBK0FhEsifP3eKlUqCKL dpsr6/4206wgw== From: Jisheng Zhang To: Paul Walmsley , Palmer Dabbelt , Albert Ou Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH 3/4] riscv: uaccess: use 'asm goto' for put_user() Date: Tue, 25 Jun 2024 12:04:59 +0800 Message-ID: <20240625040500.1788-4-jszhang@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240625040500.1788-1-jszhang@kernel.org> References: <20240625040500.1788-1-jszhang@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" 'asm goto' generates noticeably better code since we don't need to test the error etc, the exception just jumps to the error handling directly. Signed-off-by: Jisheng Zhang --- arch/riscv/include/asm/uaccess.h | 68 +++++++++++++++----------------- 1 file changed, 32 insertions(+), 36 deletions(-) diff --git a/arch/riscv/include/asm/uaccess.h b/arch/riscv/include/asm/uacc= ess.h index 84b084e388a7..d8c44705b61d 100644 --- a/arch/riscv/include/asm/uaccess.h +++ b/arch/riscv/include/asm/uaccess.h @@ -181,61 +181,66 @@ do { \ ((x) =3D (__force __typeof__(x))0, -EFAULT); \ }) =20 -#define __put_user_asm(insn, x, ptr, err) \ +#define __put_user_asm(insn, x, ptr, label) \ do { \ __typeof__(*(ptr)) __x =3D x; \ - __asm__ __volatile__ ( \ + asm goto( \ "1:\n" \ - " " insn " %z1, %2\n" \ - "2:\n" \ - _ASM_EXTABLE_UACCESS_ERR(1b, 2b, %0) \ - : "+r" (err) \ - : "rJ" (__x), "m"(*(ptr))); \ + " " insn " %z0, %1\n" \ + _ASM_EXTABLE(1b, %l2) \ + : : "rJ" (__x), "m"(*(ptr)) : : label); \ } while (0) =20 #ifdef CONFIG_64BIT -#define __put_user_8(x, ptr, err) \ - __put_user_asm("sd", x, ptr, err) +#define __put_user_8(x, ptr, label) \ + __put_user_asm("sd", x, ptr, label) #else /* !CONFIG_64BIT */ -#define __put_user_8(x, ptr, err) \ +#define __put_user_8(x, ptr, label) \ do { \ u32 __user *__ptr =3D (u32 __user *)(ptr); \ u64 __x =3D (__typeof__((x)-(x)))(x); \ __asm__ __volatile__ ( \ "1:\n" \ - " sw %z1, %3\n" \ + " sw %z0, %2\n" \ "2:\n" \ - " sw %z2, %4\n" \ - "3:\n" \ - _ASM_EXTABLE_UACCESS_ERR(1b, 3b, %0) \ - _ASM_EXTABLE_UACCESS_ERR(2b, 3b, %0) \ - : "+r" (err) \ - : "rJ" (__x), "rJ" (__x >> 32), \ + " sw %z1, %3\n" \ + _ASM_EXTABLE(1b, %l4) \ + _ASM_EXTABLE(2b, %l4) \ + : : "rJ" (__x), "rJ" (__x >> 32), \ "m" (__ptr[__LSW]), \ - "m" (__ptr[__MSW])); \ + "m" (__ptr[__MSW]) : : label); \ } while (0) #endif /* CONFIG_64BIT */ =20 -#define __put_user_nocheck(x, __gu_ptr, __pu_err) \ +#define __put_user_nocheck(x, __gu_ptr, label) \ do { \ switch (sizeof(*__gu_ptr)) { \ case 1: \ - __put_user_asm("sb", (x), __gu_ptr, __pu_err); \ + __put_user_asm("sb", (x), __gu_ptr, label); \ break; \ case 2: \ - __put_user_asm("sh", (x), __gu_ptr, __pu_err); \ + __put_user_asm("sh", (x), __gu_ptr, label); \ break; \ case 4: \ - __put_user_asm("sw", (x), __gu_ptr, __pu_err); \ + __put_user_asm("sw", (x), __gu_ptr, label); \ break; \ case 8: \ - __put_user_8((x), __gu_ptr, __pu_err); \ + __put_user_8((x), __gu_ptr, label); \ break; \ default: \ BUILD_BUG(); \ } \ } while (0) =20 +#define __put_user_error(x, ptr, err) \ +do { \ + __label__ err_label; \ + __put_user_nocheck(x, ptr, err_label); \ + break; \ +err_label: \ + (err) =3D -EFAULT; \ +} while (0) + /** * __put_user: - Write a simple value into user space, with less checking. * @x: Value to copy to user space. @@ -266,7 +271,7 @@ do { \ __chk_user_ptr(__gu_ptr); \ \ __enable_user_access(); \ - __put_user_nocheck(__val, __gu_ptr, __pu_err); \ + __put_user_error(__val, __gu_ptr, __pu_err); \ __disable_user_access(); \ \ __pu_err; \ @@ -340,13 +345,7 @@ do { \ } while (0) =20 #define __put_kernel_nofault(dst, src, type, err_label) \ -do { \ - long __kr_err =3D 0; \ - \ - __put_user_nocheck(*((type *)(src)), (type *)(dst), __kr_err); \ - if (unlikely(__kr_err)) \ - goto err_label; \ -} while (0) + __put_user_nocheck(*((type *)(src)), (type *)(dst), err_label); =20 static __must_check __always_inline bool user_access_begin(const void __us= er *ptr, size_t len) { @@ -361,11 +360,8 @@ static __must_check __always_inline bool user_access_b= egin(const void __user *pt static inline unsigned long user_access_save(void) { return 0UL; } static inline void user_access_restore(unsigned long enabled) { } =20 -#define unsafe_put_user(x, ptr, label) do { \ - long __kr_err =3D 0; \ - __put_user_nocheck(x, (ptr), __kr_err); \ - if (__kr_err) goto label; \ -} while (0) +#define unsafe_put_user(x, ptr, label) \ + __put_user_nocheck(x, (ptr), label); =20 #define unsafe_get_user(x, ptr, label) do { \ long __kr_err =3D 0; \ --=20 2.43.0