From nobody Wed Dec 17 19:16:27 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 EC5C41419A0 for ; Tue, 25 Jun 2024 04:19:10 +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=1719289151; cv=none; b=q65xhb5kmni9g30dPyQj4bc01MPl3vlyeJq/L4+LPZav3DKGqJt50WK0j0TGj6t3Ti4HPAc2CBMde/xyN9OWAIzC1o9MWny0KzAtI2QYxjrSPc4dLdJY9XY0wVrPcZrN3uVnpDZHmog6vw3mhWkRt9w7ljJAa7d13/sPSFwWmgs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719289151; c=relaxed/simple; bh=DRenIR1h1uckRbamCPlOygD4TulcG8SHfUvGTveeorc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=G/+Ed3MJOXWnOOHQoBblGcoJvURd/GovX2ls+YyUuDKLgP+z/ET84fh0Y1gANWFkkS3UdYT6B+kUSddtCQAt7WGcwQvNOAwFMmhPiz/+6yW1Qa0QMiA/1qxl+pzaBhcuAagw4IEOivzj+5aNVLygdrJiBEW0E+dMNlnDcGpTNPA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=YpozG22I; 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="YpozG22I" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9F93CC4AF09; Tue, 25 Jun 2024 04:19:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1719289150; bh=DRenIR1h1uckRbamCPlOygD4TulcG8SHfUvGTveeorc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=YpozG22IEVA2nBqJ8c0xsbZt6uPkG5mxT2ifhOUxfWWnac5+tPiACBAcWM39RmioP WAEp3VD2DsbwQ/h9ZTjWxVMH1tZ3Cf1o8lnm9vddSd8BJPc/EW5SxdOZb7p+JcGTfv FtQ2CzUQdlD73BebltlmD75xZ0Xr6cOCwDW5z578rwoZN/2mqabQeVQ2EcrbH4ukK/ Sp0FKEHrsCvORglBeIDtt3mX3/ke4g3/aq1MA+0Hkf8hLAgR1my5jQYWl4xrXOGeae wuCggyCvHUqWM6Vv7RI9FJddfZOIUT+7HCOX/iTXnN8b8STZcIKMfmLqYwEaCT+kyW IbkiXTEg1mXKA== From: Jisheng Zhang To: Paul Walmsley , Palmer Dabbelt , Albert Ou Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH 4/4] riscv: uaccess: use 'asm goto output' for get_user Date: Tue, 25 Jun 2024 12:05:00 +0800 Message-ID: <20240625040500.1788-5-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 output' 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 | 88 +++++++++++++++++++++++--------- 1 file changed, 63 insertions(+), 25 deletions(-) diff --git a/arch/riscv/include/asm/uaccess.h b/arch/riscv/include/asm/uacc= ess.h index d8c44705b61d..d9c32b4f7d13 100644 --- a/arch/riscv/include/asm/uaccess.h +++ b/arch/riscv/include/asm/uaccess.h @@ -63,27 +63,54 @@ * call. */ =20 -#define __get_user_asm(insn, x, ptr, err) \ +#ifdef CONFIG_CC_HAS_ASM_GOTO_OUTPUT +#define __get_user_asm(insn, x, ptr, label) \ + asm_goto_output( \ + "1:\n" \ + " " insn " %0, %1\n" \ + _ASM_EXTABLE_UACCESS_ERR(1b, %l2, %0) \ + : "=3D&r" (x) \ + : "m" (*(ptr)) : : label) +#else /* !CONFIG_CC_HAS_ASM_GOTO_OUTPUT */ +#define __get_user_asm(insn, x, ptr, label) \ do { \ - __typeof__(x) __x; \ + long __gua_err =3D 0; \ __asm__ __volatile__ ( \ "1:\n" \ " " insn " %1, %2\n" \ "2:\n" \ _ASM_EXTABLE_UACCESS_ERR_ZERO(1b, 2b, %0, %1) \ - : "+r" (err), "=3D&r" (__x) \ + : "+r" (__gua_err), "=3D&r" (x) \ : "m" (*(ptr))); \ - (x) =3D __x; \ + if (__gua_err) \ + goto label; \ } while (0) +#endif /* CONFIG_CC_HAS_ASM_GOTO_OUTPUT */ =20 #ifdef CONFIG_64BIT -#define __get_user_8(x, ptr, err) \ - __get_user_asm("ld", x, ptr, err) +#define __get_user_8(x, ptr, label) \ + __get_user_asm("ld", x, ptr, label) #else /* !CONFIG_64BIT */ -#define __get_user_8(x, ptr, err) \ + +#ifdef CONFIG_CC_HAS_ASM_GOTO_OUTPUT +#define __get_user_8(x, ptr, label) \ + asm_goto_output( \ + "1:\n" \ + " lw %0, %2\n" \ + "2:\n" \ + " lw %1, %3\n" \ + _ASM_EXTABLE_UACCESS_ERR(1b, %l4, %0) \ + _ASM_EXTABLE_UACCESS_ERR(2b, %l4, %0) \ + : "=3D&r" (__lo), "=3Dr" (__hi) \ + : "m" (__ptr[__LSW]), "m" (__ptr[__MSW]) \ + : : label) + +#else /* !CONFIG_CC_HAS_ASM_GOTO_OUTPUT */ +#define __get_user_8(x, ptr, label) \ do { \ u32 __user *__ptr =3D (u32 __user *)(ptr); \ u32 __lo, __hi; \ + long __gu8_err =3D 0; \ __asm__ __volatile__ ( \ "1:\n" \ " lw %1, %3\n" \ @@ -92,35 +119,51 @@ do { \ "3:\n" \ _ASM_EXTABLE_UACCESS_ERR_ZERO(1b, 3b, %0, %1) \ _ASM_EXTABLE_UACCESS_ERR_ZERO(2b, 3b, %0, %1) \ - : "+r" (err), "=3D&r" (__lo), "=3Dr" (__hi) \ + : "+r" (__gu8_err), "=3D&r" (__lo), "=3Dr" (__hi) \ : "m" (__ptr[__LSW]), "m" (__ptr[__MSW])); \ - if (err) \ + if (__gu8_err) { \ __hi =3D 0; \ + goto label; \ + } \ (x) =3D (__typeof__(x))((__typeof__((x)-(x)))( \ (((u64)__hi << 32) | __lo))); \ } while (0) +#endif /* CONFIG_CC_HAS_ASM_GOTO_OUTPUT */ + #endif /* CONFIG_64BIT */ =20 -#define __get_user_nocheck(x, __gu_ptr, __gu_err) \ +#define __get_user_nocheck(x, __gu_ptr, label) \ do { \ switch (sizeof(*__gu_ptr)) { \ case 1: \ - __get_user_asm("lb", (x), __gu_ptr, __gu_err); \ + __get_user_asm("lb", (x), __gu_ptr, label); \ break; \ case 2: \ - __get_user_asm("lh", (x), __gu_ptr, __gu_err); \ + __get_user_asm("lh", (x), __gu_ptr, label); \ break; \ case 4: \ - __get_user_asm("lw", (x), __gu_ptr, __gu_err); \ + __get_user_asm("lw", (x), __gu_ptr, label); \ break; \ case 8: \ - __get_user_8((x), __gu_ptr, __gu_err); \ + __get_user_8((x), __gu_ptr, label); \ break; \ default: \ BUILD_BUG(); \ } \ } while (0) =20 +#define __get_user_error(x, ptr, err) \ +do { \ + __label__ __gu_failed; \ + \ + __get_user_nocheck(x, ptr, __gu_failed); \ + err =3D 0; \ + break; \ +__gu_failed: \ + x =3D 0; \ + err =3D -EFAULT; \ +} while (0) + /** * __get_user: - Get a simple variable from user space, with less checking. * @x: Variable to store result. @@ -145,13 +188,16 @@ do { \ ({ \ const __typeof__(*(ptr)) __user *__gu_ptr =3D (ptr); \ long __gu_err =3D 0; \ + __typeof__(x) __gu_val; \ \ __chk_user_ptr(__gu_ptr); \ \ __enable_user_access(); \ - __get_user_nocheck(x, __gu_ptr, __gu_err); \ + __get_user_error(__gu_val, __gu_ptr, __gu_err); \ __disable_user_access(); \ \ + (x) =3D __gu_val; \ + \ __gu_err; \ }) =20 @@ -336,13 +382,7 @@ unsigned long __must_check clear_user(void __user *to,= unsigned long n) } =20 #define __get_kernel_nofault(dst, src, type, err_label) \ -do { \ - long __kr_err =3D 0; \ - \ - __get_user_nocheck(*((type *)(dst)), (type *)(src), __kr_err); \ - if (unlikely(__kr_err)) \ - goto err_label; \ -} while (0) + __get_user_nocheck(*((type *)(dst)), (type *)(src), err_label); =20 #define __put_kernel_nofault(dst, src, type, err_label) \ __put_user_nocheck(*((type *)(src)), (type *)(dst), err_label); @@ -364,11 +404,9 @@ static inline void user_access_restore(unsigned long e= nabled) { } __put_user_nocheck(x, (ptr), label); =20 #define unsafe_get_user(x, ptr, label) do { \ - long __kr_err =3D 0; \ __inttype(*(ptr)) __gu_val; \ - __get_user_nocheck(__gu_val, (ptr), __kr_err); \ + __get_user_nocheck(__gu_val, (ptr), label); \ (x) =3D (__force __typeof__(*(ptr)))__gu_val; \ - if (__kr_err) goto label; \ } while (0) =20 /* --=20 2.43.0