From nobody Thu Dec 18 06:00:24 2025 Received: from mail-oi1-f177.google.com (mail-oi1-f177.google.com [209.85.167.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6686422AE7F for ; Thu, 20 Mar 2025 22:44:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.167.177 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742510675; cv=none; b=BafX7FW8yT5v9ZGHcnqInMD2bUyTOCP8ffWF/MiPCiD+9zAA1V2nijLt68/vjYojzqI6dUcgrRTPfzZrz0PIxKmJ/iIzDGN2MSGGdIwZD2Uz36JJRb7QCOmFnLiVtxIUP1+6dYYBjBRAFx0CmsdtDCzLxaYDG9QFMrBaedyo4A8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742510675; c=relaxed/simple; bh=/4Jn1Ns5m8J/PS8HTpLyGbF9ChF8Fk4/RvIEUizoI+k=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=NXeW9k53QdWYorqs58dXhqEwrJm3UUfupje5uOYt8dJzKnIlh/c4FXDSsYj124zL2fpbfLl81OUJyWJi1Tadm5G/vSQS5YJNO4Lj32vek/TIuXUhopPPowPXXEM+PxUrJMbtfLGg6aa4cKhgD8L1+GxpYNHFL19wEpsTq3HII/Q= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=tenstorrent.com; spf=pass smtp.mailfrom=tenstorrent.com; dkim=pass (2048-bit key) header.d=tenstorrent.com header.i=@tenstorrent.com header.b=DeHttRIq; arc=none smtp.client-ip=209.85.167.177 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=tenstorrent.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=tenstorrent.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=tenstorrent.com header.i=@tenstorrent.com header.b="DeHttRIq" Received: by mail-oi1-f177.google.com with SMTP id 5614622812f47-3fa0eb29cebso1475242b6e.0 for ; Thu, 20 Mar 2025 15:44:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=tenstorrent.com; s=google; t=1742510672; x=1743115472; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=aUM4cL2icpLrYe67mQWolXHTOhfxBr7CeU0SRh8tC7k=; b=DeHttRIqzYg1KebH4c5Rc2gr4ur2MPIAk3PXJCaXLfhIucGyDvriscnkhzWZAuw7g0 FvJtIcGCPsglo98tlWo+1UiOBce9r9w+GiWHPR5agnLpvUtP+xYgUyqvAIt1FooQkaPu DfcHpRyw6wC8vgHAbIYqrET/IIVZG2LUC6XDxcJRky5SZJGRmaUJWofXpnbaKSE4xDY3 PHDx745WVh5ezJ86tx+1zhLyTBgnLNdNEJ20X1jSkC783+5+gvuBcYTDKndIrXNE1wKT YKgXfb6IAeaHPpRHqiTiajCvp6INO0QiYE4B1UipDTIwsy9LtG7wWiLqo7M63s1TzGTn MYxA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1742510672; x=1743115472; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=aUM4cL2icpLrYe67mQWolXHTOhfxBr7CeU0SRh8tC7k=; b=GvUj/sSizhJD5Ba1loTbuS7i6f8W+uHh3XXhcYvfmoU2xCgVMPZ0uhSdV/CfSnehUN Q1jM7WcEbOK+/PE0RgdxFB8hvVtVI1+bj3Jm9hPLckNR8BRrX4Fx9yO9WfB/cMHmj9Mx U0+AzTgYYXwykVULGMNsILyMUE56edrDmkAQI4MBSLFE2RS7luYZ0NMMVSoVsKCi7ELM Z2ektV4HGEfKJvnrDPcooHEUkojsRs2PM3N9vF2TUNeZNZCXSYyK6c6EgImcWNZaFioZ h8slx1By5mnMmeBbA7TLxT0Np//tvL846loigteqV3jn00qyVPmKFiK1nhTqasgixpic J0hw== X-Forwarded-Encrypted: i=1; AJvYcCVGyOaRKpdrLnGRwjQTdtsd8cDmJTuKzzakC2n9a60z8OXopMF48q1fCvujgULu1YrdI3sqzZBq8nXitik=@vger.kernel.org X-Gm-Message-State: AOJu0Yw/oCCgAbV1/GplxZaDwXRV6YCF1qMuxROFLKrgjGgjJbXsLhGP uu1r7FbpFaHWQ0q/0d1qX17N/CHJaM2DyVzI19xNYKUn41jW0jonm4loxIh12g== X-Gm-Gg: ASbGncvkjAPlHpQi6p3MC4qVH42K5LPxNzcnclYgK5ER8Fdaq+EKaiUMq3YtoEznfFB K1wISDZsbjH9eGhHPB8K0F8L0Z+FQMJF3WYuAmvYG8Ko6c3EN/Gte0jzZfLX223wrPKL+dB6JK9 SNLL6+LMbMKTDnbo5/rfoe/DHDKH0mFyAG7V3wcypS+iRXOJC4+bxvYWGvLrQqr+uVPeYML0gVO KPLbHQPsr8wEUlM71NqxHTMI7N2RkcZGs0WfEQ3QcD6W8zxmp01cB+a8M3CaV+7eUxKadRZ37UT NSzPQ5p4riciVr2QArWLr/beUx5XSsrKQuvvBhtVvx6+atg2yWsXHR2/VVkzpCs= X-Google-Smtp-Source: AGHT+IHChpwGgXIo7oPDkSwy3Z8aUFaMgcTSyEt/gVcKCBKfeFe7Livn0EfqfYGjYKQnsyWXdaZjLg== X-Received: by 2002:a05:6808:444b:b0:3fa:10b4:698c with SMTP id 5614622812f47-3febeea9cf6mr1033217b6e.17.1742510672433; Thu, 20 Mar 2025 15:44:32 -0700 (PDT) Received: from aus-ird.tenstorrent.com ([38.104.49.66]) by smtp.gmail.com with ESMTPSA id 5614622812f47-3febf6dcc09sm103524b6e.12.2025.03.20.15.44.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 20 Mar 2025 15:44:31 -0700 (PDT) From: Cyril Bur To: palmer@dabbelt.com, aou@eecs.berkeley.edu, paul.walmsley@sifive.com, charlie@rivosinc.com, jrtc27@jrtc27.com, ben.dooks@codethink.co.uk, alex@ghiti.fr Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, jszhang@kernel.org Subject: [PATCH v5 5/5] riscv: uaccess: use 'asm_goto_output' for get_user() Date: Thu, 20 Mar 2025 22:44:23 +0000 Message-Id: <20250320224423.1838493-6-cyrilbur@tenstorrent.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20250320224423.1838493-1-cyrilbur@tenstorrent.com> References: <20250320224423.1838493-1-cyrilbur@tenstorrent.com> 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" From: Jisheng Zhang With 'asm goto' we don't need to test the error etc, the exception just jumps to the error handling directly. Unlike put_user(), get_user() must work around GCC bugs [1] when using output clobbers in an asm goto statement. Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D113921 # 1 Signed-off-by: Jisheng Zhang [Cyril Bur: Rewritten commit message] Signed-off-by: Cyril Bur --- arch/riscv/include/asm/uaccess.h | 95 +++++++++++++++++++++++--------- 1 file changed, 68 insertions(+), 27 deletions(-) diff --git a/arch/riscv/include/asm/uaccess.h b/arch/riscv/include/asm/uacc= ess.h index 719c9179a751..8823471b201f 100644 --- a/arch/riscv/include/asm/uaccess.h +++ b/arch/riscv/include/asm/uaccess.h @@ -96,27 +96,58 @@ static inline unsigned long __untagged_addr_remote(stru= ct mm_struct *mm, unsigne * 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) \ + u32 __user *__ptr =3D (u32 __user *)(ptr); \ + u32 __lo, __hi; \ + 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) \ + (x) =3D (__typeof__(x))((__typeof__((x) - (x)))( \ + (((u64)__hi << 32) | __lo))); \ + +#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" \ @@ -125,35 +156,51 @@ 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; \ - (x) =3D (__typeof__(x))((__typeof__((x)-(x)))( \ + 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. @@ -178,13 +225,16 @@ do { \ ({ \ const __typeof__(*(ptr)) __user *__gu_ptr =3D untagged_addr(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 @@ -369,13 +419,7 @@ 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) @@ -401,12 +445,9 @@ 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 __err =3D 0; \ __inttype(*(ptr)) __gu_val; \ - __get_user_nocheck(__gu_val, (ptr), __err); \ + __get_user_nocheck(__gu_val, (ptr), label); \ (x) =3D (__force __typeof__(*(ptr)))__gu_val; \ - if (__err) \ - goto label; \ } while (0) =20 #define unsafe_copy_loop(dst, src, len, type, op, label) \ --=20 2.34.1