From mboxrd@z Thu Jan 1 00:00:00 1970 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 8F7BC37524F for ; Sat, 28 Feb 2026 18:15:39 +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=1772302539; cv=none; b=p7w4t2j8oWyLVAmU2eVpzDya8vV7NNyRjwsRDHlQNXc4BEgDYErvMesen0mCFuLIADFnbXosDAZwE7qlWSpihRS5d5B5Efe+/+hARGRrw01yfIgqSpLK7kLj7glyt85LIy1yP1MADRnx9TEiR+H0k0DY6O45w/m3t/gv9h/1TCo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772302539; c=relaxed/simple; bh=UNrchGeV8kDcwdhSg4Q/Cv1EoZZJ4XVcWrWkkePnwBs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=qoBYGkA7whUNQIJ4HSUTqiggfY3ZvO+qCRbLlkl/nGjrGbGx/pBarOYmEQUvsWnWnd4urKIp0l1KGhJroLrMue6Mq1+20Gzk1UWRXUU4OpZnjQLo8QHmLlEqNqFwjxM3B10kE71/hgdTBhY+YKoc58UTlqoW1kmvCK1M2w/qBD8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Uu5tqXR8; 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="Uu5tqXR8" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EDA77C116D0; Sat, 28 Feb 2026 18:15:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772302539; bh=UNrchGeV8kDcwdhSg4Q/Cv1EoZZJ4XVcWrWkkePnwBs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Uu5tqXR8AzLVO/WbUErAoW5rqqCO4S35sMeB3EWOrRESR5z/FrPxPdLPDPcFps/l8 OnelkIwdcik0EJw4WLo9WX7/WYBpwoeY+QNy7ZRkwD1SZhW98XKbN/xEg9uFG2cjRD +qx2jE6AcxMqUwgVGgKtYCEIXXbXCudeeO++1A0JaqGCVuabWsSZd7bd/6VNcDT39t mveq25dCVc5uHdX1xAoUNC4PN0fnZZfAB+BByh2ie8C5+CcRH81o9zsdeiFBx9jxDV 3d3iR+jGaXLirsnPT4m/JEjCUgDWhKto85eTiSGVd6tlqarf7ibXuq9ZTJDD2NYXNv K2QkMxfeg4pYQ== From: Sasha Levin To: patches@lists.linux.dev Cc: Christophe Leroy , Madhavan Srinivasan , Sasha Levin Subject: [PATCH 5.15 040/164] powerpc/uaccess: Move barrier_nospec() out of allow_read_{from/write}_user() Date: Sat, 28 Feb 2026 13:12:59 -0500 Message-ID: <20260228181505.1600663-40-sashal@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20260228181505.1600663-1-sashal@kernel.org> References: <20260228181505.1600663-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit From: Christophe Leroy [ Upstream commit 5fbc09eb0b4f4b1a4b33abebacbeee0d29f195e9 ] Commit 74e19ef0ff80 ("uaccess: Add speculation barrier to copy_from_user()") added a redundant barrier_nospec() in copy_from_user(), because powerpc is already calling barrier_nospec() in allow_read_from_user() and allow_read_write_user(). But on other architectures that call to barrier_nospec() was missing. So change powerpc instead of reverting the above commit and having to fix other architectures one by one. This is now possible because barrier_nospec() has also been added in copy_from_user_iter(). Move barrier_nospec() out of allow_read_from_user() and allow_read_write_user(). This will also allow reuse of those functions when implementing masked user access which doesn't require barrier_nospec(). Don't add it back in raw_copy_from_user() as it is already called by copy_from_user() and copy_from_user_iter(). Fixes: 74e19ef0ff80 ("uaccess: Add speculation barrier to copy_from_user()") Signed-off-by: Christophe Leroy Signed-off-by: Madhavan Srinivasan Link: https://patch.msgid.link/f29612105c5fcbc8ceb7303808ddc1a781f0f6b5.1766574657.git.chleroy@kernel.org Signed-off-by: Sasha Levin --- arch/powerpc/include/asm/kup.h | 2 -- arch/powerpc/include/asm/uaccess.h | 4 ++++ 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/include/asm/kup.h b/arch/powerpc/include/asm/kup.h index 34ff86e3686ea..eb048b6be6d83 100644 --- a/arch/powerpc/include/asm/kup.h +++ b/arch/powerpc/include/asm/kup.h @@ -81,7 +81,6 @@ static __always_inline void setup_kup(void) static __always_inline void allow_read_from_user(const void __user *from, unsigned long size) { - barrier_nospec(); allow_user_access(NULL, from, size, KUAP_READ); } @@ -93,7 +92,6 @@ static __always_inline void allow_write_to_user(void __user *to, unsigned long s static __always_inline void allow_read_write_user(void __user *to, const void __user *from, unsigned long size) { - barrier_nospec(); allow_user_access(to, from, size, KUAP_READ_WRITE); } diff --git a/arch/powerpc/include/asm/uaccess.h b/arch/powerpc/include/asm/uaccess.h index 6013a7fc74ba7..7781f6dd51390 100644 --- a/arch/powerpc/include/asm/uaccess.h +++ b/arch/powerpc/include/asm/uaccess.h @@ -276,6 +276,7 @@ do { \ __typeof__(sizeof(*(ptr))) __gu_size = sizeof(*(ptr)); \ \ might_fault(); \ + barrier_nospec(); \ allow_read_from_user(__gu_addr, __gu_size); \ __get_user_size_allowed(__gu_val, __gu_addr, __gu_size, __gu_err); \ prevent_read_from_user(__gu_addr, __gu_size); \ @@ -304,6 +305,7 @@ raw_copy_in_user(void __user *to, const void __user *from, unsigned long n) { unsigned long ret; + barrier_nospec(); allow_read_write_user(to, from, n); ret = __copy_tofrom_user(to, from, n); prevent_read_write_user(to, from, n); @@ -392,6 +394,7 @@ static __must_check inline bool user_access_begin(const void __user *ptr, size_t might_fault(); + barrier_nospec(); allow_read_write_user((void __user *)ptr, ptr, len); return true; } @@ -408,6 +411,7 @@ user_read_access_begin(const void __user *ptr, size_t len) might_fault(); + barrier_nospec(); allow_read_from_user(ptr, len); return true; } -- 2.51.0