From nobody Wed Dec 17 07:35:14 2025 Received: from pegase2.c-s.fr (pegase2.c-s.fr [93.17.235.10]) by smtp.subspace.kernel.org (Postfix) with ESMTP id E4B8331C584; Thu, 6 Nov 2025 11:50:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=93.17.235.10 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762429827; cv=none; b=AaZCy6QILGeT+sGNfxITOk5M2o3XKCUEzSoC8fyYCfOiBNqNw5y7up2bTL7tK9w8yrUK9rmXkpTq2FL+0BQFNxjZENzhfy7+wMG5JljFVOt9xYK7M3eKGA4M6mLN/ZZqWMjIM5+eZ3ouo6mSmrYhu7NBSdumTit/roiD8BLBgdM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762429827; c=relaxed/simple; bh=CInTZPEi9ILbXu4UpfN2lm4dHyQfqcOZ4rC45zzBAr0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=dlONuJfgefjCU1UvQkXPoVcwbe3bz1sonqP0sdtxN/buLJ6UwHFSgqHKzic/KK6HbqFrVsrxT9NM92CVYD0IrfxxQcxARjIMKrec+p1SDNv/3wENCErPFdyW6Yibri6btap82vfa4sD0h/wgV3MkFpC9VUY4QNIfvCaXgzN06cc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=csgroup.eu; spf=pass smtp.mailfrom=csgroup.eu; arc=none smtp.client-ip=93.17.235.10 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=csgroup.eu Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=csgroup.eu Received: from localhost (mailhub4.si.c-s.fr [172.26.127.67]) by localhost (Postfix) with ESMTP id 4d2KmF1dFkz9sS8; Thu, 6 Nov 2025 12:32:13 +0100 (CET) X-Virus-Scanned: amavisd-new at c-s.fr Received: from pegase2.c-s.fr ([172.26.127.65]) by localhost (pegase2.c-s.fr [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 343GnQeFijfY; Thu, 6 Nov 2025 12:32:13 +0100 (CET) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase2.c-s.fr (Postfix) with ESMTP id 4d2KmF0qPPz9sRy; Thu, 6 Nov 2025 12:32:13 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 03FE98B773; Thu, 6 Nov 2025 12:32:13 +0100 (CET) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id 5UWr0kMelD5U; Thu, 6 Nov 2025 12:32:12 +0100 (CET) Received: from PO20335.idsi0.si.c-s.fr (unknown [192.168.235.99]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 3723C8B77B; Thu, 6 Nov 2025 12:32:12 +0100 (CET) From: Christophe Leroy To: Alexander Viro , Christian Brauner , Jan Kara , Thomas Gleixner , Ingo Molnar , Peter Zijlstra , Darren Hart , Davidlohr Bueso , "Andre Almeida" , Andrew Morton , Eric Dumazet , Kuniyuki Iwashima , Paolo Abeni , Willem de Bruijn , "David S. Miller" , Jakub Kicinski , Simon Horman , Daniel Borkmann , Dave Hansen , Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin Cc: Christophe Leroy , linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Subject: [PATCH v4 01/10] iter: Avoid barrier_nospec() in copy_from_user_iter() Date: Thu, 6 Nov 2025 12:31:19 +0100 Message-ID: <1c3b7384c5231dff292a3d447e0bfafa61015d64.1762427933.git.christophe.leroy@csgroup.eu> X-Mailer: git-send-email 2.49.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1326; i=christophe.leroy@csgroup.eu; h=from:subject:message-id; bh=CInTZPEi9ILbXu4UpfN2lm4dHyQfqcOZ4rC45zzBAr0=; b=owGbwMvMwCV2d0KB2p7V54MZT6slMWTytGvuVHhy9KbbDsPkpU2r9d8dfDpFfuKFsmQW9hDDq 7e3FvL/6ShlYRDjYpAVU2Q5/p9714yuL6n5U3fpw8xhZQIZwsDFKQATmZ3D8L9C6W/6lK8J3p37 lbyv2GhNrn45dU+58XqlPZUHVdpNs8UY/tmG9ys7NYupMV914dmx7f0fh8UnP02okW3kXffjuZD ZP0YA X-Developer-Key: i=christophe.leroy@csgroup.eu; a=openpgp; fpr=10FFE6F8B390DE17ACC2632368A92FEB01B8DD78 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Following patch will add missing barrier_nospec() to copy_from_user_iter(). Avoid it for architectures supporting masked user accesses, the same way as done for copy_from_user() by commit 0fc810ae3ae1 ("x86/uaccess: Avoid barrier_nospec() in 64-bit copy_from_user()") Signed-off-by: Christophe Leroy --- v2: New in v2 --- lib/iov_iter.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) diff --git a/lib/iov_iter.c b/lib/iov_iter.c index 2fe66a6b8789e..a589935bf3025 100644 --- a/lib/iov_iter.c +++ b/lib/iov_iter.c @@ -49,12 +49,16 @@ size_t copy_from_user_iter(void __user *iter_from, size= _t progress, =20 if (should_fail_usercopy()) return len; - if (access_ok(iter_from, len)) { - to +=3D progress; - instrument_copy_from_user_before(to, iter_from, len); - res =3D raw_copy_from_user(to, iter_from, len); - instrument_copy_from_user_after(to, iter_from, len, res); - } + if (can_do_masked_user_access()) + iter_from =3D mask_user_address(iter_from); + else if (!access_ok(iter_from, len)) + return res; + + to +=3D progress; + instrument_copy_from_user_before(to, iter_from, len); + res =3D raw_copy_from_user(to, iter_from, len); + instrument_copy_from_user_after(to, iter_from, len, res); + return res; } =20 --=20 2.49.0 From nobody Wed Dec 17 07:35:14 2025 Received: from pegase2.c-s.fr (pegase2.c-s.fr [93.17.235.10]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 90C0B3101DC; Thu, 6 Nov 2025 11:50:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=93.17.235.10 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762429846; cv=none; b=nW22boax026XFxT1lgSbPpsFOxdbSaZWLhHlI+JOCd8WfZfWx/DDUUM5cv+G7Ky6teQGJIuf6hijO+vbQtPMSI6qC7F9U5iMCiny3QYv0rturRyWI4lhcA0BLsqTjfoBZmkIkSu5zjVjJGOmeoUkQCh8D8lzM7BxtxPEWlNX1/k= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762429846; c=relaxed/simple; bh=W82BJoxsF/uaSl8+888M/Hm7CO4JVyWj0vi85xuDhyA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=turtuIv8Ss0w+QnM0C5a10UB4+ImmffHyYiFYo7mu83butGcfFhzVduN7s+bnYwEnIA4qfGsVPd9/3fy/ZfHwIKmtXwCyxY9Ah6mAfj4YQJklQhfS+Giy73KH0LdMahBw4lcbiJFkJ+4EynivMc8Z1EZgVQUIny5lmPJkBdkW+U= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=csgroup.eu; spf=pass smtp.mailfrom=csgroup.eu; arc=none smtp.client-ip=93.17.235.10 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=csgroup.eu Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=csgroup.eu Received: from localhost (mailhub4.si.c-s.fr [172.26.127.67]) by localhost (Postfix) with ESMTP id 4d2KmG0g3gz9sSN; Thu, 6 Nov 2025 12:32:14 +0100 (CET) X-Virus-Scanned: amavisd-new at c-s.fr Received: from pegase2.c-s.fr ([172.26.127.65]) by localhost (pegase2.c-s.fr [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id kumAkxYI07Um; Thu, 6 Nov 2025 12:32:14 +0100 (CET) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase2.c-s.fr (Postfix) with ESMTP id 4d2KmF6QcGz9sSL; Thu, 6 Nov 2025 12:32:13 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id C72008B773; Thu, 6 Nov 2025 12:32:13 +0100 (CET) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id Uo2LeIc8mkPM; Thu, 6 Nov 2025 12:32:13 +0100 (CET) Received: from PO20335.idsi0.si.c-s.fr (unknown [192.168.235.99]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 05BB88B77E; Thu, 6 Nov 2025 12:32:12 +0100 (CET) From: Christophe Leroy To: Alexander Viro , Christian Brauner , Jan Kara , Thomas Gleixner , Ingo Molnar , Peter Zijlstra , Darren Hart , Davidlohr Bueso , "Andre Almeida" , Andrew Morton , Eric Dumazet , Kuniyuki Iwashima , Paolo Abeni , Willem de Bruijn , "David S. Miller" , Jakub Kicinski , Simon Horman , Daniel Borkmann , Dave Hansen , Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin Cc: Christophe Leroy , linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Subject: [PATCH v4 02/10] uaccess: Add speculation barrier to copy_from_user_iter() Date: Thu, 6 Nov 2025 12:31:20 +0100 Message-ID: <598e9ec31716ce351f1456c81eee140477d4ecc4.1762427933.git.christophe.leroy@csgroup.eu> X-Mailer: git-send-email 2.49.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1421; i=christophe.leroy@csgroup.eu; h=from:subject:message-id; bh=W82BJoxsF/uaSl8+888M/Hm7CO4JVyWj0vi85xuDhyA=; b=owGbwMvMwCV2d0KB2p7V54MZT6slMWTytGve97+tP2FVN7v3eoEWN4s9bSpm+1+6PJ2l/vDvq t8873PdOkpZGMS4GGTFFFmO/+feNaPrS2r+1F36MHNYmUCGMHBxCsBELs1m+MPztej3jq2bH5ja rG9ssJMyjNktePpbi6LdgvWW2ft+zprE8M8scqPoI/46Z6HHk5kvRPc/uKp9c+OTpLgnTOEXlju 6O3MDAA== X-Developer-Key: i=christophe.leroy@csgroup.eu; a=openpgp; fpr=10FFE6F8B390DE17ACC2632368A92FEB01B8DD78 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" The results of "access_ok()" can be mis-speculated. The result is that you can end speculatively: if (access_ok(from, size)) // Right here For the same reason as done in copy_from_user() by commit 74e19ef0ff80 ("uaccess: Add speculation barrier to copy_from_user()"), add a speculation barrier to copy_from_user_iter(). See commit 74e19ef0ff80 ("uaccess: Add speculation barrier to copy_from_user()") for more details. Signed-off-by: Christophe Leroy --- lib/iov_iter.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) diff --git a/lib/iov_iter.c b/lib/iov_iter.c index a589935bf3025..896760bad455f 100644 --- a/lib/iov_iter.c +++ b/lib/iov_iter.c @@ -49,11 +49,19 @@ size_t copy_from_user_iter(void __user *iter_from, size= _t progress, =20 if (should_fail_usercopy()) return len; - if (can_do_masked_user_access()) + if (can_do_masked_user_access()) { iter_from =3D mask_user_address(iter_from); - else if (!access_ok(iter_from, len)) - return res; + } else { + if (!access_ok(iter_from, len)) + return res; =20 + /* + * Ensure that bad access_ok() speculation will not + * lead to nasty side effects *after* the copy is + * finished: + */ + barrier_nospec(); + } to +=3D progress; instrument_copy_from_user_before(to, iter_from, len); res =3D raw_copy_from_user(to, iter_from, len); --=20 2.49.0 From nobody Wed Dec 17 07:35:14 2025 Received: from pegase2.c-s.fr (pegase2.c-s.fr [93.17.235.10]) by smtp.subspace.kernel.org (Postfix) with ESMTP id BA085322533; Thu, 6 Nov 2025 11:50:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=93.17.235.10 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762429832; cv=none; b=WJh7F6ebMW20xGaMNyW16A+hIjLE5o60XxpUT5YQWLxK15qZzeRSkxrICc4fRW0ThgE/iXGMdl/8rKjcRPOElm9t38bmpPBnSr+3fhWBJTpek4x4nyENpiFacxnbd6vdGH95gHfybqtxQCXiAovZ3fpOXyiK40+UbNUF8igURBM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762429832; c=relaxed/simple; bh=JbwTKyEVJnLxf6vUj4X6LS+htzn0H89SnAxtpthgjmY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=DiFy7nPQ0JX5BexeKa6jlTw+xt2ePsvkYe5O8lUIHLq05eig4ATv9mTKvHHKKVz+pOFFxTHz/PbHVI6BNgiMoXyTxdNs3Xy+aql1+8fxyLmWCRnZ+Vealwkiezo3WnUf26X+PKaGLjwU3JJW3vzckHuc/zB4CIK+76Qu8wh7Pig= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=csgroup.eu; spf=pass smtp.mailfrom=csgroup.eu; arc=none smtp.client-ip=93.17.235.10 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=csgroup.eu Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=csgroup.eu Received: from localhost (mailhub4.si.c-s.fr [172.26.127.67]) by localhost (Postfix) with ESMTP id 4d2KmH1bTsz9sSS; Thu, 6 Nov 2025 12:32:15 +0100 (CET) X-Virus-Scanned: amavisd-new at c-s.fr Received: from pegase2.c-s.fr ([172.26.127.65]) by localhost (pegase2.c-s.fr [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id e6NDt_p5pCji; Thu, 6 Nov 2025 12:32:15 +0100 (CET) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase2.c-s.fr (Postfix) with ESMTP id 4d2KmG5Dshz9sSR; Thu, 6 Nov 2025 12:32:14 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 9C6C38B77E; Thu, 6 Nov 2025 12:32:14 +0100 (CET) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id WhhXQCFH8cNy; Thu, 6 Nov 2025 12:32:14 +0100 (CET) Received: from PO20335.idsi0.si.c-s.fr (unknown [192.168.235.99]) by messagerie.si.c-s.fr (Postfix) with ESMTP id C88D58B77B; Thu, 6 Nov 2025 12:32:13 +0100 (CET) From: Christophe Leroy To: Alexander Viro , Christian Brauner , Jan Kara , Thomas Gleixner , Ingo Molnar , Peter Zijlstra , Darren Hart , Davidlohr Bueso , "Andre Almeida" , Andrew Morton , Eric Dumazet , Kuniyuki Iwashima , Paolo Abeni , Willem de Bruijn , "David S. Miller" , Jakub Kicinski , Simon Horman , Daniel Borkmann , Dave Hansen , Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin Cc: Christophe Leroy , linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Subject: [PATCH v4 03/10] uaccess: Use masked_user_{read/write}_access_begin when required Date: Thu, 6 Nov 2025 12:31:21 +0100 Message-ID: <5effda898b110d413dc84a53c5664d4c9d11c1bf.1762427933.git.christophe.leroy@csgroup.eu> X-Mailer: git-send-email 2.49.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=2644; i=christophe.leroy@csgroup.eu; h=from:subject:message-id; bh=JbwTKyEVJnLxf6vUj4X6LS+htzn0H89SnAxtpthgjmY=; b=owGbwMvMwCV2d0KB2p7V54MZT6slMWTytGtV3awWzTHfJtQUKdunn7/rKJefqp9Svuu84yfzM w/Xx6l0lLIwiHExyIopshz/z71rRteX1Pypu/Rh5rAygQxh4OIUgImE+zP8FX27es3+1X056vcK S2LiedpF+ht7Kn5VLpq0qFw/vrzDheF/pu3bJymrPmnY5rxwYawqja3bl/mDddbpQzkGS/X2bJj GBQA= X-Developer-Key: i=christophe.leroy@csgroup.eu; a=openpgp; fpr=10FFE6F8B390DE17ACC2632368A92FEB01B8DD78 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Properly use masked_user_read_access_begin() and masked_user_write_access_begin() instead of masked_user_access_begin() in order to match user_read_access_end() and user_write_access_end(). This is important for architectures like powerpc that enable separately user reads and user writes. That means masked_user_read_access_begin() is used when user memory is exclusively read during the window and masked_user_write_access_begin() is used when user memory is exclusively writen during the window. masked_user_access_begin() remains and is used when both reads and writes are performed during the open window. Each of them is expected to be terminated by the matching user_read_access_end(), user_write_access_end() and user_access_end(). Signed-off-by: Christophe Leroy --- v4: Rebased on top of core-scoped-uaccess tag v3: Rebased on top of v6.18-rc1 =3D=3D> change in net/core/scm.c v2: Added more explanations in the commit message following comments receiv= ed. --- lib/strncpy_from_user.c | 2 +- lib/strnlen_user.c | 2 +- net/core/scm.c | 2 +- 3 files changed, 3 insertions(+), 3 deletions(-) diff --git a/lib/strncpy_from_user.c b/lib/strncpy_from_user.c index 6dc234913dd58..5bb752ff7c61b 100644 --- a/lib/strncpy_from_user.c +++ b/lib/strncpy_from_user.c @@ -126,7 +126,7 @@ long strncpy_from_user(char *dst, const char __user *sr= c, long count) if (can_do_masked_user_access()) { long retval; =20 - src =3D masked_user_access_begin(src); + src =3D masked_user_read_access_begin(src); retval =3D do_strncpy_from_user(dst, src, count, count); user_read_access_end(); return retval; diff --git a/lib/strnlen_user.c b/lib/strnlen_user.c index 6e489f9e90f15..4a6574b67f824 100644 --- a/lib/strnlen_user.c +++ b/lib/strnlen_user.c @@ -99,7 +99,7 @@ long strnlen_user(const char __user *str, long count) if (can_do_masked_user_access()) { long retval; =20 - str =3D masked_user_access_begin(str); + str =3D masked_user_read_access_begin(str); retval =3D do_strnlen_user(str, count, count); user_read_access_end(); return retval; diff --git a/net/core/scm.c b/net/core/scm.c index 66eaee783e8be..4a65f9baa87e7 100644 --- a/net/core/scm.c +++ b/net/core/scm.c @@ -274,7 +274,7 @@ int put_cmsg(struct msghdr * msg, int level, int type, = int len, void *data) check_object_size(data, cmlen - sizeof(*cm), true); =20 if (can_do_masked_user_access()) - cm =3D masked_user_access_begin(cm); + cm =3D masked_user_write_access_begin(cm); else if (!user_write_access_begin(cm, cmlen)) goto efault; =20 --=20 2.49.0 From nobody Wed Dec 17 07:35:14 2025 Received: from pegase2.c-s.fr (pegase2.c-s.fr [93.17.235.10]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 9614931770F; Thu, 6 Nov 2025 11:50:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=93.17.235.10 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762429851; cv=none; b=Nql2Y0elUYd7NSKEGD0TPsGCLA8vSo/EC1oN7MNkj86HYYZkjrlZZqedDKUb8/+WYPq4JjsrzjmDCwbYSBgMxOtRO5TSyk7IoQvJ66LwEBheEkKhtMqeVQO3Q3PJJxE7ELzP3Mr/sf5CmVKE3MzYybXIIqAzU5xx6Ueny3iML9E= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762429851; c=relaxed/simple; bh=SP89nN/bAz8F7I59QHbXctObg5wVHeAlY6VivanYito=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=eLc5lbMRjAS3hoWgSxmb2hDEk0IUqhBjpZ+Mrruo75LvOvSl9+Ksgms1fHmuqlm+IupuORcX07C8xgpERzD5ssRXKocp5Tz9HX5uMwtSwcsEY+M0SO2YxQR6mJ5D7g6Jd07fh6okn9FovWa8M64Rah6SrXsOtHvbe3GU/0XImPo= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=csgroup.eu; spf=pass smtp.mailfrom=csgroup.eu; arc=none smtp.client-ip=93.17.235.10 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=csgroup.eu Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=csgroup.eu Received: from localhost (mailhub4.si.c-s.fr [172.26.127.67]) by localhost (Postfix) with ESMTP id 4d2KmJ0fPhz9sSW; Thu, 6 Nov 2025 12:32:16 +0100 (CET) X-Virus-Scanned: amavisd-new at c-s.fr Received: from pegase2.c-s.fr ([172.26.127.65]) by localhost (pegase2.c-s.fr [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id MizX5N8sg6KO; Thu, 6 Nov 2025 12:32:16 +0100 (CET) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase2.c-s.fr (Postfix) with ESMTP id 4d2KmH5KMCz9sSV; Thu, 6 Nov 2025 12:32:15 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id A112E8B77E; Thu, 6 Nov 2025 12:32:15 +0100 (CET) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id wngg6LqnutZq; Thu, 6 Nov 2025 12:32:15 +0100 (CET) Received: from PO20335.idsi0.si.c-s.fr (unknown [192.168.235.99]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 944FF8B773; Thu, 6 Nov 2025 12:32:14 +0100 (CET) From: Christophe Leroy To: Alexander Viro , Christian Brauner , Jan Kara , Thomas Gleixner , Ingo Molnar , Peter Zijlstra , Darren Hart , Davidlohr Bueso , "Andre Almeida" , Andrew Morton , Eric Dumazet , Kuniyuki Iwashima , Paolo Abeni , Willem de Bruijn , "David S. Miller" , Jakub Kicinski , Simon Horman , Daniel Borkmann , Dave Hansen , Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin Cc: Christophe Leroy , linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Subject: [PATCH v4 04/10] powerpc/uaccess: Move barrier_nospec() out of allow_read_{from/write}_user() Date: Thu, 6 Nov 2025 12:31:22 +0100 Message-ID: X-Mailer: git-send-email 2.49.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=3132; i=christophe.leroy@csgroup.eu; h=from:subject:message-id; bh=SP89nN/bAz8F7I59QHbXctObg5wVHeAlY6VivanYito=; b=owGbwMvMwCV2d0KB2p7V54MZT6slMWTytGsdExYuey/S0PBzf+81ZX++TZL/N+2J5UkuP2965 +up0NWKHaUsDGJcDLJiiizH/3PvmtH1JTV/6i59mDmsTCBDGLg4BWAic44wMnwR32Pz0XlH+raH HPv++6WV7fKr5ur/YDhv8WVGDp5072aG32yS3VuzbkVZ/M1Z+fFvS2N+dcPKlKp7SWLrFu2yFTh qxwgA X-Developer-Key: i=christophe.leroy@csgroup.eu; a=openpgp; fpr=10FFE6F8B390DE17ACC2632368A92FEB01B8DD78 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" 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 --- 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 dab63b82a8d4f..f2009d7c8cfa7 100644 --- a/arch/powerpc/include/asm/kup.h +++ b/arch/powerpc/include/asm/kup.h @@ -134,7 +134,6 @@ static __always_inline void kuap_assert_locked(void) =20 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); } =20 @@ -146,7 +145,6 @@ 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 v= oid __user *from, unsigned long size) { - barrier_nospec(); allow_user_access(to, from, size, KUAP_READ_WRITE); } =20 diff --git a/arch/powerpc/include/asm/uaccess.h b/arch/powerpc/include/asm/= uaccess.h index 784a00e681fa3..3e622e647d622 100644 --- a/arch/powerpc/include/asm/uaccess.h +++ b/arch/powerpc/include/asm/uaccess.h @@ -301,6 +301,7 @@ do { \ __typeof__(sizeof(*(ptr))) __gu_size =3D 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); \ @@ -329,6 +330,7 @@ raw_copy_in_user(void __user *to, const void __user *fr= om, unsigned long n) { unsigned long ret; =20 + barrier_nospec(); allow_read_write_user(to, from, n); ret =3D __copy_tofrom_user(to, from, n); prevent_read_write_user(to, from, n); @@ -415,6 +417,7 @@ static __must_check __always_inline bool user_access_be= gin(const void __user *pt =20 might_fault(); =20 + barrier_nospec(); allow_read_write_user((void __user *)ptr, ptr, len); return true; } @@ -431,6 +434,7 @@ user_read_access_begin(const void __user *ptr, size_t l= en) =20 might_fault(); =20 + barrier_nospec(); allow_read_from_user(ptr, len); return true; } --=20 2.49.0 From nobody Wed Dec 17 07:35:14 2025 Received: from pegase2.c-s.fr (pegase2.c-s.fr [93.17.235.10]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 1B64231985F; Thu, 6 Nov 2025 11:50:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=93.17.235.10 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762429818; cv=none; b=QhprNwBxFubvpm2LUXejNdmyOfH9jkT79sLkVw+SQN37zD9WSjg05Byw4BkS9UMraO0JRw1YQ1jxbIcEDCrFXI48OdGAMqMjMVLIpBPi+aw0RD2R3HdAEga4tNqEzsZ2W58QjPmIGEulk3181yq/kxg1dL5B/8pFzCrhdL3Tt9w= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762429818; c=relaxed/simple; bh=KnzlfUS7b6A05GpPdjrBHv7ZFNA1ZFx8E2W+mgIICCo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=mAVOtJn02StU/h5O8iupvyOuNAqFuSLxh83xw8f7ON+WuTcxyTXMv+WUhzJDfhmL2oGQq4iaO48bmIXJREBJKNtvnZDzybxKG8HU4LiOctb2Xj/U8cd5DAROlLwZDPDP51PGIMBxWOy6mC7lG6aNpafMq31rNIxzJqe7JNQV6oQ= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=csgroup.eu; spf=pass smtp.mailfrom=csgroup.eu; arc=none smtp.client-ip=93.17.235.10 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=csgroup.eu Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=csgroup.eu Received: from localhost (mailhub4.si.c-s.fr [172.26.127.67]) by localhost (Postfix) with ESMTP id 4d2KmQ28qdz9sSf; Thu, 6 Nov 2025 12:32:22 +0100 (CET) X-Virus-Scanned: amavisd-new at c-s.fr Received: from pegase2.c-s.fr ([172.26.127.65]) by localhost (pegase2.c-s.fr [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id YVf_i7GoCn0I; Thu, 6 Nov 2025 12:32:22 +0100 (CET) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase2.c-s.fr (Postfix) with ESMTP id 4d2KmJ4Mjpz9sSh; Thu, 6 Nov 2025 12:32:16 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 7C8418B792; Thu, 6 Nov 2025 12:32:16 +0100 (CET) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id JO5LBR2iyzW5; Thu, 6 Nov 2025 12:32:16 +0100 (CET) Received: from PO20335.idsi0.si.c-s.fr (unknown [192.168.235.99]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 97B858B77B; Thu, 6 Nov 2025 12:32:15 +0100 (CET) From: Christophe Leroy To: Alexander Viro , Christian Brauner , Jan Kara , Thomas Gleixner , Ingo Molnar , Peter Zijlstra , Darren Hart , Davidlohr Bueso , "Andre Almeida" , Andrew Morton , Eric Dumazet , Kuniyuki Iwashima , Paolo Abeni , Willem de Bruijn , "David S. Miller" , Jakub Kicinski , Simon Horman , Daniel Borkmann , Dave Hansen , Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin Cc: Christophe Leroy , linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Subject: [PATCH v4 05/10] powerpc/uaccess: Remove unused size and from parameters from allow_access_user() Date: Thu, 6 Nov 2025 12:31:23 +0100 Message-ID: X-Mailer: git-send-email 2.49.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=5364; i=christophe.leroy@csgroup.eu; h=from:subject:message-id; bh=KnzlfUS7b6A05GpPdjrBHv7ZFNA1ZFx8E2W+mgIICCo=; b=kA0DAAoW3ZBwJryrz1MByyZiAGkMhyqi7HXpCsd+qcBnUJl2gCnVLOzgpgcKPJ7chMABwclmX 4h1BAAWCgAdFiEEx/8LupiK9GVvlbov3ZBwJryrz1MFAmkMhyoACgkQ3ZBwJryrz1MeKwEAy0ha N7ps/87sD4oYwH26bIktbycULo/IbbKxgPhsgTsBANqE9t7CuwL1fTq/tdbdBaVJdXFbCT9dMNp HA5cqzQAK X-Developer-Key: i=christophe.leroy@csgroup.eu; a=openpgp; fpr=10FFE6F8B390DE17ACC2632368A92FEB01B8DD78 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Since commit 16132529cee5 ("powerpc/32s: Rework Kernel Userspace Access Protection") the size parameter is unused on all platforms. And the 'from' parameter has never been used. Remove them. Signed-off-by: Christophe Leroy --- v2: Also remove 'from' param. --- arch/powerpc/include/asm/book3s/32/kup.h | 3 +-- arch/powerpc/include/asm/book3s/64/kup.h | 6 ++---- arch/powerpc/include/asm/kup.h | 9 ++++----- arch/powerpc/include/asm/nohash/32/kup-8xx.h | 3 +-- arch/powerpc/include/asm/nohash/kup-booke.h | 3 +-- 5 files changed, 9 insertions(+), 15 deletions(-) diff --git a/arch/powerpc/include/asm/book3s/32/kup.h b/arch/powerpc/includ= e/asm/book3s/32/kup.h index 873c5146e3261..a3558419c41b1 100644 --- a/arch/powerpc/include/asm/book3s/32/kup.h +++ b/arch/powerpc/include/asm/book3s/32/kup.h @@ -97,8 +97,7 @@ static __always_inline unsigned long __kuap_get_and_asser= t_locked(void) } #define __kuap_get_and_assert_locked __kuap_get_and_assert_locked =20 -static __always_inline void allow_user_access(void __user *to, const void = __user *from, - u32 size, unsigned long dir) +static __always_inline void allow_user_access(void __user *to, unsigned lo= ng dir) { BUILD_BUG_ON(!__builtin_constant_p(dir)); =20 diff --git a/arch/powerpc/include/asm/book3s/64/kup.h b/arch/powerpc/includ= e/asm/book3s/64/kup.h index 03aec3c6c851c..9ccf8a5e0926f 100644 --- a/arch/powerpc/include/asm/book3s/64/kup.h +++ b/arch/powerpc/include/asm/book3s/64/kup.h @@ -353,8 +353,7 @@ __bad_kuap_fault(struct pt_regs *regs, unsigned long ad= dress, bool is_write) return (regs->amr & AMR_KUAP_BLOCK_READ) =3D=3D AMR_KUAP_BLOCK_READ; } =20 -static __always_inline void allow_user_access(void __user *to, const void = __user *from, - unsigned long size, unsigned long dir) +static __always_inline void allow_user_access(void __user *to, unsigned lo= ng dir) { unsigned long thread_amr =3D 0; =20 @@ -383,8 +382,7 @@ static __always_inline unsigned long get_kuap(void) =20 static __always_inline void set_kuap(unsigned long value) { } =20 -static __always_inline void allow_user_access(void __user *to, const void = __user *from, - unsigned long size, unsigned long dir) +static __always_inline void allow_user_access(void __user *to, unsigned lo= ng dir) { } =20 #endif /* !CONFIG_PPC_KUAP */ diff --git a/arch/powerpc/include/asm/kup.h b/arch/powerpc/include/asm/kup.h index f2009d7c8cfa7..3963584ac1cf1 100644 --- a/arch/powerpc/include/asm/kup.h +++ b/arch/powerpc/include/asm/kup.h @@ -72,8 +72,7 @@ static __always_inline void __kuap_kernel_restore(struct = pt_regs *regs, unsigned * platforms. */ #ifndef CONFIG_PPC_BOOK3S_64 -static __always_inline void allow_user_access(void __user *to, const void = __user *from, - unsigned long size, unsigned long dir) { } +static __always_inline void allow_user_access(void __user *to, unsigned lo= ng dir) { } static __always_inline void prevent_user_access(unsigned long dir) { } static __always_inline unsigned long prevent_user_access_return(void) { re= turn 0UL; } static __always_inline void restore_user_access(unsigned long flags) { } @@ -134,18 +133,18 @@ static __always_inline void kuap_assert_locked(void) =20 static __always_inline void allow_read_from_user(const void __user *from, = unsigned long size) { - allow_user_access(NULL, from, size, KUAP_READ); + allow_user_access(NULL, KUAP_READ); } =20 static __always_inline void allow_write_to_user(void __user *to, unsigned = long size) { - allow_user_access(to, NULL, size, KUAP_WRITE); + allow_user_access(to, KUAP_WRITE); } =20 static __always_inline void allow_read_write_user(void __user *to, const v= oid __user *from, unsigned long size) { - allow_user_access(to, from, size, KUAP_READ_WRITE); + allow_user_access(to, KUAP_READ_WRITE); } =20 static __always_inline void prevent_read_from_user(const void __user *from= , unsigned long size) diff --git a/arch/powerpc/include/asm/nohash/32/kup-8xx.h b/arch/powerpc/in= clude/asm/nohash/32/kup-8xx.h index 08486b15b2075..efffb5006d190 100644 --- a/arch/powerpc/include/asm/nohash/32/kup-8xx.h +++ b/arch/powerpc/include/asm/nohash/32/kup-8xx.h @@ -49,8 +49,7 @@ static __always_inline void uaccess_end_8xx(void) "i"(SPRN_MD_AP), "r"(MD_APG_KUAP), "i"(MMU_FTR_KUAP) : "memory"); } =20 -static __always_inline void allow_user_access(void __user *to, const void = __user *from, - unsigned long size, unsigned long dir) +static __always_inline void allow_user_access(void __user *to, unsigned lo= ng dir) { uaccess_begin_8xx(MD_APG_INIT); } diff --git a/arch/powerpc/include/asm/nohash/kup-booke.h b/arch/powerpc/inc= lude/asm/nohash/kup-booke.h index d6bbb6d78bbe4..cb2d5a96c3df7 100644 --- a/arch/powerpc/include/asm/nohash/kup-booke.h +++ b/arch/powerpc/include/asm/nohash/kup-booke.h @@ -73,8 +73,7 @@ static __always_inline void uaccess_end_booke(void) "i"(SPRN_PID), "r"(0), "i"(MMU_FTR_KUAP) : "memory"); } =20 -static __always_inline void allow_user_access(void __user *to, const void = __user *from, - unsigned long size, unsigned long dir) +static __always_inline void allow_user_access(void __user *to, unsigned lo= ng dir) { uaccess_begin_booke(current->thread.pid); } --=20 2.49.0 From nobody Wed Dec 17 07:35:14 2025 Received: from pegase2.c-s.fr (pegase2.c-s.fr [93.17.235.10]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 1A28A3101DC; 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Thu, 6 Nov 2025 12:32:17 +0100 (CET) Received: from PO20335.idsi0.si.c-s.fr (unknown [192.168.235.99]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 740078B78F; Thu, 6 Nov 2025 12:32:16 +0100 (CET) From: Christophe Leroy To: Alexander Viro , Christian Brauner , Jan Kara , Thomas Gleixner , Ingo Molnar , Peter Zijlstra , Darren Hart , Davidlohr Bueso , "Andre Almeida" , Andrew Morton , Eric Dumazet , Kuniyuki Iwashima , Paolo Abeni , Willem de Bruijn , "David S. Miller" , Jakub Kicinski , Simon Horman , Daniel Borkmann , Dave Hansen , Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin Cc: Christophe Leroy , linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Subject: [PATCH v4 06/10] powerpc/uaccess: Remove {allow/prevent}_{read/write/read_write}_{from/to/}_user() Date: Thu, 6 Nov 2025 12:31:24 +0100 Message-ID: X-Mailer: git-send-email 2.49.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=5385; i=christophe.leroy@csgroup.eu; h=from:subject:message-id; bh=fcju2KL6HfO0NoLFgdd2flZ1YHYvh2/fvlhLhAc9ihw=; b=owGbwMvMwCV2d0KB2p7V54MZT6slMWTytGvJqyis8VimY+Bl2hUyL/T7hr5VeYvuX8gLN3Y2r GmIP+bcUcrCIMbFICumyHL8P/euGV1fUvOn7tKHmcPKBDKEgYtTACaiU8rIsGvavIyK6M3XFY50 LpoTeGfdwblrL67i+X5kQ7FNxU9zXR+Gv9JGZYXrxO8ozzmprXDyxryFat7l558s+HRhr1F4+oe pzHwA X-Developer-Key: i=christophe.leroy@csgroup.eu; a=openpgp; fpr=10FFE6F8B390DE17ACC2632368A92FEB01B8DD78 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" The six following functions have become simple single-line fonctions that do not have much added value anymore: - allow_read_from_user() - allow_write_to_user() - allow_read_write_user() - prevent_read_from_user() - prevent_write_to_user() - prevent_read_write_user() Directly call allow_user_access() and prevent_user_access(), it doesn't reduce the readability and it removes unnecessary middle functions. Signed-off-by: Christophe Leroy --- v2: New --- arch/powerpc/include/asm/kup.h | 47 ------------------------------ arch/powerpc/include/asm/uaccess.h | 30 +++++++++---------- 2 files changed, 15 insertions(+), 62 deletions(-) diff --git a/arch/powerpc/include/asm/kup.h b/arch/powerpc/include/asm/kup.h index 3963584ac1cf1..4a4145a244f29 100644 --- a/arch/powerpc/include/asm/kup.h +++ b/arch/powerpc/include/asm/kup.h @@ -131,53 +131,6 @@ static __always_inline void kuap_assert_locked(void) kuap_get_and_assert_locked(); } =20 -static __always_inline void allow_read_from_user(const void __user *from, = unsigned long size) -{ - allow_user_access(NULL, KUAP_READ); -} - -static __always_inline void allow_write_to_user(void __user *to, unsigned = long size) -{ - allow_user_access(to, KUAP_WRITE); -} - -static __always_inline void allow_read_write_user(void __user *to, const v= oid __user *from, - unsigned long size) -{ - allow_user_access(to, KUAP_READ_WRITE); -} - -static __always_inline void prevent_read_from_user(const void __user *from= , unsigned long size) -{ - prevent_user_access(KUAP_READ); -} - -static __always_inline void prevent_write_to_user(void __user *to, unsigne= d long size) -{ - prevent_user_access(KUAP_WRITE); -} - -static __always_inline void prevent_read_write_user(void __user *to, const= void __user *from, - unsigned long size) -{ - prevent_user_access(KUAP_READ_WRITE); -} - -static __always_inline void prevent_current_access_user(void) -{ - prevent_user_access(KUAP_READ_WRITE); -} - -static __always_inline void prevent_current_read_from_user(void) -{ - prevent_user_access(KUAP_READ); -} - -static __always_inline void prevent_current_write_to_user(void) -{ - prevent_user_access(KUAP_WRITE); -} - #endif /* !__ASSEMBLER__ */ =20 #endif /* _ASM_POWERPC_KUAP_H_ */ diff --git a/arch/powerpc/include/asm/uaccess.h b/arch/powerpc/include/asm/= uaccess.h index 3e622e647d622..7846ee59e3747 100644 --- a/arch/powerpc/include/asm/uaccess.h +++ b/arch/powerpc/include/asm/uaccess.h @@ -45,14 +45,14 @@ do { \ __label__ __pu_failed; \ \ - allow_write_to_user(__pu_addr, __pu_size); \ + allow_user_access(__pu_addr, KUAP_WRITE); \ __put_user_size_goto(__pu_val, __pu_addr, __pu_size, __pu_failed); \ - prevent_write_to_user(__pu_addr, __pu_size); \ + prevent_user_access(KUAP_WRITE); \ __pu_err =3D 0; \ break; \ \ __pu_failed: \ - prevent_write_to_user(__pu_addr, __pu_size); \ + prevent_user_access(KUAP_WRITE); \ __pu_err =3D -EFAULT; \ } while (0); \ \ @@ -302,9 +302,9 @@ do { \ \ might_fault(); \ barrier_nospec(); \ - allow_read_from_user(__gu_addr, __gu_size); \ + allow_user_access(NULL, KUAP_READ); \ __get_user_size_allowed(__gu_val, __gu_addr, __gu_size, __gu_err); \ - prevent_read_from_user(__gu_addr, __gu_size); \ + prevent_user_access(KUAP_READ); \ (x) =3D (__typeof__(*(ptr)))__gu_val; \ \ __gu_err; \ @@ -331,9 +331,9 @@ raw_copy_in_user(void __user *to, const void __user *fr= om, unsigned long n) unsigned long ret; =20 barrier_nospec(); - allow_read_write_user(to, from, n); + allow_user_access(to, KUAP_READ_WRITE); ret =3D __copy_tofrom_user(to, from, n); - prevent_read_write_user(to, from, n); + prevent_user_access(KUAP_READ_WRITE); return ret; } #endif /* __powerpc64__ */ @@ -343,9 +343,9 @@ static inline unsigned long raw_copy_from_user(void *to, { unsigned long ret; =20 - allow_read_from_user(from, n); + allow_user_access(NULL, KUAP_READ); ret =3D __copy_tofrom_user((__force void __user *)to, from, n); - prevent_read_from_user(from, n); + prevent_user_access(KUAP_READ); return ret; } =20 @@ -354,9 +354,9 @@ raw_copy_to_user(void __user *to, const void *from, uns= igned long n) { unsigned long ret; =20 - allow_write_to_user(to, n); + allow_user_access(to, KUAP_WRITE); ret =3D __copy_tofrom_user(to, (__force const void __user *)from, n); - prevent_write_to_user(to, n); + prevent_user_access(KUAP_WRITE); return ret; } =20 @@ -367,9 +367,9 @@ static inline unsigned long __clear_user(void __user *a= ddr, unsigned long size) unsigned long ret; =20 might_fault(); - allow_write_to_user(addr, size); + allow_user_access(addr, KUAP_WRITE); ret =3D __arch_clear_user(addr, size); - prevent_write_to_user(addr, size); + prevent_user_access(KUAP_WRITE); return ret; } =20 @@ -397,9 +397,9 @@ copy_mc_to_user(void __user *to, const void *from, unsi= gned long n) { if (check_copy_size(from, n, true)) { if (access_ok(to, n)) { - allow_write_to_user(to, n); + allow_user_access(to, KUAP_WRITE); n =3D copy_mc_generic((void __force *)to, from, n); - prevent_write_to_user(to, n); + prevent_user_access(KUAP_WRITE); } } =20 --=20 2.49.0 From nobody Wed Dec 17 07:35:14 2025 Received: from pegase2.c-s.fr (pegase2.c-s.fr [93.17.235.10]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 2B1A7324B32; Thu, 6 Nov 2025 11:50:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=93.17.235.10 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762429836; cv=none; b=PCfFZh4fB+sFUtx/TrkuCvoB9IuKbl12Nke48OU62jUakP/kkeyJtcEMm9V3c5PX2qOfmNvtfD+n/7YzODUrRybNcvO0PFRMKqBVS5us7OuzScELyJX9Y5UA4tHXS70xD8cDByzVWg8loNMGOUzQOVX2P2KCZsYapHZ71ynMAu4= ARC-Message-Signature: i=1; a=rsa-sha256; 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Thu, 6 Nov 2025 12:32:24 +0100 (CET) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase2.c-s.fr (Postfix) with ESMTP id 4d2KmL1Gslz9sSZ; Thu, 6 Nov 2025 12:32:18 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 168E18B77E; Thu, 6 Nov 2025 12:32:18 +0100 (CET) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id jSiq6pmmL0kj; Thu, 6 Nov 2025 12:32:17 +0100 (CET) Received: from PO20335.idsi0.si.c-s.fr (unknown [192.168.235.99]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 424918B773; Thu, 6 Nov 2025 12:32:17 +0100 (CET) From: Christophe Leroy To: Alexander Viro , Christian Brauner , Jan Kara , Thomas Gleixner , Ingo Molnar , Peter Zijlstra , Darren Hart , Davidlohr Bueso , "Andre Almeida" , Andrew Morton , Eric Dumazet , Kuniyuki Iwashima , Paolo Abeni , Willem de Bruijn , "David S. Miller" , Jakub Kicinski , Simon Horman , Daniel Borkmann , Dave Hansen , Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin Cc: Christophe Leroy , linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Subject: [PATCH v4 07/10] powerpc/uaccess: Refactor user_{read/write/}_access_begin() Date: Thu, 6 Nov 2025 12:31:25 +0100 Message-ID: <0dd24b956d4b974b896d9b5f4fca594e06fb69fa.1762427933.git.christophe.leroy@csgroup.eu> X-Mailer: git-send-email 2.49.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=3587; i=christophe.leroy@csgroup.eu; h=from:subject:message-id; bh=OkVBp0dNkP4Ptywt73R1Ln/6ZQlLCXnewEL9kTrdGjQ=; b=owGbwMvMwCV2d0KB2p7V54MZT6slMWTytGsffp7BqTJB+bSwRHe1BkPvjOWRQlJZDpIMB0qvV byMF3/cUcrCIMbFICumyHL8P/euGV1fUvOn7tKHmcPKBDKEgYtTACbyYxcjw4oZSVF/+z1Cb6WW m/w83VD7PrRQ/c3z3TcUn4o1GRV5hTD8r3AU3tewQVr/YnJJzNsLj1sfnW9b1fo2mFHwzNZPZzN 38wMA X-Developer-Key: i=christophe.leroy@csgroup.eu; a=openpgp; fpr=10FFE6F8B390DE17ACC2632368A92FEB01B8DD78 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" user_read_access_begin() and user_write_access_begin() and user_access_begin() are now very similar. Create a common __user_access_begin() that takes direction as parameter. In order to avoid a warning with the conditional call of barrier_nospec() which is sometimes an empty macro, change it to a do {} while (0). Signed-off-by: Christophe Leroy --- v4: Rebase on top of core-scoped-uaccess tag v2: New --- arch/powerpc/include/asm/barrier.h | 2 +- arch/powerpc/include/asm/uaccess.h | 46 +++++++++--------------------- 2 files changed, 14 insertions(+), 34 deletions(-) diff --git a/arch/powerpc/include/asm/barrier.h b/arch/powerpc/include/asm/= barrier.h index 9e9833faa4af8..9d2f612cfb1d7 100644 --- a/arch/powerpc/include/asm/barrier.h +++ b/arch/powerpc/include/asm/barrier.h @@ -102,7 +102,7 @@ do { \ =20 #else /* !CONFIG_PPC_BARRIER_NOSPEC */ #define barrier_nospec_asm -#define barrier_nospec() +#define barrier_nospec() do {} while (0) #endif /* CONFIG_PPC_BARRIER_NOSPEC */ =20 /* diff --git a/arch/powerpc/include/asm/uaccess.h b/arch/powerpc/include/asm/= uaccess.h index 7846ee59e3747..721d65dbbb2e5 100644 --- a/arch/powerpc/include/asm/uaccess.h +++ b/arch/powerpc/include/asm/uaccess.h @@ -410,50 +410,30 @@ copy_mc_to_user(void __user *to, const void *from, un= signed long n) extern long __copy_from_user_flushcache(void *dst, const void __user *src, unsigned size); =20 -static __must_check __always_inline bool user_access_begin(const void __us= er *ptr, size_t len) +static __must_check __always_inline bool __user_access_begin(const void __= user *ptr, size_t len, + unsigned long dir) { if (unlikely(!access_ok(ptr, len))) return false; =20 might_fault(); =20 - barrier_nospec(); - allow_read_write_user((void __user *)ptr, ptr, len); + if (dir & KUAP_READ) + barrier_nospec(); + allow_user_access((void __user *)ptr, dir); return true; } -#define user_access_begin user_access_begin -#define user_access_end prevent_current_access_user -#define user_access_save prevent_user_access_return -#define user_access_restore restore_user_access =20 -static __must_check __always_inline bool -user_read_access_begin(const void __user *ptr, size_t len) -{ - if (unlikely(!access_ok(ptr, len))) - return false; +#define user_access_begin(p, l) __user_access_begin(p, l, KUAP_READ_WRITE) +#define user_read_access_begin(p, l) __user_access_begin(p, l, KUAP_READ) +#define user_write_access_begin(p, l) __user_access_begin(p, l, KUAP_WRITE) =20 - might_fault(); - - barrier_nospec(); - allow_read_from_user(ptr, len); - return true; -} -#define user_read_access_begin user_read_access_begin -#define user_read_access_end prevent_current_read_from_user +#define user_access_end() prevent_user_access(KUAP_READ_WRITE) +#define user_read_access_end() prevent_user_access(KUAP_READ) +#define user_write_access_end() prevent_user_access(KUAP_WRITE) =20 -static __must_check __always_inline bool -user_write_access_begin(const void __user *ptr, size_t len) -{ - if (unlikely(!access_ok(ptr, len))) - return false; - - might_fault(); - - allow_write_to_user((void __user *)ptr, len); - return true; -} -#define user_write_access_begin user_write_access_begin -#define user_write_access_end prevent_current_write_to_user +#define user_access_save prevent_user_access_return +#define user_access_restore restore_user_access =20 #define arch_unsafe_get_user(x, p, e) do { \ __long_type(*(p)) __gu_val; \ --=20 2.49.0 From nobody Wed Dec 17 07:35:14 2025 Received: from pegase2.c-s.fr (pegase2.c-s.fr [93.17.235.10]) by smtp.subspace.kernel.org (Postfix) with ESMTP id B5D2F2E8B8D; 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Thu, 6 Nov 2025 12:32:19 +0100 (CET) Received: from PO20335.idsi0.si.c-s.fr (unknown [192.168.235.99]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 0FF3E8B77B; Thu, 6 Nov 2025 12:32:18 +0100 (CET) From: Christophe Leroy To: Alexander Viro , Christian Brauner , Jan Kara , Thomas Gleixner , Ingo Molnar , Peter Zijlstra , Darren Hart , Davidlohr Bueso , "Andre Almeida" , Andrew Morton , Eric Dumazet , Kuniyuki Iwashima , Paolo Abeni , Willem de Bruijn , "David S. Miller" , Jakub Kicinski , Simon Horman , Daniel Borkmann , Dave Hansen , Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin Cc: Christophe Leroy , linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Subject: [PATCH v4 08/10] powerpc/32s: Fix segments setup when TASK_SIZE is not a multiple of 256M Date: Thu, 6 Nov 2025 12:31:26 +0100 Message-ID: <7d9f082fcf743b91abf9530902ddc9b050b8c6d1.1762427933.git.christophe.leroy@csgroup.eu> X-Mailer: git-send-email 2.49.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=4823; i=christophe.leroy@csgroup.eu; h=from:subject:message-id; bh=zuDbabfiUqTOLj4mSt5xh9aoc6FtrRisXd/DqchyYms=; b=owGbwMvMwCV2d0KB2p7V54MZT6slMWTytGs3valleN7uUpOxZP0twUuf2Vbv8lvUsFLgiLwTB /f+3svOHaUsDGJcDLJiiizH/3PvmtH1JTV/6i59mDmsTCBDGLg4BWAi0raMDCduZDiHHQtrCns2 52DKVaHJjpHCG5ZK7/mis8Tm6ky71jSGfzYRWfJf9zJcf2Ox8zF/mNSsPwnXl5yu4Dvyf+P1zZ6 iMhwA X-Developer-Key: i=christophe.leroy@csgroup.eu; a=openpgp; fpr=10FFE6F8B390DE17ACC2632368A92FEB01B8DD78 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" For book3s/32 it is assumed that TASK_SIZE is a multiple of 256 Mbytes, but Kconfig allows any value for TASK_SIZE. In all relevant calculations, align TASK_SIZE to the upper 256 Mbytes boundary. Also use ASM_CONST() in the definition of TASK_SIZE to ensure it is seen as an unsigned constant. Signed-off-by: Christophe Leroy --- arch/powerpc/include/asm/book3s/32/mmu-hash.h | 5 ++++- arch/powerpc/include/asm/task_size_32.h | 2 +- arch/powerpc/kernel/asm-offsets.c | 2 +- arch/powerpc/kernel/head_book3s_32.S | 6 +++--- arch/powerpc/mm/book3s32/mmu.c | 2 +- arch/powerpc/mm/ptdump/segment_regs.c | 2 +- 6 files changed, 11 insertions(+), 8 deletions(-) diff --git a/arch/powerpc/include/asm/book3s/32/mmu-hash.h b/arch/powerpc/i= nclude/asm/book3s/32/mmu-hash.h index 8435bf3cdabfa..387d370c8a358 100644 --- a/arch/powerpc/include/asm/book3s/32/mmu-hash.h +++ b/arch/powerpc/include/asm/book3s/32/mmu-hash.h @@ -192,12 +192,15 @@ extern s32 patch__hash_page_B, patch__hash_page_C; extern s32 patch__flush_hash_A0, patch__flush_hash_A1, patch__flush_hash_A= 2; extern s32 patch__flush_hash_B; =20 +#include +#include + #include #include =20 static __always_inline void update_user_segment(u32 n, u32 val) { - if (n << 28 < TASK_SIZE) + if (n << 28 < ALIGN(TASK_SIZE, SZ_256M)) mtsr(val + n * 0x111, n << 28); } =20 diff --git a/arch/powerpc/include/asm/task_size_32.h b/arch/powerpc/include= /asm/task_size_32.h index de7290ee770fb..30edc21f71fbd 100644 --- a/arch/powerpc/include/asm/task_size_32.h +++ b/arch/powerpc/include/asm/task_size_32.h @@ -6,7 +6,7 @@ #error User TASK_SIZE overlaps with KERNEL_START address #endif =20 -#define TASK_SIZE (CONFIG_TASK_SIZE) +#define TASK_SIZE ASM_CONST(CONFIG_TASK_SIZE) =20 /* * This decides where the kernel will search for a free chunk of vm space = during diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-of= fsets.c index a4bc80b30410a..46149f326fd42 100644 --- a/arch/powerpc/kernel/asm-offsets.c +++ b/arch/powerpc/kernel/asm-offsets.c @@ -331,7 +331,7 @@ int main(void) =20 #ifndef CONFIG_PPC64 DEFINE(TASK_SIZE, TASK_SIZE); - DEFINE(NUM_USER_SEGMENTS, TASK_SIZE>>28); + DEFINE(NUM_USER_SEGMENTS, ALIGN(TASK_SIZE, SZ_256M) >> 28); #endif /* ! CONFIG_PPC64 */ =20 /* datapage offsets for use by vdso */ diff --git a/arch/powerpc/kernel/head_book3s_32.S b/arch/powerpc/kernel/hea= d_book3s_32.S index cb2bca76be535..c1779455ea32f 100644 --- a/arch/powerpc/kernel/head_book3s_32.S +++ b/arch/powerpc/kernel/head_book3s_32.S @@ -420,7 +420,7 @@ InstructionTLBMiss: lwz r2,0(r2) /* get pmd entry */ #ifdef CONFIG_EXECMEM rlwinm r3, r0, 4, 0xf - subi r3, r3, (TASK_SIZE >> 28) & 0xf + subi r3, r3, NUM_USER_SEGMENTS #endif rlwinm. r2,r2,0,0,19 /* extract address of pte page */ beq- InstructionAddressInvalid /* return if no mapping */ @@ -475,7 +475,7 @@ DataLoadTLBMiss: lwz r2,0(r1) /* get pmd entry */ rlwinm r3, r0, 4, 0xf rlwinm. r2,r2,0,0,19 /* extract address of pte page */ - subi r3, r3, (TASK_SIZE >> 28) & 0xf + subi r3, r3, NUM_USER_SEGMENTS beq- 2f /* bail if no mapping */ 1: rlwimi r2,r0,22,20,29 /* insert next 10 bits of address */ lwz r2,0(r2) /* get linux-style pte */ @@ -554,7 +554,7 @@ DataStoreTLBMiss: lwz r2,0(r1) /* get pmd entry */ rlwinm r3, r0, 4, 0xf rlwinm. r2,r2,0,0,19 /* extract address of pte page */ - subi r3, r3, (TASK_SIZE >> 28) & 0xf + subi r3, r3, NUM_USER_SEGMENTS beq- 2f /* bail if no mapping */ 1: rlwimi r2,r0,22,20,29 /* insert next 10 bits of address */ diff --git a/arch/powerpc/mm/book3s32/mmu.c b/arch/powerpc/mm/book3s32/mmu.c index c42ecdf94e48c..37eefc6786a72 100644 --- a/arch/powerpc/mm/book3s32/mmu.c +++ b/arch/powerpc/mm/book3s32/mmu.c @@ -225,7 +225,7 @@ int mmu_mark_initmem_nx(void) =20 BUILD_BUG_ON(ALIGN_DOWN(MODULES_VADDR, SZ_256M) < TASK_SIZE); =20 - for (i =3D TASK_SIZE >> 28; i < 16; i++) { + for (i =3D ALIGN(TASK_SIZE, SZ_256M) >> 28; i < 16; i++) { /* Do not set NX on VM space for modules */ if (is_module_segment(i << 28)) continue; diff --git a/arch/powerpc/mm/ptdump/segment_regs.c b/arch/powerpc/mm/ptdump= /segment_regs.c index 9df3af8d481f1..c06704b18a2c8 100644 --- a/arch/powerpc/mm/ptdump/segment_regs.c +++ b/arch/powerpc/mm/ptdump/segment_regs.c @@ -31,7 +31,7 @@ static int sr_show(struct seq_file *m, void *v) int i; =20 seq_puts(m, "---[ User Segments ]---\n"); - for (i =3D 0; i < TASK_SIZE >> 28; i++) + for (i =3D 0; i < ALIGN(TASK_SIZE, SZ_256M) >> 28; i++) seg_show(m, i); =20 seq_puts(m, "\n---[ Kernel Segments ]---\n"); --=20 2.49.0 From nobody Wed Dec 17 07:35:14 2025 Received: from pegase2.c-s.fr (pegase2.c-s.fr [93.17.235.10]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 32EB73195FB; Thu, 6 Nov 2025 11:50:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=93.17.235.10 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762429814; cv=none; b=kqQ0pausPLIp2rUhDBorGm7iP8eHunoJRuUJmc7N8gGiLeCmGt/x/yyJVI6Z8/pi6D9ptMoKTBoSEexGhAUjvLnQbZQhqgsD9faWfLx80ulYdUqmH3V5yOYapcrMLWS+mJGVI55XTJNs0/KdzoOYsvXXy0y3e3uYy4BgwBOBeBk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762429814; c=relaxed/simple; bh=Im9UZffnD6V0KfkjwdG+DCiJql6cfGfj6sEhY/Erl40=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=tnifTKMcpp7dXZy4WsKleCtYxYqWj8S7K2nN4hmr1p5zHORNb/pL4QELV1Jaisa7tfCubAqVCW5n3C0V3u8phR2TCY7sX/PLVOr0HuQKW8FGa+Fp0pRWEFj2pFdKZdGPC8KSCph9Poc9d5pDxRQJCjXdN79brTwxrDyAfjYIY9c= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=csgroup.eu; spf=pass smtp.mailfrom=csgroup.eu; arc=none smtp.client-ip=93.17.235.10 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=csgroup.eu Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=csgroup.eu Received: from localhost (mailhub4.si.c-s.fr [172.26.127.67]) by localhost (Postfix) with ESMTP id 4d2KmV0yffz9sSs; Thu, 6 Nov 2025 12:32:26 +0100 (CET) X-Virus-Scanned: amavisd-new at c-s.fr Received: from pegase2.c-s.fr ([172.26.127.65]) by localhost (pegase2.c-s.fr [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 1nW23pXeJc1z; Thu, 6 Nov 2025 12:32:26 +0100 (CET) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase2.c-s.fr (Postfix) with ESMTP id 4d2KmN0dwfz9sSm; Thu, 6 Nov 2025 12:32:20 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id F27D38B77E; Thu, 6 Nov 2025 12:32:19 +0100 (CET) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id aCVQquw64jeA; Thu, 6 Nov 2025 12:32:19 +0100 (CET) Received: from PO20335.idsi0.si.c-s.fr (unknown [192.168.235.99]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 2A1EA8B773; Thu, 6 Nov 2025 12:32:19 +0100 (CET) From: Christophe Leroy To: Alexander Viro , Christian Brauner , Jan Kara , Thomas Gleixner , Ingo Molnar , Peter Zijlstra , Darren Hart , Davidlohr Bueso , "Andre Almeida" , Andrew Morton , Eric Dumazet , Kuniyuki Iwashima , Paolo Abeni , Willem de Bruijn , "David S. Miller" , Jakub Kicinski , Simon Horman , Daniel Borkmann , Dave Hansen , Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin Cc: Christophe Leroy , linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Subject: [PATCH v4 09/10] powerpc/32: Automatically adapt TASK_SIZE based on constraints Date: Thu, 6 Nov 2025 12:31:27 +0100 Message-ID: X-Mailer: git-send-email 2.49.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=6170; i=christophe.leroy@csgroup.eu; h=from:subject:message-id; bh=Im9UZffnD6V0KfkjwdG+DCiJql6cfGfj6sEhY/Erl40=; b=owGbwMvMwCV2d0KB2p7V54MZT6slMWTytGufSjN8YPOiI6rmU7zZb61+yz+nMuR/19d6hi36f mXq1X/cHaUsDGJcDLJiiizH/3PvmtH1JTV/6i59mDmsTCBDGLg4BWAiW8wZGb6Gnd6h8TPC2rgo cKLR47jFHLenPVje7Gs10abnf9mC9bwM/8zsZXu+5XC6SQsyC8tu1/ngfX966yfn1+oLvzXVVzz ZygwA X-Developer-Key: i=christophe.leroy@csgroup.eu; a=openpgp; fpr=10FFE6F8B390DE17ACC2632368A92FEB01B8DD78 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" At the time being, TASK_SIZE can be customized by the user via Kconfig but it is not possible to check all constraints in Kconfig. Impossible setups are detected at compile time with BUILD_BUG() but that leads to build failure when setting crazy values. It is not a problem on its own because the user will usually either use the default value or set a well thought value. However build robots generate crazy random configs that lead to build failures, and build robots see it as a regression every time a patch adds such a constraint. So instead of failing the build when the custom TASK_SIZE is too big, just adjust it to the maximum possible value matching the setup. Several architectures already calculate TASK_SIZE based on other parameters and options. In order to do so, move MODULES_VADDR calculation into task_size_32.h and ensure that: - On book3s/32, userspace and module area have their own segments (256M) - On 8xx, userspace has its own full PGDIR entries (4M) Then TASK_SIZE is guaranteed to be correct so remove related BUILD_BUG()s. Signed-off-by: Christophe Leroy --- arch/powerpc/Kconfig | 3 +-- arch/powerpc/include/asm/book3s/32/pgtable.h | 4 --- arch/powerpc/include/asm/nohash/32/mmu-8xx.h | 4 --- arch/powerpc/include/asm/task_size_32.h | 26 ++++++++++++++++++++ arch/powerpc/mm/book3s32/mmu.c | 2 -- arch/powerpc/mm/mem.c | 2 -- arch/powerpc/mm/nohash/8xx.c | 2 -- 7 files changed, 27 insertions(+), 16 deletions(-) diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index e24f4d88885ae..10a8d4a5fea1f 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -1292,9 +1292,8 @@ config TASK_SIZE_BOOL Say N here unless you know what you are doing. =20 config TASK_SIZE - hex "Size of user task space" if TASK_SIZE_BOOL + hex "Size of maximum user task space" if TASK_SIZE_BOOL default "0x80000000" if PPC_8xx - default "0xb0000000" if PPC_BOOK3S_32 && EXECMEM default "0xc0000000" =20 config MODULES_SIZE_BOOL diff --git a/arch/powerpc/include/asm/book3s/32/pgtable.h b/arch/powerpc/in= clude/asm/book3s/32/pgtable.h index 87dcca962be78..41ae404d0b7a6 100644 --- a/arch/powerpc/include/asm/book3s/32/pgtable.h +++ b/arch/powerpc/include/asm/book3s/32/pgtable.h @@ -195,10 +195,6 @@ void unmap_kernel_page(unsigned long va); #define VMALLOC_END ioremap_bot #endif =20 -#define MODULES_END ALIGN_DOWN(PAGE_OFFSET, SZ_256M) -#define MODULES_SIZE (CONFIG_MODULES_SIZE * SZ_1M) -#define MODULES_VADDR (MODULES_END - MODULES_SIZE) - #ifndef __ASSEMBLER__ #include #include diff --git a/arch/powerpc/include/asm/nohash/32/mmu-8xx.h b/arch/powerpc/in= clude/asm/nohash/32/mmu-8xx.h index f19115db8072f..74ad32e1588cf 100644 --- a/arch/powerpc/include/asm/nohash/32/mmu-8xx.h +++ b/arch/powerpc/include/asm/nohash/32/mmu-8xx.h @@ -170,10 +170,6 @@ =20 #define mmu_linear_psize MMU_PAGE_8M =20 -#define MODULES_END PAGE_OFFSET -#define MODULES_SIZE (CONFIG_MODULES_SIZE * SZ_1M) -#define MODULES_VADDR (MODULES_END - MODULES_SIZE) - #ifndef __ASSEMBLER__ =20 #include diff --git a/arch/powerpc/include/asm/task_size_32.h b/arch/powerpc/include= /asm/task_size_32.h index 30edc21f71fbd..42a64bbd1964f 100644 --- a/arch/powerpc/include/asm/task_size_32.h +++ b/arch/powerpc/include/asm/task_size_32.h @@ -2,11 +2,37 @@ #ifndef _ASM_POWERPC_TASK_SIZE_32_H #define _ASM_POWERPC_TASK_SIZE_32_H =20 +#include + #if CONFIG_TASK_SIZE > CONFIG_KERNEL_START #error User TASK_SIZE overlaps with KERNEL_START address #endif =20 +#ifdef CONFIG_PPC_8xx +#define MODULES_END ASM_CONST(CONFIG_PAGE_OFFSET) +#define MODULES_SIZE (CONFIG_MODULES_SIZE * SZ_1M) +#define MODULES_VADDR (MODULES_END - MODULES_SIZE) +#define MODULES_BASE (MODULES_VADDR & ~(UL(SZ_4M) - 1)) +#define USER_TOP MODULES_BASE +#endif + +#ifdef CONFIG_PPC_BOOK3S_32 +#define MODULES_END (ASM_CONST(CONFIG_PAGE_OFFSET) & ~(UL(SZ_256M) - 1)) +#define MODULES_SIZE (CONFIG_MODULES_SIZE * SZ_1M) +#define MODULES_VADDR (MODULES_END - MODULES_SIZE) +#define MODULES_BASE (MODULES_VADDR & ~(UL(SZ_256M) - 1)) +#define USER_TOP MODULES_BASE +#endif + +#ifndef USER_TOP +#define USER_TOP ASM_CONST(CONFIG_PAGE_OFFSET) +#endif + +#if CONFIG_TASK_SIZE < USER_TOP #define TASK_SIZE ASM_CONST(CONFIG_TASK_SIZE) +#else +#define TASK_SIZE USER_TOP +#endif =20 /* * This decides where the kernel will search for a free chunk of vm space = during diff --git a/arch/powerpc/mm/book3s32/mmu.c b/arch/powerpc/mm/book3s32/mmu.c index 37eefc6786a72..07660e8badbda 100644 --- a/arch/powerpc/mm/book3s32/mmu.c +++ b/arch/powerpc/mm/book3s32/mmu.c @@ -223,8 +223,6 @@ int mmu_mark_initmem_nx(void) =20 update_bats(); =20 - BUILD_BUG_ON(ALIGN_DOWN(MODULES_VADDR, SZ_256M) < TASK_SIZE); - for (i =3D ALIGN(TASK_SIZE, SZ_256M) >> 28; i < 16; i++) { /* Do not set NX on VM space for modules */ if (is_module_segment(i << 28)) diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c index 3ddbfdbfa9413..bc0f1a9eb0bc0 100644 --- a/arch/powerpc/mm/mem.c +++ b/arch/powerpc/mm/mem.c @@ -401,8 +401,6 @@ struct execmem_info __init *execmem_arch_setup(void) #ifdef MODULES_VADDR unsigned long limit =3D (unsigned long)_etext - SZ_32M; =20 - BUILD_BUG_ON(TASK_SIZE > MODULES_VADDR); - /* First try within 32M limit from _etext to avoid branch trampolines */ if (MODULES_VADDR < PAGE_OFFSET && MODULES_END > limit) { start =3D limit; diff --git a/arch/powerpc/mm/nohash/8xx.c b/arch/powerpc/mm/nohash/8xx.c index ab1505cf42bf5..a9d3f4729eada 100644 --- a/arch/powerpc/mm/nohash/8xx.c +++ b/arch/powerpc/mm/nohash/8xx.c @@ -209,8 +209,6 @@ void __init setup_initial_memory_limit(phys_addr_t firs= t_memblock_base, =20 /* 8xx can only access 32MB at the moment */ memblock_set_current_limit(min_t(u64, first_memblock_size, SZ_32M)); 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Thu, 6 Nov 2025 12:32:20 +0100 (CET) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id CDTSk4xuxt-8; Thu, 6 Nov 2025 12:32:20 +0100 (CET) Received: from PO20335.idsi0.si.c-s.fr (unknown [192.168.235.99]) by messagerie.si.c-s.fr (Postfix) with ESMTP id EACB38B77B; Thu, 6 Nov 2025 12:32:19 +0100 (CET) From: Christophe Leroy To: Alexander Viro , Christian Brauner , Jan Kara , Thomas Gleixner , Ingo Molnar , Peter Zijlstra , Darren Hart , Davidlohr Bueso , "Andre Almeida" , Andrew Morton , Eric Dumazet , Kuniyuki Iwashima , Paolo Abeni , Willem de Bruijn , "David S. Miller" , Jakub Kicinski , Simon Horman , Daniel Borkmann , Dave Hansen , Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin Cc: Christophe Leroy , linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Subject: [PATCH v4 10/10] powerpc/uaccess: Implement masked user access Date: Thu, 6 Nov 2025 12:31:28 +0100 Message-ID: <5c80dddf8c7b1e75f08b3f42bddde891d6ea3f64.1762427933.git.christophe.leroy@csgroup.eu> X-Mailer: git-send-email 2.49.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=9884; i=christophe.leroy@csgroup.eu; h=from:subject:message-id; bh=KMw75R3CQH/0ajuqHZB360qVMTa6I2ec71KamG0K8Gg=; b=owGbwMvMwCV2d0KB2p7V54MZT6slMWTytGuf9TyeUesdern+qfDuDYYbd9rpbEiwT/ds6/sxf V0si/mpjlIWBjEuBlkxRZbj/7l3zej6kpo/dZc+zBxWJpAhDFycAjARB2WG/7HLlHN+nV15OTlD IupYwjPn7lUrcs++PLz1ub/FAq+m00sY/orPm5psviJK/b7Fp+Vyql7Hlre/ZjzcLxjSUCa7x33 LH14A X-Developer-Key: i=christophe.leroy@csgroup.eu; a=openpgp; fpr=10FFE6F8B390DE17ACC2632368A92FEB01B8DD78 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Masked user access avoids the address/size verification by access_ok(). Allthough its main purpose is to skip the speculation in the verification of user address and size hence avoid the need of spec mitigation, it also has the advantage of reducing the amount of instructions required so it even benefits to platforms that don't need speculation mitigation, especially when the size of the copy is not know at build time. So implement masked user access on powerpc. The only requirement is to have memory gap that faults between the top user space and the real start of kernel area. On 64 bits platforms the address space is divided that way: 0xffffffffffffffff +------------------+ | | | kernel space | | | 0xc000000000000000 +------------------+ <=3D=3D PAGE_OFFSET |//////////////////| |//////////////////| 0x8000000000000000 |//////////////////| |//////////////////| |//////////////////| 0x0010000000000000 +------------------+ <=3D=3D TASK_SIZE_MAX | | | user space | | | 0x0000000000000000 +------------------+ Kernel is always above 0x8000000000000000 and user always below, with a gap in-between. It leads to a 3 instructions sequence: 150: 7c 69 fe 76 sradi r9,r3,63 154: 79 29 00 40 clrldi r9,r9,1 158: 7c 63 48 78 andc r3,r3,r9 This sequence leaves r3 unmodified when it is below 0x8000000000000000 and clamps it to 0x8000000000000000 if it is above. On 32 bits it is more tricky. In theory user space can go up to 0xbfffffff while kernel will usually start at 0xc0000000. So a gap needs to be added in-between. Allthough in theory a single 4k page would suffice, it is easier and more efficient to enforce a 128k gap below kernel, as it simplifies the masking. e500 has the isel instruction which allows selecting one value or the other without branch and that instruction is not speculative, so use it. Allthough GCC usually generates code using that instruction, it is safer to use inline assembly to be sure. The result is: 14: 3d 20 bf fe lis r9,-16386 18: 7c 03 48 40 cmplw r3,r9 1c: 7c 69 18 5e iselgt r3,r9,r3 On other ones, when kernel space is over 0x80000000 and user space is below, the logic in mask_user_address_simple() leads to a 3 instruction sequence: 64: 7c 69 fe 70 srawi r9,r3,31 68: 55 29 00 7e clrlwi r9,r9,1 6c: 7c 63 48 78 andc r3,r3,r9 This is the default on powerpc 8xx. When the limit between user space and kernel space is not 0x80000000, mask_user_address_32() is used and a 6 instructions sequence is generated: 24: 54 69 7c 7e srwi r9,r3,17 28: 21 29 57 ff subfic r9,r9,22527 2c: 7d 29 fe 70 srawi r9,r9,31 30: 75 2a b0 00 andis. r10,r9,45056 34: 7c 63 48 78 andc r3,r3,r9 38: 7c 63 53 78 or r3,r3,r10 The constraint is that TASK_SIZE be aligned to 128K in order to get the most optimal number of instructions. When CONFIG_PPC_BARRIER_NOSPEC is not defined, fallback on the test-based masking as it is quicker than the 6 instructions sequence but not quicker than the 3 instructions sequences above. As an exemple, allthough barrier_nospec() voids on the 8xx, this change has the following impact on strncpy_from_user(): the length of the function is reduced from 488 to 340 bytes: Start of the function with the patch: 00000000 : 0: 7c ab 2b 79 mr. r11,r5 4: 40 81 01 40 ble 144 8: 7c 89 fe 70 srawi r9,r4,31 c: 55 29 00 7e clrlwi r9,r9,1 10: 7c 84 48 78 andc r4,r4,r9 14: 3d 20 dc 00 lis r9,-9216 18: 7d 3a c3 a6 mtspr 794,r9 1c: 2f 8b 00 03 cmpwi cr7,r11,3 20: 40 9d 00 b4 ble cr7,d4 ... Start of the function without the patch: 00000000 : 0: 7c a0 2b 79 mr. r0,r5 4: 40 81 01 10 ble 114 8: 2f 84 00 00 cmpwi cr7,r4,0 c: 41 9c 01 30 blt cr7,13c 10: 3d 20 80 00 lis r9,-32768 14: 7d 24 48 50 subf r9,r4,r9 18: 7f 80 48 40 cmplw cr7,r0,r9 1c: 7c 05 03 78 mr r5,r0 20: 41 9d 01 00 bgt cr7,120 24: 3d 20 80 00 lis r9,-32768 28: 7d 25 48 50 subf r9,r5,r9 2c: 7f 84 48 40 cmplw cr7,r4,r9 30: 38 e0 ff f2 li r7,-14 34: 41 9d 00 e4 bgt cr7,118 38: 94 21 ff e0 stwu r1,-32(r1) 3c: 3d 20 dc 00 lis r9,-9216 40: 7d 3a c3 a6 mtspr 794,r9 44: 2b 85 00 03 cmplwi cr7,r5,3 48: 40 9d 01 6c ble cr7,1b4 ... 118: 7c e3 3b 78 mr r3,r7 11c: 4e 80 00 20 blr 120: 7d 25 4b 78 mr r5,r9 124: 3d 20 80 00 lis r9,-32768 128: 7d 25 48 50 subf r9,r5,r9 12c: 7f 84 48 40 cmplw cr7,r4,r9 130: 38 e0 ff f2 li r7,-14 134: 41 bd ff e4 bgt cr7,118 138: 4b ff ff 00 b 38 13c: 38 e0 ff f2 li r7,-14 140: 4b ff ff d8 b 118 ... Signed-off-by: Christophe Leroy --- v4: Rebase on top of core-scoped-uaccess tag and simplified as suggested by= Gabriel v3: Rewrite mask_user_address_simple() for a smaller result on powerpc64, s= uggested by Gabriel v2: Added 'likely()' to the test in mask_user_address_fallback() --- arch/powerpc/include/asm/task_size_32.h | 6 +- arch/powerpc/include/asm/uaccess.h | 76 +++++++++++++++++++++++++ 2 files changed, 79 insertions(+), 3 deletions(-) diff --git a/arch/powerpc/include/asm/task_size_32.h b/arch/powerpc/include= /asm/task_size_32.h index 42a64bbd1964f..725ddbf06217f 100644 --- a/arch/powerpc/include/asm/task_size_32.h +++ b/arch/powerpc/include/asm/task_size_32.h @@ -13,7 +13,7 @@ #define MODULES_SIZE (CONFIG_MODULES_SIZE * SZ_1M) #define MODULES_VADDR (MODULES_END - MODULES_SIZE) #define MODULES_BASE (MODULES_VADDR & ~(UL(SZ_4M) - 1)) -#define USER_TOP MODULES_BASE +#define USER_TOP (MODULES_BASE - SZ_4M) #endif =20 #ifdef CONFIG_PPC_BOOK3S_32 @@ -21,11 +21,11 @@ #define MODULES_SIZE (CONFIG_MODULES_SIZE * SZ_1M) #define MODULES_VADDR (MODULES_END - MODULES_SIZE) #define MODULES_BASE (MODULES_VADDR & ~(UL(SZ_256M) - 1)) -#define USER_TOP MODULES_BASE +#define USER_TOP (MODULES_BASE - SZ_4M) #endif =20 #ifndef USER_TOP -#define USER_TOP ASM_CONST(CONFIG_PAGE_OFFSET) +#define USER_TOP ((ASM_CONST(CONFIG_PAGE_OFFSET) - SZ_128K) & ~(UL(SZ_128K= ) - 1)) #endif =20 #if CONFIG_TASK_SIZE < USER_TOP diff --git a/arch/powerpc/include/asm/uaccess.h b/arch/powerpc/include/asm/= uaccess.h index 721d65dbbb2e5..ba1d878c3f404 100644 --- a/arch/powerpc/include/asm/uaccess.h +++ b/arch/powerpc/include/asm/uaccess.h @@ -2,6 +2,8 @@ #ifndef _ARCH_POWERPC_UACCESS_H #define _ARCH_POWERPC_UACCESS_H =20 +#include + #include #include #include @@ -435,6 +437,80 @@ static __must_check __always_inline bool __user_access= _begin(const void __user * #define user_access_save prevent_user_access_return #define user_access_restore restore_user_access =20 +/* + * Masking the user address is an alternative to a conditional + * user_access_begin that can avoid the fencing. This only works + * for dense accesses starting at the address. + */ +static inline void __user *mask_user_address_simple(const void __user *ptr) +{ + unsigned long addr =3D (unsigned long)ptr; + unsigned long mask =3D (unsigned long)(((long)addr >> (BITS_PER_LONG - 1)= ) & LONG_MAX); + + return (void __user *)(addr & ~mask); +} + +static inline void __user *mask_user_address_isel(const void __user *ptr) +{ + unsigned long addr; + + asm("cmplw %1, %2; iselgt %0, %2, %1" : "=3Dr"(addr) : "r"(ptr), "r"(TASK= _SIZE) : "cr0"); + + return (void __user *)addr; +} + +/* TASK_SIZE is a multiple of 128K for shifting by 17 to the right */ +static inline void __user *mask_user_address_32(const void __user *ptr) +{ + unsigned long addr =3D (unsigned long)ptr; + unsigned long mask =3D (unsigned long)((long)((TASK_SIZE >> 17) - 1 - (ad= dr >> 17)) >> 31); + + addr =3D (addr & ~mask) | (TASK_SIZE & mask); + + return (void __user *)addr; +} + +static inline void __user *mask_user_address_fallback(const void __user *p= tr) +{ + unsigned long addr =3D (unsigned long)ptr; + + return (void __user *)(likely(addr < TASK_SIZE) ? addr : TASK_SIZE); +} + +static inline void __user *mask_user_address(const void __user *ptr) +{ +#ifdef MODULES_VADDR + const unsigned long border =3D MODULES_VADDR; +#else + const unsigned long border =3D PAGE_OFFSET; +#endif + + if (IS_ENABLED(CONFIG_PPC64)) + return mask_user_address_simple(ptr); + if (IS_ENABLED(CONFIG_E500)) + return mask_user_address_isel(ptr); + if (TASK_SIZE <=3D UL(SZ_2G) && border >=3D UL(SZ_2G)) + return mask_user_address_simple(ptr); + if (IS_ENABLED(CONFIG_PPC_BARRIER_NOSPEC)) + return mask_user_address_32(ptr); + return mask_user_address_fallback(ptr); +} + +static __always_inline void __user *__masked_user_access_begin(const void = __user *p, + unsigned long dir) +{ + void __user *ptr =3D mask_user_address(p); + + might_fault(); + allow_user_access(ptr, dir); + + return ptr; +} + +#define masked_user_access_begin(p) __masked_user_access_begin(p, KUAP_REA= D_WRITE) +#define masked_user_read_access_begin(p) __masked_user_access_begin(p, KUA= P_READ) +#define masked_user_write_access_begin(p) __masked_user_access_begin(p, KU= AP_WRITE) + #define arch_unsafe_get_user(x, p, e) do { \ __long_type(*(p)) __gu_val; \ __typeof__(*(p)) __user *__gu_addr =3D (p); \ --=20 2.49.0