From patchwork Wed May 23 15:14:03 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florian Weimer X-Patchwork-Id: 27464 Received: (qmail 64057 invoked by alias); 23 May 2018 15:14:09 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Delivered-To: mailing list libc-alpha@sourceware.org Received: (qmail 64045 invoked by uid 89); 23 May 2018 15:14:08 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-23.8 required=5.0 tests=AWL, BAYES_00, GIT_PATCH_0, GIT_PATCH_1, GIT_PATCH_2, GIT_PATCH_3, KAM_LAZY_DOMAIN_SECURITY, KAM_SHORT, SPF_HELO_PASS autolearn=ham version=3.3.2 spammy=keys, allocates, AMR, amr X-HELO: mx1.redhat.com To: GNU C Library From: Florian Weimer Subject: [PATCH] Implement protection key support for POWER Message-ID: Date: Wed, 23 May 2018 17:14:03 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 This still does not address the misc/tst-pkeys failure because there are kernel bugs. I'm not entirely sure if the 32-bit AMR mapping is correct because the kernel allocates keys starting with the MSB position. If in doubt, we could make this specific to powerpc64. Thanks, Florian Subject: [PATCH] powerpc: Implement memory protection key support To: libc-alpha@sourceware.org This commit adds the architecture-specific implementations for pkey_set and pkey_get. Execute-only keys are not yet supported. 2018-05-23 Florian Weimer * sysdeps/unix/sysv/linux/powerpc/arch-pkey.h: New file. * sysdeps/unix/sysv/linux/powerpc/pkey_set.c: Likewise. * sysdeps/unix/sysv/linux/powerpc/pkey_get.c: Likewise. diff --git a/sysdeps/unix/sysv/linux/powerpc/arch-pkey.h b/sysdeps/unix/sysv/linux/powerpc/arch-pkey.h new file mode 100644 index 0000000000..9431826a68 --- /dev/null +++ b/sysdeps/unix/sysv/linux/powerpc/arch-pkey.h @@ -0,0 +1,55 @@ +/* Helper functions for manipulating memory protection keys. + Copyright (C) 2017-2018 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#ifndef _ARCH_PKEY_H +#define _ARCH_PKEY_H + +/* Read and write access bits in the AMR register. Needs to be + translated from and to PKEY_DISABLE_* flags. */ +#define PKEY_AMR_READ 1UL +#define PKEY_AMR_WRITE 2UL + +/* Return the value of the AMR register. */ +static inline unsigned long int +pkey_read (void) +{ + unsigned long int result; + __asm__ volatile ("mfspr %0, 13" : "=r" (result)); + return result; +} + +/* Overwrite the AMR register with VALUE. */ +static inline void +pkey_write (unsigned long int value) +{ + __asm__ volatile ("mtspr 13, %0" : : "r" (value)); +} + +/* Number of the largest supported key. This depends on the width of + the AMR register. */ +#define PKEY_MAX (sizeof (unsigned long int) * 8 / 2 - 1) +_Static_assert (PKEY_MAX == 15 || PKEY_MAX == 31, "PKEY_MAX value"); + +/* Translate key number into AMR index position. */ +static inline int +pkey_index (int key) +{ + return 2 * (PKEY_MAX - key); +} + +#endif /* _ARCH_PKEY_H */ diff --git a/sysdeps/unix/sysv/linux/powerpc/pkey_get.c b/sysdeps/unix/sysv/linux/powerpc/pkey_get.c new file mode 100644 index 0000000000..9c315a4766 --- /dev/null +++ b/sysdeps/unix/sysv/linux/powerpc/pkey_get.c @@ -0,0 +1,42 @@ +/* Reading the per-thread memory protection key, x86_64 version. + Copyright (C) 2017-2018 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#include +#include +#include + +int +pkey_get (int key) +{ + if (key < 0 || key > PKEY_MAX) + { + __set_errno (EINVAL); + return -1; + } + unsigned int index = pkey_index (key); + unsigned long int amr = pkey_read (); + unsigned int bits = (amr >> index) & 3; + + /* Translate from AMR values. PKEY_AMR_READ standing alone is not + currently representable. */ + if (bits & PKEY_AMR_READ) + return PKEY_DISABLE_ACCESS; + else if (bits == PKEY_AMR_WRITE) + return PKEY_DISABLE_WRITE; + return 0; +} diff --git a/sysdeps/unix/sysv/linux/powerpc/pkey_set.c b/sysdeps/unix/sysv/linux/powerpc/pkey_set.c new file mode 100644 index 0000000000..f57a46f1ed --- /dev/null +++ b/sysdeps/unix/sysv/linux/powerpc/pkey_set.c @@ -0,0 +1,48 @@ +/* Changing the per-thread memory protection key, powerpc64 version. + Copyright (C) 2017-2018 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#include +#include +#include + +int +pkey_set (int key, unsigned int rights) +{ + if (key < 0 || key > PKEY_MAX || rights > 3) + { + __set_errno (EINVAL); + return -1; + } + + /* Translate to AMR bit values. */ + unsigned long int bits; + if (rights & PKEY_DISABLE_ACCESS) + /* The PKEY_DISABLE_WRITE bit does not matter. */ + bits = PKEY_AMR_READ | PKEY_AMR_WRITE; + else if (rights == PKEY_DISABLE_WRITE) + bits = PKEY_AMR_WRITE; + else + bits = 0; + + unsigned int index = pkey_index (key); + unsigned long int mask = 3UL << index; + unsigned long int amr = pkey_read (); + amr = (amr & ~mask) | (bits << index); + pkey_write (amr); + return 0; +}