Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932308AbbLGQo1 (ORCPT ); Mon, 7 Dec 2015 11:44:27 -0500 Received: from www.sr71.net ([198.145.64.142]:39326 "EHLO blackbird.sr71.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753663AbbLGQoZ (ORCPT ); Mon, 7 Dec 2015 11:44:25 -0500 Subject: Re: [PATCH 26/34] mm: implement new mprotect_key() system call To: "Michael Kerrisk (man-pages)" , linux-kernel@vger.kernel.org References: <20151204011424.8A36E365@viggo.jf.intel.com> <20151204011500.69487A6C@viggo.jf.intel.com> <5662894B.7090903@gmail.com> Cc: linux-mm@kvack.org, x86@kernel.org, dave.hansen@linux.intel.com, linux-api@vger.kernel.org From: Dave Hansen Message-ID: <5665B767.8020802@sr71.net> Date: Mon, 7 Dec 2015 08:44:23 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 MIME-Version: 1.0 In-Reply-To: <5662894B.7090903@gmail.com> Content-Type: multipart/mixed; boundary="------------070705030204010305060201" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7881 Lines: 245 This is a multi-part message in MIME format. --------------070705030204010305060201 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit On 12/04/2015 10:50 PM, Michael Kerrisk (man-pages) wrote: > On 12/04/2015 02:15 AM, Dave Hansen wrote: >> From: Dave Hansen >> >> mprotect_key() is just like mprotect, except it also takes a >> protection key as an argument. On systems that do not support >> protection keys, it still works, but requires that key=0. >> Otherwise it does exactly what mprotect does. > > Is there a man page for this API? Yep. Patch to man-pages source is attached. I actually broke it up in to a few separate pages. I was planning on submitting these after the patches themselves go upstream. --------------070705030204010305060201 Content-Type: text/x-patch; name="pkeys.patch" Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename="pkeys.patch" commit ebb12643876810931ed23992f92b7c77c2c36883 Author: Dave Hansen Date: Mon Dec 7 08:42:57 2015 -0800 pkeys diff --git a/man2/mprotect.2 b/man2/mprotect.2 index ae305f6..a3c1e62 100644 --- a/man2/mprotect.2 +++ b/man2/mprotect.2 @@ -38,16 +38,19 @@ .\" .TH MPROTECT 2 2015-07-23 "Linux" "Linux Programmer's Manual" .SH NAME -mprotect \- set protection on a region of memory +mprotect, mprotect_key \- set protection on a region of memory .SH SYNOPSIS .nf .B #include .sp .BI "int mprotect(void *" addr ", size_t " len ", int " prot ); +.BI "int mprotect_key(void *" addr ", size_t " len ", int " prot , " int " key); .fi .SH DESCRIPTION .BR mprotect () -changes protection for the calling process's memory page(s) +and +.BR mprotect_key () +change protection for the calling process's memory page(s) containing any part of the address range in the interval [\fIaddr\fP,\ \fIaddr\fP+\fIlen\fP\-1]. .I addr @@ -74,10 +77,17 @@ The memory can be modified. .TP .B PROT_EXEC The memory can be executed. +.PP +.I key +is the protection or storage key to assign to the memory. +A key must be allocated with pkey_alloc () before it is +passed to pkey_mprotect (). .SH RETURN VALUE On success, .BR mprotect () -returns zero. +and +.BR mprotect_key () +return zero. On error, \-1 is returned, and .I errno is set appropriately. diff --git a/man2/pkey_alloc.2 b/man2/pkey_alloc.2 new file mode 100644 index 0000000..980ce3e --- /dev/null +++ b/man2/pkey_alloc.2 @@ -0,0 +1,72 @@ +.\" Copyright (C) 2007 Michael Kerrisk +.\" and Copyright (C) 1995 Michael Shields . +.\" +.\" %%%LICENSE_START(VERBATIM) +.\" Permission is granted to make and distribute verbatim copies of this +.\" manual provided the copyright notice and this permission notice are +.\" preserved on all copies. +.\" +.\" Permission is granted to copy and distribute modified versions of this +.\" manual under the conditions for verbatim copying, provided that the +.\" entire resulting derived work is distributed under the terms of a +.\" permission notice identical to this one. +.\" +.\" Since the Linux kernel and libraries are constantly changing, this +.\" manual page may be incorrect or out-of-date. The author(s) assume no +.\" responsibility for errors or omissions, or for damages resulting from +.\" the use of the information contained herein. The author(s) may not +.\" have taken the same level of care in the production of this manual, +.\" which is licensed free of charge, as they might when working +.\" professionally. +.\" +.\" Formatted or processed versions of this manual, if unaccompanied by +.\" the source, must acknowledge the copyright and author of this work. +.\" %%%LICENSE_END +.\" +.\" Modified 2015-12-04 by Dave Hansen +.\" +.\" +.TH PKEY_ALLOC 2 2015-12-04 "Linux" "Linux Programmer's Manual" +.SH NAME +pkey_alloc, pkey_free \- allocate or free a protection key +.SH SYNOPSIS +.nf +.B #include +.sp +.BI "int pkey_alloc(unsigned long" flags ", unsigned long " init_val); +.BI "int pkey_free(int " pkey); +.fi +.SH DESCRIPTION +.BR pkey_alloc () +and +.BR pkey_free () +allow or disallow the calling process's to use the given +protection key for all protection-key-related operations. + +.PP +.I flags +is may contain zero or more disable operation: +.B PKEY_DISABLE_ACCESS +and/or +.B PKEY_DISABLE_WRITE +.SH RETURN VALUE +On success, +.BR pkey_alloc () +and +.BR pkey_free () +return zero. +On error, \-1 is returned, and +.I errno +is set appropriately. +.SH ERRORS +.TP +.B EINVAL +An invalid protection key, flag, or init_val was specified. +.TP +.B ENOSPC +All protection keys available for the current process have +been allocated. +.SH SEE ALSO +.BR mprotect_pkey (2), +.BR pkey_get (2), +.BR pkey_set (2), diff --git a/man2/pkey_get.2 b/man2/pkey_get.2 new file mode 100644 index 0000000..4cfdea9 --- /dev/null +++ b/man2/pkey_get.2 @@ -0,0 +1,76 @@ +.\" Copyright (C) 2007 Michael Kerrisk +.\" and Copyright (C) 1995 Michael Shields . +.\" +.\" %%%LICENSE_START(VERBATIM) +.\" Permission is granted to make and distribute verbatim copies of this +.\" manual provided the copyright notice and this permission notice are +.\" preserved on all copies. +.\" +.\" Permission is granted to copy and distribute modified versions of this +.\" manual under the conditions for verbatim copying, provided that the +.\" entire resulting derived work is distributed under the terms of a +.\" permission notice identical to this one. +.\" +.\" Since the Linux kernel and libraries are constantly changing, this +.\" manual page may be incorrect or out-of-date. The author(s) assume no +.\" responsibility for errors or omissions, or for damages resulting from +.\" the use of the information contained herein. The author(s) may not +.\" have taken the same level of care in the production of this manual, +.\" which is licensed free of charge, as they might when working +.\" professionally. +.\" +.\" Formatted or processed versions of this manual, if unaccompanied by +.\" the source, must acknowledge the copyright and author of this work. +.\" %%%LICENSE_END +.\" +.\" Modified 2015-12-04 by Dave Hansen +.\" +.\" +.TH PKEY_GET 2 2015-12-04 "Linux" "Linux Programmer's Manual" +.SH NAME +pkey_get, pkey_set \- manage protection key access permissions +.SH SYNOPSIS +.nf +.B #include +.sp +.BI "int pkey_get(int " pkey); +.BI "int pkey_set(int " pkey ", unsigned long " access_rights); +.fi +.SH DESCRIPTION +.BR pkey_get () +and +.BR pkey_set () +query or set the current set of rights for the calling +task for the given protection key. +When rights for a key are disabled, any future access +to any memory region with that key set will generate +a SIGSEGV. The rights are local to the calling thread and +do not affect any other threads. +.PP +Upon entering any signal handler, the process is given a +default set of protection key rights which are separate from +the main thread's. Any calls to pkey_set () in a signal +will not persist upon a return to the calling process. +.PP +.I access_rights +is may contain zero or more disable operation: +.B PKEY_DISABLE_ACCESS +and/or +.B PKEY_DISABLE_WRITE +.SH RETURN VALUE +On success, +.BR pkey_get () +and +.BR pkey_set () +return zero. +On error, \-1 is returned, and +.I errno +is set appropriately. +.SH ERRORS +.TP +.B EINVAL +An invalid protection key or access_rights was specified. +.SH SEE ALSO +.BR mprotect_pkey (2), +.BR pkey_alloc (2), +.BR pkey_free (2), --------------070705030204010305060201-- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/