Signed-off-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> --- b/man2/pkey_get.2 | 109 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 109 insertions(+) diff -puN /dev/null man2/pkey_get.2 --- /dev/null 2016-03-09 16:12:12.816871985 -0800 +++ b/man2/pkey_get.2 2016-06-08 10:32:43.916409601 -0700 @@ -0,0 +1,109 @@ +.\" Copyright (C) 2016 Intel Corporation +.\" +.\" %%%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 +.\" +.\" Since the Linux kernel and libraries are constantly changing, this +.\" manual page may be incorrect or out-of-date.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 +.\" +.TH PKEY_GET 2 2016-03-03 "Linux" "Linux Programmer's Manual" +.SH NAME +pkey_get, pkey_set \- manage protection key access permissions +.SH SYNOPSIS +.nf +.B #include <sys/mman.h> +.sp +.BI "int pkey_get(int " pkey ", unsigned long " flags "); +.BI "int pkey_set(int " pkey ", unsigned long " access_rights ", unsigned long " flags ");" +.fi +.SH DESCRIPTION +.BR pkey_set () +sets the current set of rights for the calling +thread for the protection key specified by +.IR pkey . +When rights for a key are disabled, any future access +to any memory region with that key set will generate a +.B SIGSEGV +signal. +Access rights are private to each thread. +.PP +.I access_rights +may contain zero or more disable operations: +.TP +.B PKEY_DISABLE_ACCESS +Disable all access to memory protected by the specified protection key. +.TP +.B PKEY_DISABLE_WRITE +Disable write access to memory protected by the specified protection key. +.SH RETURN VALUE +On success, +.BR pkey_set () +returns zero. +.BR pkey_get () +returns a mask containing zero or more of the disable operations +listed above. +On error, \-1 is returned, and +.I errno +is set appropriately. +.SH ERRORS +.TP +.B EINVAL +.I pkey +or +.I access_rights +is invalid. +.SH NOTES +When any signal handler is invoked, the thread is temporarily +given a new, default set of protection key rights that override +whatever rights were set in the interrupted context. +The thread's protection key rights are restored when the signal +handler returns. + +The effects of a call to +.BR pkey_set () +from a signal handler will not persist when control passes out of +the signal handler. +This is true both when the handler returns to a normal, +nonsignal context, and when the signal handler is interrupted +by another signal handler. + +This signal behavior is unusual and is due to the fact that +the x86 PKRU register (which stores \fIaccess_rights\fP) +is managed with the same hardware mechanism (XSAVE) that +manages +floating-point registers. +The signal behavior is the same as that of a floating point +register. +.SH VERSIONS +.BR pkey_get () +and +.BR pkey_set () +were added to Linux in kernel <FIXME>; +library support was added to glibc in version <FIXME>. +.SH CONFORMING TO +The +.BR pkey_get () +and +.BR pkey_set () +system calls are Linux-specific. +.SH SEE ALSO +.BR pkey_alloc (2), +.BR pkey_free (2), +.BR pkey_mprotect (2), +.BR pkey (7), _ -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
