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| author | Alejandro Colomar <alx@kernel.org> | 2024-04-26 15:06:49 +0200 |
|---|---|---|
| committer | Alejandro Colomar <alx@kernel.org> | 2024-05-02 01:24:19 +0200 |
| commit | dcde2f70372b49ec43efc5db864c9ff585d0a2dd (patch) | |
| tree | 78b9b7425130e4a5858e4c01a524d802423879ed /man/man2/pkey_alloc.2 | |
| parent | 12aca537ce78a41bbcdaf485209691e10f8002d7 (diff) | |
| download | man-pages-dcde2f70372b49ec43efc5db864c9ff585d0a2dd.tar.gz | |
man/, share/mk/: Move man*/ to man/
This is a scripted change:
$ mkdir man/;
$ mv man* man/;
$ ln -st . man/man*;
$ find share/mk/ -type f \
| xargs grep -l '^MANDIR *:=' \
| xargs sed -i '/^MANDIR *:=/s,$,/man,';
$ find share/mk/dist/ -type f \
| xargs grep -l man \
| xargs sed -i 's,man%,man/%,g';
Link: <https://lore.kernel.org/linux-man/YxcV4h+Xn7cd6+q2@pevik/T/>
Cc: Petr Vorel <pvorel@suse.cz>
Cc: Jakub Wilk <jwilk@jwilk.net>
Cc: Stefan Puiu <stefan.puiu@gmail.com>
Signed-off-by: Alejandro Colomar <alx@kernel.org>
Diffstat (limited to 'man/man2/pkey_alloc.2')
| -rw-r--r-- | man/man2/pkey_alloc.2 | 115 |
1 files changed, 115 insertions, 0 deletions
diff --git a/man/man2/pkey_alloc.2 b/man/man2/pkey_alloc.2 new file mode 100644 index 0000000000..0f706e7dac --- /dev/null +++ b/man/man2/pkey_alloc.2 @@ -0,0 +1,115 @@ +.\" Copyright (C) 2016 Intel Corporation +.\" +.\" SPDX-License-Identifier: Linux-man-pages-copyleft +.\" +.TH pkey_alloc 2 (date) "Linux man-pages (unreleased)" +.SH NAME +pkey_alloc, pkey_free \- allocate or free a protection key +.SH LIBRARY +Standard C library +.RI ( libc ", " \-lc ) +.SH SYNOPSIS +.nf +.BR "#define _GNU_SOURCE" " /* See feature_test_macros(7) */" +.B #include <sys/mman.h> +.P +.BI "int pkey_alloc(unsigned int " flags ", unsigned int " access_rights ");" +.BI "int pkey_free(int " pkey ");" +.fi +.SH DESCRIPTION +.BR pkey_alloc () +allocates a protection key (pkey) and allows it to be passed to +.BR pkey_mprotect (2). +.P +The +.BR pkey_alloc () +.I flags +is reserved for future use and currently must always be specified as 0. +.P +The +.BR pkey_alloc () +.I access_rights +argument may contain zero or more disable operations: +.TP +.B PKEY_DISABLE_ACCESS +Disable all data access to memory covered by the returned protection key. +.TP +.B PKEY_DISABLE_WRITE +Disable write access to memory covered by the returned protection key. +.P +.BR pkey_free () +frees a protection key and makes it available for later +allocations. +After a protection key has been freed, it may no longer be used +in any protection-key-related operations. +.P +An application should not call +.BR pkey_free () +on any protection key which has been assigned to an address +range by +.BR pkey_mprotect (2) +and which is still in use. +The behavior in this case is undefined and may result in an error. +.SH RETURN VALUE +On success, +.BR pkey_alloc () +returns a positive protection key value. +On success, +.BR pkey_free () +returns zero. +On error, \-1 is returned, and +.I errno +is set to indicate the error. +.SH ERRORS +.TP +.B EINVAL +.IR pkey , +.IR flags , +or +.I access_rights +is invalid. +.TP +.B ENOSPC +.RB ( pkey_alloc ()) +All protection keys available for the current process have +been allocated. +The number of keys available is architecture-specific and +implementation-specific and may be reduced by kernel-internal use +of certain keys. +There are currently 15 keys available to user programs on x86. +.IP +This error will also be returned if the processor or operating system +does not support protection keys. +Applications should always be prepared to handle this error, since +factors outside of the application's control can reduce the number +of available pkeys. +.SH STANDARDS +Linux. +.SH HISTORY +Linux 4.9, +glibc 2.27. +.SH NOTES +.BR pkey_alloc () +is always safe to call regardless of whether or not the operating system +supports protection keys. +It can be used in lieu of any other mechanism for detecting pkey support +and will simply fail with the error +.B ENOSPC +if the operating system has no pkey support. +.P +The kernel guarantees that the contents of the hardware rights +register (PKRU) will be preserved only for allocated protection +keys. +Any time a key is unallocated (either before the first call +returning that key from +.BR pkey_alloc () +or after it is freed via +.BR pkey_free ()), +the kernel may make arbitrary changes to the parts of the +rights register affecting access to that key. +.SH EXAMPLES +See +.BR pkeys (7). +.SH SEE ALSO +.BR pkey_mprotect (2), +.BR pkeys (7) |