Changes since v1: * Fixed description of PROT_GROWSUP/PROT_GROWSDOWN from "whole mapping" to "up to end/down to beginning". * Clarified situation regarding obtaining VMA with VM_GROWSUP/VM_GROWSDOWN bit set. * Clarified meaning of "invalid flag" * Some rewording, typo fixes. --- man2/mprotect.2 | 65 ++++++++++++++++++++++++++++++++++++++++++++++++++------- 1 file changed, 57 insertions(+), 8 deletions(-) diff --git a/man2/mprotect.2 b/man2/mprotect.2 index 440fa65..f3b2b1a 100644 --- a/man2/mprotect.2 +++ b/man2/mprotect.2 @@ -30,12 +30,6 @@ .\" 2007-06-02, mtk: Fairly substantial rewrites and additions, and .\" a much improved example program. .\" -.\" FIXME The following protection flags need documenting: -.\" PROT_SEM -.\" PROT_GROWSDOWN -.\" PROT_GROWSUP -.\" PROT_SAO (PowerPC) -.\" .TH MPROTECT 2 2015-07-23 "Linux" "Linux Programmer's Manual" .SH NAME mprotect, pkey_mprotect \- set protection on a region of memory @@ -60,7 +54,7 @@ that violates the protection, then the kernel generates a signal for the process. .PP .I prot -is either +is a combination of the following access flags: .B PROT_NONE or a bitwise-or of the other values in the following list: .TP 1.1i @@ -75,6 +69,42 @@ The memory can be modified. .TP .B PROT_EXEC The memory can be executed. +'\" 882ad449046cec136c484dd2b3659fb4c683e0a3 +.TP +.BR PROT_SEM " (since Linux 2.5.7)" +The memory can be used for atomic operations. It was introduced as part of +.BR futex (2) +implementation (in order), but not actually used in any currently supported +architecture so far. +'\" aba46c5027cb59d98052231b36efcbbde9c77a1d ef3d3246a0d06be622867d21af25f997aeeb105f +.TP +.BR PROT_SAO " (since Linux 2.6.26)" +The memory should have strong access ordering. This feature is specific to +PowerPC architecture (version 2.06 of architecture specification adds SAO CPU +feature, and it is available on POWER 7 or PowerPC A2, for example). +.PP +'\" c1dd59582e5b518983b0f4db66f0f8a969139c1b +Additionally (since Linux 2.6.0), +.I prot +can have one of the following flags set: +.TP 1.1i +'\" mm/mmap.c: +'\" vm_flags |= calc_vm_prot_bits(prot, pkey) | calc_vm_flag_bits(flags) | +'\" mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC; +'\" And calc_vm_flag_bits converts only GROWSDOWN/DENYWRITE/LOCKED. +.B PROT_GROWSUP +Apply protection mode up to the end of the VMA which grows up (it should be a +stack segment on HP PA-RISC, since there are no other ways to map a segment with +.B VM_GROWSUP +even if architecture has support for it.) +.TP +.B PROT_GROWSDOWN +Apply protection mode down to the beginning of the VMA which grows down (it +should be stack segment or mapped with +.B MAP_GROWSDOWN +flag set.) +.PP +This is especially useful for stacks and other mappings which can grow. .PP Like .BR mprotect (), @@ -122,7 +152,26 @@ or not a multiple of the system page size. .RB ( pkey_mprotect ()) \fIpkey\fP has not been allocated with .BR pkey_alloc (2) -.\" Or: both PROT_GROWSUP and PROT_GROWSDOWN were specified in 'prot'. +.TP +.BR EINVAL +Both +.BR PROT_GROWSUP " and " PROT_GROWSDOWN +were specified in +.IR prot . +.TP +.BR EINVAL +Invalid (other than +.BR PROT_READ ", " PROT_WRITE ", " PROT_EXEC ", " PROT_SEM ", " +.BR PROT_SAO " (on PowerPC only), " PROT_GROWSUP ", " PROT_GROWSDOWN ) +flags specified in +.IR prot . +.TP +.BR EINVAL +(PowerPC architecture) +.B PROT_SAO +specified in +.IR prot , +but SAO hardware feature is not available. .TP .B ENOMEM Internal kernel structures could not be allocated. -- 2.10.2 -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
