[PATCH 3/3] prctl.2, proc.5: document arm alignment trap via /proc/apu/alignment
From: Shawn Landden <hidden>
Date: 2012-08-04 20:46:44
Subsystem:
the rest · Maintainer:
Linus Torvalds
Possibly related (same subject, not in this thread)
- 2012-08-04 · Re: [PATCH 3/3] prctl.2, proc.5: document arm alignment trap via /proc/apu/alignment · shawn <hidden>
- 2012-08-04 · Re: [PATCH 3/3] prctl.2, proc.5: document arm alignment trap via /proc/apu/alignment · shawn <hidden>
--- man2/prctl.2 | 7 +++++-- man5/proc.5 | 21 ++++++++++++++++++++- 2 files changed, 25 insertions(+), 3 deletions(-)
diff --git a/man2/prctl.2 b/man2/prctl.2
index f4db191..b68bea2 100644
--- a/man2/prctl.2
+++ b/man2/prctl.2@@ -44,7 +44,7 @@ .\" 2012-08-03 Shawn Landden, Document PR_SET_NO_NEW_PRIVS, PR_GET_NO_NEW_PRIVS, .\" SECCOMP_MODE_STRICT, SECCOMP_MODE_FILTER .\" (thx Andy Lutomirski <luto-kltTT9wpgjJwATOyAt5JVQ@public.gmane.org> 259e5e6c) -.\" PR_SET_TIMERSLACK, PR_GET_TIMESLACK +.\" PR_SET_TIMERSLACK, PR_GET_TIMESLACK, ARM alignment trap handler .\" .TH PRCTL 2 2012-08-03 "Linux" "Linux Programmer's Manual" .SH NAME
@@ -406,7 +406,10 @@ Pass \fBPR_UNALIGN_NOPRINT\fP to silently fix up unaligned user accesses, or \fBPR_UNALIGN_SIGBUS\fP to generate .B SIGBUS -on unaligned user access. +on unaligned user access. ARM is set system-wide via /proc/cpu/alignment (see +.IR Documentation/arm/mem_alignment +or +.BR proc (5)). .TP .B PR_GET_UNALIGN (see
diff --git a/man5/proc.5 b/man5/proc.5
index 2ba1daa..e7ca611 100644
--- a/man5/proc.5
+++ b/man5/proc.5@@ -58,7 +58,7 @@ .\" to see what information could be imported from that file .\" into this file. .\" -.TH PROC 5 2012-05-03 "Linux" "Linux Programmer's Manual" +.TH PROC 5 2012-08-04 "Linux" "Linux Programmer's Manual" .SH NAME proc \- process information pseudo-file system .SH DESCRIPTION
@@ -1229,6 +1229,25 @@ cat /lib/modules/$(uname \-r)/build/.config is only provided if the kernel is configured with .BR CONFIG_IKCONFIG_PROC . .TP +.IR /proc/cpu/alignment " (ARM only)" +Set the behavior of the user-mode alignment trap handler. When writing, takes a +number that is the sum of the fallowing: 1, print message to syslog; (signal) 2, +fix up the user process performing the unaligned access; (fixup) 4, send a +.BR SIGBUS +signal ( +.BR SIGILL +before 2.6.35) to the user process performing the unaligned access. (signal) +Signal and fixup cannot be used together. On armv6+ either fixup or signal must +be used, to prevent possible deadlock. + +Reading will provide statistics on fixups performed since boot in user and +system mode, as well as the current user-mode trap behavior. + +Other architectures set this behavior on a per-process level, via +.B prctl(PR_SET_UNALIGN). +See +.BR prctl (2). +.TP .I /proc/cpuinfo This is a collection of CPU and system architecture dependent items, for each supported architecture a different list.
--
1.7.9.5
--
To unsubscribe from this list: send the line "unsubscribe linux-man" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at http://vger.kernel.org/majordomo-info.html