diff options
author | Artur Grabowski <art@cvs.openbsd.org> | 2002-05-15 23:18:07 +0000 |
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committer | Artur Grabowski <art@cvs.openbsd.org> | 2002-05-15 23:18:07 +0000 |
commit | 185458f11b88168f350bbef3cc54c79e75dab746 (patch) | |
tree | fc26be7ee5562b8985ab3710b89c2a1d0d80a6f1 /share/man | |
parent | 521b6d5ed6d0633e343be800c3599f0a5e72217a (diff) |
Document splassert.
Diffstat (limited to 'share/man')
-rw-r--r-- | share/man/man9/spl.9 | 42 |
1 files changed, 41 insertions, 1 deletions
diff --git a/share/man/man9/spl.9 b/share/man/man9/spl.9 index dc025ac246b..d5df6563c58 100644 --- a/share/man/man9/spl.9 +++ b/share/man/man9/spl.9 @@ -1,4 +1,4 @@ -.\" $OpenBSD: spl.9,v 1.9 2002/05/15 11:51:45 art Exp $ +.\" $OpenBSD: spl.9,v 1.10 2002/05/15 23:18:06 art Exp $ .\" $NetBSD: spl.9,v 1.1 1997/03/11 06:15:05 mikel Exp $ .\" .\" Copyright (c) 1997 Michael Long. @@ -68,6 +68,8 @@ .Fn spl0 void .Ft void .Fn splx "int s" +.Ft void +.Fn splassert "int s" .Sh DESCRIPTION These functions raise and lower the system priority level. They are used by kernel code to block interrupts with priority less @@ -168,3 +170,41 @@ macro restores the system priority level to the one encoded in which must be a value previously returned by one of the other .Nm macros. +.Pp +The +.Fn splassert +function makes that the system is running at a certain priority level. +The argument +.Fa s +should be one of these constants: +.Bl -tag -width IPL_SOFTCLOCKXX +.It Dv IPL_CLOCK +.It Dv IPL_VM +.It Dv IPL_BIO +.It Dv IPL_TTY +.It Dv IPL_NET +.It Dv IPL_SOFTNET +.It Dv IPL_SOFTCLOCK +.It Dv IPL_0 +.El +.Pp +The +.Fn splassert +function is optional and is not necessarily implemented on +all architectures nor enabled in all kernel configurations. +It checks the current system priority level too see if it's +at least at the level specified in the argument +.Fa s . +If possible, it also checks if it hasn't been called from an +interrupt handler with a level higher than the one requested, which +must be an error (if some code is protected from +.Dv IPL_SOFTNET +interrupts, but accessed from an +.Dv IPL_NET +interrupt, it must be a design error in the code). +The behavior of the +.Fn splassert +function is controlled by the kern.splassert +.Xr sysctl 8 . +Set to 0 it disables error checking, set to 1 it prints an error message +if error is detected, any other value causes a system panic on errors. |