Re: port-alpha/48488: pmap.h modify cause Kernel Panic on NetBSD/alpha current version.

[Izumi Tsutsui <tsutsui%ceres.dti.ne.jp@localhost>]

The following reply was made to PR port-alpha/48488; it has been noted by GNATS.

From: Izumi Tsutsui <tsutsui%ceres.dti.ne.jp@localhost>
To: matt%3am-software.com@localhost
Cc: gnats-bugs%NetBSD.org@localhost, nullnilaki%gmail.com@localhost, 
tsutsui%ceres.dti.ne.jp@localhost
Subject: Re: port-alpha/48488: pmap.h modify cause Kernel Panic on NetBSD/alpha
         current version.
Date: Thu, 2 Jan 2014 02:56:27 +0900

 matt@ wrote:
 
 > On Jan 1, 2014, at 8:59 AM, Izumi Tsutsui 
 > <tsutsui%ceres.dti.ne.jp@localhost> wrote:
 > 
 > > What about this reference?
 > > http://nxr.netbsd.org/xref/src/sys/arch/alpha/alpha/pmap.c?r=1.258#220
 > >    220 static struct pmap  kernel_pmap_store
 > >    221     [(PMAP_SIZEOF(ALPHA_MAXPROCS) + sizeof(struct pmap) - 1)
 > >    222             / sizeof(struct pmap)];
 > 
 > That should be fine.  Since struct pmap is smaller than 
 > PMAP_SIZEOF(ALPHA_MAXPROCS) you need more than one pmap struct to store
 > that.
 
 Ah, I see the original code intended a larger array was safe.
 
 > I thought of changing that to 
 > roundup(PMAP_SIZEOF(ALPHA_MAXPROCS), sizeof(struct pmap)).
 
 I have a feeling that using a union of struct pmap and
 full-sized PMAP_SIZEOF(ALPHA_MAXPROCS) storage for kernel_pmap_store
 would be more readable..
 
 ---
 Izumi Tsutsui