Date: Sat, 16 Sep 2006 19:10:19 +0200 From: Marcin Cieslak <saper@SYSTEM.PL> To: Maxim Sobolev <sobomax@FreeBSD.org>, Marcel Moolenaar <marcel@FreeBSD.org> Cc: emulation@FreeBSD.org, Alexander Leidinger <Alexander@Leidinger.net>, Tim Robins <tjr@FreeBSD.org> Subject: Re: fixing linux mmap() Message-ID: <450C2FFB.3050209@SYSTEM.PL> In-Reply-To: <450C2A46.9010609@FreeBSD.org> References: <450C0C0E.8060402@SYSTEM.PL> <20060916171840.5dd744b7@Magellan.Leidinger.net> <450C2A46.9010609@FreeBSD.org>
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Maxim Sobolev wrote:
> Actually it's confusion on your part. This code was there since version
> 1.1 and long before 1.31 (my change that touched this line):
Yes, the code is very old. However things has changed in the FreeBSD
mmap() in the meantime, but Linux emulator code was left as it was.
I just wondered if we need this PROT_READ thing at all.
amd64 code illustrates this confusion even better:
/sys/amd64/linux32/linux32_machdep.c
1.1 (tjr 16-Aug-04): /*
1.1 (tjr 16-Aug-04): * XXX i386 Linux always emulator forces
PROT_READ on (why?)
1.1 (tjr 16-Aug-04): * so we do the same. We add PROT_EXEC
to work around buggy
1.1 (tjr 16-Aug-04): * applications (e.g. Java) that take
advantage of the fact
1.1 (tjr 16-Aug-04): * that execute permissions are not
enforced by x86 CPUs.
1.1 (tjr 16-Aug-04): */
1.1 (tjr 16-Aug-04): bsd_args.prot = linux_args->prot |
PROT_EXEC | PROT_READ;
I *guess* adding PROT_READ is no longer necessary (at least since 1.333 version
of /sys/vm/vm_map.c). PROT_EXEC also wonders me, but I lack amd64 hardware and
mmap() clue to check this...
--
<< Marcin Cieslak // saper@system.pl >>
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