svn commit: r226343 - head/sys/vm

[Kostik Belousov]

On Fri, Oct 14, 2011 at 02:35:15PM -0700, Marcel Moolenaar wrote:
> 
> On Oct 14, 2011, at 11:24 AM, Kostik Belousov wrote:
> >>> 
> > After more thought about the issue, I do not agree with you.
> > Elf specification says about the PF_R flag that only read permission
> > for the memory image of the segment is required, but read and execute
> > is allowed.
> 
> The ELF specification does not contain CPU specifics. Those are
> always covered by processor supplements. Since this is very i386
> specific behaviour we're talking about, it's a non sequitur to
> use the generic ELF specification to argue a point in this
> respect.
This is not quite accurate. The ELF specification does contain the
CPU-specific bits for i386. But, the interpretation of the PF_R/PF_X
flags in the program header is described under the OS-specific section,
and not under the CPU-specific. That is, I am sure that the situation
shall be interpreted as the bug in the program.

> 
> 
> > I want to commit the following refinement:
> 
> The patch is good.
Thanks, committed.

> 
> > diff --git a/sys/kern/imgact_elf.c b/sys/kern/imgact_elf.c
> > index 669c652..9970386 100644
> > --- a/sys/kern/imgact_elf.c
> > +++ b/sys/kern/imgact_elf.c
> > @@ -118,11 +118,24 @@ static int elf_legacy_coredump = 0;
> > SYSCTL_INT(_debug, OID_AUTO, __elfN(legacy_coredump), CTLFLAG_RW, 
> >     &elf_legacy_coredump, 0, "");
> > 
> > -static int __elfN(nxstack) = 0;
> > +static int __elfN(nxstack) =
> > +#if defined(__amd64__) || defined(__powerpc__) /* both 64 and 32 bit */
> > +	1;
> > +#else
> > +	0;
> > +#endif
> > SYSCTL_INT(__CONCAT(_kern_elf, __ELF_WORD_SIZE), OID_AUTO,
> >     nxstack, CTLFLAG_RW, &__elfN(nxstack), 0,
> >     __XSTRING(__CONCAT(ELF, __ELF_WORD_SIZE)) ": enable non-executable stack");
> 
> Please do not commit this change with the rest. It's
> not to the point. In fact, if you're changing it to
> the above, please add ia64 to the list as well.

Yes, sure. The inclusion of the chunk was a mistake.
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