Re: updating COMPAT_LINUX for linux 2.6.x support (take 2)

[christos%astron.com@localhost (Christos Zoulas)]

In article <20100706192101.GB12811%spathi.chuq.com@localhost>,
Chuck Silvers  <chuq%chuq.com@localhost> wrote:
>On Fri, Jul 02, 2010 at 08:55:30AM +1000, matthew green wrote:
>> 
>> > On Thu, Jul 01, 2010 at 01:32:47AM +0200, Rhialto wrote:
>> > > On Wed 30 Jun 2010 at 08:57:44 -0700, Chuck Silvers wrote:
>> > > >    - the assembler apparently now uses a different opcode for
>reloading %gs
>> > > >      than it used to, so the check for this instruction in INTRFASTEXIT
>> > > >      being the cause of a kernel trap wasn't working.  I fixed the 
>> > > > check
>> > > >      to match the current generated code.
>> > > 
>> > > Would it not be necessary for compatibility with older binaries (how
>> > > much older??) to check for both cases?
>> > 
>> > there's no compatibility issue here, the kernel is looking at its own
>> > instructions, not an application's.  we require that a kernel be built
>> > with the matching toolchain, so there's only one version of the assembler
>> > that would matter for a particular kernel binary.
>> 
>> we shouldn't depend upon GCC/gas versions so heavily IMO.  testing for
>> both should be failry easy, right?
>> 
>> sometimes newer / older toolchain components are useful for various
>> reasons.. 
>
>
>well, I'll still argue that it's not useful to use the wrong toolchain,
>but (as we discovered in private mail over the last few days),
>sometimes dopey people (like me in this case) use the wrong toolchain
>by accident and then get very confused when things don't work right.
>
>the executive summary is that the problem with recognizing faults due to
>loading %gs doesn't exist in -current, so I'm going to leave that alone.
>I'm going to leave the fix for other existing bug (panic due to bad %cs value)
>out of the linux changes as well, but I'll come back to it once the linux
>changes are in.
>
>and since no one had any other objections, I'm going to check in
>the linux changes this afternoon.

Go for it!

christos