Re: PowerPC programming on as400. was: Analyzing SAV save filesfrom a PC

Steve,

Security level 10 hasn't been supported in a long time. It merely
auto-created users at signon time (with Allobj authority).  Kind of a
nuisance as any misspelled name becomes a user profile.

 I think you mean that below 40, (20 and 30) the user/system domain is not
enforced.



----- Original Message ----- 
From: "Steve Richter" <srichter@xxxxxxxxxxxxx>
To: "MI Programming on the AS400 / iSeries" <mi400@xxxxxxxxxxxx>
Sent: Thursday, August 26, 2004 12:28 PM
Subject: [MI400] PowerPC programming on as400. was: Analyzing SAV save
filesfrom a PC


> ok, it is doable to compile PowerPC assembler code on a PC into binary
form.
> The next step is to place that binary code in a user space on the 400.
> Done.  The 400 can also be run at security level 10.  That allows patched
> programs that have not been ok'd by the trusted compiler to still run on
the
> system, right?
>
> Now comes the part that might cause IBM to have any offending parties
> deported or banished from the planet.  I know the PowerPC jump instruction
> can jump execution to any virtual address on the system.  Correct?  That
> means, thanks to the single level store design of the 400, a space pointer
> can be set to the location of the PowerPC binary code stored in the user
> space.  To jump to that code would require two PPC instructions:
transform
> the space pointer to an instruction pointer.  Jump to the instruction
> pointer address.
>
> Do the PPC instructions exist to do this?:
>   - create an instruction pointer that points to a location in a user
space
>   - far jump to an instruction pointer address
>
> If so, is doing this on a security 10 system a simple matter of using SST
to
> patch those series of instructions into an existing AS400 program?
>
> -Steve
>
> -----Original Message-----
> From: mi400-bounces+srichter=autocoder.com@xxxxxxxxxxxx
> [mailto:mi400-bounces+srichter=autocoder.com@xxxxxxxxxxxx]On Behalf Of
> Dave McKenzie
> Sent: Thursday, August 26, 2004 1:47 PM
> To: MI Programming on the AS400 / iSeries
> Subject: RE: [MI400] Analyzing SAV save files from a PC
>
>
> iSeries doesn't have a PowerPC assembler, per se.  The compilers
> generate object-level W-code, which is then translated into NMI (New MI)
> and then into PowerPC machine code.  No human-readable source code is
> involved.
>
>
>
> However, there are free PowerPC assemblers in the wild.  The GCC C/C++
> compiler generates assembler source, which is then compiled by the GNU
> assembler, "as".  It supports PowerPC, such as used by OS X on Power
> Macs, including the 64-bit G5's.
>
> Since source code for "as" is available, you could adapt it to iSeries
> by adding the few iSeries-specific PowerPC machine instructions.
>
> Let us know when you have the beta ready.  I'm sure we'll all be glad to
> test it :-)
>
> --Dave
>
>
> On Thu, 2004-08-26 at 09:45, Steve Richter wrote:
> > Dave,
> >
> > this is great stuff.  For your next assignment please unlock the PowerPC
> > assembler that must lie at the core of the iSeries!  It would make my
day
> if
> > I write PPC assembler code that sets an instruction pointer to code in a
> > user space and then executes a far jump to that code.
> >
> > -Steve
>
>
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