Date: Wed, 27 Feb 2008 13:19:40 -0800 From: Julian Elischer <julian@elischer.org> To: Marcel Moolenaar <xcllnt@mac.com> Cc: FreeBSD Arch <freebsd-arch@freebsd.org> Subject: Re: Moving vm_pmap in struct vmspace last Message-ID: <47C5D3EC.4010604@elischer.org> In-Reply-To: <8D7D4892-A2E4-42BE-B856-E868E358E5CD@mac.com> References: <8D7D4892-A2E4-42BE-B856-E868E358E5CD@mac.com>
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Marcel Moolenaar wrote:
> All,
>
> On PowerPC we'll support Book E alongside the AIM processor
> and there's one area where this results in an ABI problem:
> For Book E the struct pmap is larger than for AIM. As such,
> struct vmspace will have a different layout depending on
> the configured CPU. This only affects libkvm, but is enough of a
> hassle that I want to apply the following patch to address
> that:
just for fun I'm also supporting a ppc variant called gxemul which
uses the 'test' devices in gxemul (not emulateed hardware).
I have the loader working and warner had the machine booting to almost
single user when Cisco did their linux thing. so that's not proep and
not book-E. and to make things easier, it would work for mips under
gxemul as well. I haven't figured out how to fit it as an option that
can run across several architectures..
>
> Index: sys/vm/vm_map.h
> =
> =
> =
> ========================================================================
> --- sys/vm/vm_map.h 2008/02/27 20:14:01 #56
> +++ sys/vm/vm_map.h 2008/02/27 20:14:01
> @@ -233,7 +233,6 @@
> */
> struct vmspace {
> struct vm_map vm_map; /* VM address map */
> - struct pmap vm_pmap; /* private physical map */
> struct shmmap_state *vm_shm; /* SYS5 shared memory private data
> XXX */
> segsz_t vm_swrss; /* resident set size before last swap */
> segsz_t vm_tsize; /* text size (pages) XXX */
> @@ -243,6 +242,12 @@
> caddr_t vm_daddr; /* (c) user virtual address of data */
> caddr_t vm_maxsaddr; /* user VA at max stack growth */
> int vm_refcnt; /* number of references */
> + /*
> + * Keep the PMAP last, so that per-CPU variations within a
> + * single architecture can be handled by the same toolchain
> + * without having to worry about the MI fields.
> + */
> + struct pmap vm_pmap; /* private physical map */
> };
>
> #ifdef _KERNEL
>
>
> The consequence of this patch is that the ABI will be
> broken for all arhcitectures (once). Again, this only
> affects libkvm. Do people see a problem with this change?
>
> Thanks,
>
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