Date: Wed, 10 Mar 2010 10:43:23 -0500 From: John Baldwin <jhb@freebsd.org> To: Nathan Whitehorn <nwhitehorn@freebsd.org> Cc: freebsd-emulation@freebsd.org, freebsd-amd64@freebsd.org, freebsd-ia64@freebsd.org Subject: Re: Request for review/comments: 32-bit compat for non-x86 architectures Message-ID: <201003101043.23275.jhb@freebsd.org> In-Reply-To: <4B97AF13.5040104@freebsd.org> References: <4B971CA3.9090301@freebsd.org> <201003100810.10696.jhb@freebsd.org> <4B97AF13.5040104@freebsd.org>
next in thread | previous in thread | raw e-mail | index | archive | help
On Wednesday 10 March 2010 9:39:15 am Nathan Whitehorn wrote: > John Baldwin wrote: > > On Tuesday 09 March 2010 11:14:27 pm Nathan Whitehorn wrote: > > > >> The patch at http://people.freebsd.org/~nwhitehorn/compat_freebsd32.diff > >> (pre-generated freebsd32 syscalls stuff is included, which will be done > >> in two steps on commit) provides groundwork for supporting 32-bit > >> compatibility for 64-bit MIPS and PowerPC systems. It has been tested on > >> amd64 and powerpc64, and compile-tested on ia64. There are two main > >> parts to the patch: > >> > >> 1) COMPAT_IA32 is renamed COMPAT_FREEBSD32, in analogy to > >> COMPAT_LINUX32, etc. This requires updating kernel configurations, but > >> is less painful than filling machine-independent bits of the kernel with > >> #if defined(COMPAT_IA32) || defined(COMPAT_PPC32) || > >> defined(COMPAT_MIPS32) || ..., and is no less descriptive than the old name. > >> > >> 2) Modifications to the freebsd32 compat layer to support big-endian > >> architectures. > >> > >> I would appreciate any comments, bugs, or test results on ia64. > >> > > > > This doesn't look right for non-x86 32-bit ABIs: > > > > Index: sys/kern/imgact_elf.c > > =================================================================== > > --- sys/kern/imgact_elf.c (revision 204681) > > +++ sys/kern/imgact_elf.c (working copy) > > @@ -1439,7 +1439,7 @@ > > ehdr->e_ident[EI_ABIVERSION] = 0; > > ehdr->e_ident[EI_PAD] = 0; > > ehdr->e_type = ET_CORE; > > -#if defined(COMPAT_IA32) && __ELF_WORD_SIZE == 32 > > +#if defined(COMPAT_FREEBSD32) && __ELF_WORD_SIZE == 32 > > ehdr->e_machine = EM_386; > > #else > > ehdr->e_machine = ELF_ARCH; > > > Good catch! Such are the dangers of sed. How about defining an > ELF_ARCH32 in machine/elf.h for this case? Yes, that sounds good. > > It would be nice to eliminate having <compat/ia32*> includes in MI code by > > instead including those headers in appropriate headers in <machine/*>. For > > example, we could change <machine/reg.h> on amd64 and ia64 to include these > > headers, perhaps under an #ifdef COMPAT_FREEBSD32. > > > > Hmm, actually, I'm quite convinced now that <machine/reg.h> for ia64 and amd64 > > should include <compat/ia32/ia32_reg.h> in the #ifdef _KERNEL section to avoid > > polluting those includes in MI code. I'm not sure what the various > > <machine/fpu.h> includes are for, but fixing ia32_reg.h would be a good first > > step. It would make your diffs smaller I think. > > > This is how it works on powerpc64. I didn't modify amd64 and ia64 in > order to avoid making too many changes, but I think you're right that > this is a good idea. I'll add that to the patch when fixing the EM_386 > bit you pointed out above. Ok, thanks. -- John Baldwin
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?201003101043.23275.jhb>