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?
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.
The rest of the diff looks fine to me.
Thanks for the comments!
-Nathan
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