Kostik Belousov wrote:
On Wed, Mar 10, 2010 at 09:55:40AM -0600, Nathan Whitehorn wrote:
John Baldwin wrote:
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.
I've updated the patch to incorporate these two changes, at
http://people.freebsd.org/~nwhitehorn/compat_freebsd32_2.diff. Due to
recursive inclusion issues with sys/procfs.h, it also moves prstatus32
and friends to compat/freebsd32/freebsd32.h from ia32_reg.h. They are
MI, and seems like a more appropriate place for them anyway.
First chunk for the sys_generic.c about ibits/obits looks like a bug fix ?
If yes, it probably would make sense to commit it separately to be able
to MFC it.
The same note about chunks that remove #include <compat/ia32...>, if
possible ?
It is a bug fix, but one that only matters on big-endian systems
(swizzle_fdbits needs it defined), and so goes into the
fixes-for-big-endian bucket. Disentangling all of this would be pretty
difficult, and most of the changes are pointless without their companion
changes. Some of the big endian bits could be pulled out, I guess, but
I'm not completely sure what the point of separately MFCing them is.
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