[PATCH] The o32 fstatat syscall behaves differently on 32 and 64 bit kernels

[PATCH] The o32 fstatat syscall behaves differently on 32 and 64 bit kernels

[Richard Sandiford]

While working on a glibc patch to support the fstatat() functions[1],
I noticed that the o32 implementation behaves differently on 32-bit and
64-bit kernels; the former provides a stat64 while the latter provides
a plain (o32) stat.  I think the former is what's intended, as there is
no separate fstatat64.  It's also what x86 does.

I think this is just a case of a compat too far.  The o32 stat64 is the
same as plain stat on n64, so 64-bit kernels can just use newfstatat.
(n32 already does this, and works correctly as-is.)

Tested with the glibc patch, where it fixes the test I'd written.
Please install if OK.

Richard

[1] I've seen Khem's patch, but I don't think it's right.

Signed-off-by: Richard Sandiford <richard@codesourcery.com>

diff --git a/arch/mips/kernel/scall64-o32.S b/arch/mips/kernel/scall64-o32.S
index 2ac0141..288ee4a 100644
--- a/arch/mips/kernel/scall64-o32.S
+++ b/arch/mips/kernel/scall64-o32.S
@@ -498,7 +498,7 @@ sys_call_table:
 	PTR	sys_mknodat			/* 4290 */
 	PTR	sys_fchownat
 	PTR	compat_sys_futimesat
-	PTR	compat_sys_newfstatat
+	PTR	sys_newfstatat
 	PTR	sys_unlinkat
 	PTR	sys_renameat			/* 4295 */
 	PTR	sys_linkat

Re: [PATCH] The o32 fstatat syscall behaves differently on 32 and 64 bit kernels

[Richard Sandiford]

Richard Sandiford <richard@codesourcery.com> writes:
> I think this is just a case of a compat too far.  The o32 stat64 is the
> same as plain stat on n64, so 64-bit kernels can just use newfstatat.
> (n32 already does this, and works correctly as-is.)

Huh.  The last sentence sounded like a really useful addition when I
wrote it, but even so soon after the fact, I've no idea why.  It sounds
like I was implying that stat calls require conversion on n32, but that
certainly wasn't my intention.  Please ignore. ;)

Richard