The patch titled
N32 sigset and __COMPAT_ENDIAN_SWAP__
has been added to the -mm tree. Its filename is
n32-sigset-and-__compat_endian_swap__.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: N32 sigset and __COMPAT_ENDIAN_SWAP__
>From "Joseph S. Myers" <joseph@xxxxxxxxxxxxxxxx>
I'm testing glibc on MIPS64, little-endian, N32, O32 and N64 multilibs.
Among the NPTL test failures seen are some arising from sigsuspend problems
for N32: it blocks the wrong signals, so SIGCANCEL (SIGRTMIN) is blocked
despite glibc's carefully excluding it from sets of signals to block.
Specifically, testing suggests it blocks signal N^32 instead of signal N,
so (in the example tested) blocking SIGUSR1 (17) blocks signal 49 instead.
glibc's sigset_t uses an array of unsigned long, as does the kernel.
In both cases, signal N+1 is represented as
(1UL << (N % (8 * sizeof (unsigned long)))) in word number
(N / (8 * sizeof (unsigned long))).
Thus the N32 glibc uses an array of 32-bit words and the N64 kernel uses an
array of 64-bit words. For little-endian, the layout is the same, with
signals 1-32 in the first 4 bytes, signals 33-64 in the second, etc.; for
big-endian, userspace has that layout while in the kernel each 8 bytes have
the two halves swapped from the userspace layout.
The N32 sigsuspend syscall uses sigset_from_compat to convert the userspace
sigset to kernel format. If __COMPAT_ENDIAN_SWAP__ is *not* set, this uses
logic of the form
set->sig[0] = compat->sig[0] | (((long)compat->sig[1]) << 32 )
to convert the userspace sigset to a kernel one. This looks correct to me
for both big and little endian, given that in userspace compat->sig[1] will
represent signals 33-64, and so will the high 32 bits of set->sig[0] in the
kernel. If however __COMPAT_ENDIAN_SWAP__ *is* set, as it is for
__MIPSEL__, it uses
set->sig[0] = compat->sig[1] | (((long)compat->sig[0]) << 32 );
which seems incorrect for both big and little endian, and would
explain the observed symptoms.
This code is the only use of __COMPAT_ENDIAN_SWAP__, so if incorrect
then that macro serves no purpose, in which case something like the
following patch would seem appropriate to remove it.
Signed-off-by: Joseph Myers <joseph@xxxxxxxxxxxxxxxx>
Signed-off-by: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
include/asm-mips/compat.h | 3 ---
kernel/compat.c | 7 -------
2 files changed, 10 deletions(-)
diff -puN include/asm-mips/compat.h~n32-sigset-and-__compat_endian_swap__ include/asm-mips/compat.h
--- devel/include/asm-mips/compat.h~n32-sigset-and-__compat_endian_swap__ 2006-06-08 17:43:02.000000000 -0700
+++ devel-akpm/include/asm-mips/compat.h 2006-06-08 17:43:02.000000000 -0700
@@ -145,8 +145,5 @@ static inline void __user *compat_alloc_
return (void __user *) (regs->regs[29] - len);
}
-#if defined (__MIPSEL__)
-#define __COMPAT_ENDIAN_SWAP__ 1
-#endif
#endif /* _ASM_COMPAT_H */
diff -puN kernel/compat.c~n32-sigset-and-__compat_endian_swap__ kernel/compat.c
--- devel/kernel/compat.c~n32-sigset-and-__compat_endian_swap__ 2006-06-08 17:43:02.000000000 -0700
+++ devel-akpm/kernel/compat.c 2006-06-08 17:43:02.000000000 -0700
@@ -730,17 +730,10 @@ void
sigset_from_compat (sigset_t *set, compat_sigset_t *compat)
{
switch (_NSIG_WORDS) {
-#if defined (__COMPAT_ENDIAN_SWAP__)
- case 4: set->sig[3] = compat->sig[7] | (((long)compat->sig[6]) << 32 );
- case 3: set->sig[2] = compat->sig[5] | (((long)compat->sig[4]) << 32 );
- case 2: set->sig[1] = compat->sig[3] | (((long)compat->sig[2]) << 32 );
- case 1: set->sig[0] = compat->sig[1] | (((long)compat->sig[0]) << 32 );
-#else
case 4: set->sig[3] = compat->sig[6] | (((long)compat->sig[7]) << 32 );
case 3: set->sig[2] = compat->sig[4] | (((long)compat->sig[5]) << 32 );
case 2: set->sig[1] = compat->sig[2] | (((long)compat->sig[3]) << 32 );
case 1: set->sig[0] = compat->sig[0] | (((long)compat->sig[1]) << 32 );
-#endif
}
}
_
Patches currently in -mm which might be from joseph@xxxxxxxxxxxxxxxx are
n32-sigset-and-__compat_endian_swap__.patch
-
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