kernel-ark/include/asm-mips/compat.h
akpm@osdl.org 838cd153a5 [PATCH] N32 sigset and __COMPAT_ENDIAN_SWAP__
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@codesourcery.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-25 10:01:15 -07:00

150 lines
3.0 KiB
C

#ifndef _ASM_COMPAT_H
#define _ASM_COMPAT_H
/*
* Architecture specific compatibility types
*/
#include <linux/types.h>
#include <asm/page.h>
#define COMPAT_USER_HZ 100
typedef u32 compat_size_t;
typedef s32 compat_ssize_t;
typedef s32 compat_time_t;
typedef s32 compat_clock_t;
typedef s32 compat_suseconds_t;
typedef s32 compat_pid_t;
typedef s32 __compat_uid_t;
typedef s32 __compat_gid_t;
typedef __compat_uid_t __compat_uid32_t;
typedef __compat_gid_t __compat_gid32_t;
typedef u32 compat_mode_t;
typedef u32 compat_ino_t;
typedef u32 compat_dev_t;
typedef s32 compat_off_t;
typedef s64 compat_loff_t;
typedef u32 compat_nlink_t;
typedef s32 compat_ipc_pid_t;
typedef s32 compat_daddr_t;
typedef s32 compat_caddr_t;
typedef struct {
s32 val[2];
} compat_fsid_t;
typedef s32 compat_timer_t;
typedef s32 compat_int_t;
typedef s32 compat_long_t;
typedef u32 compat_uint_t;
typedef u32 compat_ulong_t;
struct compat_timespec {
compat_time_t tv_sec;
s32 tv_nsec;
};
struct compat_timeval {
compat_time_t tv_sec;
s32 tv_usec;
};
struct compat_stat {
compat_dev_t st_dev;
s32 st_pad1[3];
compat_ino_t st_ino;
compat_mode_t st_mode;
compat_nlink_t st_nlink;
__compat_uid_t st_uid;
__compat_gid_t st_gid;
compat_dev_t st_rdev;
s32 st_pad2[2];
compat_off_t st_size;
s32 st_pad3;
compat_time_t st_atime;
s32 st_atime_nsec;
compat_time_t st_mtime;
s32 st_mtime_nsec;
compat_time_t st_ctime;
s32 st_ctime_nsec;
s32 st_blksize;
s32 st_blocks;
s32 st_pad4[14];
};
struct compat_flock {
short l_type;
short l_whence;
compat_off_t l_start;
compat_off_t l_len;
s32 l_sysid;
compat_pid_t l_pid;
short __unused;
s32 pad[4];
};
#define F_GETLK64 33
#define F_SETLK64 34
#define F_SETLKW64 35
struct compat_flock64 {
short l_type;
short l_whence;
compat_loff_t l_start;
compat_loff_t l_len;
compat_pid_t l_pid;
};
struct compat_statfs {
int f_type;
int f_bsize;
int f_frsize;
int f_blocks;
int f_bfree;
int f_files;
int f_ffree;
int f_bavail;
compat_fsid_t f_fsid;
int f_namelen;
int f_spare[6];
};
#define COMPAT_RLIM_INFINITY 0x7fffffffUL
typedef u32 compat_old_sigset_t; /* at least 32 bits */
#define _COMPAT_NSIG 128 /* Don't ask !$@#% ... */
#define _COMPAT_NSIG_BPW 32
typedef u32 compat_sigset_word;
#define COMPAT_OFF_T_MAX 0x7fffffff
#define COMPAT_LOFF_T_MAX 0x7fffffffffffffffL
/*
* A pointer passed in from user mode. This should not
* be used for syscall parameters, just declare them
* as pointers because the syscall entry code will have
* appropriately comverted them already.
*/
typedef u32 compat_uptr_t;
static inline void __user *compat_ptr(compat_uptr_t uptr)
{
return (void __user *)(long)uptr;
}
static inline compat_uptr_t ptr_to_compat(void __user *uptr)
{
return (u32)(unsigned long)uptr;
}
static inline void __user *compat_alloc_user_space(long len)
{
struct pt_regs *regs = (struct pt_regs *)
((unsigned long) current_thread_info() + THREAD_SIZE - 32) - 1;
return (void __user *) (regs->regs[29] - len);
}
#endif /* _ASM_COMPAT_H */