linux/arch/sparc/include/asm/compat.h
David S. Miller 517ffce4e1 sparc64: Make montmul/montsqr/mpmul usable in 32-bit threads.
The Montgomery Multiply, Montgomery Square, and Multiple-Precision
Multiply instructions work by loading a combination of the floating
point and multiple register windows worth of integer registers
with the inputs.

These values are 64-bit.  But for 32-bit userland processes we only
save the low 32-bits of each integer register during a register spill.
This is because the register window save area is in the user stack and
has a fixed layout.

Therefore, the only way to use these instruction in 32-bit mode is to
perform the following sequence:

1) Load the top-32bits of a choosen integer register with a sentinel,
   say "-1".  This will be in the outer-most register window.

   The idea is that we're trying to see if the outer-most register
   window gets spilled, and thus the 64-bit values were truncated.

2) Load all the inputs for the montmul/montsqr/mpmul instruction,
   down to the inner-most register window.

3) Execute the opcode.

4) Traverse back up to the outer-most register window.

5) Check the sentinel, if it's still "-1" store the results.
   Otherwise retry the entire sequence.

This retry is extremely troublesome.  If you're just unlucky and an
interrupt or other trap happens, it'll push that outer-most window to
the stack and clear the sentinel when we restore it.

We could retry forever and never make forward progress if interrupts
arrive at a fast enough rate (consider perf events as one example).
So we have do limited retries and fallback to software which is
extremely non-deterministic.

Luckily it's very straightforward to provide a mechanism to let
32-bit applications use a 64-bit stack.  Stacks in 64-bit mode are
biased by 2047 bytes, which means that the lowest bit is set in the
actual %sp register value.

So if we see bit zero set in a 32-bit application's stack we treat
it like a 64-bit stack.

Runtime detection of such a facility is tricky, and cumbersome at
best.  For example, just trying to use a biased stack and seeing if it
works is hard to recover from (the signal handler will need to use an
alt stack, plus something along the lines of longjmp).  Therefore, we
add a system call to report a bitmask of arch specific features like
this in a cheap and less hairy way.

With help from Andy Polyakov.

Signed-off-by: David S. Miller <davem@davemloft.net>
2012-10-26 15:18:37 -07:00

311 lines
6.3 KiB
C

#ifndef _ASM_SPARC64_COMPAT_H
#define _ASM_SPARC64_COMPAT_H
/*
* Architecture specific compatibility types
*/
#include <linux/types.h>
#define COMPAT_USER_HZ 100
#define COMPAT_UTS_MACHINE "sparc\0\0"
typedef u32 compat_size_t;
typedef s32 compat_ssize_t;
typedef s32 compat_time_t;
typedef s32 compat_clock_t;
typedef s32 compat_pid_t;
typedef u16 __compat_uid_t;
typedef u16 __compat_gid_t;
typedef u32 __compat_uid32_t;
typedef u32 __compat_gid32_t;
typedef u16 compat_mode_t;
typedef u32 compat_ino_t;
typedef u16 compat_dev_t;
typedef s32 compat_off_t;
typedef s64 compat_loff_t;
typedef s16 compat_nlink_t;
typedef u16 compat_ipc_pid_t;
typedef s32 compat_daddr_t;
typedef u32 compat_caddr_t;
typedef __kernel_fsid_t compat_fsid_t;
typedef s32 compat_key_t;
typedef s32 compat_timer_t;
typedef s32 compat_int_t;
typedef s32 compat_long_t;
typedef s64 compat_s64;
typedef u32 compat_uint_t;
typedef u32 compat_ulong_t;
typedef u64 compat_u64;
typedef u32 compat_uptr_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;
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;
compat_off_t st_size;
compat_time_t st_atime;
compat_ulong_t st_atime_nsec;
compat_time_t st_mtime;
compat_ulong_t st_mtime_nsec;
compat_time_t st_ctime;
compat_ulong_t st_ctime_nsec;
compat_off_t st_blksize;
compat_off_t st_blocks;
u32 __unused4[2];
};
struct compat_stat64 {
unsigned long long st_dev;
unsigned long long st_ino;
unsigned int st_mode;
unsigned int st_nlink;
unsigned int st_uid;
unsigned int st_gid;
unsigned long long st_rdev;
unsigned char __pad3[8];
long long st_size;
unsigned int st_blksize;
unsigned char __pad4[8];
unsigned int st_blocks;
unsigned int st_atime;
unsigned int st_atime_nsec;
unsigned int st_mtime;
unsigned int st_mtime_nsec;
unsigned int st_ctime;
unsigned int st_ctime_nsec;
unsigned int __unused4;
unsigned int __unused5;
};
struct compat_flock {
short l_type;
short l_whence;
compat_off_t l_start;
compat_off_t l_len;
compat_pid_t l_pid;
short __unused;
};
#define F_GETLK64 12
#define F_SETLK64 13
#define F_SETLKW64 14
struct compat_flock64 {
short l_type;
short l_whence;
compat_loff_t l_start;
compat_loff_t l_len;
compat_pid_t l_pid;
short __unused;
};
struct compat_statfs {
int f_type;
int f_bsize;
int f_blocks;
int f_bfree;
int f_bavail;
int f_files;
int f_ffree;
compat_fsid_t f_fsid;
int f_namelen; /* SunOS ignores this field. */
int f_frsize;
int f_flags;
int f_spare[4];
};
#define COMPAT_RLIM_INFINITY 0x7fffffff
typedef u32 compat_old_sigset_t;
#define _COMPAT_NSIG 64
#define _COMPAT_NSIG_BPW 32
typedef u32 compat_sigset_word;
typedef union compat_sigval {
compat_int_t sival_int;
compat_uptr_t sival_ptr;
} compat_sigval_t;
#define SI_PAD_SIZE32 (128/sizeof(int) - 3)
typedef struct compat_siginfo {
int si_signo;
int si_errno;
int si_code;
union {
int _pad[SI_PAD_SIZE32];
/* kill() */
struct {
compat_pid_t _pid; /* sender's pid */
unsigned int _uid; /* sender's uid */
} _kill;
/* POSIX.1b timers */
struct {
compat_timer_t _tid; /* timer id */
int _overrun; /* overrun count */
compat_sigval_t _sigval; /* same as below */
int _sys_private; /* not to be passed to user */
} _timer;
/* POSIX.1b signals */
struct {
compat_pid_t _pid; /* sender's pid */
unsigned int _uid; /* sender's uid */
compat_sigval_t _sigval;
} _rt;
/* SIGCHLD */
struct {
compat_pid_t _pid; /* which child */
unsigned int _uid; /* sender's uid */
int _status; /* exit code */
compat_clock_t _utime;
compat_clock_t _stime;
} _sigchld;
/* SIGILL, SIGFPE, SIGSEGV, SIGBUS, SIGEMT */
struct {
u32 _addr; /* faulting insn/memory ref. */
int _trapno;
} _sigfault;
/* SIGPOLL */
struct {
int _band; /* POLL_IN, POLL_OUT, POLL_MSG */
int _fd;
} _sigpoll;
} _sifields;
} compat_siginfo_t;
#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 converted them already.
*/
static inline void __user *compat_ptr(compat_uptr_t uptr)
{
return (void __user *)(unsigned long)uptr;
}
static inline compat_uptr_t ptr_to_compat(void __user *uptr)
{
return (u32)(unsigned long)uptr;
}
static inline void __user *arch_compat_alloc_user_space(long len)
{
struct pt_regs *regs = current_thread_info()->kregs;
unsigned long usp = regs->u_regs[UREG_I6];
if (test_thread_64bit_stack(usp))
usp += STACK_BIAS;
if (test_thread_flag(TIF_32BIT))
usp &= 0xffffffffUL;
usp -= len;
usp &= ~0x7UL;
return (void __user *) usp;
}
struct compat_ipc64_perm {
compat_key_t key;
__compat_uid32_t uid;
__compat_gid32_t gid;
__compat_uid32_t cuid;
__compat_gid32_t cgid;
unsigned short __pad1;
compat_mode_t mode;
unsigned short __pad2;
unsigned short seq;
unsigned long __unused1; /* yes they really are 64bit pads */
unsigned long __unused2;
};
struct compat_semid64_ds {
struct compat_ipc64_perm sem_perm;
unsigned int __pad1;
compat_time_t sem_otime;
unsigned int __pad2;
compat_time_t sem_ctime;
u32 sem_nsems;
u32 __unused1;
u32 __unused2;
};
struct compat_msqid64_ds {
struct compat_ipc64_perm msg_perm;
unsigned int __pad1;
compat_time_t msg_stime;
unsigned int __pad2;
compat_time_t msg_rtime;
unsigned int __pad3;
compat_time_t msg_ctime;
unsigned int msg_cbytes;
unsigned int msg_qnum;
unsigned int msg_qbytes;
compat_pid_t msg_lspid;
compat_pid_t msg_lrpid;
unsigned int __unused1;
unsigned int __unused2;
};
struct compat_shmid64_ds {
struct compat_ipc64_perm shm_perm;
unsigned int __pad1;
compat_time_t shm_atime;
unsigned int __pad2;
compat_time_t shm_dtime;
unsigned int __pad3;
compat_time_t shm_ctime;
compat_size_t shm_segsz;
compat_pid_t shm_cpid;
compat_pid_t shm_lpid;
unsigned int shm_nattch;
unsigned int __unused1;
unsigned int __unused2;
};
static inline int is_compat_task(void)
{
return test_thread_flag(TIF_32BIT);
}
#endif /* _ASM_SPARC64_COMPAT_H */