linux-hardened/include/linux/compat.h
Linus Torvalds 601cc11d05 Make non-compat preadv/pwritev use native register size
Instead of always splitting the file offset into 32-bit 'high' and 'low'
parts, just split them into the largest natural word-size - which in C
terms is 'unsigned long'.

This allows 64-bit architectures to avoid the unnecessary 32-bit
shifting and masking for native format (while the compat interfaces will
obviously always have to do it).

This also changes the order of 'high' and 'low' to be "low first".  Why?
Because when we have it like this, the 64-bit system calls now don't use
the "pos_high" argument at all, and it makes more sense for the native
system call to simply match the user-mode prototype.

This results in a much more natural calling convention, and allows the
compiler to generate much more straightforward code.  On x86-64, we now
generate

        testq   %rcx, %rcx      # pos_l
        js      .L122   #,
        movq    %rcx, -48(%rbp) # pos_l, pos

from the C source

        loff_t pos = pos_from_hilo(pos_h, pos_l);
	...
        if (pos < 0)
                return -EINVAL;

and the 'pos_h' register isn't even touched.  It used to generate code
like

        mov     %r8d, %r8d      # pos_low, pos_low
        salq    $32, %rcx       #, tmp71
        movq    %r8, %rax       # pos_low, pos.386
        orq     %rcx, %rax      # tmp71, pos.386
        js      .L122   #,
        movq    %rax, -48(%rbp) # pos.386, pos

which isn't _that_ horrible, but it does show how the natural word size
is just a more sensible interface (same arguments will hold in the user
level glibc wrapper function, of course, so the kernel side is just half
of the equation!)

Note: in all cases the user code wrapper can again be the same. You can
just do

	#define HALF_BITS (sizeof(unsigned long)*4)
	__syscall(PWRITEV, fd, iov, count, offset, (offset >> HALF_BITS) >> HALF_BITS);

or something like that.  That way the user mode wrapper will also be
nicely passing in a zero (it won't actually have to do the shifts, the
compiler will understand what is going on) for the last argument.

And that is a good idea, even if nobody will necessarily ever care: if
we ever do move to a 128-bit lloff_t, this particular system call might
be left alone.  Of course, that will be the least of our worries if we
really ever need to care, so this may not be worth really caring about.

[ Fixed for lost 'loff_t' cast noticed by Andrew Morton ]

Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-api@vger.kernel.org
Cc: linux-arch@vger.kernel.org
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Ralf Baechle <ralf@linux-mips.org>>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-04 14:20:34 -07:00

311 lines
9.3 KiB
C

#ifndef _LINUX_COMPAT_H
#define _LINUX_COMPAT_H
/*
* These are the type definitions for the architecture specific
* syscall compatibility layer.
*/
#ifdef CONFIG_COMPAT
#include <linux/stat.h>
#include <linux/param.h> /* for HZ */
#include <linux/sem.h>
#include <asm/compat.h>
#include <asm/siginfo.h>
#include <asm/signal.h>
#define compat_jiffies_to_clock_t(x) \
(((unsigned long)(x) * COMPAT_USER_HZ) / HZ)
typedef __compat_uid32_t compat_uid_t;
typedef __compat_gid32_t compat_gid_t;
struct rusage;
struct compat_itimerspec {
struct compat_timespec it_interval;
struct compat_timespec it_value;
};
struct compat_utimbuf {
compat_time_t actime;
compat_time_t modtime;
};
struct compat_itimerval {
struct compat_timeval it_interval;
struct compat_timeval it_value;
};
struct compat_tms {
compat_clock_t tms_utime;
compat_clock_t tms_stime;
compat_clock_t tms_cutime;
compat_clock_t tms_cstime;
};
struct compat_timex {
compat_uint_t modes;
compat_long_t offset;
compat_long_t freq;
compat_long_t maxerror;
compat_long_t esterror;
compat_int_t status;
compat_long_t constant;
compat_long_t precision;
compat_long_t tolerance;
struct compat_timeval time;
compat_long_t tick;
compat_long_t ppsfreq;
compat_long_t jitter;
compat_int_t shift;
compat_long_t stabil;
compat_long_t jitcnt;
compat_long_t calcnt;
compat_long_t errcnt;
compat_long_t stbcnt;
compat_int_t tai;
compat_int_t :32; compat_int_t :32; compat_int_t :32; compat_int_t :32;
compat_int_t :32; compat_int_t :32; compat_int_t :32; compat_int_t :32;
compat_int_t :32; compat_int_t :32; compat_int_t :32;
};
#define _COMPAT_NSIG_WORDS (_COMPAT_NSIG / _COMPAT_NSIG_BPW)
typedef struct {
compat_sigset_word sig[_COMPAT_NSIG_WORDS];
} compat_sigset_t;
extern int get_compat_timespec(struct timespec *, const struct compat_timespec __user *);
extern int put_compat_timespec(const struct timespec *, struct compat_timespec __user *);
struct compat_iovec {
compat_uptr_t iov_base;
compat_size_t iov_len;
};
struct compat_rlimit {
compat_ulong_t rlim_cur;
compat_ulong_t rlim_max;
};
struct compat_rusage {
struct compat_timeval ru_utime;
struct compat_timeval ru_stime;
compat_long_t ru_maxrss;
compat_long_t ru_ixrss;
compat_long_t ru_idrss;
compat_long_t ru_isrss;
compat_long_t ru_minflt;
compat_long_t ru_majflt;
compat_long_t ru_nswap;
compat_long_t ru_inblock;
compat_long_t ru_oublock;
compat_long_t ru_msgsnd;
compat_long_t ru_msgrcv;
compat_long_t ru_nsignals;
compat_long_t ru_nvcsw;
compat_long_t ru_nivcsw;
};
extern int put_compat_rusage(const struct rusage *, struct compat_rusage __user *);
struct compat_siginfo;
extern asmlinkage long compat_sys_waitid(int, compat_pid_t,
struct compat_siginfo __user *, int,
struct compat_rusage __user *);
struct compat_dirent {
u32 d_ino;
compat_off_t d_off;
u16 d_reclen;
char d_name[256];
};
struct compat_ustat {
compat_daddr_t f_tfree;
compat_ino_t f_tinode;
char f_fname[6];
char f_fpack[6];
};
typedef union compat_sigval {
compat_int_t sival_int;
compat_uptr_t sival_ptr;
} compat_sigval_t;
#define COMPAT_SIGEV_PAD_SIZE ((SIGEV_MAX_SIZE/sizeof(int)) - 3)
typedef struct compat_sigevent {
compat_sigval_t sigev_value;
compat_int_t sigev_signo;
compat_int_t sigev_notify;
union {
compat_int_t _pad[COMPAT_SIGEV_PAD_SIZE];
compat_int_t _tid;
struct {
compat_uptr_t _function;
compat_uptr_t _attribute;
} _sigev_thread;
} _sigev_un;
} compat_sigevent_t;
struct compat_robust_list {
compat_uptr_t next;
};
struct compat_robust_list_head {
struct compat_robust_list list;
compat_long_t futex_offset;
compat_uptr_t list_op_pending;
};
extern void compat_exit_robust_list(struct task_struct *curr);
asmlinkage long
compat_sys_set_robust_list(struct compat_robust_list_head __user *head,
compat_size_t len);
asmlinkage long
compat_sys_get_robust_list(int pid, compat_uptr_t __user *head_ptr,
compat_size_t __user *len_ptr);
long compat_sys_semctl(int first, int second, int third, void __user *uptr);
long compat_sys_msgsnd(int first, int second, int third, void __user *uptr);
long compat_sys_msgrcv(int first, int second, int msgtyp, int third,
int version, void __user *uptr);
long compat_sys_msgctl(int first, int second, void __user *uptr);
long compat_sys_shmat(int first, int second, compat_uptr_t third, int version,
void __user *uptr);
long compat_sys_shmctl(int first, int second, void __user *uptr);
long compat_sys_semtimedop(int semid, struct sembuf __user *tsems,
unsigned nsems, const struct compat_timespec __user *timeout);
asmlinkage long compat_sys_keyctl(u32 option,
u32 arg2, u32 arg3, u32 arg4, u32 arg5);
asmlinkage long compat_sys_ustat(unsigned dev, struct compat_ustat __user *u32);
asmlinkage ssize_t compat_sys_readv(unsigned long fd,
const struct compat_iovec __user *vec, unsigned long vlen);
asmlinkage ssize_t compat_sys_writev(unsigned long fd,
const struct compat_iovec __user *vec, unsigned long vlen);
asmlinkage ssize_t compat_sys_preadv(unsigned long fd,
const struct compat_iovec __user *vec,
unsigned long vlen, u32 pos_low, u32 pos_high);
asmlinkage ssize_t compat_sys_pwritev(unsigned long fd,
const struct compat_iovec __user *vec,
unsigned long vlen, u32 pos_low, u32 pos_high);
int compat_do_execve(char * filename, compat_uptr_t __user *argv,
compat_uptr_t __user *envp, struct pt_regs * regs);
asmlinkage long compat_sys_select(int n, compat_ulong_t __user *inp,
compat_ulong_t __user *outp, compat_ulong_t __user *exp,
struct compat_timeval __user *tvp);
asmlinkage long compat_sys_wait4(compat_pid_t pid,
compat_uint_t __user *stat_addr, int options,
struct compat_rusage __user *ru);
#define BITS_PER_COMPAT_LONG (8*sizeof(compat_long_t))
#define BITS_TO_COMPAT_LONGS(bits) \
(((bits)+BITS_PER_COMPAT_LONG-1)/BITS_PER_COMPAT_LONG)
long compat_get_bitmap(unsigned long *mask, const compat_ulong_t __user *umask,
unsigned long bitmap_size);
long compat_put_bitmap(compat_ulong_t __user *umask, unsigned long *mask,
unsigned long bitmap_size);
int copy_siginfo_from_user32(siginfo_t *to, struct compat_siginfo __user *from);
int copy_siginfo_to_user32(struct compat_siginfo __user *to, siginfo_t *from);
int get_compat_sigevent(struct sigevent *event,
const struct compat_sigevent __user *u_event);
static inline int compat_timeval_compare(struct compat_timeval *lhs,
struct compat_timeval *rhs)
{
if (lhs->tv_sec < rhs->tv_sec)
return -1;
if (lhs->tv_sec > rhs->tv_sec)
return 1;
return lhs->tv_usec - rhs->tv_usec;
}
static inline int compat_timespec_compare(struct compat_timespec *lhs,
struct compat_timespec *rhs)
{
if (lhs->tv_sec < rhs->tv_sec)
return -1;
if (lhs->tv_sec > rhs->tv_sec)
return 1;
return lhs->tv_nsec - rhs->tv_nsec;
}
extern int get_compat_itimerspec(struct itimerspec *dst,
const struct compat_itimerspec __user *src);
extern int put_compat_itimerspec(struct compat_itimerspec __user *dst,
const struct itimerspec *src);
asmlinkage long compat_sys_gettimeofday(struct compat_timeval __user *tv,
struct timezone __user *tz);
asmlinkage long compat_sys_settimeofday(struct compat_timeval __user *tv,
struct timezone __user *tz);
asmlinkage long compat_sys_adjtimex(struct compat_timex __user *utp);
extern int compat_printk(const char *fmt, ...);
extern void sigset_from_compat(sigset_t *set, compat_sigset_t *compat);
asmlinkage long compat_sys_migrate_pages(compat_pid_t pid,
compat_ulong_t maxnode, const compat_ulong_t __user *old_nodes,
const compat_ulong_t __user *new_nodes);
extern int compat_ptrace_request(struct task_struct *child,
compat_long_t request,
compat_ulong_t addr, compat_ulong_t data);
extern long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
compat_ulong_t addr, compat_ulong_t data);
asmlinkage long compat_sys_ptrace(compat_long_t request, compat_long_t pid,
compat_long_t addr, compat_long_t data);
/*
* epoll (fs/eventpoll.c) compat bits follow ...
*/
struct epoll_event;
#define compat_epoll_event epoll_event
asmlinkage long compat_sys_epoll_pwait(int epfd,
struct compat_epoll_event __user *events,
int maxevents, int timeout,
const compat_sigset_t __user *sigmask,
compat_size_t sigsetsize);
asmlinkage long compat_sys_utimensat(unsigned int dfd, char __user *filename,
struct compat_timespec __user *t, int flags);
asmlinkage long compat_sys_signalfd(int ufd,
const compat_sigset_t __user *sigmask,
compat_size_t sigsetsize);
asmlinkage long compat_sys_timerfd_settime(int ufd, int flags,
const struct compat_itimerspec __user *utmr,
struct compat_itimerspec __user *otmr);
asmlinkage long compat_sys_timerfd_gettime(int ufd,
struct compat_itimerspec __user *otmr);
asmlinkage long compat_sys_move_pages(pid_t pid, unsigned long nr_page,
__u32 __user *pages,
const int __user *nodes,
int __user *status,
int flags);
asmlinkage long compat_sys_futimesat(unsigned int dfd, char __user *filename,
struct compat_timeval __user *t);
asmlinkage long compat_sys_newfstatat(unsigned int dfd, char __user * filename,
struct compat_stat __user *statbuf,
int flag);
asmlinkage long compat_sys_openat(unsigned int dfd, const char __user *filename,
int flags, int mode);
#endif /* CONFIG_COMPAT */
#endif /* _LINUX_COMPAT_H */