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linux/arch/alpha/include/asm/uaccess.h
Ivan Kokshaysky 08a42e86bc alpha: exception table sorting 
Exception fixups for sections other than .text (like one in futex_init())
break the natural ordering of fixup entries, so sorting is required.

Without that the result of the exception table search depends on phase of
the moon.

Signed-off-by: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Richard Henderson <rth@twiddle.net
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-05-02 15:36:10 -07:00

514 lines
14 KiB
C
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#ifndef __ALPHA_UACCESS_H
#define __ALPHA_UACCESS_H
#include <linux/errno.h>
#include <linux/sched.h>
/*
* The fs value determines whether argument validity checking should be
* performed or not. If get_fs() == USER_DS, checking is performed, with
* get_fs() == KERNEL_DS, checking is bypassed.
*
* Or at least it did once upon a time. Nowadays it is a mask that
* defines which bits of the address space are off limits. This is a
* wee bit faster than the above.
*
* For historical reasons, these macros are grossly misnamed.
*/
#define KERNEL_DS ((mm_segment_t) { 0UL })
#define USER_DS ((mm_segment_t) { -0x40000000000UL })
#define VERIFY_READ 0
#define VERIFY_WRITE 1
#define get_fs() (current_thread_info()->addr_limit)
#define get_ds() (KERNEL_DS)
#define set_fs(x) (current_thread_info()->addr_limit = (x))
#define segment_eq(a,b) ((a).seg == (b).seg)
/*
* Is a address valid? This does a straightforward calculation rather
* than tests.
*
* Address valid if:
* - "addr" doesn't have any high-bits set
* - AND "size" doesn't have any high-bits set
* - AND "addr+size" doesn't have any high-bits set
* - OR we are in kernel mode.
*/
#define __access_ok(addr,size,segment) \
(((segment).seg & (addr | size | (addr+size))) == 0)
#define access_ok(type,addr,size) \
({ \
__chk_user_ptr(addr); \
__access_ok(((unsigned long)(addr)),(size),get_fs()); \
})
/*
* These are the main single-value transfer routines. They automatically
* use the right size if we just have the right pointer type.
*
* As the alpha uses the same address space for kernel and user
* data, we can just do these as direct assignments. (Of course, the
* exception handling means that it's no longer "just"...)
*
* Careful to not
* (a) re-use the arguments for side effects (sizeof/typeof is ok)
* (b) require any knowledge of processes at this stage
*/
#define put_user(x,ptr) \
__put_user_check((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)),get_fs())
#define get_user(x,ptr) \
__get_user_check((x),(ptr),sizeof(*(ptr)),get_fs())
/*
* The "__xxx" versions do not do address space checking, useful when
* doing multiple accesses to the same area (the programmer has to do the
* checks by hand with "access_ok()")
*/
#define __put_user(x,ptr) \
__put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
#define __get_user(x,ptr) \
__get_user_nocheck((x),(ptr),sizeof(*(ptr)))
/*
* The "lda %1, 2b-1b(%0)" bits are magic to get the assembler to
* encode the bits we need for resolving the exception. See the
* more extensive comments with fixup_inline_exception below for
* more information.
*/
extern void __get_user_unknown(void);
#define __get_user_nocheck(x,ptr,size) \
({ \
long __gu_err = 0; \
unsigned long __gu_val; \
__chk_user_ptr(ptr); \
switch (size) { \
case 1: __get_user_8(ptr); break; \
case 2: __get_user_16(ptr); break; \
case 4: __get_user_32(ptr); break; \
case 8: __get_user_64(ptr); break; \
default: __get_user_unknown(); break; \
} \
(x) = (__typeof__(*(ptr))) __gu_val; \
__gu_err; \
})
#define __get_user_check(x,ptr,size,segment) \
({ \
long __gu_err = -EFAULT; \
unsigned long __gu_val = 0; \
const __typeof__(*(ptr)) __user *__gu_addr = (ptr); \
if (__access_ok((unsigned long)__gu_addr,size,segment)) { \
__gu_err = 0; \
switch (size) { \
case 1: __get_user_8(__gu_addr); break; \
case 2: __get_user_16(__gu_addr); break; \
case 4: __get_user_32(__gu_addr); break; \
case 8: __get_user_64(__gu_addr); break; \
default: __get_user_unknown(); break; \
} \
} \
(x) = (__typeof__(*(ptr))) __gu_val; \
__gu_err; \
})
struct __large_struct { unsigned long buf[100]; };
#define __m(x) (*(struct __large_struct __user *)(x))
#define __get_user_64(addr) \
__asm__("1: ldq %0,%2\n" \
"2:\n" \
".section __ex_table,\"a\"\n" \
" .long 1b - .\n" \
" lda %0, 2b-1b(%1)\n" \
".previous" \
: "=r"(__gu_val), "=r"(__gu_err) \
: "m"(__m(addr)), "1"(__gu_err))
#define __get_user_32(addr) \
__asm__("1: ldl %0,%2\n" \
"2:\n" \
".section __ex_table,\"a\"\n" \
" .long 1b - .\n" \
" lda %0, 2b-1b(%1)\n" \
".previous" \
: "=r"(__gu_val), "=r"(__gu_err) \
: "m"(__m(addr)), "1"(__gu_err))
#ifdef __alpha_bwx__
/* Those lucky bastards with ev56 and later CPUs can do byte/word moves. */
#define __get_user_16(addr) \
__asm__("1: ldwu %0,%2\n" \
"2:\n" \
".section __ex_table,\"a\"\n" \
" .long 1b - .\n" \
" lda %0, 2b-1b(%1)\n" \
".previous" \
: "=r"(__gu_val), "=r"(__gu_err) \
: "m"(__m(addr)), "1"(__gu_err))
#define __get_user_8(addr) \
__asm__("1: ldbu %0,%2\n" \
"2:\n" \
".section __ex_table,\"a\"\n" \
" .long 1b - .\n" \
" lda %0, 2b-1b(%1)\n" \
".previous" \
: "=r"(__gu_val), "=r"(__gu_err) \
: "m"(__m(addr)), "1"(__gu_err))
#else
/* Unfortunately, we can't get an unaligned access trap for the sub-word
load, so we have to do a general unaligned operation. */
#define __get_user_16(addr) \
{ \
long __gu_tmp; \
__asm__("1: ldq_u %0,0(%3)\n" \
"2: ldq_u %1,1(%3)\n" \
" extwl %0,%3,%0\n" \
" extwh %1,%3,%1\n" \
" or %0,%1,%0\n" \
"3:\n" \
".section __ex_table,\"a\"\n" \
" .long 1b - .\n" \
" lda %0, 3b-1b(%2)\n" \
" .long 2b - .\n" \
" lda %0, 3b-2b(%2)\n" \
".previous" \
: "=&r"(__gu_val), "=&r"(__gu_tmp), "=r"(__gu_err) \
: "r"(addr), "2"(__gu_err)); \
}
#define __get_user_8(addr) \
__asm__("1: ldq_u %0,0(%2)\n" \
" extbl %0,%2,%0\n" \
"2:\n" \
".section __ex_table,\"a\"\n" \
" .long 1b - .\n" \
" lda %0, 2b-1b(%1)\n" \
".previous" \
: "=&r"(__gu_val), "=r"(__gu_err) \
: "r"(addr), "1"(__gu_err))
#endif
extern void __put_user_unknown(void);
#define __put_user_nocheck(x,ptr,size) \
({ \
long __pu_err = 0; \
__chk_user_ptr(ptr); \
switch (size) { \
case 1: __put_user_8(x,ptr); break; \
case 2: __put_user_16(x,ptr); break; \
case 4: __put_user_32(x,ptr); break; \
case 8: __put_user_64(x,ptr); break; \
default: __put_user_unknown(); break; \
} \
__pu_err; \
})
#define __put_user_check(x,ptr,size,segment) \
({ \
long __pu_err = -EFAULT; \
__typeof__(*(ptr)) __user *__pu_addr = (ptr); \
if (__access_ok((unsigned long)__pu_addr,size,segment)) { \
__pu_err = 0; \
switch (size) { \
case 1: __put_user_8(x,__pu_addr); break; \
case 2: __put_user_16(x,__pu_addr); break; \
case 4: __put_user_32(x,__pu_addr); break; \
case 8: __put_user_64(x,__pu_addr); break; \
default: __put_user_unknown(); break; \
} \
} \
__pu_err; \
})
/*
* The "__put_user_xx()" macros tell gcc they read from memory
* instead of writing: this is because they do not write to
* any memory gcc knows about, so there are no aliasing issues
*/
#define __put_user_64(x,addr) \
__asm__ __volatile__("1: stq %r2,%1\n" \
"2:\n" \
".section __ex_table,\"a\"\n" \
" .long 1b - .\n" \
" lda $31,2b-1b(%0)\n" \
".previous" \
: "=r"(__pu_err) \
: "m" (__m(addr)), "rJ" (x), "0"(__pu_err))
#define __put_user_32(x,addr) \
__asm__ __volatile__("1: stl %r2,%1\n" \
"2:\n" \
".section __ex_table,\"a\"\n" \
" .long 1b - .\n" \
" lda $31,2b-1b(%0)\n" \
".previous" \
: "=r"(__pu_err) \
: "m"(__m(addr)), "rJ"(x), "0"(__pu_err))
#ifdef __alpha_bwx__
/* Those lucky bastards with ev56 and later CPUs can do byte/word moves. */
#define __put_user_16(x,addr) \
__asm__ __volatile__("1: stw %r2,%1\n" \
"2:\n" \
".section __ex_table,\"a\"\n" \
" .long 1b - .\n" \
" lda $31,2b-1b(%0)\n" \
".previous" \
: "=r"(__pu_err) \
: "m"(__m(addr)), "rJ"(x), "0"(__pu_err))
#define __put_user_8(x,addr) \
__asm__ __volatile__("1: stb %r2,%1\n" \
"2:\n" \
".section __ex_table,\"a\"\n" \
" .long 1b - .\n" \
" lda $31,2b-1b(%0)\n" \
".previous" \
: "=r"(__pu_err) \
: "m"(__m(addr)), "rJ"(x), "0"(__pu_err))
#else
/* Unfortunately, we can't get an unaligned access trap for the sub-word
write, so we have to do a general unaligned operation. */
#define __put_user_16(x,addr) \
{ \
long __pu_tmp1, __pu_tmp2, __pu_tmp3, __pu_tmp4; \
__asm__ __volatile__( \
"1: ldq_u %2,1(%5)\n" \
"2: ldq_u %1,0(%5)\n" \
" inswh %6,%5,%4\n" \
" inswl %6,%5,%3\n" \
" mskwh %2,%5,%2\n" \
" mskwl %1,%5,%1\n" \
" or %2,%4,%2\n" \
" or %1,%3,%1\n" \
"3: stq_u %2,1(%5)\n" \
"4: stq_u %1,0(%5)\n" \
"5:\n" \
".section __ex_table,\"a\"\n" \
" .long 1b - .\n" \
" lda $31, 5b-1b(%0)\n" \
" .long 2b - .\n" \
" lda $31, 5b-2b(%0)\n" \
" .long 3b - .\n" \
" lda $31, 5b-3b(%0)\n" \
" .long 4b - .\n" \
" lda $31, 5b-4b(%0)\n" \
".previous" \
: "=r"(__pu_err), "=&r"(__pu_tmp1), \
"=&r"(__pu_tmp2), "=&r"(__pu_tmp3), \
"=&r"(__pu_tmp4) \
: "r"(addr), "r"((unsigned long)(x)), "0"(__pu_err)); \
}
#define __put_user_8(x,addr) \
{ \
long __pu_tmp1, __pu_tmp2; \
__asm__ __volatile__( \
"1: ldq_u %1,0(%4)\n" \
" insbl %3,%4,%2\n" \
" mskbl %1,%4,%1\n" \
" or %1,%2,%1\n" \
"2: stq_u %1,0(%4)\n" \
"3:\n" \
".section __ex_table,\"a\"\n" \
" .long 1b - .\n" \
" lda $31, 3b-1b(%0)\n" \
" .long 2b - .\n" \
" lda $31, 3b-2b(%0)\n" \
".previous" \
: "=r"(__pu_err), \
"=&r"(__pu_tmp1), "=&r"(__pu_tmp2) \
: "r"((unsigned long)(x)), "r"(addr), "0"(__pu_err)); \
}
#endif
/*
* Complex access routines
*/
/* This little bit of silliness is to get the GP loaded for a function
that ordinarily wouldn't. Otherwise we could have it done by the macro
directly, which can be optimized the linker. */
#ifdef MODULE
#define __module_address(sym) "r"(sym),
#define __module_call(ra, arg, sym) "jsr $" #ra ",(%" #arg ")," #sym
#else
#define __module_address(sym)
#define __module_call(ra, arg, sym) "bsr $" #ra "," #sym " !samegp"
#endif
extern void __copy_user(void);
extern inline long
__copy_tofrom_user_nocheck(void *to, const void *from, long len)
{
register void * __cu_to __asm__("$6") = to;
register const void * __cu_from __asm__("$7") = from;
register long __cu_len __asm__("$0") = len;
__asm__ __volatile__(
__module_call(28, 3, __copy_user)
: "=r" (__cu_len), "=r" (__cu_from), "=r" (__cu_to)
: __module_address(__copy_user)
"0" (__cu_len), "1" (__cu_from), "2" (__cu_to)
: "$1","$2","$3","$4","$5","$28","memory");
return __cu_len;
}
extern inline long
__copy_tofrom_user(void *to, const void *from, long len, const void __user *validate)
{
if (__access_ok((unsigned long)validate, len, get_fs()))
len = __copy_tofrom_user_nocheck(to, from, len);
return len;
}
#define __copy_to_user(to,from,n) \
({ \
__chk_user_ptr(to); \
__copy_tofrom_user_nocheck((__force void *)(to),(from),(n)); \
})
#define __copy_from_user(to,from,n) \
({ \
__chk_user_ptr(from); \
__copy_tofrom_user_nocheck((to),(__force void *)(from),(n)); \
})
#define __copy_to_user_inatomic __copy_to_user
#define __copy_from_user_inatomic __copy_from_user
extern inline long
copy_to_user(void __user *to, const void *from, long n)
{
return __copy_tofrom_user((__force void *)to, from, n, to);
}
extern inline long
copy_from_user(void *to, const void __user *from, long n)
{
return __copy_tofrom_user(to, (__force void *)from, n, from);
}
extern void __do_clear_user(void);
extern inline long
__clear_user(void __user *to, long len)
{
register void __user * __cl_to __asm__("$6") = to;
register long __cl_len __asm__("$0") = len;
__asm__ __volatile__(
__module_call(28, 2, __do_clear_user)
: "=r"(__cl_len), "=r"(__cl_to)
: __module_address(__do_clear_user)
"0"(__cl_len), "1"(__cl_to)
: "$1","$2","$3","$4","$5","$28","memory");
return __cl_len;
}
extern inline long
clear_user(void __user *to, long len)
{
if (__access_ok((unsigned long)to, len, get_fs()))
len = __clear_user(to, len);
return len;
}
#undef __module_address
#undef __module_call
/* Returns: -EFAULT if exception before terminator, N if the entire
buffer filled, else strlen. */
extern long __strncpy_from_user(char *__to, const char __user *__from, long __to_len);
extern inline long
strncpy_from_user(char *to, const char __user *from, long n)
{
long ret = -EFAULT;
if (__access_ok((unsigned long)from, 0, get_fs()))
ret = __strncpy_from_user(to, from, n);
return ret;
}
/* Returns: 0 if bad, string length+1 (memory size) of string if ok */
extern long __strlen_user(const char __user *);
extern inline long strlen_user(const char __user *str)
{
return access_ok(VERIFY_READ,str,0) ? __strlen_user(str) : 0;
}
/* Returns: 0 if exception before NUL or reaching the supplied limit (N),
* a value greater than N if the limit would be exceeded, else strlen. */
extern long __strnlen_user(const char __user *, long);
extern inline long strnlen_user(const char __user *str, long n)
{
return access_ok(VERIFY_READ,str,0) ? __strnlen_user(str, n) : 0;
}
/*
* About the exception table:
*
* - insn is a 32-bit pc-relative offset from the faulting insn.
* - nextinsn is a 16-bit offset off of the faulting instruction
* (not off of the *next* instruction as branches are).
* - errreg is the register in which to place -EFAULT.
* - valreg is the final target register for the load sequence
* and will be zeroed.
*
* Either errreg or valreg may be $31, in which case nothing happens.
*
* The exception fixup information "just so happens" to be arranged
* as in a MEM format instruction. This lets us emit our three
* values like so:
*
* lda valreg, nextinsn(errreg)
*
*/
struct exception_table_entry
{
signed int insn;
union exception_fixup {
unsigned unit;
struct {
signed int nextinsn : 16;
unsigned int errreg : 5;
unsigned int valreg : 5;
} bits;
} fixup;
};
/* Returns the new pc */
#define fixup_exception(map_reg, _fixup, pc) \
({ \
if ((_fixup)->fixup.bits.valreg != 31) \
map_reg((_fixup)->fixup.bits.valreg) = 0; \
if ((_fixup)->fixup.bits.errreg != 31) \
map_reg((_fixup)->fixup.bits.errreg) = -EFAULT; \
(pc) + (_fixup)->fixup.bits.nextinsn; \
})
#define ARCH_HAS_SORT_EXTABLE
#define ARCH_HAS_SEARCH_EXTABLE
#endif /* __ALPHA_UACCESS_H */
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