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linux/include/asm-x86_64/uaccess.h
Andi Kleen 0812a579c9 [PATCH] x86-64: Add __copy_from_user_nocache 
This does user copies in fs write() into the page cache with write combining.
This pushes the destination out of the CPU's cache, but allows higher bandwidth
in some case.

The theory is that the page cache data is usually not touched by the
CPU again and it's better to not pollute the cache with it. Also it is a little
faster.

Signed-off-by: Andi Kleen <ak@suse.de>
2007-02-13 13:26:19 +01:00

385 lines
12 KiB
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#ifndef __X86_64_UACCESS_H
#define __X86_64_UACCESS_H
/*
* User space memory access functions
*/
#include <linux/compiler.h>
#include <linux/errno.h>
#include <linux/prefetch.h>
#include <asm/page.h>
#define VERIFY_READ 0
#define VERIFY_WRITE 1
/*
* 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.
*
* For historical reasons, these macros are grossly misnamed.
*/
#define MAKE_MM_SEG(s) ((mm_segment_t) { (s) })
#define KERNEL_DS MAKE_MM_SEG(0xFFFFFFFFFFFFFFFFUL)
#define USER_DS MAKE_MM_SEG(PAGE_OFFSET)
#define get_ds() (KERNEL_DS)
#define get_fs() (current_thread_info()->addr_limit)
#define set_fs(x) (current_thread_info()->addr_limit = (x))
#define segment_eq(a,b) ((a).seg == (b).seg)
#define __addr_ok(addr) (!((unsigned long)(addr) & (current_thread_info()->addr_limit.seg)))
/*
* Uhhuh, this needs 65-bit arithmetic. We have a carry..
*/
#define __range_not_ok(addr,size) ({ \
unsigned long flag,roksum; \
__chk_user_ptr(addr); \
asm("# range_ok\n\r" \
"addq %3,%1 ; sbbq %0,%0 ; cmpq %1,%4 ; sbbq $0,%0" \
:"=&r" (flag), "=r" (roksum) \
:"1" (addr),"g" ((long)(size)),"g" (current_thread_info()->addr_limit.seg)); \
flag; })
#define access_ok(type, addr, size) (__range_not_ok(addr,size) == 0)
/*
* The exception table consists of pairs of addresses: the first is the
* address of an instruction that is allowed to fault, and the second is
* the address at which the program should continue. No registers are
* modified, so it is entirely up to the continuation code to figure out
* what to do.
*
* All the routines below use bits of fixup code that are out of line
* with the main instruction path. This means when everything is well,
* we don't even have to jump over them. Further, they do not intrude
* on our cache or tlb entries.
*/
struct exception_table_entry
{
unsigned long insn, fixup;
};
#define ARCH_HAS_SEARCH_EXTABLE
/*
* These are the main single-value transfer routines. They automatically
* use the right size if we just have the right pointer type.
*
* This gets kind of ugly. We want to return _two_ values in "get_user()"
* and yet we don't want to do any pointers, because that is too much
* of a performance impact. Thus we have a few rather ugly macros here,
* and hide all the ugliness from the user.
*
* The "__xxx" versions of the user access functions are versions that
* do not verify the address space, that must have been done previously
* with a separate "access_ok()" call (this is used when we do multiple
* accesses to the same area of user memory).
*/
#define __get_user_x(size,ret,x,ptr) \
asm volatile("call __get_user_" #size \
:"=a" (ret),"=d" (x) \
:"c" (ptr) \
:"r8")
/* Careful: we have to cast the result to the type of the pointer for sign reasons */
#define get_user(x,ptr) \
({ unsigned long __val_gu; \
int __ret_gu; \
__chk_user_ptr(ptr); \
switch(sizeof (*(ptr))) { \
case 1: __get_user_x(1,__ret_gu,__val_gu,ptr); break; \
case 2: __get_user_x(2,__ret_gu,__val_gu,ptr); break; \
case 4: __get_user_x(4,__ret_gu,__val_gu,ptr); break; \
case 8: __get_user_x(8,__ret_gu,__val_gu,ptr); break; \
default: __get_user_bad(); break; \
} \
(x) = (typeof(*(ptr)))__val_gu; \
__ret_gu; \
})
extern void __put_user_1(void);
extern void __put_user_2(void);
extern void __put_user_4(void);
extern void __put_user_8(void);
extern void __put_user_bad(void);
#define __put_user_x(size,ret,x,ptr) \
asm volatile("call __put_user_" #size \
:"=a" (ret) \
:"c" (ptr),"d" (x) \
:"r8")
#define put_user(x,ptr) \
__put_user_check((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
#define __get_user(x,ptr) \
__get_user_nocheck((x),(ptr),sizeof(*(ptr)))
#define __put_user(x,ptr) \
__put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
#define __get_user_unaligned __get_user
#define __put_user_unaligned __put_user
#define __put_user_nocheck(x,ptr,size) \
({ \
int __pu_err; \
__put_user_size((x),(ptr),(size),__pu_err); \
__pu_err; \
})
#define __put_user_check(x,ptr,size) \
({ \
int __pu_err; \
typeof(*(ptr)) __user *__pu_addr = (ptr); \
switch (size) { \
case 1: __put_user_x(1,__pu_err,x,__pu_addr); break; \
case 2: __put_user_x(2,__pu_err,x,__pu_addr); break; \
case 4: __put_user_x(4,__pu_err,x,__pu_addr); break; \
case 8: __put_user_x(8,__pu_err,x,__pu_addr); break; \
default: __put_user_bad(); \
} \
__pu_err; \
})
#define __put_user_size(x,ptr,size,retval) \
do { \
retval = 0; \
__chk_user_ptr(ptr); \
switch (size) { \
case 1: __put_user_asm(x,ptr,retval,"b","b","iq",-EFAULT); break;\
case 2: __put_user_asm(x,ptr,retval,"w","w","ir",-EFAULT); break;\
case 4: __put_user_asm(x,ptr,retval,"l","k","ir",-EFAULT); break;\
case 8: __put_user_asm(x,ptr,retval,"q","","Zr",-EFAULT); break;\
default: __put_user_bad(); \
} \
} while (0)
/* FIXME: this hack is definitely wrong -AK */
struct __large_struct { unsigned long buf[100]; };
#define __m(x) (*(struct __large_struct __user *)(x))
/*
* Tell gcc we read from memory instead of writing: this is because
* we do not write to any memory gcc knows about, so there are no
* aliasing issues.
*/
#define __put_user_asm(x, addr, err, itype, rtype, ltype, errno) \
asm volatile( \
"1: mov"itype" %"rtype"1,%2\n" \
"2:\n" \
".section .fixup,\"ax\"\n" \
"3: mov %3,%0\n" \
" jmp 2b\n" \
".previous\n" \
".section __ex_table,\"a\"\n" \
" .align 8\n" \
" .quad 1b,3b\n" \
".previous" \
: "=r"(err) \
: ltype (x), "m"(__m(addr)), "i"(errno), "0"(err))
#define __get_user_nocheck(x,ptr,size) \
({ \
int __gu_err; \
unsigned long __gu_val; \
__get_user_size(__gu_val,(ptr),(size),__gu_err); \
(x) = (typeof(*(ptr)))__gu_val; \
__gu_err; \
})
extern int __get_user_1(void);
extern int __get_user_2(void);
extern int __get_user_4(void);
extern int __get_user_8(void);
extern int __get_user_bad(void);
#define __get_user_size(x,ptr,size,retval) \
do { \
retval = 0; \
__chk_user_ptr(ptr); \
switch (size) { \
case 1: __get_user_asm(x,ptr,retval,"b","b","=q",-EFAULT); break;\
case 2: __get_user_asm(x,ptr,retval,"w","w","=r",-EFAULT); break;\
case 4: __get_user_asm(x,ptr,retval,"l","k","=r",-EFAULT); break;\
case 8: __get_user_asm(x,ptr,retval,"q","","=r",-EFAULT); break;\
default: (x) = __get_user_bad(); \
} \
} while (0)
#define __get_user_asm(x, addr, err, itype, rtype, ltype, errno) \
asm volatile( \
"1: mov"itype" %2,%"rtype"1\n" \
"2:\n" \
".section .fixup,\"ax\"\n" \
"3: mov %3,%0\n" \
" xor"itype" %"rtype"1,%"rtype"1\n" \
" jmp 2b\n" \
".previous\n" \
".section __ex_table,\"a\"\n" \
" .align 8\n" \
" .quad 1b,3b\n" \
".previous" \
: "=r"(err), ltype (x) \
: "m"(__m(addr)), "i"(errno), "0"(err))
/*
* Copy To/From Userspace
*/
/* Handles exceptions in both to and from, but doesn't do access_ok */
__must_check unsigned long
copy_user_generic(void *to, const void *from, unsigned len);
__must_check unsigned long
copy_to_user(void __user *to, const void *from, unsigned len);
__must_check unsigned long
copy_from_user(void *to, const void __user *from, unsigned len);
__must_check unsigned long
copy_in_user(void __user *to, const void __user *from, unsigned len);
static __always_inline __must_check
int __copy_from_user(void *dst, const void __user *src, unsigned size)
{
int ret = 0;
if (!__builtin_constant_p(size))
return copy_user_generic(dst,(__force void *)src,size);
switch (size) {
case 1:__get_user_asm(*(u8*)dst,(u8 __user *)src,ret,"b","b","=q",1);
return ret;
case 2:__get_user_asm(*(u16*)dst,(u16 __user *)src,ret,"w","w","=r",2);
return ret;
case 4:__get_user_asm(*(u32*)dst,(u32 __user *)src,ret,"l","k","=r",4);
return ret;
case 8:__get_user_asm(*(u64*)dst,(u64 __user *)src,ret,"q","","=r",8);
return ret;
case 10:
__get_user_asm(*(u64*)dst,(u64 __user *)src,ret,"q","","=r",16);
if (unlikely(ret)) return ret;
__get_user_asm(*(u16*)(8+(char*)dst),(u16 __user *)(8+(char __user *)src),ret,"w","w","=r",2);
return ret;
case 16:
__get_user_asm(*(u64*)dst,(u64 __user *)src,ret,"q","","=r",16);
if (unlikely(ret)) return ret;
__get_user_asm(*(u64*)(8+(char*)dst),(u64 __user *)(8+(char __user *)src),ret,"q","","=r",8);
return ret;
default:
return copy_user_generic(dst,(__force void *)src,size);
}
}
static __always_inline __must_check
int __copy_to_user(void __user *dst, const void *src, unsigned size)
{
int ret = 0;
if (!__builtin_constant_p(size))
return copy_user_generic((__force void *)dst,src,size);
switch (size) {
case 1:__put_user_asm(*(u8*)src,(u8 __user *)dst,ret,"b","b","iq",1);
return ret;
case 2:__put_user_asm(*(u16*)src,(u16 __user *)dst,ret,"w","w","ir",2);
return ret;
case 4:__put_user_asm(*(u32*)src,(u32 __user *)dst,ret,"l","k","ir",4);
return ret;
case 8:__put_user_asm(*(u64*)src,(u64 __user *)dst,ret,"q","","ir",8);
return ret;
case 10:
__put_user_asm(*(u64*)src,(u64 __user *)dst,ret,"q","","ir",10);
if (unlikely(ret)) return ret;
asm("":::"memory");
__put_user_asm(4[(u16*)src],4+(u16 __user *)dst,ret,"w","w","ir",2);
return ret;
case 16:
__put_user_asm(*(u64*)src,(u64 __user *)dst,ret,"q","","ir",16);
if (unlikely(ret)) return ret;
asm("":::"memory");
__put_user_asm(1[(u64*)src],1+(u64 __user *)dst,ret,"q","","ir",8);
return ret;
default:
return copy_user_generic((__force void *)dst,src,size);
}
}
static __always_inline __must_check
int __copy_in_user(void __user *dst, const void __user *src, unsigned size)
{
int ret = 0;
if (!__builtin_constant_p(size))
return copy_user_generic((__force void *)dst,(__force void *)src,size);
switch (size) {
case 1: {
u8 tmp;
__get_user_asm(tmp,(u8 __user *)src,ret,"b","b","=q",1);
if (likely(!ret))
__put_user_asm(tmp,(u8 __user *)dst,ret,"b","b","iq",1);
return ret;
}
case 2: {
u16 tmp;
__get_user_asm(tmp,(u16 __user *)src,ret,"w","w","=r",2);
if (likely(!ret))
__put_user_asm(tmp,(u16 __user *)dst,ret,"w","w","ir",2);
return ret;
}
case 4: {
u32 tmp;
__get_user_asm(tmp,(u32 __user *)src,ret,"l","k","=r",4);
if (likely(!ret))
__put_user_asm(tmp,(u32 __user *)dst,ret,"l","k","ir",4);
return ret;
}
case 8: {
u64 tmp;
__get_user_asm(tmp,(u64 __user *)src,ret,"q","","=r",8);
if (likely(!ret))
__put_user_asm(tmp,(u64 __user *)dst,ret,"q","","ir",8);
return ret;
}
default:
return copy_user_generic((__force void *)dst,(__force void *)src,size);
}
}
__must_check long
strncpy_from_user(char *dst, const char __user *src, long count);
__must_check long
__strncpy_from_user(char *dst, const char __user *src, long count);
__must_check long strnlen_user(const char __user *str, long n);
__must_check long __strnlen_user(const char __user *str, long n);
__must_check long strlen_user(const char __user *str);
__must_check unsigned long clear_user(void __user *mem, unsigned long len);
__must_check unsigned long __clear_user(void __user *mem, unsigned long len);
__must_check long __copy_from_user_inatomic(void *dst, const void __user *src, unsigned size);
static __must_check __always_inline int
__copy_to_user_inatomic(void __user *dst, const void *src, unsigned size)
{
return copy_user_generic((__force void *)dst, src, size);
}
#define ARCH_HAS_NOCACHE_UACCESS 1
extern long __copy_user_nocache(void *dst, const void __user *src, unsigned size, int zerorest);
static inline int __copy_from_user_nocache(void *dst, const void __user *src, unsigned size)
{
might_sleep();
return __copy_user_nocache(dst, (__force void *)src, size, 1);
}
static inline int __copy_from_user_inatomic_nocache(void *dst, const void __user *src, unsigned size)
{
return __copy_user_nocache(dst, (__force void *)src, size, 0);
}
#endif /* __X86_64_UACCESS_H */
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