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Diffstat (limited to 'include/asm-i386/uaccess.h')
| -rw-r--r-- | include/asm-i386/uaccess.h | 539 |
1 files changed, 539 insertions, 0 deletions
diff --git a/include/asm-i386/uaccess.h b/include/asm-i386/uaccess.h new file mode 100644 index 00000000000..886867aea94 --- /dev/null +++ b/include/asm-i386/uaccess.h @@ -0,0 +1,539 @@ +#ifndef __i386_UACCESS_H +#define __i386_UACCESS_H + +/* + * User space memory access functions + */ +#include <linux/config.h> +#include <linux/errno.h> +#include <linux/thread_info.h> +#include <linux/prefetch.h> +#include <linux/string.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(0xFFFFFFFFUL) +#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) + +/* + * movsl can be slow when source and dest are not both 8-byte aligned + */ +#ifdef CONFIG_X86_INTEL_USERCOPY +extern struct movsl_mask { + int mask; +} ____cacheline_aligned_in_smp movsl_mask; +#endif + +#define __addr_ok(addr) ((unsigned long __force)(addr) < (current_thread_info()->addr_limit.seg)) + +/* + * Test whether a block of memory is a valid user space address. + * Returns 0 if the range is valid, nonzero otherwise. + * + * This is equivalent to the following test: + * (u33)addr + (u33)size >= (u33)current->addr_limit.seg + * + * This needs 33-bit arithmetic. We have a carry... + */ +#define __range_ok(addr,size) ({ \ + unsigned long flag,sum; \ + __chk_user_ptr(addr); \ + asm("addl %3,%1 ; sbbl %0,%0; cmpl %1,%4; sbbl $0,%0" \ + :"=&r" (flag), "=r" (sum) \ + :"1" (addr),"g" ((int)(size)),"g" (current_thread_info()->addr_limit.seg)); \ + flag; }) + +/** + * access_ok: - Checks if a user space pointer is valid + * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE. Note that + * %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe + * to write to a block, it is always safe to read from it. + * @addr: User space pointer to start of block to check + * @size: Size of block to check + * + * Context: User context only. This function may sleep. + * + * Checks if a pointer to a block of memory in user space is valid. + * + * Returns true (nonzero) if the memory block may be valid, false (zero) + * if it is definitely invalid. + * + * Note that, depending on architecture, this function probably just + * checks that the pointer is in the user space range - after calling + * this function, memory access functions may still return -EFAULT. + */ +#define access_ok(type,addr,size) (likely(__range_ok(addr,size) == 0)) + +/** + * verify_area: - Obsolete/deprecated and will go away soon, + * use access_ok() instead. + * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE + * @addr: User space pointer to start of block to check + * @size: Size of block to check + * + * Context: User context only. This function may sleep. + * + * This function has been replaced by access_ok(). + * + * Checks if a pointer to a block of memory in user space is valid. + * + * Returns zero if the memory block may be valid, -EFAULT + * if it is definitely invalid. + * + * See access_ok() for more details. + */ +static inline int __deprecated verify_area(int type, const void __user * addr, unsigned long size) +{ + return access_ok(type,addr,size) ? 0 : -EFAULT; +} + + +/* + * 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; +}; + +extern int fixup_exception(struct pt_regs *regs); + +/* + * 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). + */ + +extern void __get_user_1(void); +extern void __get_user_2(void); +extern void __get_user_4(void); + +#define __get_user_x(size,ret,x,ptr) \ + __asm__ __volatile__("call __get_user_" #size \ + :"=a" (ret),"=d" (x) \ + :"0" (ptr)) + + +/* Careful: we have to cast the result to the type of the pointer for sign reasons */ +/** + * get_user: - Get a simple variable from user space. + * @x: Variable to store result. + * @ptr: Source address, in user space. + * + * Context: User context only. This function may sleep. + * + * This macro copies a single simple variable from user space to kernel + * space. It supports simple types like char and int, but not larger + * data types like structures or arrays. + * + * @ptr must have pointer-to-simple-variable type, and the result of + * dereferencing @ptr must be assignable to @x without a cast. + * + * Returns zero on success, or -EFAULT on error. + * On error, the variable @x is set to zero. + */ +#define get_user(x,ptr) \ +({ int __ret_gu; \ + unsigned long __val_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; \ + default: __get_user_x(X,__ret_gu,__val_gu,ptr); break; \ + } \ + (x) = (__typeof__(*(ptr)))__val_gu; \ + __ret_gu; \ +}) + +extern void __put_user_bad(void); + +/* + * Strange magic calling convention: pointer in %ecx, + * value in %eax(:%edx), return value in %eax, no clobbers. + */ +extern void __put_user_1(void); +extern void __put_user_2(void); +extern void __put_user_4(void); +extern void __put_user_8(void); + +#define __put_user_1(x, ptr) __asm__ __volatile__("call __put_user_1":"=a" (__ret_pu):"0" ((typeof(*(ptr)))(x)), "c" (ptr)) +#define __put_user_2(x, ptr) __asm__ __volatile__("call __put_user_2":"=a" (__ret_pu):"0" ((typeof(*(ptr)))(x)), "c" (ptr)) +#define __put_user_4(x, ptr) __asm__ __volatile__("call __put_user_4":"=a" (__ret_pu):"0" ((typeof(*(ptr)))(x)), "c" (ptr)) +#define __put_user_8(x, ptr) __asm__ __volatile__("call __put_user_8":"=a" (__ret_pu):"A" ((typeof(*(ptr)))(x)), "c" (ptr)) +#define __put_user_X(x, ptr) __asm__ __volatile__("call __put_user_X":"=a" (__ret_pu):"c" (ptr)) + +/** + * put_user: - Write a simple value into user space. + * @x: Value to copy to user space. + * @ptr: Destination address, in user space. + * + * Context: User context only. This function may sleep. + * + * This macro copies a single simple value from kernel space to user + * space. It supports simple types like char and int, but not larger + * data types like structures or arrays. + * + * @ptr must have pointer-to-simple-variable type, and @x must be assignable + * to the result of dereferencing @ptr. + * + * Returns zero on success, or -EFAULT on error. + */ +#ifdef CONFIG_X86_WP_WORKS_OK + +#define put_user(x,ptr) \ +({ int __ret_pu; \ + __chk_user_ptr(ptr); \ + switch(sizeof(*(ptr))) { \ + case 1: __put_user_1(x, ptr); break; \ + case 2: __put_user_2(x, ptr); break; \ + case 4: __put_user_4(x, ptr); break; \ + case 8: __put_user_8(x, ptr); break; \ + default:__put_user_X(x, ptr); break; \ + } \ + __ret_pu; \ +}) + +#else +#define put_user(x,ptr) \ +({ \ + int __ret_pu; \ + __typeof__(*(ptr)) __pus_tmp = x; \ + __ret_pu=0; \ + if(unlikely(__copy_to_user_ll(ptr, &__pus_tmp, \ + sizeof(*(ptr))) != 0)) \ + __ret_pu=-EFAULT; \ + __ret_pu; \ + }) + + +#endif + +/** + * __get_user: - Get a simple variable from user space, with less checking. + * @x: Variable to store result. + * @ptr: Source address, in user space. + * + * Context: User context only. This function may sleep. + * + * This macro copies a single simple variable from user space to kernel + * space. It supports simple types like char and int, but not larger + * data types like structures or arrays. + * + * @ptr must have pointer-to-simple-variable type, and the result of + * dereferencing @ptr must be assignable to @x without a cast. + * + * Caller must check the pointer with access_ok() before calling this + * function. + * + * Returns zero on success, or -EFAULT on error. + * On error, the variable @x is set to zero. + */ +#define __get_user(x,ptr) \ + __get_user_nocheck((x),(ptr),sizeof(*(ptr))) + + +/** + * __put_user: - Write a simple value into user space, with less checking. + * @x: Value to copy to user space. + * @ptr: Destination address, in user space. + * + * Context: User context only. This function may sleep. + * + * This macro copies a single simple value from kernel space to user + * space. It supports simple types like char and int, but not larger + * data types like structures or arrays. + * + * @ptr must have pointer-to-simple-variable type, and @x must be assignable + * to the result of dereferencing @ptr. + * + * Caller must check the pointer with access_ok() before calling this + * function. + * + * Returns zero on success, or -EFAULT on error. + */ +#define __put_user(x,ptr) \ + __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr))) + +#define __put_user_nocheck(x,ptr,size) \ +({ \ + long __pu_err; \ + __put_user_size((x),(ptr),(size),__pu_err,-EFAULT); \ + __pu_err; \ +}) + + +#define __put_user_u64(x, addr, err) \ + __asm__ __volatile__( \ + "1: movl %%eax,0(%2)\n" \ + "2: movl %%edx,4(%2)\n" \ + "3:\n" \ + ".section .fixup,\"ax\"\n" \ + "4: movl %3,%0\n" \ + " jmp 3b\n" \ + ".previous\n" \ + ".section __ex_table,\"a\"\n" \ + " .align 4\n" \ + " .long 1b,4b\n" \ + " .long 2b,4b\n" \ + ".previous" \ + : "=r"(err) \ + : "A" (x), "r" (addr), "i"(-EFAULT), "0"(err)) + +#ifdef CONFIG_X86_WP_WORKS_OK + +#define __put_user_size(x,ptr,size,retval,errret) \ +do { \ + retval = 0; \ + __chk_user_ptr(ptr); \ + switch (size) { \ + case 1: __put_user_asm(x,ptr,retval,"b","b","iq",errret);break; \ + case 2: __put_user_asm(x,ptr,retval,"w","w","ir",errret);break; \ + case 4: __put_user_asm(x,ptr,retval,"l","","ir",errret); break; \ + case 8: __put_user_u64((__typeof__(*ptr))(x),ptr,retval); break;\ + default: __put_user_bad(); \ + } \ +} while (0) + +#else + +#define __put_user_size(x,ptr,size,retval,errret) \ +do { \ + __typeof__(*(ptr)) __pus_tmp = x; \ + retval = 0; \ + \ + if(unlikely(__copy_to_user_ll(ptr, &__pus_tmp, size) != 0)) \ + retval = errret; \ +} while (0) + +#endif +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, errret) \ + __asm__ __volatile__( \ + "1: mov"itype" %"rtype"1,%2\n" \ + "2:\n" \ + ".section .fixup,\"ax\"\n" \ + "3: movl %3,%0\n" \ + " jmp 2b\n" \ + ".previous\n" \ + ".section __ex_table,\"a\"\n" \ + " .align 4\n" \ + " .long 1b,3b\n" \ + ".previous" \ + : "=r"(err) \ + : ltype (x), "m"(__m(addr)), "i"(errret), "0"(err)) + + +#define __get_user_nocheck(x,ptr,size) \ +({ \ + long __gu_err; \ + unsigned long __gu_val; \ + __get_user_size(__gu_val,(ptr),(size),__gu_err,-EFAULT);\ + (x) = (__typeof__(*(ptr)))__gu_val; \ + __gu_err; \ +}) + +extern long __get_user_bad(void); + +#define __get_user_size(x,ptr,size,retval,errret) \ +do { \ + retval = 0; \ + __chk_user_ptr(ptr); \ + switch (size) { \ + case 1: __get_user_asm(x,ptr,retval,"b","b","=q",errret);break; \ + case 2: __get_user_asm(x,ptr,retval,"w","w","=r",errret);break; \ + case 4: __get_user_asm(x,ptr,retval,"l","","=r",errret);break; \ + default: (x) = __get_user_bad(); \ + } \ +} while (0) + +#define __get_user_asm(x, addr, err, itype, rtype, ltype, errret) \ + __asm__ __volatile__( \ + "1: mov"itype" %2,%"rtype"1\n" \ + "2:\n" \ + ".section .fixup,\"ax\"\n" \ + "3: movl %3,%0\n" \ + " xor"itype" %"rtype"1,%"rtype"1\n" \ + " jmp 2b\n" \ + ".previous\n" \ + ".section __ex_table,\"a\"\n" \ + " .align 4\n" \ + " .long 1b,3b\n" \ + ".previous" \ + : "=r"(err), ltype (x) \ + : "m"(__m(addr)), "i"(errret), "0"(err)) + + +unsigned long __must_check __copy_to_user_ll(void __user *to, + const void *from, unsigned long n); +unsigned long __must_check __copy_from_user_ll(void *to, + const void __user *from, unsigned long n); + +/* + * Here we special-case 1, 2 and 4-byte copy_*_user invocations. On a fault + * we return the initial request size (1, 2 or 4), as copy_*_user should do. + * If a store crosses a page boundary and gets a fault, the x86 will not write + * anything, so this is accurate. + */ + +/** + * __copy_to_user: - Copy a block of data into user space, with less checking. + * @to: Destination address, in user space. + * @from: Source address, in kernel space. + * @n: Number of bytes to copy. + * + * Context: User context only. This function may sleep. + * + * Copy data from kernel space to user space. Caller must check + * the specified block with access_ok() before calling this function. + * + * Returns number of bytes that could not be copied. + * On success, this will be zero. + */ +static inline unsigned long __must_check +__copy_to_user_inatomic(void __user *to, const void *from, unsigned long n) +{ + if (__builtin_constant_p(n)) { + unsigned long ret; + + switch (n) { + case 1: + __put_user_size(*(u8 *)from, (u8 __user *)to, 1, ret, 1); + return ret; + case 2: + __put_user_size(*(u16 *)from, (u16 __user *)to, 2, ret, 2); + return ret; + case 4: + __put_user_size(*(u32 *)from, (u32 __user *)to, 4, ret, 4); + return ret; + } + } + return __copy_to_user_ll(to, from, n); +} + +static inline unsigned long __must_check +__copy_to_user(void __user *to, const void *from, unsigned long n) +{ + might_sleep(); + return __copy_to_user_inatomic(to, from, n); +} + +/** + * __copy_from_user: - Copy a block of data from user space, with less checking. + * @to: Destination address, in kernel space. + * @from: Source address, in user space. + * @n: Number of bytes to copy. + * + * Context: User context only. This function may sleep. + * + * Copy data from user space to kernel space. Caller must check + * the specified block with access_ok() before calling this function. + * + * Returns number of bytes that could not be copied. + * On success, this will be zero. + * + * If some data could not be copied, this function will pad the copied + * data to the requested size using zero bytes. + */ +static inline unsigned long +__copy_from_user_inatomic(void *to, const void __user *from, unsigned long n) +{ + if (__builtin_constant_p(n)) { + unsigned long ret; + + switch (n) { + case 1: + __get_user_size(*(u8 *)to, from, 1, ret, 1); + return ret; + case 2: + __get_user_size(*(u16 *)to, from, 2, ret, 2); + return ret; + case 4: + __get_user_size(*(u32 *)to, from, 4, ret, 4); + return ret; + } + } + return __copy_from_user_ll(to, from, n); +} + +static inline unsigned long +__copy_from_user(void *to, const void __user *from, unsigned long n) +{ + might_sleep(); + return __copy_from_user_inatomic(to, from, n); +} +unsigned long __must_check copy_to_user(void __user *to, + const void *from, unsigned long n); +unsigned long __must_check copy_from_user(void *to, + const void __user *from, unsigned long n); +long __must_check strncpy_from_user(char *dst, const char __user *src, + long count); +long __must_check __strncpy_from_user(char *dst, + const char __user *src, long count); + +/** + * strlen_user: - Get the size of a string in user space. + * @str: The string to measure. + * + * Context: User context only. This function may sleep. + * + * Get the size of a NUL-terminated string in user space. + * + * Returns the size of the string INCLUDING the terminating NUL. + * On exception, returns 0. + * + * If there is a limit on the length of a valid string, you may wish to + * consider using strnlen_user() instead. + */ +#define strlen_user(str) strnlen_user(str, ~0UL >> 1) + +long strnlen_user(const char __user *str, long n); +unsigned long __must_check clear_user(void __user *mem, unsigned long len); +unsigned long __must_check __clear_user(void __user *mem, unsigned long len); + +#endif /* __i386_UACCESS_H */ |