/* * Copyright 2010 Tilera Corporation. All Rights Reserved. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation, version 2. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or * NON INFRINGEMENT. See the GNU General Public License for * more details. */ #ifndef _ASM_TILE_UACCESS_H #define _ASM_TILE_UACCESS_H /* * User space memory access functions */ #include <linux/sched.h> #include <linux/mm.h> #include <asm-generic/uaccess-unaligned.h> #include <asm/processor.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(a) ((mm_segment_t) { (a) }) #define KERNEL_DS MAKE_MM_SEG(-1UL) #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) #ifndef __tilegx__ /* * We could allow mapping all 16 MB at 0xfc000000, but we set up a * special hack in arch_setup_additional_pages() to auto-create a mapping * for the first 16 KB, and it would seem strange to have different * user-accessible semantics for memory at 0xfc000000 and above 0xfc004000. */ static inline int is_arch_mappable_range(unsigned long addr, unsigned long size) { return (addr >= MEM_USER_INTRPT && addr < (MEM_USER_INTRPT + INTRPT_SIZE) && size <= (MEM_USER_INTRPT + INTRPT_SIZE) - addr); } #define is_arch_mappable_range is_arch_mappable_range #else #define is_arch_mappable_range(addr, size) 0 #endif /* * Test whether a block of memory is a valid user space address. * Returns 0 if the range is valid, nonzero otherwise. */ int __range_ok(unsigned long addr, unsigned long size); /** * 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) ({ \ __chk_user_ptr(addr); \ likely(__range_ok((unsigned long)(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; }; extern int fixup_exception(struct pt_regs *regs); /* * We return the __get_user_N function results in a structure, * thus in r0 and r1. If "err" is zero, "val" is the result * of the read; otherwise, "err" is -EFAULT. * * We rarely need 8-byte values on a 32-bit architecture, but * we size the structure to accommodate. In practice, for the * the smaller reads, we can zero the high word for free, and * the caller will ignore it by virtue of casting anyway. */ struct __get_user { unsigned long long val; int err; }; /* * FIXME: we should express these as inline extended assembler, since * they're fundamentally just a variable dereference and some * supporting exception_table gunk. Note that (a la i386) we can * extend the copy_to_user and copy_from_user routines to call into * such extended assembler routines, though we will have to use a * different return code in that case (1, 2, or 4, rather than -EFAULT). */ extern struct __get_user __get_user_1(const void __user *); extern struct __get_user __get_user_2(const void __user *); extern struct __get_user __get_user_4(const void __user *); extern struct __get_user __get_user_8(const void __user *); extern int __put_user_1(long, void __user *); extern int __put_user_2(long, void __user *); extern int __put_user_4(long, void __user *); extern int __put_user_8(long long, void __user *); /* Unimplemented routines to cause linker failures */ extern struct __get_user __get_user_bad(void); extern int __put_user_bad(void); /* * 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, 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. * * Returns zero on success, or -EFAULT on error. * On error, the variable @x is set to zero. * * Caller must check the pointer with access_ok() before calling this * function. */ #define __get_user(x, ptr) \ ({ struct __get_user __ret; \ __typeof__(*(ptr)) const __user *__gu_addr = (ptr); \ __chk_user_ptr(__gu_addr); \ switch (sizeof(*(__gu_addr))) { \ case 1: \ __ret = __get_user_1(__gu_addr); \ break; \ case 2: \ __ret = __get_user_2(__gu_addr); \ break; \ case 4: \ __ret = __get_user_4(__gu_addr); \ break; \ case 8: \ __ret = __get_user_8(__gu_addr); \ break; \ default: \ __ret = __get_user_bad(); \ break; \ } \ (x) = (__typeof__(*__gu_addr)) (__typeof__(*__gu_addr - *__gu_addr)) \ __ret.val; \ __ret.err; \ }) /** * __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. * * Implementation note: The "case 8" logic of casting to the type of * the result of subtracting the value from itself is basically a way * of keeping all integer types the same, but casting any pointers to * ptrdiff_t, i.e. also an integer type. This way there are no * questionable casts seen by the compiler on an ILP32 platform. */ #define __put_user(x, ptr) \ ({ \ int __pu_err = 0; \ __typeof__(*(ptr)) __user *__pu_addr = (ptr); \ typeof(*__pu_addr) __pu_val = (x); \ __chk_user_ptr(__pu_addr); \ switch (sizeof(__pu_val)) { \ case 1: \ __pu_err = __put_user_1((long)__pu_val, __pu_addr); \ break; \ case 2: \ __pu_err = __put_user_2((long)__pu_val, __pu_addr); \ break; \ case 4: \ __pu_err = __put_user_4((long)__pu_val, __pu_addr); \ break; \ case 8: \ __pu_err = \ __put_user_8((__typeof__(__pu_val - __pu_val))__pu_val,\ __pu_addr); \ break; \ default: \ __pu_err = __put_user_bad(); \ break; \ } \ __pu_err; \ }) /* * The versions of get_user and put_user without initial underscores * check the address of their arguments to make sure they are not * in kernel space. */ #define put_user(x, ptr) \ ({ \ __typeof__(*(ptr)) __user *__Pu_addr = (ptr); \ access_ok(VERIFY_WRITE, (__Pu_addr), sizeof(*(__Pu_addr))) ? \ __put_user((x), (__Pu_addr)) : \ -EFAULT; \ }) #define get_user(x, ptr) \ ({ \ __typeof__(*(ptr)) const __user *__Gu_addr = (ptr); \ access_ok(VERIFY_READ, (__Gu_addr), sizeof(*(__Gu_addr))) ? \ __get_user((x), (__Gu_addr)) : \ ((x) = 0, -EFAULT); \ }) /** * __copy_to_user() - copy 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. * * An alternate version - __copy_to_user_inatomic() - is designed * to be called from atomic context, typically bracketed by calls * to pagefault_disable() and pagefault_enable(). */ extern unsigned long __must_check __copy_to_user_inatomic( void __user *to, const void *from, unsigned long n); static inline unsigned long __must_check __copy_to_user(void __user *to, const void *from, unsigned long n) { might_fault(); return __copy_to_user_inatomic(to, from, n); } static inline unsigned long __must_check copy_to_user(void __user *to, const void *from, unsigned long n) { if (access_ok(VERIFY_WRITE, to, n)) n = __copy_to_user(to, from, n); return n; } /** * __copy_from_user() - copy 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. * * An alternate version - __copy_from_user_inatomic() - is designed * to be called from atomic context, typically bracketed by calls * to pagefault_disable() and pagefault_enable(). This version * does *NOT* pad with zeros. */ extern unsigned long __must_check __copy_from_user_inatomic( void *to, const void __user *from, unsigned long n); extern unsigned long __must_check __copy_from_user_zeroing( void *to, const void __user *from, unsigned long n); static inline unsigned long __must_check __copy_from_user(void *to, const void __user *from, unsigned long n) { might_fault(); return __copy_from_user_zeroing(to, from, n); } static inline unsigned long __must_check _copy_from_user(void *to, const void __user *from, unsigned long n) { if (access_ok(VERIFY_READ, from, n)) n = __copy_from_user(to, from, n); else memset(to, 0, n); return n; } #ifdef CONFIG_DEBUG_COPY_FROM_USER extern void copy_from_user_overflow(void) __compiletime_warning("copy_from_user() size is not provably correct"); static inline unsigned long __must_check copy_from_user(void *to, const void __user *from, unsigned long n) { int sz = __compiletime_object_size(to); if (likely(sz == -1 || sz >= n)) n = _copy_from_user(to, from, n); else copy_from_user_overflow(); return n; } #else #define copy_from_user _copy_from_user #endif #ifdef __tilegx__ /** * __copy_in_user() - copy data within 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 user space to user space. Caller must check * the specified blocks with access_ok() before calling this function. * * Returns number of bytes that could not be copied. * On success, this will be zero. */ extern unsigned long __copy_in_user_inatomic( void __user *to, const void __user *from, unsigned long n); static inline unsigned long __must_check __copy_in_user(void __user *to, const void __user *from, unsigned long n) { might_sleep(); return __copy_in_user_inatomic(to, from, n); } static inline unsigned long __must_check copy_in_user(void __user *to, const void __user *from, unsigned long n) { if (access_ok(VERIFY_WRITE, to, n) && access_ok(VERIFY_READ, from, n)) n = __copy_in_user(to, from, n); return n; } #endif /** * 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. */ extern long strnlen_user_asm(const char __user *str, long n); static inline long __must_check strnlen_user(const char __user *str, long n) { might_fault(); return strnlen_user_asm(str, n); } #define strlen_user(str) strnlen_user(str, LONG_MAX) /** * strncpy_from_user: - Copy a NUL terminated string from userspace, with less checking. * @dst: Destination address, in kernel space. This buffer must be at * least @count bytes long. * @src: Source address, in user space. * @count: Maximum number of bytes to copy, including the trailing NUL. * * Copies a NUL-terminated string from userspace to kernel space. * Caller must check the specified block with access_ok() before calling * this function. * * On success, returns the length of the string (not including the trailing * NUL). * * If access to userspace fails, returns -EFAULT (some data may have been * copied). * * If @count is smaller than the length of the string, copies @count bytes * and returns @count. */ extern long strncpy_from_user_asm(char *dst, const char __user *src, long); static inline long __must_check __strncpy_from_user( char *dst, const char __user *src, long count) { might_fault(); return strncpy_from_user_asm(dst, src, count); } static inline long __must_check strncpy_from_user( char *dst, const char __user *src, long count) { if (access_ok(VERIFY_READ, src, 1)) return __strncpy_from_user(dst, src, count); return -EFAULT; } /** * clear_user: - Zero a block of memory in user space. * @mem: Destination address, in user space. * @len: Number of bytes to zero. * * Zero a block of memory in user space. * * Returns number of bytes that could not be cleared. * On success, this will be zero. */ extern unsigned long clear_user_asm(void __user *mem, unsigned long len); static inline unsigned long __must_check __clear_user( void __user *mem, unsigned long len) { might_fault(); return clear_user_asm(mem, len); } static inline unsigned long __must_check clear_user( void __user *mem, unsigned long len) { if (access_ok(VERIFY_WRITE, mem, len)) return __clear_user(mem, len); return len; } /** * flush_user: - Flush a block of memory in user space from cache. * @mem: Destination address, in user space. * @len: Number of bytes to flush. * * Returns number of bytes that could not be flushed. * On success, this will be zero. */ extern unsigned long flush_user_asm(void __user *mem, unsigned long len); static inline unsigned long __must_check __flush_user( void __user *mem, unsigned long len) { int retval; might_fault(); retval = flush_user_asm(mem, len); mb_incoherent(); return retval; } static inline unsigned long __must_check flush_user( void __user *mem, unsigned long len) { if (access_ok(VERIFY_WRITE, mem, len)) return __flush_user(mem, len); return len; } /** * inv_user: - Invalidate a block of memory in user space from cache. * @mem: Destination address, in user space. * @len: Number of bytes to invalidate. * * Returns number of bytes that could not be invalidated. * On success, this will be zero. * * Note that on Tile64, the "inv" operation is in fact a * "flush and invalidate", so cache write-backs will occur prior * to the cache being marked invalid. */ extern unsigned long inv_user_asm(void __user *mem, unsigned long len); static inline unsigned long __must_check __inv_user( void __user *mem, unsigned long len) { int retval; might_fault(); retval = inv_user_asm(mem, len); mb_incoherent(); return retval; } static inline unsigned long __must_check inv_user( void __user *mem, unsigned long len) { if (access_ok(VERIFY_WRITE, mem, len)) return __inv_user(mem, len); return len; } /** * finv_user: - Flush-inval a block of memory in user space from cache. * @mem: Destination address, in user space. * @len: Number of bytes to invalidate. * * Returns number of bytes that could not be flush-invalidated. * On success, this will be zero. */ extern unsigned long finv_user_asm(void __user *mem, unsigned long len); static inline unsigned long __must_check __finv_user( void __user *mem, unsigned long len) { int retval; might_fault(); retval = finv_user_asm(mem, len); mb_incoherent(); return retval; } static inline unsigned long __must_check finv_user( void __user *mem, unsigned long len) { if (access_ok(VERIFY_WRITE, mem, len)) return __finv_user(mem, len); return len; } #endif /* _ASM_TILE_UACCESS_H */