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Diffstat (limited to 'arch/tile/include/asm/uaccess.h')
| -rw-r--r-- | arch/tile/include/asm/uaccess.h | 578 |
1 files changed, 578 insertions, 0 deletions
diff --git a/arch/tile/include/asm/uaccess.h b/arch/tile/include/asm/uaccess.h new file mode 100644 index 00000000000..f3058afd5a8 --- /dev/null +++ b/arch/tile/include/asm/uaccess.h @@ -0,0 +1,578 @@ +/* + * 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) \ + (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 *); +extern struct __get_user __get_user_2(const void *); +extern struct __get_user __get_user_4(const void *); +extern struct __get_user __get_user_8(const void *); +extern int __put_user_1(long, void *); +extern int __put_user_2(long, void *); +extern int __put_user_4(long, void *); +extern int __put_user_8(long long, void *); + +/* 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_asm( + 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_asm(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 */ |