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Diffstat (limited to 'arch/x86/include/asm/uaccess.h')
| -rw-r--r-- | arch/x86/include/asm/uaccess.h | 454 |
1 files changed, 454 insertions, 0 deletions
diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h new file mode 100644 index 00000000000..35c54921b2e --- /dev/null +++ b/arch/x86/include/asm/uaccess.h @@ -0,0 +1,454 @@ +#ifndef _ASM_X86_UACCESS_H +#define _ASM_X86_UACCESS_H +/* + * User space memory access functions + */ +#include <linux/errno.h> +#include <linux/compiler.h> +#include <linux/thread_info.h> +#include <linux/prefetch.h> +#include <linux/string.h> +#include <asm/asm.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(-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) + +#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 (u65 for x86_64) + * + * This needs 33-bit (65-bit for x86_64) arithmetic. We have a carry... + */ + +#define __range_not_ok(addr, size) \ +({ \ + unsigned long flag, roksum; \ + __chk_user_ptr(addr); \ + asm("add %3,%1 ; sbb %0,%0 ; cmp %1,%4 ; sbb $0,%0" \ + : "=&r" (flag), "=r" (roksum) \ + : "1" (addr), "g" ((long)(size)), \ + "rm" (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_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; +}; + +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 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_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. + */ +#ifdef CONFIG_X86_32 +#define __get_user_8(__ret_gu, __val_gu, ptr) \ + __get_user_x(X, __ret_gu, __val_gu, ptr) +#else +#define __get_user_8(__ret_gu, __val_gu, ptr) \ + __get_user_x(8, __ret_gu, __val_gu, ptr) +#endif + +#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; \ + case 8: \ + __get_user_8(__ret_gu, __val_gu, ptr); \ + break; \ + default: \ + __get_user_x(X, __ret_gu, __val_gu, ptr); \ + break; \ + } \ + (x) = (__typeof__(*(ptr)))__val_gu; \ + __ret_gu; \ +}) + +#define __put_user_x(size, x, ptr, __ret_pu) \ + asm volatile("call __put_user_" #size : "=a" (__ret_pu) \ + :"0" ((typeof(*(ptr)))(x)), "c" (ptr) : "ebx") + + + +#ifdef CONFIG_X86_32 +#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" \ + _ASM_EXTABLE(1b, 4b) \ + _ASM_EXTABLE(2b, 4b) \ + : "=r" (err) \ + : "A" (x), "r" (addr), "i" (-EFAULT), "0" (err)) + +#define __put_user_x8(x, ptr, __ret_pu) \ + asm volatile("call __put_user_8" : "=a" (__ret_pu) \ + : "A" ((typeof(*(ptr)))(x)), "c" (ptr) : "ebx") +#else +#define __put_user_u64(x, ptr, retval) \ + __put_user_asm(x, ptr, retval, "q", "", "Zr", -EFAULT) +#define __put_user_x8(x, ptr, __ret_pu) __put_user_x(8, x, ptr, __ret_pu) +#endif + +extern void __put_user_bad(void); + +/* + * Strange magic calling convention: pointer in %ecx, + * value in %eax(:%edx), return value in %eax. clobbers %rbx + */ +extern void __put_user_1(void); +extern void __put_user_2(void); +extern void __put_user_4(void); +extern void __put_user_8(void); + +#ifdef CONFIG_X86_WP_WORKS_OK + +/** + * 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. + */ +#define put_user(x, ptr) \ +({ \ + int __ret_pu; \ + __typeof__(*(ptr)) __pu_val; \ + __chk_user_ptr(ptr); \ + __pu_val = x; \ + switch (sizeof(*(ptr))) { \ + case 1: \ + __put_user_x(1, __pu_val, ptr, __ret_pu); \ + break; \ + case 2: \ + __put_user_x(2, __pu_val, ptr, __ret_pu); \ + break; \ + case 4: \ + __put_user_x(4, __pu_val, ptr, __ret_pu); \ + break; \ + case 8: \ + __put_user_x8(__pu_val, ptr, __ret_pu); \ + break; \ + default: \ + __put_user_x(X, __pu_val, ptr, __ret_pu); \ + break; \ + } \ + __ret_pu; \ +}) + +#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", "k", "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) + +#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 + +#ifdef CONFIG_X86_32 +#define __get_user_asm_u64(x, ptr, retval, errret) (x) = __get_user_bad() +#else +#define __get_user_asm_u64(x, ptr, retval, errret) \ + __get_user_asm(x, ptr, retval, "q", "", "=r", errret) +#endif + +#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", "k", "=r", errret); \ + break; \ + case 8: \ + __get_user_asm_u64(x, ptr, retval, 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: mov %3,%0\n" \ + " xor"itype" %"rtype"1,%"rtype"1\n" \ + " jmp 2b\n" \ + ".previous\n" \ + _ASM_EXTABLE(1b, 3b) \ + : "=r" (err), ltype(x) \ + : "m" (__m(addr)), "i" (errret), "0" (err)) + +#define __put_user_nocheck(x, ptr, size) \ +({ \ + long __pu_err; \ + __put_user_size((x), (ptr), (size), __pu_err, -EFAULT); \ + __pu_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) = (__force __typeof__(*(ptr)))__gu_val; \ + __gu_err; \ +}) + +/* 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, errret) \ + 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" \ + _ASM_EXTABLE(1b, 3b) \ + : "=r"(err) \ + : ltype(x), "m" (__m(addr)), "i" (errret), "0" (err)) +/** + * __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 __get_user_unaligned __get_user +#define __put_user_unaligned __put_user + +/* + * 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 ARCH_HAS_NOCACHE_UACCESS 1 + +#ifdef CONFIG_X86_32 +# include "uaccess_32.h" +#else +# define ARCH_HAS_SEARCH_EXTABLE +# include "uaccess_64.h" +#endif + +#endif /* _ASM_X86_UACCESS_H */ + |