/* SPDX-License-Identifier: GPL-2.0-only */ /* * Copyright (C) 2012 Regents of the University of California * * This file was copied from include/asm-generic/uaccess.h */ #ifndef _ASM_RISCV_UACCESS_H #define _ASM_RISCV_UACCESS_H #include #include /* for TASK_SIZE */ /* * User space memory access functions */ #ifdef CONFIG_MMU #include #include #include #include #include #include #define __enable_user_access() \ __asm__ __volatile__ ("csrs sstatus, %0" : : "r" (SR_SUM) : "memory") #define __disable_user_access() \ __asm__ __volatile__ ("csrc sstatus, %0" : : "r" (SR_SUM) : "memory") /** * access_ok: - Checks if a user space pointer is valid * @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(addr, size) ({ \ __chk_user_ptr(addr); \ likely(__access_ok((unsigned long __force)(addr), (size))); \ }) /* * Ensure that the range [addr, addr+size) is within the process's * address space */ static inline int __access_ok(unsigned long addr, unsigned long size) { return size <= TASK_SIZE && addr <= TASK_SIZE - size; } /* * 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. */ #define __LSW 0 #define __MSW 1 /* * The "__xxx" versions of the user access functions do not verify the address * space - it must have been done previously with a separate "access_ok()" * call. */ #define __get_user_asm(insn, x, ptr, err) \ do { \ uintptr_t __tmp; \ __typeof__(x) __x; \ __asm__ __volatile__ ( \ "1:\n" \ " " insn " %1, %3\n" \ "2:\n" \ " .section .fixup,\"ax\"\n" \ " .balign 4\n" \ "3:\n" \ " li %0, %4\n" \ " li %1, 0\n" \ " jump 2b, %2\n" \ " .previous\n" \ _ASM_EXTABLE(1b, 3b) \ : "+r" (err), "=&r" (__x), "=r" (__tmp) \ : "m" (*(ptr)), "i" (-EFAULT)); \ (x) = __x; \ } while (0) #ifdef CONFIG_64BIT #define __get_user_8(x, ptr, err) \ __get_user_asm("ld", x, ptr, err) #else /* !CONFIG_64BIT */ #define __get_user_8(x, ptr, err) \ do { \ u32 __user *__ptr = (u32 __user *)(ptr); \ u32 __lo, __hi; \ uintptr_t __tmp; \ __asm__ __volatile__ ( \ "1:\n" \ " lw %1, %4\n" \ "2:\n" \ " lw %2, %5\n" \ "3:\n" \ " .section .fixup,\"ax\"\n" \ " .balign 4\n" \ "4:\n" \ " li %0, %6\n" \ " li %1, 0\n" \ " li %2, 0\n" \ " jump 3b, %3\n" \ " .previous\n" \ _ASM_EXTABLE(1b, 4b) \ _ASM_EXTABLE(2b, 4b) \ : "+r" (err), "=&r" (__lo), "=r" (__hi), \ "=r" (__tmp) \ : "m" (__ptr[__LSW]), "m" (__ptr[__MSW]), \ "i" (-EFAULT)); \ (x) = (__typeof__(x))((__typeof__((x)-(x)))( \ (((u64)__hi << 32) | __lo))); \ } while (0) #endif /* CONFIG_64BIT */ #define __get_user_nocheck(x, __gu_ptr, __gu_err) \ do { \ switch (sizeof(*__gu_ptr)) { \ case 1: \ __get_user_asm("lb", (x), __gu_ptr, __gu_err); \ break; \ case 2: \ __get_user_asm("lh", (x), __gu_ptr, __gu_err); \ break; \ case 4: \ __get_user_asm("lw", (x), __gu_ptr, __gu_err); \ break; \ case 8: \ __get_user_8((x), __gu_ptr, __gu_err); \ break; \ default: \ BUILD_BUG(); \ } \ } while (0) /** * __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) \ ({ \ const __typeof__(*(ptr)) __user *__gu_ptr = (ptr); \ long __gu_err = 0; \ \ __chk_user_ptr(__gu_ptr); \ \ __enable_user_access(); \ __get_user_nocheck(x, __gu_ptr, __gu_err); \ __disable_user_access(); \ \ __gu_err; \ }) /** * 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) \ ({ \ const __typeof__(*(ptr)) __user *__p = (ptr); \ might_fault(); \ access_ok(__p, sizeof(*__p)) ? \ __get_user((x), __p) : \ ((x) = 0, -EFAULT); \ }) #define __put_user_asm(insn, x, ptr, err) \ do { \ uintptr_t __tmp; \ __typeof__(*(ptr)) __x = x; \ __asm__ __volatile__ ( \ "1:\n" \ " " insn " %z3, %2\n" \ "2:\n" \ " .section .fixup,\"ax\"\n" \ " .balign 4\n" \ "3:\n" \ " li %0, %4\n" \ " jump 2b, %1\n" \ " .previous\n" \ _ASM_EXTABLE(1b, 3b) \ : "+r" (err), "=r" (__tmp), "=m" (*(ptr)) \ : "rJ" (__x), "i" (-EFAULT)); \ } while (0) #ifdef CONFIG_64BIT #define __put_user_8(x, ptr, err) \ __put_user_asm("sd", x, ptr, err) #else /* !CONFIG_64BIT */ #define __put_user_8(x, ptr, err) \ do { \ u32 __user *__ptr = (u32 __user *)(ptr); \ u64 __x = (__typeof__((x)-(x)))(x); \ uintptr_t __tmp; \ __asm__ __volatile__ ( \ "1:\n" \ " sw %z4, %2\n" \ "2:\n" \ " sw %z5, %3\n" \ "3:\n" \ " .section .fixup,\"ax\"\n" \ " .balign 4\n" \ "4:\n" \ " li %0, %6\n" \ " jump 3b, %1\n" \ " .previous\n" \ _ASM_EXTABLE(1b, 4b) \ _ASM_EXTABLE(2b, 4b) \ : "+r" (err), "=r" (__tmp), \ "=m" (__ptr[__LSW]), \ "=m" (__ptr[__MSW]) \ : "rJ" (__x), "rJ" (__x >> 32), "i" (-EFAULT)); \ } while (0) #endif /* CONFIG_64BIT */ #define __put_user_nocheck(x, __gu_ptr, __pu_err) \ do { \ switch (sizeof(*__gu_ptr)) { \ case 1: \ __put_user_asm("sb", (x), __gu_ptr, __pu_err); \ break; \ case 2: \ __put_user_asm("sh", (x), __gu_ptr, __pu_err); \ break; \ case 4: \ __put_user_asm("sw", (x), __gu_ptr, __pu_err); \ break; \ case 8: \ __put_user_8((x), __gu_ptr, __pu_err); \ break; \ default: \ BUILD_BUG(); \ } \ } while (0) /** * __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. The value of @x is copied to avoid * re-ordering where @x is evaluated inside the block that enables user-space * access (thus bypassing user space protection if @x is a function). * * 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) \ ({ \ __typeof__(*(ptr)) __user *__gu_ptr = (ptr); \ __typeof__(*__gu_ptr) __val = (x); \ long __pu_err = 0; \ \ __chk_user_ptr(__gu_ptr); \ \ __enable_user_access(); \ __put_user_nocheck(__val, __gu_ptr, __pu_err); \ __disable_user_access(); \ \ __pu_err; \ }) /** * 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) \ ({ \ __typeof__(*(ptr)) __user *__p = (ptr); \ might_fault(); \ access_ok(__p, sizeof(*__p)) ? \ __put_user((x), __p) : \ -EFAULT; \ }) unsigned long __must_check __asm_copy_to_user(void __user *to, const void *from, unsigned long n); unsigned long __must_check __asm_copy_from_user(void *to, const void __user *from, unsigned long n); static inline unsigned long raw_copy_from_user(void *to, const void __user *from, unsigned long n) { return __asm_copy_from_user(to, from, n); } static inline unsigned long raw_copy_to_user(void __user *to, const void *from, unsigned long n) { return __asm_copy_to_user(to, from, n); } extern long strncpy_from_user(char *dest, const char __user *src, long count); extern long __must_check strnlen_user(const char __user *str, long n); extern unsigned long __must_check __clear_user(void __user *addr, unsigned long n); static inline unsigned long __must_check clear_user(void __user *to, unsigned long n) { might_fault(); return access_ok(to, n) ? __clear_user(to, n) : n; } #define HAVE_GET_KERNEL_NOFAULT #define __get_kernel_nofault(dst, src, type, err_label) \ do { \ long __kr_err; \ \ __get_user_nocheck(*((type *)(dst)), (type *)(src), __kr_err); \ if (unlikely(__kr_err)) \ goto err_label; \ } while (0) #define __put_kernel_nofault(dst, src, type, err_label) \ do { \ long __kr_err; \ \ __put_user_nocheck(*((type *)(src)), (type *)(dst), __kr_err); \ if (unlikely(__kr_err)) \ goto err_label; \ } while (0) #else /* CONFIG_MMU */ #include #endif /* CONFIG_MMU */ #endif /* _ASM_RISCV_UACCESS_H */