| /* 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 |
| |
| /* |
| * User space memory access functions |
| */ |
| #include <linux/errno.h> |
| #include <linux/compiler.h> |
| #include <linux/thread_info.h> |
| #include <asm/byteorder.h> |
| #include <asm/extable.h> |
| #include <asm/asm.h> |
| |
| #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") |
| |
| /* |
| * 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(~0UL) |
| #define USER_DS MAKE_MM_SEG(TASK_SIZE) |
| |
| #define get_fs() (current_thread_info()->addr_limit) |
| |
| static inline void set_fs(mm_segment_t fs) |
| { |
| current_thread_info()->addr_limit = fs; |
| } |
| |
| #define segment_eq(a, b) ((a).seg == (b).seg) |
| |
| #define user_addr_max() (get_fs().seg) |
| |
| |
| /** |
| * 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) |
| { |
| const mm_segment_t fs = get_fs(); |
| |
| return size <= fs.seg && addr <= fs.seg - 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; \ |
| __enable_user_access(); \ |
| __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" \ |
| " .section __ex_table,\"a\"\n" \ |
| " .balign " RISCV_SZPTR "\n" \ |
| " " RISCV_PTR " 1b, 3b\n" \ |
| " .previous" \ |
| : "+r" (err), "=&r" (__x), "=r" (__tmp) \ |
| : "m" (*(ptr)), "i" (-EFAULT)); \ |
| __disable_user_access(); \ |
| (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; \ |
| __enable_user_access(); \ |
| __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" \ |
| " .section __ex_table,\"a\"\n" \ |
| " .balign " RISCV_SZPTR "\n" \ |
| " " RISCV_PTR " 1b, 4b\n" \ |
| " " RISCV_PTR " 2b, 4b\n" \ |
| " .previous" \ |
| : "+r" (err), "=&r" (__lo), "=r" (__hi), \ |
| "=r" (__tmp) \ |
| : "m" (__ptr[__LSW]), "m" (__ptr[__MSW]), \ |
| "i" (-EFAULT)); \ |
| __disable_user_access(); \ |
| (x) = (__typeof__(x))((__typeof__((x)-(x)))( \ |
| (((u64)__hi << 32) | __lo))); \ |
| } while (0) |
| #endif /* CONFIG_64BIT */ |
| |
| |
| /** |
| * __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) \ |
| ({ \ |
| register long __gu_err = 0; \ |
| const __typeof__(*(ptr)) __user *__gu_ptr = (ptr); \ |
| __chk_user_ptr(__gu_ptr); \ |
| 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(); \ |
| } \ |
| __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; \ |
| __enable_user_access(); \ |
| __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" \ |
| " .section __ex_table,\"a\"\n" \ |
| " .balign " RISCV_SZPTR "\n" \ |
| " " RISCV_PTR " 1b, 3b\n" \ |
| " .previous" \ |
| : "+r" (err), "=r" (__tmp), "=m" (*(ptr)) \ |
| : "rJ" (__x), "i" (-EFAULT)); \ |
| __disable_user_access(); \ |
| } 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; \ |
| __enable_user_access(); \ |
| __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" \ |
| " .section __ex_table,\"a\"\n" \ |
| " .balign " RISCV_SZPTR "\n" \ |
| " " RISCV_PTR " 1b, 4b\n" \ |
| " " RISCV_PTR " 2b, 4b\n" \ |
| " .previous" \ |
| : "+r" (err), "=r" (__tmp), \ |
| "=m" (__ptr[__LSW]), \ |
| "=m" (__ptr[__MSW]) \ |
| : "rJ" (__x), "rJ" (__x >> 32), "i" (-EFAULT)); \ |
| __disable_user_access(); \ |
| } while (0) |
| #endif /* CONFIG_64BIT */ |
| |
| |
| /** |
| * __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) \ |
| ({ \ |
| register long __pu_err = 0; \ |
| __typeof__(*(ptr)) __user *__gu_ptr = (ptr); \ |
| __chk_user_ptr(__gu_ptr); \ |
| 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(); \ |
| } \ |
| __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; \ |
| }) |
| |
| |
| extern unsigned long __must_check __asm_copy_to_user(void __user *to, |
| const void *from, unsigned long n); |
| extern 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 strlen_user(const char __user *str); |
| 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; |
| } |
| |
| /* |
| * Atomic compare-and-exchange, but with a fixup for userspace faults. Faults |
| * will set "err" to -EFAULT, while successful accesses return the previous |
| * value. |
| */ |
| #define __cmpxchg_user(ptr, old, new, err, size, lrb, scb) \ |
| ({ \ |
| __typeof__(ptr) __ptr = (ptr); \ |
| __typeof__(*(ptr)) __old = (old); \ |
| __typeof__(*(ptr)) __new = (new); \ |
| __typeof__(*(ptr)) __ret; \ |
| __typeof__(err) __err = 0; \ |
| register unsigned int __rc; \ |
| __enable_user_access(); \ |
| switch (size) { \ |
| case 4: \ |
| __asm__ __volatile__ ( \ |
| "0:\n" \ |
| " lr.w" #scb " %[ret], %[ptr]\n" \ |
| " bne %[ret], %z[old], 1f\n" \ |
| " sc.w" #lrb " %[rc], %z[new], %[ptr]\n" \ |
| " bnez %[rc], 0b\n" \ |
| "1:\n" \ |
| ".section .fixup,\"ax\"\n" \ |
| ".balign 4\n" \ |
| "2:\n" \ |
| " li %[err], %[efault]\n" \ |
| " jump 1b, %[rc]\n" \ |
| ".previous\n" \ |
| ".section __ex_table,\"a\"\n" \ |
| ".balign " RISCV_SZPTR "\n" \ |
| " " RISCV_PTR " 1b, 2b\n" \ |
| ".previous\n" \ |
| : [ret] "=&r" (__ret), \ |
| [rc] "=&r" (__rc), \ |
| [ptr] "+A" (*__ptr), \ |
| [err] "=&r" (__err) \ |
| : [old] "rJ" (__old), \ |
| [new] "rJ" (__new), \ |
| [efault] "i" (-EFAULT)); \ |
| break; \ |
| case 8: \ |
| __asm__ __volatile__ ( \ |
| "0:\n" \ |
| " lr.d" #scb " %[ret], %[ptr]\n" \ |
| " bne %[ret], %z[old], 1f\n" \ |
| " sc.d" #lrb " %[rc], %z[new], %[ptr]\n" \ |
| " bnez %[rc], 0b\n" \ |
| "1:\n" \ |
| ".section .fixup,\"ax\"\n" \ |
| ".balign 4\n" \ |
| "2:\n" \ |
| " li %[err], %[efault]\n" \ |
| " jump 1b, %[rc]\n" \ |
| ".previous\n" \ |
| ".section __ex_table,\"a\"\n" \ |
| ".balign " RISCV_SZPTR "\n" \ |
| " " RISCV_PTR " 1b, 2b\n" \ |
| ".previous\n" \ |
| : [ret] "=&r" (__ret), \ |
| [rc] "=&r" (__rc), \ |
| [ptr] "+A" (*__ptr), \ |
| [err] "=&r" (__err) \ |
| : [old] "rJ" (__old), \ |
| [new] "rJ" (__new), \ |
| [efault] "i" (-EFAULT)); \ |
| break; \ |
| default: \ |
| BUILD_BUG(); \ |
| } \ |
| __disable_user_access(); \ |
| (err) = __err; \ |
| __ret; \ |
| }) |
| |
| #endif /* _ASM_RISCV_UACCESS_H */ |