479 lines
13 KiB
C
479 lines
13 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* Copyright (C) 2012 Regents of the University of California
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*
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* This file was copied from include/asm-generic/uaccess.h
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*/
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#ifndef _ASM_RISCV_UACCESS_H
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#define _ASM_RISCV_UACCESS_H
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/*
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* User space memory access functions
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*/
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#include <linux/errno.h>
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#include <linux/compiler.h>
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#include <linux/thread_info.h>
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#include <asm/byteorder.h>
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#include <asm/extable.h>
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#include <asm/asm.h>
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#define __enable_user_access() \
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__asm__ __volatile__ ("csrs sstatus, %0" : : "r" (SR_SUM) : "memory")
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#define __disable_user_access() \
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__asm__ __volatile__ ("csrc sstatus, %0" : : "r" (SR_SUM) : "memory")
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/*
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* The fs value determines whether argument validity checking should be
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* performed or not. If get_fs() == USER_DS, checking is performed, with
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* get_fs() == KERNEL_DS, checking is bypassed.
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*
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* For historical reasons, these macros are grossly misnamed.
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*/
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#define MAKE_MM_SEG(s) ((mm_segment_t) { (s) })
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#define KERNEL_DS MAKE_MM_SEG(~0UL)
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#define USER_DS MAKE_MM_SEG(TASK_SIZE)
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#define get_fs() (current_thread_info()->addr_limit)
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static inline void set_fs(mm_segment_t fs)
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{
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current_thread_info()->addr_limit = fs;
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}
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#define segment_eq(a, b) ((a).seg == (b).seg)
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#define user_addr_max() (get_fs().seg)
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/**
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* access_ok: - Checks if a user space pointer is valid
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* @addr: User space pointer to start of block to check
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* @size: Size of block to check
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*
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* Context: User context only. This function may sleep.
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*
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* Checks if a pointer to a block of memory in user space is valid.
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*
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* Returns true (nonzero) if the memory block may be valid, false (zero)
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* if it is definitely invalid.
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*
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* Note that, depending on architecture, this function probably just
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* checks that the pointer is in the user space range - after calling
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* this function, memory access functions may still return -EFAULT.
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*/
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#define access_ok(addr, size) ({ \
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__chk_user_ptr(addr); \
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likely(__access_ok((unsigned long __force)(addr), (size))); \
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})
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/*
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* Ensure that the range [addr, addr+size) is within the process's
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* address space
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*/
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static inline int __access_ok(unsigned long addr, unsigned long size)
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{
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const mm_segment_t fs = get_fs();
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return size <= fs.seg && addr <= fs.seg - size;
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}
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/*
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* The exception table consists of pairs of addresses: the first is the
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* address of an instruction that is allowed to fault, and the second is
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* the address at which the program should continue. No registers are
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* modified, so it is entirely up to the continuation code to figure out
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* what to do.
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*
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* All the routines below use bits of fixup code that are out of line
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* with the main instruction path. This means when everything is well,
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* we don't even have to jump over them. Further, they do not intrude
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* on our cache or tlb entries.
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*/
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#define __LSW 0
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#define __MSW 1
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/*
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* The "__xxx" versions of the user access functions do not verify the address
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* space - it must have been done previously with a separate "access_ok()"
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* call.
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*/
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#define __get_user_asm(insn, x, ptr, err) \
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do { \
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uintptr_t __tmp; \
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__typeof__(x) __x; \
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__enable_user_access(); \
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__asm__ __volatile__ ( \
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"1:\n" \
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" " insn " %1, %3\n" \
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"2:\n" \
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" .section .fixup,\"ax\"\n" \
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" .balign 4\n" \
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"3:\n" \
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" li %0, %4\n" \
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" li %1, 0\n" \
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" jump 2b, %2\n" \
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" .previous\n" \
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" .section __ex_table,\"a\"\n" \
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" .balign " RISCV_SZPTR "\n" \
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" " RISCV_PTR " 1b, 3b\n" \
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" .previous" \
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: "+r" (err), "=&r" (__x), "=r" (__tmp) \
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: "m" (*(ptr)), "i" (-EFAULT)); \
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__disable_user_access(); \
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(x) = __x; \
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} while (0)
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#ifdef CONFIG_64BIT
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#define __get_user_8(x, ptr, err) \
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__get_user_asm("ld", x, ptr, err)
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#else /* !CONFIG_64BIT */
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#define __get_user_8(x, ptr, err) \
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do { \
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u32 __user *__ptr = (u32 __user *)(ptr); \
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u32 __lo, __hi; \
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uintptr_t __tmp; \
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__enable_user_access(); \
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__asm__ __volatile__ ( \
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"1:\n" \
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" lw %1, %4\n" \
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"2:\n" \
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" lw %2, %5\n" \
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"3:\n" \
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" .section .fixup,\"ax\"\n" \
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" .balign 4\n" \
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"4:\n" \
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" li %0, %6\n" \
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" li %1, 0\n" \
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" li %2, 0\n" \
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" jump 3b, %3\n" \
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" .previous\n" \
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" .section __ex_table,\"a\"\n" \
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" .balign " RISCV_SZPTR "\n" \
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" " RISCV_PTR " 1b, 4b\n" \
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" " RISCV_PTR " 2b, 4b\n" \
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" .previous" \
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: "+r" (err), "=&r" (__lo), "=r" (__hi), \
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"=r" (__tmp) \
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: "m" (__ptr[__LSW]), "m" (__ptr[__MSW]), \
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"i" (-EFAULT)); \
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__disable_user_access(); \
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(x) = (__typeof__(x))((__typeof__((x)-(x)))( \
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(((u64)__hi << 32) | __lo))); \
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} while (0)
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#endif /* CONFIG_64BIT */
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/**
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* __get_user: - Get a simple variable from user space, with less checking.
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* @x: Variable to store result.
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* @ptr: Source address, in user space.
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*
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* Context: User context only. This function may sleep.
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*
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* This macro copies a single simple variable from user space to kernel
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* space. It supports simple types like char and int, but not larger
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* data types like structures or arrays.
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*
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* @ptr must have pointer-to-simple-variable type, and the result of
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* dereferencing @ptr must be assignable to @x without a cast.
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*
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* Caller must check the pointer with access_ok() before calling this
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* function.
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*
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* Returns zero on success, or -EFAULT on error.
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* On error, the variable @x is set to zero.
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*/
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#define __get_user(x, ptr) \
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({ \
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register long __gu_err = 0; \
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const __typeof__(*(ptr)) __user *__gu_ptr = (ptr); \
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__chk_user_ptr(__gu_ptr); \
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switch (sizeof(*__gu_ptr)) { \
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case 1: \
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__get_user_asm("lb", (x), __gu_ptr, __gu_err); \
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break; \
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case 2: \
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__get_user_asm("lh", (x), __gu_ptr, __gu_err); \
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break; \
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case 4: \
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__get_user_asm("lw", (x), __gu_ptr, __gu_err); \
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break; \
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case 8: \
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__get_user_8((x), __gu_ptr, __gu_err); \
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break; \
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default: \
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BUILD_BUG(); \
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} \
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__gu_err; \
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})
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/**
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* get_user: - Get a simple variable from user space.
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* @x: Variable to store result.
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* @ptr: Source address, in user space.
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*
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* Context: User context only. This function may sleep.
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*
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* This macro copies a single simple variable from user space to kernel
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* space. It supports simple types like char and int, but not larger
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* data types like structures or arrays.
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*
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* @ptr must have pointer-to-simple-variable type, and the result of
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* dereferencing @ptr must be assignable to @x without a cast.
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*
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* Returns zero on success, or -EFAULT on error.
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* On error, the variable @x is set to zero.
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*/
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#define get_user(x, ptr) \
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({ \
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const __typeof__(*(ptr)) __user *__p = (ptr); \
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might_fault(); \
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access_ok(__p, sizeof(*__p)) ? \
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__get_user((x), __p) : \
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((x) = 0, -EFAULT); \
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})
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#define __put_user_asm(insn, x, ptr, err) \
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do { \
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uintptr_t __tmp; \
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__typeof__(*(ptr)) __x = x; \
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__enable_user_access(); \
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__asm__ __volatile__ ( \
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"1:\n" \
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" " insn " %z3, %2\n" \
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"2:\n" \
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" .section .fixup,\"ax\"\n" \
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" .balign 4\n" \
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"3:\n" \
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" li %0, %4\n" \
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" jump 2b, %1\n" \
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" .previous\n" \
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" .section __ex_table,\"a\"\n" \
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" .balign " RISCV_SZPTR "\n" \
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" " RISCV_PTR " 1b, 3b\n" \
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" .previous" \
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: "+r" (err), "=r" (__tmp), "=m" (*(ptr)) \
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: "rJ" (__x), "i" (-EFAULT)); \
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__disable_user_access(); \
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} while (0)
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#ifdef CONFIG_64BIT
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#define __put_user_8(x, ptr, err) \
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__put_user_asm("sd", x, ptr, err)
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#else /* !CONFIG_64BIT */
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#define __put_user_8(x, ptr, err) \
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do { \
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u32 __user *__ptr = (u32 __user *)(ptr); \
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u64 __x = (__typeof__((x)-(x)))(x); \
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uintptr_t __tmp; \
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__enable_user_access(); \
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__asm__ __volatile__ ( \
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"1:\n" \
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" sw %z4, %2\n" \
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"2:\n" \
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" sw %z5, %3\n" \
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"3:\n" \
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" .section .fixup,\"ax\"\n" \
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" .balign 4\n" \
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"4:\n" \
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" li %0, %6\n" \
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" jump 3b, %1\n" \
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" .previous\n" \
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" .section __ex_table,\"a\"\n" \
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" .balign " RISCV_SZPTR "\n" \
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" " RISCV_PTR " 1b, 4b\n" \
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" " RISCV_PTR " 2b, 4b\n" \
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" .previous" \
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: "+r" (err), "=r" (__tmp), \
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"=m" (__ptr[__LSW]), \
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"=m" (__ptr[__MSW]) \
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: "rJ" (__x), "rJ" (__x >> 32), "i" (-EFAULT)); \
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__disable_user_access(); \
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} while (0)
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#endif /* CONFIG_64BIT */
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/**
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* __put_user: - Write a simple value into user space, with less checking.
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* @x: Value to copy to user space.
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* @ptr: Destination address, in user space.
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*
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* Context: User context only. This function may sleep.
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*
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* This macro copies a single simple value from kernel space to user
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* space. It supports simple types like char and int, but not larger
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* data types like structures or arrays.
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*
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* @ptr must have pointer-to-simple-variable type, and @x must be assignable
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* to the result of dereferencing @ptr.
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*
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* Caller must check the pointer with access_ok() before calling this
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* function.
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*
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* Returns zero on success, or -EFAULT on error.
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*/
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#define __put_user(x, ptr) \
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({ \
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register long __pu_err = 0; \
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__typeof__(*(ptr)) __user *__gu_ptr = (ptr); \
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__chk_user_ptr(__gu_ptr); \
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switch (sizeof(*__gu_ptr)) { \
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case 1: \
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__put_user_asm("sb", (x), __gu_ptr, __pu_err); \
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break; \
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case 2: \
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__put_user_asm("sh", (x), __gu_ptr, __pu_err); \
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break; \
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case 4: \
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__put_user_asm("sw", (x), __gu_ptr, __pu_err); \
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break; \
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case 8: \
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__put_user_8((x), __gu_ptr, __pu_err); \
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break; \
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default: \
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BUILD_BUG(); \
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} \
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__pu_err; \
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})
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/**
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* put_user: - Write a simple value into user space.
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* @x: Value to copy to user space.
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* @ptr: Destination address, in user space.
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*
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* Context: User context only. This function may sleep.
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*
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* This macro copies a single simple value from kernel space to user
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* space. It supports simple types like char and int, but not larger
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* data types like structures or arrays.
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*
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* @ptr must have pointer-to-simple-variable type, and @x must be assignable
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* to the result of dereferencing @ptr.
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*
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* Returns zero on success, or -EFAULT on error.
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*/
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#define put_user(x, ptr) \
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({ \
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__typeof__(*(ptr)) __user *__p = (ptr); \
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might_fault(); \
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access_ok(__p, sizeof(*__p)) ? \
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__put_user((x), __p) : \
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-EFAULT; \
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})
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extern unsigned long __must_check __asm_copy_to_user(void __user *to,
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const void *from, unsigned long n);
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extern unsigned long __must_check __asm_copy_from_user(void *to,
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const void __user *from, unsigned long n);
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static inline unsigned long
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raw_copy_from_user(void *to, const void __user *from, unsigned long n)
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{
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return __asm_copy_from_user(to, from, n);
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}
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static inline unsigned long
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raw_copy_to_user(void __user *to, const void *from, unsigned long n)
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{
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return __asm_copy_to_user(to, from, n);
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}
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extern long strncpy_from_user(char *dest, const char __user *src, long count);
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extern long __must_check strlen_user(const char __user *str);
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extern long __must_check strnlen_user(const char __user *str, long n);
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extern
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unsigned long __must_check __clear_user(void __user *addr, unsigned long n);
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static inline
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unsigned long __must_check clear_user(void __user *to, unsigned long n)
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{
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might_fault();
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return access_ok(to, n) ?
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__clear_user(to, n) : n;
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}
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/*
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* Atomic compare-and-exchange, but with a fixup for userspace faults. Faults
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* will set "err" to -EFAULT, while successful accesses return the previous
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* value.
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*/
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#define __cmpxchg_user(ptr, old, new, err, size, lrb, scb) \
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({ \
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__typeof__(ptr) __ptr = (ptr); \
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__typeof__(*(ptr)) __old = (old); \
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__typeof__(*(ptr)) __new = (new); \
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__typeof__(*(ptr)) __ret; \
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__typeof__(err) __err = 0; \
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register unsigned int __rc; \
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__enable_user_access(); \
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switch (size) { \
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case 4: \
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__asm__ __volatile__ ( \
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"0:\n" \
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" lr.w" #scb " %[ret], %[ptr]\n" \
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" bne %[ret], %z[old], 1f\n" \
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" sc.w" #lrb " %[rc], %z[new], %[ptr]\n" \
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" bnez %[rc], 0b\n" \
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"1:\n" \
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".section .fixup,\"ax\"\n" \
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".balign 4\n" \
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"2:\n" \
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" li %[err], %[efault]\n" \
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" jump 1b, %[rc]\n" \
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".previous\n" \
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".section __ex_table,\"a\"\n" \
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".balign " RISCV_SZPTR "\n" \
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" " RISCV_PTR " 1b, 2b\n" \
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".previous\n" \
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: [ret] "=&r" (__ret), \
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[rc] "=&r" (__rc), \
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[ptr] "+A" (*__ptr), \
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[err] "=&r" (__err) \
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: [old] "rJ" (__old), \
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[new] "rJ" (__new), \
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[efault] "i" (-EFAULT)); \
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break; \
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case 8: \
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__asm__ __volatile__ ( \
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"0:\n" \
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" lr.d" #scb " %[ret], %[ptr]\n" \
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" bne %[ret], %z[old], 1f\n" \
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" sc.d" #lrb " %[rc], %z[new], %[ptr]\n" \
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" bnez %[rc], 0b\n" \
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"1:\n" \
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".section .fixup,\"ax\"\n" \
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".balign 4\n" \
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"2:\n" \
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" li %[err], %[efault]\n" \
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" jump 1b, %[rc]\n" \
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".previous\n" \
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".section __ex_table,\"a\"\n" \
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".balign " RISCV_SZPTR "\n" \
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" " RISCV_PTR " 1b, 2b\n" \
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".previous\n" \
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: [ret] "=&r" (__ret), \
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[rc] "=&r" (__rc), \
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[ptr] "+A" (*__ptr), \
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[err] "=&r" (__err) \
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: [old] "rJ" (__old), \
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[new] "rJ" (__new), \
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[efault] "i" (-EFAULT)); \
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break; \
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default: \
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BUILD_BUG(); \
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} \
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__disable_user_access(); \
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(err) = __err; \
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__ret; \
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})
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#endif /* _ASM_RISCV_UACCESS_H */
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