355 lines
10 KiB
C
355 lines
10 KiB
C
/*
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* OpenRISC Linux
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*
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* Linux architectural port borrowing liberally from similar works of
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* others. All original copyrights apply as per the original source
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* declaration.
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*
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* OpenRISC implementation:
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* Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
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* Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
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* et al.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*/
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#ifndef __ASM_OPENRISC_UACCESS_H
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#define __ASM_OPENRISC_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/thread_info.h>
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#include <linux/prefetch.h>
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#include <linux/string.h>
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#include <asm/page.h>
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#define VERIFY_READ 0
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#define VERIFY_WRITE 1
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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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/* addr_limit is the maximum accessible address for the task. we misuse
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* the KERNEL_DS and USER_DS values to both assign and compare the
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* addr_limit values through the equally misnamed get/set_fs macros.
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* (see above)
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*/
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#define KERNEL_DS (~0UL)
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#define get_ds() (KERNEL_DS)
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#define USER_DS (TASK_SIZE)
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#define get_fs() (current_thread_info()->addr_limit)
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#define set_fs(x) (current_thread_info()->addr_limit = (x))
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#define segment_eq(a, b) ((a) == (b))
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/* Ensure that the range from addr to addr+size is all within the process'
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* address space
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*/
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#define __range_ok(addr, size) (size <= get_fs() && addr <= (get_fs()-size))
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/* Ensure that addr is below task's addr_limit */
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#define __addr_ok(addr) ((unsigned long) addr < get_fs())
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#define access_ok(type, addr, size) \
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__range_ok((unsigned long)addr, (unsigned long)size)
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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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struct exception_table_entry {
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unsigned long insn, fixup;
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};
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/* Returns 0 if exception not found and fixup otherwise. */
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extern unsigned long search_exception_table(unsigned long);
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extern void sort_exception_table(void);
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/*
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* These are the main single-value transfer routines. They automatically
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* use the right size if we just have the right pointer type.
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*
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* This gets kind of ugly. We want to return _two_ values in "get_user()"
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* and yet we don't want to do any pointers, because that is too much
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* of a performance impact. Thus we have a few rather ugly macros here,
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* and hide all the uglyness from the user.
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*
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* The "__xxx" versions of the user access functions are versions that
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* do not verify the address space, that must have been done previously
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* with a separate "access_ok()" call (this is used when we do multiple
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* accesses to the same area of user memory).
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*
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* As we use the same address space for kernel and user data on the
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* PowerPC, we can just do these as direct assignments. (Of course, the
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* exception handling means that it's no longer "just"...)
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*/
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#define get_user(x, ptr) \
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__get_user_check((x), (ptr), sizeof(*(ptr)))
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#define put_user(x, ptr) \
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__put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
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#define __get_user(x, ptr) \
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__get_user_nocheck((x), (ptr), sizeof(*(ptr)))
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#define __put_user(x, ptr) \
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__put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
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extern long __put_user_bad(void);
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#define __put_user_nocheck(x, ptr, size) \
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({ \
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long __pu_err; \
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__put_user_size((x), (ptr), (size), __pu_err); \
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__pu_err; \
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})
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#define __put_user_check(x, ptr, size) \
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({ \
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long __pu_err = -EFAULT; \
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__typeof__(*(ptr)) *__pu_addr = (ptr); \
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if (access_ok(VERIFY_WRITE, __pu_addr, size)) \
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__put_user_size((x), __pu_addr, (size), __pu_err); \
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__pu_err; \
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})
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#define __put_user_size(x, ptr, size, retval) \
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do { \
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retval = 0; \
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switch (size) { \
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case 1: __put_user_asm(x, ptr, retval, "l.sb"); break; \
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case 2: __put_user_asm(x, ptr, retval, "l.sh"); break; \
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case 4: __put_user_asm(x, ptr, retval, "l.sw"); break; \
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case 8: __put_user_asm2(x, ptr, retval); break; \
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default: __put_user_bad(); \
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} \
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} while (0)
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struct __large_struct {
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unsigned long buf[100];
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};
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#define __m(x) (*(struct __large_struct *)(x))
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/*
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* We don't tell gcc that we are accessing memory, but this is OK
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* because we do not write to any memory gcc knows about, so there
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* are no aliasing issues.
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*/
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#define __put_user_asm(x, addr, err, op) \
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__asm__ __volatile__( \
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"1: "op" 0(%2),%1\n" \
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"2:\n" \
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".section .fixup,\"ax\"\n" \
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"3: l.addi %0,r0,%3\n" \
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" l.j 2b\n" \
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" l.nop\n" \
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".previous\n" \
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".section __ex_table,\"a\"\n" \
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" .align 2\n" \
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" .long 1b,3b\n" \
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".previous" \
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: "=r"(err) \
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: "r"(x), "r"(addr), "i"(-EFAULT), "0"(err))
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#define __put_user_asm2(x, addr, err) \
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__asm__ __volatile__( \
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"1: l.sw 0(%2),%1\n" \
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"2: l.sw 4(%2),%H1\n" \
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"3:\n" \
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".section .fixup,\"ax\"\n" \
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"4: l.addi %0,r0,%3\n" \
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" l.j 3b\n" \
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" l.nop\n" \
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".previous\n" \
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".section __ex_table,\"a\"\n" \
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" .align 2\n" \
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" .long 1b,4b\n" \
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" .long 2b,4b\n" \
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".previous" \
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: "=r"(err) \
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: "r"(x), "r"(addr), "i"(-EFAULT), "0"(err))
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#define __get_user_nocheck(x, ptr, size) \
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({ \
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long __gu_err, __gu_val; \
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__get_user_size(__gu_val, (ptr), (size), __gu_err); \
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(x) = (__typeof__(*(ptr)))__gu_val; \
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__gu_err; \
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})
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#define __get_user_check(x, ptr, size) \
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({ \
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long __gu_err = -EFAULT, __gu_val = 0; \
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const __typeof__(*(ptr)) * __gu_addr = (ptr); \
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if (access_ok(VERIFY_READ, __gu_addr, size)) \
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__get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
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(x) = (__typeof__(*(ptr)))__gu_val; \
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__gu_err; \
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})
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extern long __get_user_bad(void);
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#define __get_user_size(x, ptr, size, retval) \
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do { \
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retval = 0; \
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switch (size) { \
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case 1: __get_user_asm(x, ptr, retval, "l.lbz"); break; \
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case 2: __get_user_asm(x, ptr, retval, "l.lhz"); break; \
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case 4: __get_user_asm(x, ptr, retval, "l.lwz"); break; \
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case 8: __get_user_asm2(x, ptr, retval); \
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default: (x) = __get_user_bad(); \
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} \
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} while (0)
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#define __get_user_asm(x, addr, err, op) \
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__asm__ __volatile__( \
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"1: "op" %1,0(%2)\n" \
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"2:\n" \
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".section .fixup,\"ax\"\n" \
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"3: l.addi %0,r0,%3\n" \
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" l.addi %1,r0,0\n" \
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" l.j 2b\n" \
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" l.nop\n" \
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".previous\n" \
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".section __ex_table,\"a\"\n" \
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" .align 2\n" \
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" .long 1b,3b\n" \
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".previous" \
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: "=r"(err), "=r"(x) \
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: "r"(addr), "i"(-EFAULT), "0"(err))
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#define __get_user_asm2(x, addr, err) \
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__asm__ __volatile__( \
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"1: l.lwz %1,0(%2)\n" \
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"2: l.lwz %H1,4(%2)\n" \
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"3:\n" \
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".section .fixup,\"ax\"\n" \
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"4: l.addi %0,r0,%3\n" \
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" l.addi %1,r0,0\n" \
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" l.addi %H1,r0,0\n" \
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" l.j 3b\n" \
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" l.nop\n" \
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".previous\n" \
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".section __ex_table,\"a\"\n" \
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" .align 2\n" \
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" .long 1b,4b\n" \
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" .long 2b,4b\n" \
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".previous" \
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: "=r"(err), "=&r"(x) \
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: "r"(addr), "i"(-EFAULT), "0"(err))
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/* more complex routines */
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extern unsigned long __must_check
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__copy_tofrom_user(void *to, const void *from, unsigned long size);
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#define __copy_from_user(to, from, size) \
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__copy_tofrom_user(to, from, size)
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#define __copy_to_user(to, from, size) \
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__copy_tofrom_user(to, from, size)
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#define __copy_to_user_inatomic __copy_to_user
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#define __copy_from_user_inatomic __copy_from_user
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static inline unsigned long
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copy_from_user(void *to, const void *from, unsigned long n)
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{
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unsigned long over;
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if (access_ok(VERIFY_READ, from, n))
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return __copy_tofrom_user(to, from, n);
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if ((unsigned long)from < TASK_SIZE) {
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over = (unsigned long)from + n - TASK_SIZE;
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return __copy_tofrom_user(to, from, n - over) + over;
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}
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return n;
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}
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static inline unsigned long
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copy_to_user(void *to, const void *from, unsigned long n)
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{
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unsigned long over;
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if (access_ok(VERIFY_WRITE, to, n))
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return __copy_tofrom_user(to, from, n);
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if ((unsigned long)to < TASK_SIZE) {
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over = (unsigned long)to + n - TASK_SIZE;
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return __copy_tofrom_user(to, from, n - over) + over;
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}
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return n;
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}
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extern unsigned long __clear_user(void *addr, unsigned long size);
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static inline __must_check unsigned long
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clear_user(void *addr, unsigned long size)
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{
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if (access_ok(VERIFY_WRITE, addr, size))
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return __clear_user(addr, size);
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if ((unsigned long)addr < TASK_SIZE) {
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unsigned long over = (unsigned long)addr + size - TASK_SIZE;
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return __clear_user(addr, size - over) + over;
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}
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return size;
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}
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extern int __strncpy_from_user(char *dst, const char *src, long count);
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static inline long strncpy_from_user(char *dst, const char *src, long count)
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{
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if (access_ok(VERIFY_READ, src, 1))
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return __strncpy_from_user(dst, src, count);
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return -EFAULT;
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}
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/*
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* Return the size of a string (including the ending 0)
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*
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* Return 0 for error
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*/
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extern int __strnlen_user(const char *str, long len, unsigned long top);
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/*
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* Returns the length of the string at str (including the null byte),
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* or 0 if we hit a page we can't access,
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* or something > len if we didn't find a null byte.
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*
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* The `top' parameter to __strnlen_user is to make sure that
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* we can never overflow from the user area into kernel space.
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*/
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static inline long strnlen_user(const char __user *str, long len)
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{
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unsigned long top = (unsigned long)get_fs();
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unsigned long res = 0;
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if (__addr_ok(str))
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res = __strnlen_user(str, len, top);
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return res;
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}
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#define strlen_user(str) strnlen_user(str, TASK_SIZE-1)
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#endif /* __ASM_OPENRISC_UACCESS_H */
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