340 lines
9.7 KiB
C
340 lines
9.7 KiB
C
#ifndef _PPC64_UACCESS_H
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#define _PPC64_UACCESS_H
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/*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#ifndef __ASSEMBLY__
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#include <linux/sched.h>
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#include <linux/errno.h>
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#include <asm/processor.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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#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(0xf000000000000000UL)
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#define get_ds() (KERNEL_DS)
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#define get_fs() (current->thread.fs)
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#define set_fs(val) (current->thread.fs = (val))
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#define segment_eq(a,b) ((a).seg == (b).seg)
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/*
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* Use the alpha trick for checking ranges:
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*
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* Is a address valid? This does a straightforward calculation rather
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* than tests.
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*
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* Address valid if:
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* - "addr" doesn't have any high-bits set
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* - AND "size" doesn't have any high-bits set
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* - OR we are in kernel mode.
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*
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* We dont have to check for high bits in (addr+size) because the first
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* two checks force the maximum result to be below the start of the
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* kernel region.
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*/
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#define __access_ok(addr,size,segment) \
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(((segment).seg & (addr | size )) == 0)
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#define access_ok(type,addr,size) \
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__access_ok(((__force unsigned long)(addr)),(size),get_fs())
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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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{
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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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/*
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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 ugliness 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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#define __get_user_unaligned __get_user
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#define __put_user_unaligned __put_user
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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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might_sleep(); \
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__chk_user_ptr(ptr); \
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__put_user_size((x),(ptr),(size),__pu_err,-EFAULT); \
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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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void __user *__pu_addr = (ptr); \
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might_sleep(); \
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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,-EFAULT); \
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__pu_err; \
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})
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#define __put_user_size(x,ptr,size,retval,errret) \
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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,"stb",errret); break; \
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case 2: __put_user_asm(x,ptr,retval,"sth",errret); break; \
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case 4: __put_user_asm(x,ptr,retval,"stw",errret); break; \
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case 8: __put_user_asm(x,ptr,retval,"std",errret); break; \
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default: __put_user_bad(); \
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} \
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} while (0)
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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, errret) \
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__asm__ __volatile__( \
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"1: "op" %1,0(%2) # put_user\n" \
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"2:\n" \
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".section .fixup,\"ax\"\n" \
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"3: li %0,%3\n" \
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" b 2b\n" \
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".previous\n" \
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".section __ex_table,\"a\"\n" \
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" .align 3\n" \
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" .llong 1b,3b\n" \
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".previous" \
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: "=r"(err) \
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: "r"(x), "b"(addr), "i"(errret), "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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might_sleep(); \
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__get_user_size(__gu_val,(ptr),(size),__gu_err,-EFAULT);\
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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)) __user *__gu_addr = (ptr); \
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might_sleep(); \
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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,-EFAULT);\
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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,errret) \
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do { \
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retval = 0; \
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__chk_user_ptr(ptr); \
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switch (size) { \
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case 1: __get_user_asm(x,ptr,retval,"lbz",errret); break; \
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case 2: __get_user_asm(x,ptr,retval,"lhz",errret); break; \
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case 4: __get_user_asm(x,ptr,retval,"lwz",errret); break; \
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case 8: __get_user_asm(x,ptr,retval,"ld",errret); break; \
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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, errret) \
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__asm__ __volatile__( \
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"1: "op" %1,0(%2) # get_user\n" \
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"2:\n" \
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".section .fixup,\"ax\"\n" \
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"3: li %0,%3\n" \
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" li %1,0\n" \
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" b 2b\n" \
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".previous\n" \
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".section __ex_table,\"a\"\n" \
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" .align 3\n" \
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" .llong 1b,3b\n" \
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".previous" \
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: "=r"(err), "=r"(x) \
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: "b"(addr), "i"(errret), "0"(err))
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/* more complex routines */
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extern unsigned long __copy_tofrom_user(void __user *to, const void __user *from,
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unsigned long size);
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static inline unsigned long
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__copy_from_user_inatomic(void *to, const void __user *from, unsigned long n)
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{
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if (__builtin_constant_p(n)) {
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unsigned long ret;
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switch (n) {
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case 1:
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__get_user_size(*(u8 *)to, from, 1, ret, 1);
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return ret;
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case 2:
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__get_user_size(*(u16 *)to, from, 2, ret, 2);
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return ret;
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case 4:
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__get_user_size(*(u32 *)to, from, 4, ret, 4);
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return ret;
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case 8:
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__get_user_size(*(u64 *)to, from, 8, ret, 8);
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return ret;
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}
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}
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return __copy_tofrom_user((__force void __user *) to, from, n);
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}
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static inline unsigned long
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__copy_from_user(void *to, const void __user *from, unsigned long n)
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{
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might_sleep();
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return __copy_from_user_inatomic(to, from, n);
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}
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static inline unsigned long
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__copy_to_user_inatomic(void __user *to, const void *from, unsigned long n)
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{
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if (__builtin_constant_p(n)) {
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unsigned long ret;
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switch (n) {
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case 1:
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__put_user_size(*(u8 *)from, (u8 __user *)to, 1, ret, 1);
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return ret;
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case 2:
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__put_user_size(*(u16 *)from, (u16 __user *)to, 2, ret, 2);
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return ret;
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case 4:
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__put_user_size(*(u32 *)from, (u32 __user *)to, 4, ret, 4);
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return ret;
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case 8:
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__put_user_size(*(u64 *)from, (u64 __user *)to, 8, ret, 8);
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return ret;
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}
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}
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return __copy_tofrom_user(to, (__force const void __user *) from, n);
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}
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static inline unsigned long
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__copy_to_user(void __user *to, const void *from, unsigned long n)
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{
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might_sleep();
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return __copy_to_user_inatomic(to, from, n);
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}
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#define __copy_in_user(to, from, size) \
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__copy_tofrom_user((to), (from), (size))
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extern unsigned long copy_from_user(void *to, const void __user *from,
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unsigned long n);
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extern unsigned long copy_to_user(void __user *to, const void *from,
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unsigned long n);
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extern unsigned long copy_in_user(void __user *to, const void __user *from,
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unsigned long n);
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extern unsigned long __clear_user(void __user *addr, unsigned long size);
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static inline unsigned long
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clear_user(void __user *addr, unsigned long size)
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{
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might_sleep();
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if (likely(access_ok(VERIFY_WRITE, addr, size)))
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size = __clear_user(addr, size);
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return size;
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}
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extern int __strncpy_from_user(char *dst, const char __user *src, long count);
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static inline long
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strncpy_from_user(char *dst, const char __user *src, long count)
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{
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might_sleep();
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if (likely(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 __user *str, long len);
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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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static inline int strnlen_user(const char __user *str, long len)
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{
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might_sleep();
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if (likely(access_ok(VERIFY_READ, str, 1)))
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return __strnlen_user(str, len);
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return 0;
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}
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#define strlen_user(str) strnlen_user((str), 0x7ffffffe)
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#endif /* __ASSEMBLY__ */
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#endif /* _PPC64_UACCESS_H */
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