318 lines
9.1 KiB
C
318 lines
9.1 KiB
C
/*
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* uaccess.h: User space memore access functions.
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*
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* Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
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* Copyright (C) 1996,1997 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
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*/
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#ifndef _ASM_UACCESS_H
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#define _ASM_UACCESS_H
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#ifdef __KERNEL__
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#include <linux/compiler.h>
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#include <linux/sched.h>
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#include <linux/string.h>
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#include <linux/errno.h>
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#endif
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#ifndef __ASSEMBLY__
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#include <asm/processor.h>
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#define ARCH_HAS_SORT_EXTABLE
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#define ARCH_HAS_SEARCH_EXTABLE
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/* Sparc is not segmented, however we need to be able to fool access_ok()
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* when doing system calls from kernel mode legitimately.
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*
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* "For historical reasons, these macros are grossly misnamed." -Linus
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*/
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#define KERNEL_DS ((mm_segment_t) { 0 })
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#define USER_DS ((mm_segment_t) { -1 })
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#define VERIFY_READ 0
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#define VERIFY_WRITE 1
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#define get_ds() (KERNEL_DS)
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#define get_fs() (current->thread.current_ds)
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#define set_fs(val) ((current->thread.current_ds) = (val))
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#define segment_eq(a, b) ((a).seg == (b).seg)
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/* We have there a nice not-mapped page at PAGE_OFFSET - PAGE_SIZE, so that this test
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* can be fairly lightweight.
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* No one can read/write anything from userland in the kernel space by setting
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* large size and address near to PAGE_OFFSET - a fault will break his intentions.
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*/
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#define __user_ok(addr, size) ({ (void)(size); (addr) < STACK_TOP; })
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#define __kernel_ok (segment_eq(get_fs(), KERNEL_DS))
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#define __access_ok(addr, size) (__user_ok((addr) & get_fs().seg, (size)))
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#define access_ok(type, addr, size) \
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({ (void)(type); __access_ok((unsigned long)(addr), 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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* There is a special way how to put a range of potentially faulting
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* insns (like twenty ldd/std's with now intervening other instructions)
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* You specify address of first in insn and 0 in fixup and in the next
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* exception_table_entry you specify last potentially faulting insn + 1
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* and in fixup the routine which should handle the fault.
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* That fixup code will get
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* (faulting_insn_address - first_insn_in_the_range_address)/4
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* in %g2 (ie. index of the faulting instruction in the range).
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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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unsigned long search_extables_range(unsigned long addr, unsigned long *g2);
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void __ret_efault(void);
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/* Uh, these should become the main single-value transfer routines..
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* They automatically use the right size if we just have the right
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* 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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#define put_user(x, ptr) ({ \
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unsigned long __pu_addr = (unsigned long)(ptr); \
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__chk_user_ptr(ptr); \
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__put_user_check((__typeof__(*(ptr)))(x), __pu_addr, sizeof(*(ptr))); \
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})
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#define get_user(x, ptr) ({ \
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unsigned long __gu_addr = (unsigned long)(ptr); \
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__chk_user_ptr(ptr); \
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__get_user_check((x), __gu_addr, sizeof(*(ptr)), __typeof__(*(ptr))); \
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})
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/*
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* The "__xxx" versions do not do address space checking, useful when
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* doing multiple accesses to the same area (the user has to do the
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* checks by hand with "access_ok()")
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*/
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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(x, ptr) \
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__get_user_nocheck((x), (ptr), sizeof(*(ptr)), __typeof__(*(ptr)))
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struct __large_struct { unsigned long buf[100]; };
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#define __m(x) ((struct __large_struct __user *)(x))
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#define __put_user_check(x, addr, size) ({ \
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register int __pu_ret; \
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if (__access_ok(addr, size)) { \
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switch (size) { \
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case 1: \
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__put_user_asm(x, b, addr, __pu_ret); \
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break; \
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case 2: \
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__put_user_asm(x, h, addr, __pu_ret); \
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break; \
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case 4: \
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__put_user_asm(x, , addr, __pu_ret); \
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break; \
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case 8: \
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__put_user_asm(x, d, addr, __pu_ret); \
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break; \
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default: \
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__pu_ret = __put_user_bad(); \
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break; \
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} \
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} else { \
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__pu_ret = -EFAULT; \
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} \
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__pu_ret; \
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})
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#define __put_user_nocheck(x, addr, size) ({ \
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register int __pu_ret; \
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switch (size) { \
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case 1: __put_user_asm(x, b, addr, __pu_ret); break; \
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case 2: __put_user_asm(x, h, addr, __pu_ret); break; \
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case 4: __put_user_asm(x, , addr, __pu_ret); break; \
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case 8: __put_user_asm(x, d, addr, __pu_ret); break; \
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default: __pu_ret = __put_user_bad(); break; \
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} \
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__pu_ret; \
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})
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#define __put_user_asm(x, size, addr, ret) \
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__asm__ __volatile__( \
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"/* Put user asm, inline. */\n" \
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"1:\t" "st"#size " %1, %2\n\t" \
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"clr %0\n" \
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"2:\n\n\t" \
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".section .fixup,#alloc,#execinstr\n\t" \
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".align 4\n" \
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"3:\n\t" \
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"b 2b\n\t" \
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" mov %3, %0\n\t" \
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".previous\n\n\t" \
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".section __ex_table,#alloc\n\t" \
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".align 4\n\t" \
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".word 1b, 3b\n\t" \
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".previous\n\n\t" \
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: "=&r" (ret) : "r" (x), "m" (*__m(addr)), \
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"i" (-EFAULT))
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int __put_user_bad(void);
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#define __get_user_check(x, addr, size, type) ({ \
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register int __gu_ret; \
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register unsigned long __gu_val; \
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if (__access_ok(addr, size)) { \
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switch (size) { \
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case 1: \
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__get_user_asm(__gu_val, ub, addr, __gu_ret); \
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break; \
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case 2: \
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__get_user_asm(__gu_val, uh, addr, __gu_ret); \
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break; \
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case 4: \
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__get_user_asm(__gu_val, , addr, __gu_ret); \
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break; \
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case 8: \
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__get_user_asm(__gu_val, d, addr, __gu_ret); \
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break; \
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default: \
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__gu_val = 0; \
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__gu_ret = __get_user_bad(); \
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break; \
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} \
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} else { \
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__gu_val = 0; \
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__gu_ret = -EFAULT; \
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} \
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x = (__force type) __gu_val; \
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__gu_ret; \
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})
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#define __get_user_nocheck(x, addr, size, type) ({ \
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register int __gu_ret; \
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register unsigned long __gu_val; \
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switch (size) { \
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case 1: __get_user_asm(__gu_val, ub, addr, __gu_ret); break; \
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case 2: __get_user_asm(__gu_val, uh, addr, __gu_ret); break; \
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case 4: __get_user_asm(__gu_val, , addr, __gu_ret); break; \
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case 8: __get_user_asm(__gu_val, d, addr, __gu_ret); break; \
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default: \
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__gu_val = 0; \
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__gu_ret = __get_user_bad(); \
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break; \
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} \
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x = (__force type) __gu_val; \
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__gu_ret; \
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})
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#define __get_user_asm(x, size, addr, ret) \
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__asm__ __volatile__( \
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"/* Get user asm, inline. */\n" \
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"1:\t" "ld"#size " %2, %1\n\t" \
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"clr %0\n" \
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"2:\n\n\t" \
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".section .fixup,#alloc,#execinstr\n\t" \
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".align 4\n" \
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"3:\n\t" \
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"clr %1\n\t" \
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"b 2b\n\t" \
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" mov %3, %0\n\n\t" \
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".previous\n\t" \
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".section __ex_table,#alloc\n\t" \
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".align 4\n\t" \
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".word 1b, 3b\n\n\t" \
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".previous\n\t" \
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: "=&r" (ret), "=&r" (x) : "m" (*__m(addr)), \
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"i" (-EFAULT))
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int __get_user_bad(void);
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unsigned long __copy_user(void __user *to, const void __user *from, unsigned long size);
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static inline unsigned long copy_to_user(void __user *to, const void *from, unsigned long n)
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{
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if (n && __access_ok((unsigned long) to, n)) {
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check_object_size(from, n, true);
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return __copy_user(to, (__force void __user *) from, n);
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} else
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return n;
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}
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static inline unsigned long __copy_to_user(void __user *to, const void *from, unsigned long n)
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{
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check_object_size(from, n, true);
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return __copy_user(to, (__force void __user *) from, n);
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}
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static inline unsigned long copy_from_user(void *to, const void __user *from, unsigned long n)
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{
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if (n && __access_ok((unsigned long) from, n)) {
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check_object_size(to, n, false);
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return __copy_user((__force void __user *) to, from, n);
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} else {
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memset(to, 0, n);
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return n;
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}
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}
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static inline unsigned long __copy_from_user(void *to, const void __user *from, unsigned long n)
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{
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return __copy_user((__force void __user *) to, from, n);
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}
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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 __clear_user(void __user *addr, unsigned long size)
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{
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unsigned long ret;
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__asm__ __volatile__ (
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".section __ex_table,#alloc\n\t"
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".align 4\n\t"
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".word 1f,3\n\t"
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".previous\n\t"
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"mov %2, %%o1\n"
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"1:\n\t"
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"call __bzero\n\t"
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" mov %1, %%o0\n\t"
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"mov %%o0, %0\n"
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: "=r" (ret) : "r" (addr), "r" (size) :
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"o0", "o1", "o2", "o3", "o4", "o5", "o7",
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"g1", "g2", "g3", "g4", "g5", "g7", "cc");
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return ret;
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}
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static inline unsigned long clear_user(void __user *addr, unsigned long n)
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{
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if (n && __access_ok((unsigned long) addr, n))
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return __clear_user(addr, n);
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else
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return n;
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}
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__must_check long strlen_user(const char __user *str);
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__must_check long strnlen_user(const char __user *str, long n);
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#endif /* __ASSEMBLY__ */
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#endif /* _ASM_UACCESS_H */
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