296 lines
9.9 KiB
C
296 lines
9.9 KiB
C
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/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_IA64_UACCESS_H
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#define _ASM_IA64_UACCESS_H
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/*
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* This file defines various macros to transfer memory areas across
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* the user/kernel boundary. This needs to be done carefully because
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* this code is executed in kernel mode and uses user-specified
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* addresses. Thus, we need to be careful not to let the user to
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* trick us into accessing kernel memory that would normally be
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* inaccessible. This code is also fairly performance sensitive,
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* so we want to spend as little time doing safety checks as
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* possible.
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*
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* To make matters a bit more interesting, these macros sometimes also
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* called from within the kernel itself, in which case the address
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* validity check must be skipped. The get_fs() macro tells us what
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* to do: if get_fs()==USER_DS, checking is performed, if
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* get_fs()==KERNEL_DS, checking is bypassed.
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*
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* Note that even if the memory area specified by the user is in a
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* valid address range, it is still possible that we'll get a page
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* fault while accessing it. This is handled by filling out an
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* exception handler fixup entry for each instruction that has the
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* potential to fault. When such a fault occurs, the page fault
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* handler checks to see whether the faulting instruction has a fixup
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* associated and, if so, sets r8 to -EFAULT and clears r9 to 0 and
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* then resumes execution at the continuation point.
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*
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* Based on <asm-alpha/uaccess.h>.
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*
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* Copyright (C) 1998, 1999, 2001-2004 Hewlett-Packard Co
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* David Mosberger-Tang <davidm@hpl.hp.com>
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*/
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#include <linux/compiler.h>
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#include <linux/page-flags.h>
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#include <linux/mm.h>
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#include <asm/intrinsics.h>
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#include <asm/pgtable.h>
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#include <asm/io.h>
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#include <asm/extable.h>
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/*
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* For historical reasons, the following macros are grossly misnamed:
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*/
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#define KERNEL_DS ((mm_segment_t) { ~0UL }) /* cf. access_ok() */
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#define USER_DS ((mm_segment_t) { TASK_SIZE-1 }) /* cf. access_ok() */
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#define get_ds() (KERNEL_DS)
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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).seg == (b).seg)
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/*
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* When accessing user memory, we need to make sure the entire area really is in
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* user-level space. In order to do this efficiently, we make sure that the page at
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* address TASK_SIZE is never valid. We also need to make sure that the address doesn't
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* point inside the virtually mapped linear page table.
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*/
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static inline int __access_ok(const void __user *p, unsigned long size)
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{
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unsigned long addr = (unsigned long)p;
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unsigned long seg = get_fs().seg;
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return likely(addr <= seg) &&
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(seg == KERNEL_DS.seg || likely(REGION_OFFSET(addr) < RGN_MAP_LIMIT));
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}
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#define access_ok(type, addr, size) __access_ok((addr), (size))
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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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* Careful to not
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* (a) re-use the arguments for side effects (sizeof/typeof is ok)
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* (b) require any knowledge of processes at this stage
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*/
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#define put_user(x, ptr) __put_user_check((__typeof__(*(ptr))) (x), (ptr), sizeof(*(ptr)))
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#define get_user(x, ptr) __get_user_check((x), (ptr), sizeof(*(ptr)))
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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 programmer 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) __put_user_nocheck((__typeof__(*(ptr))) (x), (ptr), sizeof(*(ptr)))
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#define __get_user(x, ptr) __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
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#ifdef ASM_SUPPORTED
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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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/* We need to declare the __ex_table section before we can use it in .xdata. */
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asm (".section \"__ex_table\", \"a\"\n\t.previous");
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# define __get_user_size(val, addr, n, err) \
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do { \
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register long __gu_r8 asm ("r8") = 0; \
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register long __gu_r9 asm ("r9"); \
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asm ("\n[1:]\tld"#n" %0=%2%P2\t// %0 and %1 get overwritten by exception handler\n" \
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"\t.xdata4 \"__ex_table\", 1b-., 1f-.+4\n" \
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"[1:]" \
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: "=r"(__gu_r9), "=r"(__gu_r8) : "m"(__m(addr)), "1"(__gu_r8)); \
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(err) = __gu_r8; \
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(val) = __gu_r9; \
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} while (0)
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/*
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* The "__put_user_size()" macro tells gcc it reads from memory instead of writing it. This
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* is because they do not write to any memory gcc knows about, so there are no aliasing
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* issues.
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*/
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# define __put_user_size(val, addr, n, err) \
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do { \
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register long __pu_r8 asm ("r8") = 0; \
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asm volatile ("\n[1:]\tst"#n" %1=%r2%P1\t// %0 gets overwritten by exception handler\n" \
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"\t.xdata4 \"__ex_table\", 1b-., 1f-.\n" \
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"[1:]" \
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: "=r"(__pu_r8) : "m"(__m(addr)), "rO"(val), "0"(__pu_r8)); \
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(err) = __pu_r8; \
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} while (0)
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#else /* !ASM_SUPPORTED */
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# define RELOC_TYPE 2 /* ip-rel */
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# define __get_user_size(val, addr, n, err) \
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do { \
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__ld_user("__ex_table", (unsigned long) addr, n, RELOC_TYPE); \
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(err) = ia64_getreg(_IA64_REG_R8); \
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(val) = ia64_getreg(_IA64_REG_R9); \
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} while (0)
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# define __put_user_size(val, addr, n, err) \
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do { \
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__st_user("__ex_table", (unsigned long) addr, n, RELOC_TYPE, \
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(__force unsigned long) (val)); \
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(err) = ia64_getreg(_IA64_REG_R8); \
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} while (0)
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#endif /* !ASM_SUPPORTED */
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extern void __get_user_unknown (void);
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/*
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* Evaluating arguments X, PTR, SIZE, and SEGMENT may involve subroutine-calls, which
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* could clobber r8 and r9 (among others). Thus, be careful not to evaluate it while
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* using r8/r9.
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*/
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#define __do_get_user(check, x, ptr, size) \
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({ \
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const __typeof__(*(ptr)) __user *__gu_ptr = (ptr); \
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__typeof__ (size) __gu_size = (size); \
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long __gu_err = -EFAULT; \
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unsigned long __gu_val = 0; \
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if (!check || __access_ok(__gu_ptr, size)) \
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switch (__gu_size) { \
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case 1: __get_user_size(__gu_val, __gu_ptr, 1, __gu_err); break; \
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case 2: __get_user_size(__gu_val, __gu_ptr, 2, __gu_err); break; \
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case 4: __get_user_size(__gu_val, __gu_ptr, 4, __gu_err); break; \
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case 8: __get_user_size(__gu_val, __gu_ptr, 8, __gu_err); break; \
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default: __get_user_unknown(); break; \
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} \
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(x) = (__force __typeof__(*(__gu_ptr))) __gu_val; \
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__gu_err; \
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})
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#define __get_user_nocheck(x, ptr, size) __do_get_user(0, x, ptr, size)
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#define __get_user_check(x, ptr, size) __do_get_user(1, x, ptr, size)
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extern void __put_user_unknown (void);
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/*
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* Evaluating arguments X, PTR, SIZE, and SEGMENT may involve subroutine-calls, which
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* could clobber r8 (among others). Thus, be careful not to evaluate them while using r8.
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*/
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#define __do_put_user(check, x, ptr, size) \
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({ \
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__typeof__ (x) __pu_x = (x); \
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__typeof__ (*(ptr)) __user *__pu_ptr = (ptr); \
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__typeof__ (size) __pu_size = (size); \
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long __pu_err = -EFAULT; \
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\
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if (!check || __access_ok(__pu_ptr, __pu_size)) \
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switch (__pu_size) { \
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case 1: __put_user_size(__pu_x, __pu_ptr, 1, __pu_err); break; \
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case 2: __put_user_size(__pu_x, __pu_ptr, 2, __pu_err); break; \
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case 4: __put_user_size(__pu_x, __pu_ptr, 4, __pu_err); break; \
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case 8: __put_user_size(__pu_x, __pu_ptr, 8, __pu_err); break; \
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default: __put_user_unknown(); break; \
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} \
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__pu_err; \
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})
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#define __put_user_nocheck(x, ptr, size) __do_put_user(0, x, ptr, size)
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#define __put_user_check(x, ptr, size) __do_put_user(1, x, ptr, size)
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/*
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* Complex access routines
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*/
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extern unsigned long __must_check __copy_user (void __user *to, const void __user *from,
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unsigned long count);
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static inline unsigned long
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raw_copy_to_user(void __user *to, const void *from, unsigned long count)
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{
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return __copy_user(to, (__force void __user *) from, count);
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}
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static inline unsigned long
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raw_copy_from_user(void *to, const void __user *from, unsigned long count)
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{
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return __copy_user((__force void __user *) to, from, count);
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}
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#define INLINE_COPY_FROM_USER
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#define INLINE_COPY_TO_USER
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extern unsigned long __do_clear_user (void __user *, unsigned long);
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#define __clear_user(to, n) __do_clear_user(to, n)
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#define clear_user(to, n) \
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({ \
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unsigned long __cu_len = (n); \
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if (__access_ok(to, __cu_len)) \
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__cu_len = __do_clear_user(to, __cu_len); \
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__cu_len; \
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})
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/*
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* Returns: -EFAULT if exception before terminator, N if the entire buffer filled, else
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* strlen.
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*/
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extern long __must_check __strncpy_from_user (char *to, const char __user *from, long to_len);
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#define strncpy_from_user(to, from, n) \
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({ \
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const char __user * __sfu_from = (from); \
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long __sfu_ret = -EFAULT; \
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if (__access_ok(__sfu_from, 0)) \
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__sfu_ret = __strncpy_from_user((to), __sfu_from, (n)); \
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__sfu_ret; \
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})
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/*
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* Returns: 0 if exception before NUL or reaching the supplied limit
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* (N), a value greater than N if the limit would be exceeded, else
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* strlen.
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*/
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extern unsigned long __strnlen_user (const char __user *, long);
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#define strnlen_user(str, len) \
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({ \
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const char __user *__su_str = (str); \
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unsigned long __su_ret = 0; \
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if (__access_ok(__su_str, 0)) \
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__su_ret = __strnlen_user(__su_str, len); \
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__su_ret; \
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})
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#define ARCH_HAS_TRANSLATE_MEM_PTR 1
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static __inline__ void *
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xlate_dev_mem_ptr(phys_addr_t p)
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{
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struct page *page;
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void *ptr;
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page = pfn_to_page(p >> PAGE_SHIFT);
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if (PageUncached(page))
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ptr = (void *)p + __IA64_UNCACHED_OFFSET;
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else
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ptr = __va(p);
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return ptr;
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}
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/*
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* Convert a virtual cached kernel memory pointer to an uncached pointer
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*/
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static __inline__ void *
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xlate_dev_kmem_ptr(void *p)
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{
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struct page *page;
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void *ptr;
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page = virt_to_page((unsigned long)p);
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if (PageUncached(page))
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ptr = (void *)__pa(p) + __IA64_UNCACHED_OFFSET;
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else
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ptr = p;
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return ptr;
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}
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#endif /* _ASM_IA64_UACCESS_H */
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