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Diffstat (limited to '')
| -rw-r--r-- | arch/ia64/include/asm/uaccess.h | 293 |
1 files changed, 293 insertions, 0 deletions
diff --git a/arch/ia64/include/asm/uaccess.h b/arch/ia64/include/asm/uaccess.h new file mode 100644 index 000000000..179243c3d --- /dev/null +++ b/arch/ia64/include/asm/uaccess.h @@ -0,0 +1,293 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_IA64_UACCESS_H +#define _ASM_IA64_UACCESS_H + +/* + * This file defines various macros to transfer memory areas across + * the user/kernel boundary. This needs to be done carefully because + * this code is executed in kernel mode and uses user-specified + * addresses. Thus, we need to be careful not to let the user to + * trick us into accessing kernel memory that would normally be + * inaccessible. This code is also fairly performance sensitive, + * so we want to spend as little time doing safety checks as + * possible. + * + * To make matters a bit more interesting, these macros sometimes also + * called from within the kernel itself, in which case the address + * validity check must be skipped. The get_fs() macro tells us what + * to do: if get_fs()==USER_DS, checking is performed, if + * get_fs()==KERNEL_DS, checking is bypassed. + * + * Note that even if the memory area specified by the user is in a + * valid address range, it is still possible that we'll get a page + * fault while accessing it. This is handled by filling out an + * exception handler fixup entry for each instruction that has the + * potential to fault. When such a fault occurs, the page fault + * handler checks to see whether the faulting instruction has a fixup + * associated and, if so, sets r8 to -EFAULT and clears r9 to 0 and + * then resumes execution at the continuation point. + * + * Based on <asm-alpha/uaccess.h>. + * + * Copyright (C) 1998, 1999, 2001-2004 Hewlett-Packard Co + * David Mosberger-Tang <davidm@hpl.hp.com> + */ + +#include <linux/compiler.h> +#include <linux/page-flags.h> + +#include <asm/intrinsics.h> +#include <linux/pgtable.h> +#include <asm/io.h> +#include <asm/extable.h> + +/* + * For historical reasons, the following macros are grossly misnamed: + */ +#define KERNEL_DS ((mm_segment_t) { ~0UL }) /* cf. access_ok() */ +#define USER_DS ((mm_segment_t) { TASK_SIZE-1 }) /* cf. access_ok() */ + +#define get_fs() (current_thread_info()->addr_limit) +#define set_fs(x) (current_thread_info()->addr_limit = (x)) + +#define uaccess_kernel() (get_fs().seg == KERNEL_DS.seg) + +/* + * When accessing user memory, we need to make sure the entire area really is in + * user-level space. In order to do this efficiently, we make sure that the page at + * address TASK_SIZE is never valid. We also need to make sure that the address doesn't + * point inside the virtually mapped linear page table. + */ +static inline int __access_ok(const void __user *p, unsigned long size) +{ + unsigned long addr = (unsigned long)p; + unsigned long seg = get_fs().seg; + return likely(addr <= seg) && + (seg == KERNEL_DS.seg || likely(REGION_OFFSET(addr) < RGN_MAP_LIMIT)); +} +#define access_ok(addr, size) __access_ok((addr), (size)) + +/* + * These are the main single-value transfer routines. They automatically + * use the right size if we just have the right pointer type. + * + * Careful to not + * (a) re-use the arguments for side effects (sizeof/typeof is ok) + * (b) require any knowledge of processes at this stage + */ +#define put_user(x, ptr) __put_user_check((__typeof__(*(ptr))) (x), (ptr), sizeof(*(ptr))) +#define get_user(x, ptr) __get_user_check((x), (ptr), sizeof(*(ptr))) + +/* + * The "__xxx" versions do not do address space checking, useful when + * doing multiple accesses to the same area (the programmer has to do the + * checks by hand with "access_ok()") + */ +#define __put_user(x, ptr) __put_user_nocheck((__typeof__(*(ptr))) (x), (ptr), sizeof(*(ptr))) +#define __get_user(x, ptr) __get_user_nocheck((x), (ptr), sizeof(*(ptr))) + +#ifdef ASM_SUPPORTED + struct __large_struct { unsigned long buf[100]; }; +# define __m(x) (*(struct __large_struct __user *)(x)) + +/* We need to declare the __ex_table section before we can use it in .xdata. */ +asm (".section \"__ex_table\", \"a\"\n\t.previous"); + +# define __get_user_size(val, addr, n, err) \ +do { \ + register long __gu_r8 asm ("r8") = 0; \ + register long __gu_r9 asm ("r9"); \ + asm ("\n[1:]\tld"#n" %0=%2%P2\t// %0 and %1 get overwritten by exception handler\n" \ + "\t.xdata4 \"__ex_table\", 1b-., 1f-.+4\n" \ + "[1:]" \ + : "=r"(__gu_r9), "=r"(__gu_r8) : "m"(__m(addr)), "1"(__gu_r8)); \ + (err) = __gu_r8; \ + (val) = __gu_r9; \ +} while (0) + +/* + * The "__put_user_size()" macro tells gcc it reads from memory instead of writing it. This + * is because they do not write to any memory gcc knows about, so there are no aliasing + * issues. + */ +# define __put_user_size(val, addr, n, err) \ +do { \ + register long __pu_r8 asm ("r8") = 0; \ + asm volatile ("\n[1:]\tst"#n" %1=%r2%P1\t// %0 gets overwritten by exception handler\n" \ + "\t.xdata4 \"__ex_table\", 1b-., 1f-.\n" \ + "[1:]" \ + : "=r"(__pu_r8) : "m"(__m(addr)), "rO"(val), "0"(__pu_r8)); \ + (err) = __pu_r8; \ +} while (0) + +#else /* !ASM_SUPPORTED */ +# define RELOC_TYPE 2 /* ip-rel */ +# define __get_user_size(val, addr, n, err) \ +do { \ + __ld_user("__ex_table", (unsigned long) addr, n, RELOC_TYPE); \ + (err) = ia64_getreg(_IA64_REG_R8); \ + (val) = ia64_getreg(_IA64_REG_R9); \ +} while (0) +# define __put_user_size(val, addr, n, err) \ +do { \ + __st_user("__ex_table", (unsigned long) addr, n, RELOC_TYPE, \ + (__force unsigned long) (val)); \ + (err) = ia64_getreg(_IA64_REG_R8); \ +} while (0) +#endif /* !ASM_SUPPORTED */ + +extern void __get_user_unknown (void); + +/* + * Evaluating arguments X, PTR, SIZE, and SEGMENT may involve subroutine-calls, which + * could clobber r8 and r9 (among others). Thus, be careful not to evaluate it while + * using r8/r9. + */ +#define __do_get_user(check, x, ptr, size) \ +({ \ + const __typeof__(*(ptr)) __user *__gu_ptr = (ptr); \ + __typeof__ (size) __gu_size = (size); \ + long __gu_err = -EFAULT; \ + unsigned long __gu_val = 0; \ + if (!check || __access_ok(__gu_ptr, size)) \ + switch (__gu_size) { \ + case 1: __get_user_size(__gu_val, __gu_ptr, 1, __gu_err); break; \ + case 2: __get_user_size(__gu_val, __gu_ptr, 2, __gu_err); break; \ + case 4: __get_user_size(__gu_val, __gu_ptr, 4, __gu_err); break; \ + case 8: __get_user_size(__gu_val, __gu_ptr, 8, __gu_err); break; \ + default: __get_user_unknown(); break; \ + } \ + (x) = (__force __typeof__(*(__gu_ptr))) __gu_val; \ + __gu_err; \ +}) + +#define __get_user_nocheck(x, ptr, size) __do_get_user(0, x, ptr, size) +#define __get_user_check(x, ptr, size) __do_get_user(1, x, ptr, size) + +extern void __put_user_unknown (void); + +/* + * Evaluating arguments X, PTR, SIZE, and SEGMENT may involve subroutine-calls, which + * could clobber r8 (among others). Thus, be careful not to evaluate them while using r8. + */ +#define __do_put_user(check, x, ptr, size) \ +({ \ + __typeof__ (x) __pu_x = (x); \ + __typeof__ (*(ptr)) __user *__pu_ptr = (ptr); \ + __typeof__ (size) __pu_size = (size); \ + long __pu_err = -EFAULT; \ + \ + if (!check || __access_ok(__pu_ptr, __pu_size)) \ + switch (__pu_size) { \ + case 1: __put_user_size(__pu_x, __pu_ptr, 1, __pu_err); break; \ + case 2: __put_user_size(__pu_x, __pu_ptr, 2, __pu_err); break; \ + case 4: __put_user_size(__pu_x, __pu_ptr, 4, __pu_err); break; \ + case 8: __put_user_size(__pu_x, __pu_ptr, 8, __pu_err); break; \ + default: __put_user_unknown(); break; \ + } \ + __pu_err; \ +}) + +#define __put_user_nocheck(x, ptr, size) __do_put_user(0, x, ptr, size) +#define __put_user_check(x, ptr, size) __do_put_user(1, x, ptr, size) + +/* + * Complex access routines + */ +extern unsigned long __must_check __copy_user (void __user *to, const void __user *from, + unsigned long count); + +static inline unsigned long +raw_copy_to_user(void __user *to, const void *from, unsigned long count) +{ + return __copy_user(to, (__force void __user *) from, count); +} + +static inline unsigned long +raw_copy_from_user(void *to, const void __user *from, unsigned long count) +{ + return __copy_user((__force void __user *) to, from, count); +} + +#define INLINE_COPY_FROM_USER +#define INLINE_COPY_TO_USER + +extern unsigned long __do_clear_user (void __user *, unsigned long); + +#define __clear_user(to, n) __do_clear_user(to, n) + +#define clear_user(to, n) \ +({ \ + unsigned long __cu_len = (n); \ + if (__access_ok(to, __cu_len)) \ + __cu_len = __do_clear_user(to, __cu_len); \ + __cu_len; \ +}) + + +/* + * Returns: -EFAULT if exception before terminator, N if the entire buffer filled, else + * strlen. + */ +extern long __must_check __strncpy_from_user (char *to, const char __user *from, long to_len); + +#define strncpy_from_user(to, from, n) \ +({ \ + const char __user * __sfu_from = (from); \ + long __sfu_ret = -EFAULT; \ + if (__access_ok(__sfu_from, 0)) \ + __sfu_ret = __strncpy_from_user((to), __sfu_from, (n)); \ + __sfu_ret; \ +}) + +/* + * Returns: 0 if exception before NUL or reaching the supplied limit + * (N), a value greater than N if the limit would be exceeded, else + * strlen. + */ +extern unsigned long __strnlen_user (const char __user *, long); + +#define strnlen_user(str, len) \ +({ \ + const char __user *__su_str = (str); \ + unsigned long __su_ret = 0; \ + if (__access_ok(__su_str, 0)) \ + __su_ret = __strnlen_user(__su_str, len); \ + __su_ret; \ +}) + +#define ARCH_HAS_TRANSLATE_MEM_PTR 1 +static __inline__ void * +xlate_dev_mem_ptr(phys_addr_t p) +{ + struct page *page; + void *ptr; + + page = pfn_to_page(p >> PAGE_SHIFT); + if (PageUncached(page)) + ptr = (void *)p + __IA64_UNCACHED_OFFSET; + else + ptr = __va(p); + + return ptr; +} + +/* + * Convert a virtual cached kernel memory pointer to an uncached pointer + */ +static __inline__ void * +xlate_dev_kmem_ptr(void *p) +{ + struct page *page; + void *ptr; + + page = virt_to_page((unsigned long)p); + if (PageUncached(page)) + ptr = (void *)__pa(p) + __IA64_UNCACHED_OFFSET; + else + ptr = p; + + return ptr; +} + +#endif /* _ASM_IA64_UACCESS_H */ |