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1965aae3c9
Change header guards named "ASM_X86__*" to "_ASM_X86_*" since: a. the double underscore is ugly and pointless. b. no leading underscore violates namespace constraints. Signed-off-by: H. Peter Anvin <hpa@zytor.com>
455 lines
13 KiB
C
455 lines
13 KiB
C
#ifndef _ASM_X86_UACCESS_H
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#define _ASM_X86_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/compiler.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/asm.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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#define MAKE_MM_SEG(s) ((mm_segment_t) { (s) })
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#define KERNEL_DS MAKE_MM_SEG(-1UL)
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#define USER_DS MAKE_MM_SEG(PAGE_OFFSET)
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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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#define __addr_ok(addr) \
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((unsigned long __force)(addr) < \
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(current_thread_info()->addr_limit.seg))
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/*
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* Test whether a block of memory is a valid user space address.
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* Returns 0 if the range is valid, nonzero otherwise.
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*
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* This is equivalent to the following test:
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* (u33)addr + (u33)size >= (u33)current->addr_limit.seg (u65 for x86_64)
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*
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* This needs 33-bit (65-bit for x86_64) arithmetic. We have a carry...
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*/
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#define __range_not_ok(addr, size) \
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({ \
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unsigned long flag, roksum; \
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__chk_user_ptr(addr); \
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asm("add %3,%1 ; sbb %0,%0 ; cmp %1,%4 ; sbb $0,%0" \
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: "=&r" (flag), "=r" (roksum) \
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: "1" (addr), "g" ((long)(size)), \
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"rm" (current_thread_info()->addr_limit.seg)); \
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flag; \
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})
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/**
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* access_ok: - Checks if a user space pointer is valid
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* @type: Type of access: %VERIFY_READ or %VERIFY_WRITE. Note that
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* %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe
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* to write to a block, it is always safe to read from it.
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* @addr: User space pointer to start of block to check
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* @size: Size of block to check
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*
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* Context: User context only. This function may sleep.
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*
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* Checks if a pointer to a block of memory in user space is valid.
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*
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* Returns true (nonzero) if the memory block may be valid, false (zero)
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* if it is definitely invalid.
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*
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* Note that, depending on architecture, this function probably just
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* checks that the pointer is in the user space range - after calling
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* this function, memory access functions may still return -EFAULT.
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*/
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#define access_ok(type, addr, size) (likely(__range_not_ok(addr, size) == 0))
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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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extern int fixup_exception(struct pt_regs *regs);
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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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extern int __get_user_1(void);
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extern int __get_user_2(void);
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extern int __get_user_4(void);
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extern int __get_user_8(void);
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extern int __get_user_bad(void);
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#define __get_user_x(size, ret, x, ptr) \
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asm volatile("call __get_user_" #size \
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: "=a" (ret),"=d" (x) \
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: "0" (ptr)) \
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/* Careful: we have to cast the result to the type of the pointer
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* for sign reasons */
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/**
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* get_user: - Get a simple variable from user space.
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* @x: Variable to store result.
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* @ptr: Source address, in user space.
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*
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* Context: User context only. This function may sleep.
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*
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* This macro copies a single simple variable from user space to kernel
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* space. It supports simple types like char and int, but not larger
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* data types like structures or arrays.
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*
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* @ptr must have pointer-to-simple-variable type, and the result of
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* dereferencing @ptr must be assignable to @x without a cast.
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*
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* Returns zero on success, or -EFAULT on error.
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* On error, the variable @x is set to zero.
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*/
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#ifdef CONFIG_X86_32
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#define __get_user_8(__ret_gu, __val_gu, ptr) \
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__get_user_x(X, __ret_gu, __val_gu, ptr)
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#else
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#define __get_user_8(__ret_gu, __val_gu, ptr) \
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__get_user_x(8, __ret_gu, __val_gu, ptr)
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#endif
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#define get_user(x, ptr) \
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({ \
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int __ret_gu; \
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unsigned long __val_gu; \
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__chk_user_ptr(ptr); \
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switch (sizeof(*(ptr))) { \
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case 1: \
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__get_user_x(1, __ret_gu, __val_gu, ptr); \
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break; \
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case 2: \
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__get_user_x(2, __ret_gu, __val_gu, ptr); \
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break; \
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case 4: \
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__get_user_x(4, __ret_gu, __val_gu, ptr); \
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break; \
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case 8: \
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__get_user_8(__ret_gu, __val_gu, ptr); \
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break; \
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default: \
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__get_user_x(X, __ret_gu, __val_gu, ptr); \
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break; \
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} \
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(x) = (__typeof__(*(ptr)))__val_gu; \
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__ret_gu; \
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})
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#define __put_user_x(size, x, ptr, __ret_pu) \
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asm volatile("call __put_user_" #size : "=a" (__ret_pu) \
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:"0" ((typeof(*(ptr)))(x)), "c" (ptr) : "ebx")
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#ifdef CONFIG_X86_32
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#define __put_user_u64(x, addr, err) \
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asm volatile("1: movl %%eax,0(%2)\n" \
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"2: movl %%edx,4(%2)\n" \
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"3:\n" \
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".section .fixup,\"ax\"\n" \
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"4: movl %3,%0\n" \
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" jmp 3b\n" \
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".previous\n" \
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_ASM_EXTABLE(1b, 4b) \
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_ASM_EXTABLE(2b, 4b) \
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: "=r" (err) \
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: "A" (x), "r" (addr), "i" (-EFAULT), "0" (err))
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#define __put_user_x8(x, ptr, __ret_pu) \
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asm volatile("call __put_user_8" : "=a" (__ret_pu) \
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: "A" ((typeof(*(ptr)))(x)), "c" (ptr) : "ebx")
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#else
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#define __put_user_u64(x, ptr, retval) \
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__put_user_asm(x, ptr, retval, "q", "", "Zr", -EFAULT)
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#define __put_user_x8(x, ptr, __ret_pu) __put_user_x(8, x, ptr, __ret_pu)
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#endif
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extern void __put_user_bad(void);
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/*
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* Strange magic calling convention: pointer in %ecx,
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* value in %eax(:%edx), return value in %eax. clobbers %rbx
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*/
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extern void __put_user_1(void);
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extern void __put_user_2(void);
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extern void __put_user_4(void);
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extern void __put_user_8(void);
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#ifdef CONFIG_X86_WP_WORKS_OK
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/**
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* put_user: - Write a simple value into user space.
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* @x: Value to copy to user space.
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* @ptr: Destination address, in user space.
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*
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* Context: User context only. This function may sleep.
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*
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* This macro copies a single simple value from kernel space to user
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* space. It supports simple types like char and int, but not larger
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* data types like structures or arrays.
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*
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* @ptr must have pointer-to-simple-variable type, and @x must be assignable
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* to the result of dereferencing @ptr.
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*
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* Returns zero on success, or -EFAULT on error.
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*/
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#define put_user(x, ptr) \
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({ \
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int __ret_pu; \
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__typeof__(*(ptr)) __pu_val; \
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__chk_user_ptr(ptr); \
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__pu_val = x; \
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switch (sizeof(*(ptr))) { \
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case 1: \
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__put_user_x(1, __pu_val, ptr, __ret_pu); \
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break; \
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case 2: \
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__put_user_x(2, __pu_val, ptr, __ret_pu); \
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break; \
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case 4: \
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__put_user_x(4, __pu_val, ptr, __ret_pu); \
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break; \
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case 8: \
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__put_user_x8(__pu_val, ptr, __ret_pu); \
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break; \
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default: \
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__put_user_x(X, __pu_val, ptr, __ret_pu); \
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break; \
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} \
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__ret_pu; \
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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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__chk_user_ptr(ptr); \
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switch (size) { \
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case 1: \
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__put_user_asm(x, ptr, retval, "b", "b", "iq", errret); \
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break; \
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case 2: \
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__put_user_asm(x, ptr, retval, "w", "w", "ir", errret); \
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break; \
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case 4: \
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__put_user_asm(x, ptr, retval, "l", "k", "ir", errret);\
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break; \
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case 8: \
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__put_user_u64((__typeof__(*ptr))(x), ptr, retval); \
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break; \
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default: \
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__put_user_bad(); \
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} \
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} while (0)
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#else
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#define __put_user_size(x, ptr, size, retval, errret) \
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do { \
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__typeof__(*(ptr))__pus_tmp = x; \
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retval = 0; \
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\
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if (unlikely(__copy_to_user_ll(ptr, &__pus_tmp, size) != 0)) \
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retval = errret; \
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} while (0)
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#define put_user(x, ptr) \
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({ \
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int __ret_pu; \
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__typeof__(*(ptr))__pus_tmp = x; \
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__ret_pu = 0; \
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if (unlikely(__copy_to_user_ll(ptr, &__pus_tmp, \
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sizeof(*(ptr))) != 0)) \
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__ret_pu = -EFAULT; \
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__ret_pu; \
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})
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#endif
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#ifdef CONFIG_X86_32
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#define __get_user_asm_u64(x, ptr, retval, errret) (x) = __get_user_bad()
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#else
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#define __get_user_asm_u64(x, ptr, retval, errret) \
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__get_user_asm(x, ptr, retval, "q", "", "=r", errret)
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#endif
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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: \
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__get_user_asm(x, ptr, retval, "b", "b", "=q", errret); \
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break; \
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case 2: \
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__get_user_asm(x, ptr, retval, "w", "w", "=r", errret); \
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break; \
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case 4: \
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__get_user_asm(x, ptr, retval, "l", "k", "=r", errret); \
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break; \
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case 8: \
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__get_user_asm_u64(x, ptr, retval, errret); \
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break; \
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default: \
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(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, itype, rtype, ltype, errret) \
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asm volatile("1: mov"itype" %2,%"rtype"1\n" \
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"2:\n" \
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".section .fixup,\"ax\"\n" \
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"3: mov %3,%0\n" \
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" xor"itype" %"rtype"1,%"rtype"1\n" \
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" jmp 2b\n" \
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".previous\n" \
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_ASM_EXTABLE(1b, 3b) \
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: "=r" (err), ltype(x) \
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: "m" (__m(addr)), "i" (errret), "0" (err))
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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, -EFAULT); \
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__pu_err; \
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})
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#define __get_user_nocheck(x, ptr, size) \
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({ \
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long __gu_err; \
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unsigned long __gu_val; \
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__get_user_size(__gu_val, (ptr), (size), __gu_err, -EFAULT); \
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(x) = (__force __typeof__(*(ptr)))__gu_val; \
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__gu_err; \
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})
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/* FIXME: this hack is definitely wrong -AK */
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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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/*
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* Tell gcc we read from memory instead of writing: this is because
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* we do not write to any memory gcc knows about, so there are no
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* aliasing issues.
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*/
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#define __put_user_asm(x, addr, err, itype, rtype, ltype, errret) \
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asm volatile("1: mov"itype" %"rtype"1,%2\n" \
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"2:\n" \
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".section .fixup,\"ax\"\n" \
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"3: mov %3,%0\n" \
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" jmp 2b\n" \
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".previous\n" \
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_ASM_EXTABLE(1b, 3b) \
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: "=r"(err) \
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: ltype(x), "m" (__m(addr)), "i" (errret), "0" (err))
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/**
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* __get_user: - Get a simple variable from user space, with less checking.
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* @x: Variable to store result.
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* @ptr: Source address, in user space.
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*
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* Context: User context only. This function may sleep.
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*
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* This macro copies a single simple variable from user space to kernel
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* space. It supports simple types like char and int, but not larger
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* data types like structures or arrays.
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*
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* @ptr must have pointer-to-simple-variable type, and the result of
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* dereferencing @ptr must be assignable to @x without a cast.
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*
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* Caller must check the pointer with access_ok() before calling this
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* function.
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*
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* Returns zero on success, or -EFAULT on error.
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* On error, the variable @x is set to zero.
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*/
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#define __get_user(x, ptr) \
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__get_user_nocheck((x), (ptr), sizeof(*(ptr)))
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/**
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* __put_user: - Write a simple value into user space, with less checking.
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* @x: Value to copy to user space.
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* @ptr: Destination address, in user space.
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*
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* Context: User context only. This function may sleep.
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*
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* This macro copies a single simple value from kernel space to user
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* space. It supports simple types like char and int, but not larger
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* data types like structures or arrays.
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*
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* @ptr must have pointer-to-simple-variable type, and @x must be assignable
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* to the result of dereferencing @ptr.
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*
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* Caller must check the pointer with access_ok() before calling this
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* function.
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*
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* Returns zero on success, or -EFAULT on error.
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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_unaligned __get_user
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#define __put_user_unaligned __put_user
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/*
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* movsl can be slow when source and dest are not both 8-byte aligned
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*/
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#ifdef CONFIG_X86_INTEL_USERCOPY
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extern struct movsl_mask {
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int mask;
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} ____cacheline_aligned_in_smp movsl_mask;
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#endif
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#define ARCH_HAS_NOCACHE_UACCESS 1
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#ifdef CONFIG_X86_32
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# include "uaccess_32.h"
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#else
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# define ARCH_HAS_SEARCH_EXTABLE
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# include "uaccess_64.h"
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#endif
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#endif /* _ASM_X86_UACCESS_H */
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