From ca23386216b9d4fc3bb211101205077d2b2916ae Mon Sep 17 00:00:00 2001 From: Glauber Costa Date: Fri, 13 Jun 2008 14:39:25 -0300 Subject: x86: merge common parts of uaccess. Common parts of uaccess_32.h and uaccess_64.h are put in uaccess.h. Bits in uaccess_32.h and uaccess_64.h that come to this file are equal except for comments and whitespaces differences. Signed-off-by: Glauber Costa Signed-off-by: H. Peter Anvin Signed-off-by: Ingo Molnar --- include/asm-x86/uaccess.h | 124 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 124 insertions(+) (limited to 'include/asm-x86/uaccess.h') diff --git a/include/asm-x86/uaccess.h b/include/asm-x86/uaccess.h index 9fefd2947e7..2fc30c2a8a9 100644 --- a/include/asm-x86/uaccess.h +++ b/include/asm-x86/uaccess.h @@ -1,5 +1,129 @@ +#ifndef _ASM_UACCES_H_ +#define _ASM_UACCES_H_ +/* + * User space memory access functions + */ +#include +#include +#include +#include +#include +#include +#include + +#define VERIFY_READ 0 +#define VERIFY_WRITE 1 + +/* + * The fs value determines whether argument validity checking should be + * performed or not. If get_fs() == USER_DS, checking is performed, with + * get_fs() == KERNEL_DS, checking is bypassed. + * + * For historical reasons, these macros are grossly misnamed. + */ + +#define MAKE_MM_SEG(s) ((mm_segment_t) { (s) }) + +#define KERNEL_DS MAKE_MM_SEG(-1UL) +#define USER_DS MAKE_MM_SEG(PAGE_OFFSET) + +#define get_ds() (KERNEL_DS) +#define get_fs() (current_thread_info()->addr_limit) +#define set_fs(x) (current_thread_info()->addr_limit = (x)) + +#define segment_eq(a, b) ((a).seg == (b).seg) + +/* + * Test whether a block of memory is a valid user space address. + * Returns 0 if the range is valid, nonzero otherwise. + * + * This is equivalent to the following test: + * (u33)addr + (u33)size >= (u33)current->addr_limit.seg (u65 for x86_64) + * + * This needs 33-bit (65-bit for x86_64) arithmetic. We have a carry... + */ + +#define __range_not_ok(addr, size) \ +({ \ + unsigned long flag, roksum; \ + __chk_user_ptr(addr); \ + asm("add %3,%1 ; sbb %0,%0 ; cmp %1,%4 ; sbb $0,%0" \ + : "=&r" (flag), "=r" (roksum) \ + : "1" (addr), "g" ((long)(size)), \ + "rm" (current_thread_info()->addr_limit.seg)); \ + flag; \ +}) + +/** + * access_ok: - Checks if a user space pointer is valid + * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE. Note that + * %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe + * to write to a block, it is always safe to read from it. + * @addr: User space pointer to start of block to check + * @size: Size of block to check + * + * Context: User context only. This function may sleep. + * + * Checks if a pointer to a block of memory in user space is valid. + * + * Returns true (nonzero) if the memory block may be valid, false (zero) + * if it is definitely invalid. + * + * Note that, depending on architecture, this function probably just + * checks that the pointer is in the user space range - after calling + * this function, memory access functions may still return -EFAULT. + */ +#define access_ok(type, addr, size) (likely(__range_not_ok(addr, size) == 0)) + +/* + * The exception table consists of pairs of addresses: the first is the + * address of an instruction that is allowed to fault, and the second is + * the address at which the program should continue. No registers are + * modified, so it is entirely up to the continuation code to figure out + * what to do. + * + * All the routines below use bits of fixup code that are out of line + * with the main instruction path. This means when everything is well, + * we don't even have to jump over them. Further, they do not intrude + * on our cache or tlb entries. + */ + +struct exception_table_entry { + unsigned long insn, fixup; +}; + +extern int fixup_exception(struct pt_regs *regs); + +/* + * These are the main single-value transfer routines. They automatically + * use the right size if we just have the right pointer type. + * + * This gets kind of ugly. We want to return _two_ values in "get_user()" + * and yet we don't want to do any pointers, because that is too much + * of a performance impact. Thus we have a few rather ugly macros here, + * and hide all the ugliness from the user. + * + * The "__xxx" versions of the user access functions are versions that + * do not verify the address space, that must have been done previously + * with a separate "access_ok()" call (this is used when we do multiple + * accesses to the same area of user memory). + */ + +extern int __get_user_1(void); +extern int __get_user_2(void); +extern int __get_user_4(void); +extern int __get_user_8(void); +extern int __get_user_bad(void); + +#define __get_user_x(size, ret, x, ptr) \ + asm volatile("call __get_user_" #size \ + : "=a" (ret),"=d" (x) \ + : "0" (ptr)) \ + #ifdef CONFIG_X86_32 # include "uaccess_32.h" #else # include "uaccess_64.h" #endif + +#endif -- cgit v1.2.3