/* $Id: uaccess.h,v 1.24 2001/10/30 04:32:24 davem Exp $ * uaccess.h: User space memore access functions. * * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu) * Copyright (C) 1996,1997 Jakub Jelinek (jj@sunsite.mff.cuni.cz) */ #ifndef _ASM_UACCESS_H #define _ASM_UACCESS_H #ifdef __KERNEL__ #include <linux/compiler.h> #include <linux/sched.h> #include <linux/string.h> #include <linux/errno.h> #include <asm/vac-ops.h> #include <asm/a.out.h> #endif #ifndef __ASSEMBLY__ /* Sparc is not segmented, however we need to be able to fool access_ok() * when doing system calls from kernel mode legitimately. * * "For historical reasons, these macros are grossly misnamed." -Linus */ #define KERNEL_DS ((mm_segment_t) { 0 }) #define USER_DS ((mm_segment_t) { -1 }) #define VERIFY_READ 0 #define VERIFY_WRITE 1 #define get_ds() (KERNEL_DS) #define get_fs() (current->thread.current_ds) #define set_fs(val) ((current->thread.current_ds) = (val)) #define segment_eq(a,b) ((a).seg == (b).seg) /* We have there a nice not-mapped page at PAGE_OFFSET - PAGE_SIZE, so that this test * can be fairly lightweight. * No one can read/write anything from userland in the kernel space by setting * large size and address near to PAGE_OFFSET - a fault will break his intentions. */ #define __user_ok(addr, size) ({ (void)(size); (addr) < STACK_TOP; }) #define __kernel_ok (segment_eq(get_fs(), KERNEL_DS)) #define __access_ok(addr,size) (__user_ok((addr) & get_fs().seg,(size))) #define access_ok(type, addr, size) \ ({ (void)(type); __access_ok((unsigned long)(addr), size); }) /* * 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. * * There is a special way how to put a range of potentially faulting * insns (like twenty ldd/std's with now intervening other instructions) * You specify address of first in insn and 0 in fixup and in the next * exception_table_entry you specify last potentially faulting insn + 1 * and in fixup the routine which should handle the fault. * That fixup code will get * (faulting_insn_address - first_insn_in_the_range_address)/4 * in %g2 (ie. index of the faulting instruction in the range). */ struct exception_table_entry { unsigned long insn, fixup; }; /* Returns 0 if exception not found and fixup otherwise. */ extern unsigned long search_extables_range(unsigned long addr, unsigned long *g2); extern void __ret_efault(void); /* Uh, these should become 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. */ #define put_user(x,ptr) ({ \ unsigned long __pu_addr = (unsigned long)(ptr); \ __chk_user_ptr(ptr); \ __put_user_check((__typeof__(*(ptr)))(x),__pu_addr,sizeof(*(ptr))); }) #define get_user(x,ptr) ({ \ unsigned long __gu_addr = (unsigned long)(ptr); \ __chk_user_ptr(ptr); \ __get_user_check((x),__gu_addr,sizeof(*(ptr)),__typeof__(*(ptr))); }) /* * The "__xxx" versions do not do address space checking, useful when * doing multiple accesses to the same area (the user 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)),__typeof__(*(ptr))) struct __large_struct { unsigned long buf[100]; }; #define __m(x) ((struct __large_struct __user *)(x)) #define __put_user_check(x,addr,size) ({ \ register int __pu_ret; \ if (__access_ok(addr,size)) { \ switch (size) { \ case 1: __put_user_asm(x,b,addr,__pu_ret); break; \ case 2: __put_user_asm(x,h,addr,__pu_ret); break; \ case 4: __put_user_asm(x,,addr,__pu_ret); break; \ case 8: __put_user_asm(x,d,addr,__pu_ret); break; \ default: __pu_ret = __put_user_bad(); break; \ } } else { __pu_ret = -EFAULT; } __pu_ret; }) #define __put_user_nocheck(x,addr,size) ({ \ register int __pu_ret; \ switch (size) { \ case 1: __put_user_asm(x,b,addr,__pu_ret); break; \ case 2: __put_user_asm(x,h,addr,__pu_ret); break; \ case 4: __put_user_asm(x,,addr,__pu_ret); break; \ case 8: __put_user_asm(x,d,addr,__pu_ret); break; \ default: __pu_ret = __put_user_bad(); break; \ } __pu_ret; }) #define __put_user_asm(x,size,addr,ret) \ __asm__ __volatile__( \ "/* Put user asm, inline. */\n" \ "1:\t" "st"#size " %1, %2\n\t" \ "clr %0\n" \ "2:\n\n\t" \ ".section .fixup,#alloc,#execinstr\n\t" \ ".align 4\n" \ "3:\n\t" \ "b 2b\n\t" \ " mov %3, %0\n\t" \ ".previous\n\n\t" \ ".section __ex_table,#alloc\n\t" \ ".align 4\n\t" \ ".word 1b, 3b\n\t" \ ".previous\n\n\t" \ : "=&r" (ret) : "r" (x), "m" (*__m(addr)), \ "i" (-EFAULT)) extern int __put_user_bad(void); #define __get_user_check(x,addr,size,type) ({ \ register int __gu_ret; \ register unsigned long __gu_val; \ if (__access_ok(addr,size)) { \ switch (size) { \ case 1: __get_user_asm(__gu_val,ub,addr,__gu_ret); break; \ case 2: __get_user_asm(__gu_val,uh,addr,__gu_ret); break; \ case 4: __get_user_asm(__gu_val,,addr,__gu_ret); break; \ case 8: __get_user_asm(__gu_val,d,addr,__gu_ret); break; \ default: __gu_val = 0; __gu_ret = __get_user_bad(); break; \ } } else { __gu_val = 0; __gu_ret = -EFAULT; } x = (type) __gu_val; __gu_ret; }) #define __get_user_check_ret(x,addr,size,type,retval) ({ \ register unsigned long __gu_val __asm__ ("l1"); \ if (__access_ok(addr,size)) { \ switch (size) { \ case 1: __get_user_asm_ret(__gu_val,ub,addr,retval); break; \ case 2: __get_user_asm_ret(__gu_val,uh,addr,retval); break; \ case 4: __get_user_asm_ret(__gu_val,,addr,retval); break; \ case 8: __get_user_asm_ret(__gu_val,d,addr,retval); break; \ default: if (__get_user_bad()) return retval; \ } x = (type) __gu_val; } else return retval; }) #define __get_user_nocheck(x,addr,size,type) ({ \ register int __gu_ret; \ register unsigned long __gu_val; \ switch (size) { \ case 1: __get_user_asm(__gu_val,ub,addr,__gu_ret); break; \ case 2: __get_user_asm(__gu_val,uh,addr,__gu_ret); break; \ case 4: __get_user_asm(__gu_val,,addr,__gu_ret); break; \ case 8: __get_user_asm(__gu_val,d,addr,__gu_ret); break; \ default: __gu_val = 0; __gu_ret = __get_user_bad(); break; \ } x = (type) __gu_val; __gu_ret; }) #define __get_user_nocheck_ret(x,addr,size,type,retval) ({ \ register unsigned long __gu_val __asm__ ("l1"); \ switch (size) { \ case 1: __get_user_asm_ret(__gu_val,ub,addr,retval); break; \ case 2: __get_user_asm_ret(__gu_val,uh,addr,retval); break; \ case 4: __get_user_asm_ret(__gu_val,,addr,retval); break; \ case 8: __get_user_asm_ret(__gu_val,d,addr,retval); break; \ default: if (__get_user_bad()) return retval; \ } x = (type) __gu_val; }) #define __get_user_asm(x,size,addr,ret) \ __asm__ __volatile__( \ "/* Get user asm, inline. */\n" \ "1:\t" "ld"#size " %2, %1\n\t" \ "clr %0\n" \ "2:\n\n\t" \ ".section .fixup,#alloc,#execinstr\n\t" \ ".align 4\n" \ "3:\n\t" \ "clr %1\n\t" \ "b 2b\n\t" \ " mov %3, %0\n\n\t" \ ".previous\n\t" \ ".section __ex_table,#alloc\n\t" \ ".align 4\n\t" \ ".word 1b, 3b\n\n\t" \ ".previous\n\t" \ : "=&r" (ret), "=&r" (x) : "m" (*__m(addr)), \ "i" (-EFAULT)) #define __get_user_asm_ret(x,size,addr,retval) \ if (__builtin_constant_p(retval) && retval == -EFAULT) \ __asm__ __volatile__( \ "/* Get user asm ret, inline. */\n" \ "1:\t" "ld"#size " %1, %0\n\n\t" \ ".section __ex_table,#alloc\n\t" \ ".align 4\n\t" \ ".word 1b,__ret_efault\n\n\t" \ ".previous\n\t" \ : "=&r" (x) : "m" (*__m(addr))); \ else \ __asm__ __volatile__( \ "/* Get user asm ret, inline. */\n" \ "1:\t" "ld"#size " %1, %0\n\n\t" \ ".section .fixup,#alloc,#execinstr\n\t" \ ".align 4\n" \ "3:\n\t" \ "ret\n\t" \ " restore %%g0, %2, %%o0\n\n\t" \ ".previous\n\t" \ ".section __ex_table,#alloc\n\t" \ ".align 4\n\t" \ ".word 1b, 3b\n\n\t" \ ".previous\n\t" \ : "=&r" (x) : "m" (*__m(addr)), "i" (retval)) extern int __get_user_bad(void); extern unsigned long __copy_user(void __user *to, const void __user *from, unsigned long size); static inline unsigned long copy_to_user(void __user *to, const void *from, unsigned long n) { if (n && __access_ok((unsigned long) to, n)) return __copy_user(to, (__force void __user *) from, n); else return n; } static inline unsigned long __copy_to_user(void __user *to, const void *from, unsigned long n) { return __copy_user(to, (__force void __user *) from, n); } static inline unsigned long copy_from_user(void *to, const void __user *from, unsigned long n) { if (n && __access_ok((unsigned long) from, n)) return __copy_user((__force void __user *) to, from, n); else return n; } static inline unsigned long __copy_from_user(void *to, const void __user *from, unsigned long n) { return __copy_user((__force void __user *) to, from, n); } #define __copy_to_user_inatomic __copy_to_user #define __copy_from_user_inatomic __copy_from_user static inline unsigned long __clear_user(void __user *addr, unsigned long size) { unsigned long ret; __asm__ __volatile__ ( ".section __ex_table,#alloc\n\t" ".align 4\n\t" ".word 1f,3\n\t" ".previous\n\t" "mov %2, %%o1\n" "1:\n\t" "call __bzero\n\t" " mov %1, %%o0\n\t" "mov %%o0, %0\n" : "=r" (ret) : "r" (addr), "r" (size) : "o0", "o1", "o2", "o3", "o4", "o5", "o7", "g1", "g2", "g3", "g4", "g5", "g7", "cc"); return ret; } static inline unsigned long clear_user(void __user *addr, unsigned long n) { if (n && __access_ok((unsigned long) addr, n)) return __clear_user(addr, n); else return n; } extern long __strncpy_from_user(char *dest, const char __user *src, long count); static inline long strncpy_from_user(char *dest, const char __user *src, long count) { if (__access_ok((unsigned long) src, count)) return __strncpy_from_user(dest, src, count); else return -EFAULT; } extern long __strlen_user(const char __user *); extern long __strnlen_user(const char __user *, long len); static inline long strlen_user(const char __user *str) { if (!access_ok(VERIFY_READ, str, 0)) return 0; else return __strlen_user(str); } static inline long strnlen_user(const char __user *str, long len) { if (!access_ok(VERIFY_READ, str, 0)) return 0; else return __strnlen_user(str, len); } #endif /* __ASSEMBLY__ */ #endif /* _ASM_UACCESS_H */