/* * User address space access functions. * The non inlined parts of asm-i386/uaccess.h are here. * * Copyright 1997 Andi Kleen <ak@muc.de> * Copyright 1997 Linus Torvalds */ #include <linux/mm.h> #include <linux/highmem.h> #include <linux/blkdev.h> #include <linux/module.h> #include <linux/backing-dev.h> #include <linux/interrupt.h> #include <asm/uaccess.h> #include <asm/mmx.h> static inline int __movsl_is_ok(unsigned long a1, unsigned long a2, unsigned long n) { #ifdef CONFIG_X86_INTEL_USERCOPY if (n >= 64 && ((a1 ^ a2) & movsl_mask.mask)) return 0; #endif return 1; } #define movsl_is_ok(a1,a2,n) \ __movsl_is_ok((unsigned long)(a1),(unsigned long)(a2),(n)) /* * Copy a null terminated string from userspace. */ #define __do_strncpy_from_user(dst,src,count,res) \ do { \ int __d0, __d1, __d2; \ might_sleep(); \ __asm__ __volatile__( \ " testl %1,%1\n" \ " jz 2f\n" \ "0: lodsb\n" \ " stosb\n" \ " testb %%al,%%al\n" \ " jz 1f\n" \ " decl %1\n" \ " jnz 0b\n" \ "1: subl %1,%0\n" \ "2:\n" \ ".section .fixup,\"ax\"\n" \ "3: movl %5,%0\n" \ " jmp 2b\n" \ ".previous\n" \ ".section __ex_table,\"a\"\n" \ " .align 4\n" \ " .long 0b,3b\n" \ ".previous" \ : "=d"(res), "=c"(count), "=&a" (__d0), "=&S" (__d1), \ "=&D" (__d2) \ : "i"(-EFAULT), "0"(count), "1"(count), "3"(src), "4"(dst) \ : "memory"); \ } while (0) /** * __strncpy_from_user: - Copy a NUL terminated string from userspace, with less checking. * @dst: Destination address, in kernel space. This buffer must be at * least @count bytes long. * @src: Source address, in user space. * @count: Maximum number of bytes to copy, including the trailing NUL. * * Copies a NUL-terminated string from userspace to kernel space. * Caller must check the specified block with access_ok() before calling * this function. * * On success, returns the length of the string (not including the trailing * NUL). * * If access to userspace fails, returns -EFAULT (some data may have been * copied). * * If @count is smaller than the length of the string, copies @count bytes * and returns @count. */ long __strncpy_from_user(char *dst, const char __user *src, long count) { long res; __do_strncpy_from_user(dst, src, count, res); return res; } EXPORT_SYMBOL(__strncpy_from_user); /** * strncpy_from_user: - Copy a NUL terminated string from userspace. * @dst: Destination address, in kernel space. This buffer must be at * least @count bytes long. * @src: Source address, in user space. * @count: Maximum number of bytes to copy, including the trailing NUL. * * Copies a NUL-terminated string from userspace to kernel space. * * On success, returns the length of the string (not including the trailing * NUL). * * If access to userspace fails, returns -EFAULT (some data may have been * copied). * * If @count is smaller than the length of the string, copies @count bytes * and returns @count. */ long strncpy_from_user(char *dst, const char __user *src, long count) { long res = -EFAULT; if (access_ok(VERIFY_READ, src, 1)) __do_strncpy_from_user(dst, src, count, res); return res; } EXPORT_SYMBOL(strncpy_from_user); /* * Zero Userspace */ #define __do_clear_user(addr,size) \ do { \ int __d0; \ might_sleep(); \ __asm__ __volatile__( \ "0: rep; stosl\n" \ " movl %2,%0\n" \ "1: rep; stosb\n" \ "2:\n" \ ".section .fixup,\"ax\"\n" \ "3: lea 0(%2,%0,4),%0\n" \ " jmp 2b\n" \ ".previous\n" \ ".section __ex_table,\"a\"\n" \ " .align 4\n" \ " .long 0b,3b\n" \ " .long 1b,2b\n" \ ".previous" \ : "=&c"(size), "=&D" (__d0) \ : "r"(size & 3), "0"(size / 4), "1"(addr), "a"(0)); \ } while (0) /** * clear_user: - Zero a block of memory in user space. * @to: Destination address, in user space. * @n: Number of bytes to zero. * * Zero a block of memory in user space. * * Returns number of bytes that could not be cleared. * On success, this will be zero. */ unsigned long clear_user(void __user *to, unsigned long n) { might_sleep(); if (access_ok(VERIFY_WRITE, to, n)) __do_clear_user(to, n); return n; } EXPORT_SYMBOL(clear_user); /** * __clear_user: - Zero a block of memory in user space, with less checking. * @to: Destination address, in user space. * @n: Number of bytes to zero. * * Zero a block of memory in user space. Caller must check * the specified block with access_ok() before calling this function. * * Returns number of bytes that could not be cleared. * On success, this will be zero. */ unsigned long __clear_user(void __user *to, unsigned long n) { __do_clear_user(to, n); return n; } EXPORT_SYMBOL(__clear_user); /** * strnlen_user: - Get the size of a string in user space. * @s: The string to measure. * @n: The maximum valid length * * Get the size of a NUL-terminated string in user space. * * Returns the size of the string INCLUDING the terminating NUL. * On exception, returns 0. * If the string is too long, returns a value greater than @n. */ long strnlen_user(const char __user *s, long n) { unsigned long mask = -__addr_ok(s); unsigned long res, tmp; might_sleep(); __asm__ __volatile__( " testl %0, %0\n" " jz 3f\n" " andl %0,%%ecx\n" "0: repne; scasb\n" " setne %%al\n" " subl %%ecx,%0\n" " addl %0,%%eax\n" "1:\n" ".section .fixup,\"ax\"\n" "2: xorl %%eax,%%eax\n" " jmp 1b\n" "3: movb $1,%%al\n" " jmp 1b\n" ".previous\n" ".section __ex_table,\"a\"\n" " .align 4\n" " .long 0b,2b\n" ".previous" :"=r" (n), "=D" (s), "=a" (res), "=c" (tmp) :"0" (n), "1" (s), "2" (0), "3" (mask) :"cc"); return res & mask; } EXPORT_SYMBOL(strnlen_user); #ifdef CONFIG_X86_INTEL_USERCOPY static unsigned long __copy_user_intel(void __user *to, const void *from, unsigned long size) { int d0, d1; __asm__ __volatile__( " .align 2,0x90\n" "1: movl 32(%4), %%eax\n" " cmpl $67, %0\n" " jbe 3f\n" "2: movl 64(%4), %%eax\n" " .align 2,0x90\n" "3: movl 0(%4), %%eax\n" "4: movl 4(%4), %%edx\n" "5: movl %%eax, 0(%3)\n" "6: movl %%edx, 4(%3)\n" "7: movl 8(%4), %%eax\n" "8: movl 12(%4),%%edx\n" "9: movl %%eax, 8(%3)\n" "10: movl %%edx, 12(%3)\n" "11: movl 16(%4), %%eax\n" "12: movl 20(%4), %%edx\n" "13: movl %%eax, 16(%3)\n" "14: movl %%edx, 20(%3)\n" "15: movl 24(%4), %%eax\n" "16: movl 28(%4), %%edx\n" "17: movl %%eax, 24(%3)\n" "18: movl %%edx, 28(%3)\n" "19: movl 32(%4), %%eax\n" "20: movl 36(%4), %%edx\n" "21: movl %%eax, 32(%3)\n" "22: movl %%edx, 36(%3)\n" "23: movl 40(%4), %%eax\n" "24: movl 44(%4), %%edx\n" "25: movl %%eax, 40(%3)\n" "26: movl %%edx, 44(%3)\n" "27: movl 48(%4), %%eax\n" "28: movl 52(%4), %%edx\n" "29: movl %%eax, 48(%3)\n" "30: movl %%edx, 52(%3)\n" "31: movl 56(%4), %%eax\n" "32: movl 60(%4), %%edx\n" "33: movl %%eax, 56(%3)\n" "34: movl %%edx, 60(%3)\n" " addl $-64, %0\n" " addl $64, %4\n" " addl $64, %3\n" " cmpl $63, %0\n" " ja 1b\n" "35: movl %0, %%eax\n" " shrl $2, %0\n" " andl $3, %%eax\n" " cld\n" "99: rep; movsl\n" "36: movl %%eax, %0\n" "37: rep; movsb\n" "100:\n" ".section .fixup,\"ax\"\n" "101: lea 0(%%eax,%0,4),%0\n" " jmp 100b\n" ".previous\n" ".section __ex_table,\"a\"\n" " .align 4\n" " .long 1b,100b\n" " .long 2b,100b\n" " .long 3b,100b\n" " .long 4b,100b\n" " .long 5b,100b\n" " .long 6b,100b\n" " .long 7b,100b\n" " .long 8b,100b\n" " .long 9b,100b\n" " .long 10b,100b\n" " .long 11b,100b\n" " .long 12b,100b\n" " .long 13b,100b\n" " .long 14b,100b\n" " .long 15b,100b\n" " .long 16b,100b\n" " .long 17b,100b\n" " .long 18b,100b\n" " .long 19b,100b\n" " .long 20b,100b\n" " .long 21b,100b\n" " .long 22b,100b\n" " .long 23b,100b\n" " .long 24b,100b\n" " .long 25b,100b\n" " .long 26b,100b\n" " .long 27b,100b\n" " .long 28b,100b\n" " .long 29b,100b\n" " .long 30b,100b\n" " .long 31b,100b\n" " .long 32b,100b\n" " .long 33b,100b\n" " .long 34b,100b\n" " .long 35b,100b\n" " .long 36b,100b\n" " .long 37b,100b\n" " .long 99b,101b\n" ".previous" : "=&c"(size), "=&D" (d0), "=&S" (d1) : "1"(to), "2"(from), "0"(size) : "eax", "edx", "memory"); return size; } static unsigned long __copy_user_zeroing_intel(void *to, const void __user *from, unsigned long size) { int d0, d1; __asm__ __volatile__( " .align 2,0x90\n" "0: movl 32(%4), %%eax\n" " cmpl $67, %0\n" " jbe 2f\n" "1: movl 64(%4), %%eax\n" " .align 2,0x90\n" "2: movl 0(%4), %%eax\n" "21: movl 4(%4), %%edx\n" " movl %%eax, 0(%3)\n" " movl %%edx, 4(%3)\n" "3: movl 8(%4), %%eax\n" "31: movl 12(%4),%%edx\n" " movl %%eax, 8(%3)\n" " movl %%edx, 12(%3)\n" "4: movl 16(%4), %%eax\n" "41: movl 20(%4), %%edx\n" " movl %%eax, 16(%3)\n" " movl %%edx, 20(%3)\n" "10: movl 24(%4), %%eax\n" "51: movl 28(%4), %%edx\n" " movl %%eax, 24(%3)\n" " movl %%edx, 28(%3)\n" "11: movl 32(%4), %%eax\n" "61: movl 36(%4), %%edx\n" " movl %%eax, 32(%3)\n" " movl %%edx, 36(%3)\n" "12: movl 40(%4), %%eax\n" "71: movl 44(%4), %%edx\n" " movl %%eax, 40(%3)\n" " movl %%edx, 44(%3)\n" "13: movl 48(%4), %%eax\n" "81: movl 52(%4), %%edx\n" " movl %%eax, 48(%3)\n" " movl %%edx, 52(%3)\n" "14: movl 56(%4), %%eax\n" "91: movl 60(%4), %%edx\n" " movl %%eax, 56(%3)\n" " movl %%edx, 60(%3)\n" " addl $-64, %0\n" " addl $64, %4\n" " addl $64, %3\n" " cmpl $63, %0\n" " ja 0b\n" "5: movl %0, %%eax\n" " shrl $2, %0\n" " andl $3, %%eax\n" " cld\n" "6: rep; movsl\n" " movl %%eax,%0\n" "7: rep; movsb\n" "8:\n" ".section .fixup,\"ax\"\n" "9: lea 0(%%eax,%0,4),%0\n" "16: pushl %0\n" " pushl %%eax\n" " xorl %%eax,%%eax\n" " rep; stosb\n" " popl %%eax\n" " popl %0\n" " jmp 8b\n" ".previous\n" ".section __ex_table,\"a\"\n" " .align 4\n" " .long 0b,16b\n" " .long 1b,16b\n" " .long 2b,16b\n" " .long 21b,16b\n" " .long 3b,16b\n" " .long 31b,16b\n" " .long 4b,16b\n" " .long 41b,16b\n" " .long 10b,16b\n" " .long 51b,16b\n" " .long 11b,16b\n" " .long 61b,16b\n" " .long 12b,16b\n" " .long 71b,16b\n" " .long 13b,16b\n" " .long 81b,16b\n" " .long 14b,16b\n" " .long 91b,16b\n" " .long 6b,9b\n" " .long 7b,16b\n" ".previous" : "=&c"(size), "=&D" (d0), "=&S" (d1) : "1"(to), "2"(from), "0"(size) : "eax", "edx", "memory"); return size; } /* * Non Temporal Hint version of __copy_user_zeroing_intel. It is cache aware. * hyoshiok@miraclelinux.com */ static unsigned long __copy_user_zeroing_intel_nocache(void *to, const void __user *from, unsigned long size) { int d0, d1; __asm__ __volatile__( " .align 2,0x90\n" "0: movl 32(%4), %%eax\n" " cmpl $67, %0\n" " jbe 2f\n" "1: movl 64(%4), %%eax\n" " .align 2,0x90\n" "2: movl 0(%4), %%eax\n" "21: movl 4(%4), %%edx\n" " movnti %%eax, 0(%3)\n" " movnti %%edx, 4(%3)\n" "3: movl 8(%4), %%eax\n" "31: movl 12(%4),%%edx\n" " movnti %%eax, 8(%3)\n" " movnti %%edx, 12(%3)\n" "4: movl 16(%4), %%eax\n" "41: movl 20(%4), %%edx\n" " movnti %%eax, 16(%3)\n" " movnti %%edx, 20(%3)\n" "10: movl 24(%4), %%eax\n" "51: movl 28(%4), %%edx\n" " movnti %%eax, 24(%3)\n" " movnti %%edx, 28(%3)\n" "11: movl 32(%4), %%eax\n" "61: movl 36(%4), %%edx\n" " movnti %%eax, 32(%3)\n" " movnti %%edx, 36(%3)\n" "12: movl 40(%4), %%eax\n" "71: movl 44(%4), %%edx\n" " movnti %%eax, 40(%3)\n" " movnti %%edx, 44(%3)\n" "13: movl 48(%4), %%eax\n" "81: movl 52(%4), %%edx\n" " movnti %%eax, 48(%3)\n" " movnti %%edx, 52(%3)\n" "14: movl 56(%4), %%eax\n" "91: movl 60(%4), %%edx\n" " movnti %%eax, 56(%3)\n" " movnti %%edx, 60(%3)\n" " addl $-64, %0\n" " addl $64, %4\n" " addl $64, %3\n" " cmpl $63, %0\n" " ja 0b\n" " sfence \n" "5: movl %0, %%eax\n" " shrl $2, %0\n" " andl $3, %%eax\n" " cld\n" "6: rep; movsl\n" " movl %%eax,%0\n" "7: rep; movsb\n" "8:\n" ".section .fixup,\"ax\"\n" "9: lea 0(%%eax,%0,4),%0\n" "16: pushl %0\n" " pushl %%eax\n" " xorl %%eax,%%eax\n" " rep; stosb\n" " popl %%eax\n" " popl %0\n" " jmp 8b\n" ".previous\n" ".section __ex_table,\"a\"\n" " .align 4\n" " .long 0b,16b\n" " .long 1b,16b\n" " .long 2b,16b\n" " .long 21b,16b\n" " .long 3b,16b\n" " .long 31b,16b\n" " .long 4b,16b\n" " .long 41b,16b\n" " .long 10b,16b\n" " .long 51b,16b\n" " .long 11b,16b\n" " .long 61b,16b\n" " .long 12b,16b\n" " .long 71b,16b\n" " .long 13b,16b\n" " .long 81b,16b\n" " .long 14b,16b\n" " .long 91b,16b\n" " .long 6b,9b\n" " .long 7b,16b\n" ".previous" : "=&c"(size), "=&D" (d0), "=&S" (d1) : "1"(to), "2"(from), "0"(size) : "eax", "edx", "memory"); return size; } static unsigned long __copy_user_intel_nocache(void *to, const void __user *from, unsigned long size) { int d0, d1; __asm__ __volatile__( " .align 2,0x90\n" "0: movl 32(%4), %%eax\n" " cmpl $67, %0\n" " jbe 2f\n" "1: movl 64(%4), %%eax\n" " .align 2,0x90\n" "2: movl 0(%4), %%eax\n" "21: movl 4(%4), %%edx\n" " movnti %%eax, 0(%3)\n" " movnti %%edx, 4(%3)\n" "3: movl 8(%4), %%eax\n" "31: movl 12(%4),%%edx\n" " movnti %%eax, 8(%3)\n" " movnti %%edx, 12(%3)\n" "4: movl 16(%4), %%eax\n" "41: movl 20(%4), %%edx\n" " movnti %%eax, 16(%3)\n" " movnti %%edx, 20(%3)\n" "10: movl 24(%4), %%eax\n" "51: movl 28(%4), %%edx\n" " movnti %%eax, 24(%3)\n" " movnti %%edx, 28(%3)\n" "11: movl 32(%4), %%eax\n" "61: movl 36(%4), %%edx\n" " movnti %%eax, 32(%3)\n" " movnti %%edx, 36(%3)\n" "12: movl 40(%4), %%eax\n" "71: movl 44(%4), %%edx\n" " movnti %%eax, 40(%3)\n" " movnti %%edx, 44(%3)\n" "13: movl 48(%4), %%eax\n" "81: movl 52(%4), %%edx\n" " movnti %%eax, 48(%3)\n" " movnti %%edx, 52(%3)\n" "14: movl 56(%4), %%eax\n" "91: movl 60(%4), %%edx\n" " movnti %%eax, 56(%3)\n" " movnti %%edx, 60(%3)\n" " addl $-64, %0\n" " addl $64, %4\n" " addl $64, %3\n" " cmpl $63, %0\n" " ja 0b\n" " sfence \n" "5: movl %0, %%eax\n" " shrl $2, %0\n" " andl $3, %%eax\n" " cld\n" "6: rep; movsl\n" " movl %%eax,%0\n" "7: rep; movsb\n" "8:\n" ".section .fixup,\"ax\"\n" "9: lea 0(%%eax,%0,4),%0\n" "16: jmp 8b\n" ".previous\n" ".section __ex_table,\"a\"\n" " .align 4\n" " .long 0b,16b\n" " .long 1b,16b\n" " .long 2b,16b\n" " .long 21b,16b\n" " .long 3b,16b\n" " .long 31b,16b\n" " .long 4b,16b\n" " .long 41b,16b\n" " .long 10b,16b\n" " .long 51b,16b\n" " .long 11b,16b\n" " .long 61b,16b\n" " .long 12b,16b\n" " .long 71b,16b\n" " .long 13b,16b\n" " .long 81b,16b\n" " .long 14b,16b\n" " .long 91b,16b\n" " .long 6b,9b\n" " .long 7b,16b\n" ".previous" : "=&c"(size), "=&D" (d0), "=&S" (d1) : "1"(to), "2"(from), "0"(size) : "eax", "edx", "memory"); return size; } #else /* * Leave these declared but undefined. They should not be any references to * them */ unsigned long __copy_user_zeroing_intel(void *to, const void __user *from, unsigned long size); unsigned long __copy_user_intel(void __user *to, const void *from, unsigned long size); unsigned long __copy_user_zeroing_intel_nocache(void *to, const void __user *from, unsigned long size); #endif /* CONFIG_X86_INTEL_USERCOPY */ /* Generic arbitrary sized copy. */ #define __copy_user(to,from,size) \ do { \ int __d0, __d1, __d2; \ __asm__ __volatile__( \ " cmp $7,%0\n" \ " jbe 1f\n" \ " movl %1,%0\n" \ " negl %0\n" \ " andl $7,%0\n" \ " subl %0,%3\n" \ "4: rep; movsb\n" \ " movl %3,%0\n" \ " shrl $2,%0\n" \ " andl $3,%3\n" \ " .align 2,0x90\n" \ "0: rep; movsl\n" \ " movl %3,%0\n" \ "1: rep; movsb\n" \ "2:\n" \ ".section .fixup,\"ax\"\n" \ "5: addl %3,%0\n" \ " jmp 2b\n" \ "3: lea 0(%3,%0,4),%0\n" \ " jmp 2b\n" \ ".previous\n" \ ".section __ex_table,\"a\"\n" \ " .align 4\n" \ " .long 4b,5b\n" \ " .long 0b,3b\n" \ " .long 1b,2b\n" \ ".previous" \ : "=&c"(size), "=&D" (__d0), "=&S" (__d1), "=r"(__d2) \ : "3"(size), "0"(size), "1"(to), "2"(from) \ : "memory"); \ } while (0) #define __copy_user_zeroing(to,from,size) \ do { \ int __d0, __d1, __d2; \ __asm__ __volatile__( \ " cmp $7,%0\n" \ " jbe 1f\n" \ " movl %1,%0\n" \ " negl %0\n" \ " andl $7,%0\n" \ " subl %0,%3\n" \ "4: rep; movsb\n" \ " movl %3,%0\n" \ " shrl $2,%0\n" \ " andl $3,%3\n" \ " .align 2,0x90\n" \ "0: rep; movsl\n" \ " movl %3,%0\n" \ "1: rep; movsb\n" \ "2:\n" \ ".section .fixup,\"ax\"\n" \ "5: addl %3,%0\n" \ " jmp 6f\n" \ "3: lea 0(%3,%0,4),%0\n" \ "6: pushl %0\n" \ " pushl %%eax\n" \ " xorl %%eax,%%eax\n" \ " rep; stosb\n" \ " popl %%eax\n" \ " popl %0\n" \ " jmp 2b\n" \ ".previous\n" \ ".section __ex_table,\"a\"\n" \ " .align 4\n" \ " .long 4b,5b\n" \ " .long 0b,3b\n" \ " .long 1b,6b\n" \ ".previous" \ : "=&c"(size), "=&D" (__d0), "=&S" (__d1), "=r"(__d2) \ : "3"(size), "0"(size), "1"(to), "2"(from) \ : "memory"); \ } while (0) unsigned long __copy_to_user_ll(void __user *to, const void *from, unsigned long n) { #ifndef CONFIG_X86_WP_WORKS_OK if (unlikely(boot_cpu_data.wp_works_ok == 0) && ((unsigned long )to) < TASK_SIZE) { /* * When we are in an atomic section (see * mm/filemap.c:file_read_actor), return the full * length to take the slow path. */ if (in_atomic()) return n; /* * CPU does not honor the WP bit when writing * from supervisory mode, and due to preemption or SMP, * the page tables can change at any time. * Do it manually. Manfred <manfred@colorfullife.com> */ while (n) { unsigned long offset = ((unsigned long)to)%PAGE_SIZE; unsigned long len = PAGE_SIZE - offset; int retval; struct page *pg; void *maddr; if (len > n) len = n; survive: down_read(¤t->mm->mmap_sem); retval = get_user_pages(current, current->mm, (unsigned long )to, 1, 1, 0, &pg, NULL); if (retval == -ENOMEM && is_init(current)) { up_read(¤t->mm->mmap_sem); congestion_wait(WRITE, HZ/50); goto survive; } if (retval != 1) { up_read(¤t->mm->mmap_sem); break; } maddr = kmap_atomic(pg, KM_USER0); memcpy(maddr + offset, from, len); kunmap_atomic(maddr, KM_USER0); set_page_dirty_lock(pg); put_page(pg); up_read(¤t->mm->mmap_sem); from += len; to += len; n -= len; } return n; } #endif if (movsl_is_ok(to, from, n)) __copy_user(to, from, n); else n = __copy_user_intel(to, from, n); return n; } EXPORT_SYMBOL(__copy_to_user_ll); unsigned long __copy_from_user_ll(void *to, const void __user *from, unsigned long n) { if (movsl_is_ok(to, from, n)) __copy_user_zeroing(to, from, n); else n = __copy_user_zeroing_intel(to, from, n); return n; } EXPORT_SYMBOL(__copy_from_user_ll); unsigned long __copy_from_user_ll_nozero(void *to, const void __user *from, unsigned long n) { if (movsl_is_ok(to, from, n)) __copy_user(to, from, n); else n = __copy_user_intel((void __user *)to, (const void *)from, n); return n; } EXPORT_SYMBOL(__copy_from_user_ll_nozero); unsigned long __copy_from_user_ll_nocache(void *to, const void __user *from, unsigned long n) { #ifdef CONFIG_X86_INTEL_USERCOPY if ( n > 64 && cpu_has_xmm2) n = __copy_user_zeroing_intel_nocache(to, from, n); else __copy_user_zeroing(to, from, n); #else __copy_user_zeroing(to, from, n); #endif return n; } unsigned long __copy_from_user_ll_nocache_nozero(void *to, const void __user *from, unsigned long n) { #ifdef CONFIG_X86_INTEL_USERCOPY if ( n > 64 && cpu_has_xmm2) n = __copy_user_intel_nocache(to, from, n); else __copy_user(to, from, n); #else __copy_user(to, from, n); #endif return n; } /** * copy_to_user: - Copy a block of data into user space. * @to: Destination address, in user space. * @from: Source address, in kernel space. * @n: Number of bytes to copy. * * Context: User context only. This function may sleep. * * Copy data from kernel space to user space. * * Returns number of bytes that could not be copied. * On success, this will be zero. */ unsigned long copy_to_user(void __user *to, const void *from, unsigned long n) { if (access_ok(VERIFY_WRITE, to, n)) n = __copy_to_user(to, from, n); return n; } EXPORT_SYMBOL(copy_to_user); /** * copy_from_user: - Copy a block of data from user space. * @to: Destination address, in kernel space. * @from: Source address, in user space. * @n: Number of bytes to copy. * * Context: User context only. This function may sleep. * * Copy data from user space to kernel space. * * Returns number of bytes that could not be copied. * On success, this will be zero. * * If some data could not be copied, this function will pad the copied * data to the requested size using zero bytes. */ unsigned long copy_from_user(void *to, const void __user *from, unsigned long n) { if (access_ok(VERIFY_READ, from, n)) n = __copy_from_user(to, from, n); else memset(to, 0, n); return n; } EXPORT_SYMBOL(copy_from_user);