diff options
Diffstat (limited to 'arch/i386/lib/usercopy.c')
| -rw-r--r-- | arch/i386/lib/usercopy.c | 636 |
1 files changed, 636 insertions, 0 deletions
diff --git a/arch/i386/lib/usercopy.c b/arch/i386/lib/usercopy.c new file mode 100644 index 0000000..51aa2bb --- /dev/null +++ b/arch/i386/lib/usercopy.c @@ -0,0 +1,636 @@ +/* + * 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/config.h> +#include <linux/mm.h> +#include <linux/highmem.h> +#include <linux/blkdev.h> +#include <linux/module.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; +} + +/** + * 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; +} + + +/* + * 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; +} + +/** + * __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; +} + +/** + * strlen_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; +} + +#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; +} +#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); +#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) +{ + BUG_ON((long) n < 0); +#ifndef CONFIG_X86_WP_WORKS_OK + if (unlikely(boot_cpu_data.wp_works_ok == 0) && + ((unsigned long )to) < TASK_SIZE) { + /* + * 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 && current->pid == 1) { + up_read(¤t->mm->mmap_sem); + blk_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; +} + +unsigned long +__copy_from_user_ll(void *to, const void __user *from, unsigned long n) +{ + BUG_ON((long)n < 0); + if (movsl_is_ok(to, from, n)) + __copy_user_zeroing(to, from, n); + else + n = __copy_user_zeroing_intel(to, from, n); + 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) +{ + might_sleep(); + BUG_ON((long) n < 0); + 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) +{ + might_sleep(); + BUG_ON((long) n < 0); + 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); |