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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/i386/lib/usercopy.c
downloadconfigs-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'arch/i386/lib/usercopy.c')
-rw-r--r--arch/i386/lib/usercopy.c636
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 00000000000..51aa2bbb026
--- /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(&current->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(&current->mm->mmap_sem);
+ blk_congestion_wait(WRITE, HZ/50);
+ goto survive;
+ }
+
+ if (retval != 1) {
+ up_read(&current->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(&current->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);