powerpc: merge uaccess.h

There is still a bug to be fixed and more merging to be done.

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>

1 files changed, 504 insertions, 0 deletions

diff --git a/include/asm-powerpc/uaccess.h b/include/asm-powerpc/uaccess.h
new file mode 100644
index 00000000000..2ecc3e16e49
--- /dev/null
+++ b/include/asm-powerpc/uaccess.h
@@ -0,0 +1,504 @@
+#ifndef _ARCH_POWERPC_UACCESS_H
+#define _ARCH_POWERPC_UACCESS_H
+
+#ifdef __KERNEL__
+#ifndef __ASSEMBLY__
+
+#include <linux/sched.h>
+#include <linux/errno.h>
+#include <asm/processor.h>
+
+#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.
+ *
+ * The fs/ds values are now the highest legal address in the "segment".
+ * This simplifies the checking in the routines below.
+ */
+
+#define MAKE_MM_SEG(s)  ((mm_segment_t) { (s) })
+
+#ifdef __powerpc64__
+#define KERNEL_DS	MAKE_MM_SEG(0UL)
+#define USER_DS		MAKE_MM_SEG(0xf000000000000000UL)
+#else
+#define KERNEL_DS	MAKE_MM_SEG(~0UL)
+#define USER_DS		MAKE_MM_SEG(TASK_SIZE - 1)
+#endif
+
+#define get_ds()	(KERNEL_DS)
+#define get_fs()	(current->thread.fs)
+#define set_fs(val)	(current->thread.fs = (val))
+
+#define segment_eq(a, b)	((a).seg == (b).seg)
+
+#ifdef __powerpc64__
+/*
+ * Use the alpha trick for checking ranges:
+ *
+ * Is a address valid? This does a straightforward calculation rather
+ * than tests.
+ *
+ * Address valid if:
+ *  - "addr" doesn't have any high-bits set
+ *  - AND "size" doesn't have any high-bits set
+ *  - OR we are in kernel mode.
+ *
+ * We dont have to check for high bits in (addr+size) because the first
+ * two checks force the maximum result to be below the start of the
+ * kernel region.
+ */
+#define __access_ok(addr, size, segment)	\
+	(((segment).seg & (addr | size )) == 0)
+
+#else
+
+#define __access_ok(addr, size, segment)	\
+	(((addr) <= (segment).seg) &&		\
+	 (((size) == 0) || (((size) - 1) <= ((segment).seg - (addr)))))
+
+#endif
+
+#define access_ok(type, addr, size)		\
+	(__chk_user_ptr(addr),			\
+	 __access_ok((__force unsigned long)(addr), (size), get_fs()))
+
+/*
+ * 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;
+	unsigned long fixup;
+};
+
+/*
+ * 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).
+ *
+ * As we use the same address space for kernel and user data on the
+ * PowerPC, we can just do these as direct assignments.  (Of course, the
+ * exception handling means that it's no longer "just"...)
+ *
+ * The "user64" versions of the user access functions are versions that
+ * allow access of 64-bit data. The "get_user" functions do not
+ * properly handle 64-bit data because the value gets down cast to a long.
+ * The "put_user" functions already handle 64-bit data properly but we add
+ * "user64" versions for completeness
+ */
+#define get_user(x, ptr) \
+	__get_user_check((x), (ptr), sizeof(*(ptr)))
+#define put_user(x, ptr) \
+	__put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
+
+#define __get_user(x, ptr) \
+	__get_user_nocheck((x), (ptr), sizeof(*(ptr)))
+#define __put_user(x, ptr) \
+	__put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
+#ifndef __powerpc64__
+#define __get_user64(x, ptr) \
+	__get_user64_nocheck((x), (ptr), sizeof(*(ptr)))
+#define __put_user64(x, ptr) __put_user(x, ptr)
+#endif
+
+#ifdef __powerpc64__
+#define __get_user_unaligned __get_user
+#define __put_user_unaligned __put_user
+#endif
+
+extern long __put_user_bad(void);
+
+#ifdef __powerpc64__
+#define __EX_TABLE_ALIGN	"3"
+#define __EX_TABLE_TYPE		"llong"
+#else
+#define __EX_TABLE_ALIGN	"2"
+#define __EX_TABLE_TYPE		"long"
+#endif
+
+/*
+ * We don't tell gcc that we are accessing memory, but this is OK
+ * because we do not write to any memory gcc knows about, so there
+ * are no aliasing issues.
+ */
+#define __put_user_asm(x, addr, err, op)			\
+	__asm__ __volatile__(					\
+		"1:	" op " %1,0(%2)	# put_user\n"		\
+		"2:\n"						\
+		".section .fixup,\"ax\"\n"			\
+		"3:	li %0,%3\n"				\
+		"	b 2b\n"					\
+		".previous\n"					\
+		".section __ex_table,\"a\"\n"			\
+		"	.align " __EX_TABLE_ALIGN "\n"		\
+		"	."__EX_TABLE_TYPE" 1b,3b\n"		\
+		".previous"					\
+		: "=r" (err)					\
+		: "r" (x), "b" (addr), "i" (-EFAULT), "0" (err))
+
+#ifndef __powerpc64__
+#define __put_user_asm2(x, addr, err)				\
+	__asm__ __volatile__(					\
+		"1:	stw %1,0(%2)\n"				\
+		"2:	stw %1+1,4(%2)\n"			\
+		"3:\n"						\
+		".section .fixup,\"ax\"\n"			\
+		"4:	li %0,%3\n"				\
+		"	b 3b\n"					\
+		".previous\n"					\
+		".section __ex_table,\"a\"\n"			\
+		"	.align " __EX_TABLE_ALIGN "\n"		\
+		"	." __EX_TABLE_TYPE " 1b,4b\n"		\
+		"	." __EX_TABLE_TYPE " 2b,4b\n"		\
+		".previous"					\
+		: "=r" (err)					\
+		: "r" (x), "b" (addr), "i" (-EFAULT), "0" (err))
+#else /* __powerpc64__ */
+#define __put_user_asm2(x, ptr, retval)				\
+	  __put_user_asm(x, ptr, retval, "std")
+#endif /* __powerpc64__ */
+
+#define __put_user_size(x, ptr, size, retval)			\
+do {								\
+	retval = 0;						\
+	switch (size) {						\
+	  case 1: __put_user_asm(x, ptr, retval, "stb"); break;	\
+	  case 2: __put_user_asm(x, ptr, retval, "sth"); break;	\
+	  case 4: __put_user_asm(x, ptr, retval, "stw"); break;	\
+	  case 8: __put_user_asm2(x, ptr, retval); break;	\
+	  default: __put_user_bad();				\
+	}							\
+} while (0)
+
+#define __put_user_nocheck(x, ptr, size)			\
+({								\
+	long __pu_err;						\
+	might_sleep();						\
+	__chk_user_ptr(ptr);					\
+	__put_user_size((x), (ptr), (size), __pu_err);		\
+	__pu_err;						\
+})
+
+#define __put_user_check(x, ptr, size)					\
+({									\
+	long __pu_err = -EFAULT;					\
+	__typeof__(*(ptr)) __user *__pu_addr = (ptr);			\
+	might_sleep();							\
+	if (access_ok(VERIFY_WRITE, __pu_addr, size))			\
+		__put_user_size((x), __pu_addr, (size), __pu_err);	\
+	__pu_err;							\
+})
+
+extern long __get_user_bad(void);
+
+#define __get_user_asm(x, addr, err, op)		\
+	__asm__ __volatile__(				\
+		"1:	"op" %1,0(%2)	# get_user\n"  	\
+		"2:\n"					\
+		".section .fixup,\"ax\"\n"		\
+		"3:	li %0,%3\n"			\
+		"	li %1,0\n"			\
+		"	b 2b\n"				\
+		".previous\n"				\
+		".section __ex_table,\"a\"\n"		\
+		"	.align "__EX_TABLE_ALIGN "\n"	\
+		"	." __EX_TABLE_TYPE " 1b,3b\n"	\
+		".previous"				\
+		: "=r" (err), "=r" (x)			\
+		: "b" (addr), "i" (-EFAULT), "0" (err))
+
+#ifndef __powerpc64__
+#define __get_user_asm2(x, addr, err)	 		\
+	__asm__ __volatile__(				\
+		"1:	lwz %1,0(%2)\n"			\
+		"2:	lwz %1+1,4(%2)\n"		\
+		"3:\n"					\
+		".section .fixup,\"ax\"\n"		\
+		"4:	li %0,%3\n"			\
+		"	li %1,0\n"			\
+		"	li %1+1,0\n"			\
+		"	b 3b\n"				\
+		".previous\n"				\
+		".section __ex_table,\"a\"\n"		\
+		"	.align " __EX_TABLE_ALIGN "\n"	\
+		"	." __EX_TABLE_TYPE " 1b,4b\n"	\
+		"	." __EX_TABLE_TYPE " 2b,4b\n"	\
+		".previous"				\
+		: "=r" (err), "=&r" (x)			\
+		: "b" (addr), "i" (-EFAULT), "0" (err))
+#else
+#define __get_user_asm2(x, addr, err)	 		\
+	__get_user_asm(x, addr, err, "ld")
+#endif /* __powerpc64__ */
+
+#define __get_user_size(x, ptr, size, retval)			\
+do {								\
+	retval = 0;						\
+	__chk_user_ptr(ptr);					\
+ 	if (size > sizeof(x))					\
+ 		(x) = __get_user_bad();				\
+	switch (size) {						\
+	case 1: __get_user_asm(x, ptr, retval, "lbz"); break;	\
+	case 2: __get_user_asm(x, ptr, retval, "lhz"); break;	\
+	case 4: __get_user_asm(x, ptr, retval, "lwz"); break;	\
+	case 8: __get_user_asm2(x, ptr, retval);  break;	\
+	default: (x) = __get_user_bad();			\
+	}							\
+} while (0)
+
+#define __get_user_nocheck(x, ptr, size)			\
+({								\
+	long __gu_err;						\
+	unsigned long __gu_val;					\
+	__chk_user_ptr(ptr);					\
+	might_sleep();						\
+	__get_user_size(__gu_val, (ptr), (size), __gu_err);	\
+	(x) = (__typeof__(*(ptr)))__gu_val;			\
+	__gu_err;						\
+})
+
+#ifndef __powerpc64__
+#define __get_user64_nocheck(x, ptr, size)			\
+({								\
+	long __gu_err;						\
+	long long __gu_val;					\
+	__chk_user_ptr(ptr);					\
+	might_sleep();						\
+	__get_user_size(__gu_val, (ptr), (size), __gu_err);	\
+	(x) = (__typeof__(*(ptr)))__gu_val;			\
+	__gu_err;						\
+})
+#endif /* __powerpc64__ */
+
+#define __get_user_check(x, ptr, size)					\
+({									\
+	long __gu_err = -EFAULT;					\
+	unsigned long  __gu_val = 0;					\
+	const __typeof__(*(ptr)) __user *__gu_addr = (ptr);		\
+ 	might_sleep();							\
+	if (access_ok(VERIFY_READ, __gu_addr, (size)))			\
+		__get_user_size(__gu_val, __gu_addr, (size), __gu_err);	\
+	(x) = (__typeof__(*(ptr)))__gu_val;				\
+	__gu_err;							\
+})
+
+/* more complex routines */
+
+extern unsigned long __copy_tofrom_user(void __user *to,
+		const void __user *from, unsigned long size);
+
+#ifndef __powerpc64__
+extern inline unsigned long
+copy_from_user(void *to, const void __user *from, unsigned long n)
+{
+	unsigned long over;
+
+	if (access_ok(VERIFY_READ, from, n))
+		return __copy_tofrom_user((__force void __user *)to, from, n);
+	if ((unsigned long)from < TASK_SIZE) {
+		over = (unsigned long)from + n - TASK_SIZE;
+		return __copy_tofrom_user((__force void __user *)to, from,
+				n - over) + over;
+	}
+	return n;
+}
+
+extern inline unsigned long
+copy_to_user(void __user *to, const void *from, unsigned long n)
+{
+	unsigned long over;
+
+	if (access_ok(VERIFY_WRITE, to, n))
+		return __copy_tofrom_user(to, (__force void __user *)from, n);
+	if ((unsigned long)to < TASK_SIZE) {
+		over = (unsigned long)to + n - TASK_SIZE;
+		return __copy_tofrom_user(to, (__force void __user *)from,
+				n - over) + over;
+	}
+	return n;
+}
+
+#else /* __powerpc64__ */
+
+static inline unsigned long
+__copy_from_user_inatomic(void *to, const void __user *from, unsigned long n)
+{
+	if (__builtin_constant_p(n) && (n <= 8)) {
+		unsigned long ret;
+
+		switch (n) {
+		case 1:
+			__get_user_size(*(u8 *)to, from, 1, ret);
+			break;
+		case 2:
+			__get_user_size(*(u16 *)to, from, 2, ret);
+			break;
+		case 4:
+			__get_user_size(*(u32 *)to, from, 4, ret);
+			break;
+		case 8:
+			__get_user_size(*(u64 *)to, from, 8, ret);
+			break;
+		}
+		return (ret == -EFAULT) ? n : 0;
+	}
+	return __copy_tofrom_user((__force void __user *) to, from, n);
+}
+
+static inline unsigned long
+__copy_to_user_inatomic(void __user *to, const void *from, unsigned long n)
+{
+	if (__builtin_constant_p(n) && (n <= 8)) {
+		unsigned long ret;
+
+		switch (n) {
+		case 1:
+			__put_user_size(*(u8 *)from, (u8 __user *)to, 1, ret);
+			break;
+		case 2:
+			__put_user_size(*(u16 *)from, (u16 __user *)to, 2, ret);
+			break;
+		case 4:
+			__put_user_size(*(u32 *)from, (u32 __user *)to, 4, ret);
+			break;
+		case 8:
+			__put_user_size(*(u64 *)from, (u64 __user *)to, 8, ret);
+			break;
+		}
+		return (ret == -EFAULT) ? n : 0;
+	}
+	return __copy_tofrom_user(to, (__force const void __user *) from, n);
+}
+
+#endif /* __powerpc64__ */
+
+static inline unsigned long
+__copy_from_user(void *to, const void __user *from, unsigned long size)
+{
+	might_sleep();
+#ifndef __powerpc64__
+	return __copy_tofrom_user((__force void __user *)to, from, size);
+#else /* __powerpc64__ */
+	return __copy_from_user_inatomic(to, from, size);
+#endif /* __powerpc64__ */
+}
+
+static inline unsigned long
+__copy_to_user(void __user *to, const void *from, unsigned long size)
+{
+	might_sleep();
+#ifndef __powerpc64__
+	return __copy_tofrom_user(to, (__force void __user *)from, size);
+#else /* __powerpc64__ */
+	return __copy_to_user_inatomic(to, from, size);
+#endif /* __powerpc64__ */
+}
+
+#ifndef __powerpc64__
+#define __copy_to_user_inatomic __copy_to_user
+#define __copy_from_user_inatomic __copy_from_user
+#else /* __powerpc64__ */
+#define __copy_in_user(to, from, size) \
+	__copy_tofrom_user((to), (from), (size))
+
+extern unsigned long copy_from_user(void *to, const void __user *from,
+				    unsigned long n);
+extern unsigned long copy_to_user(void __user *to, const void *from,
+				  unsigned long n);
+extern unsigned long copy_in_user(void __user *to, const void __user *from,
+				  unsigned long n);
+#endif /* __powerpc64__ */
+
+extern unsigned long __clear_user(void __user *addr, unsigned long size);
+
+static inline unsigned long clear_user(void __user *addr, unsigned long size)
+{
+	might_sleep();
+	if (likely(access_ok(VERIFY_WRITE, addr, size)))
+		return __clear_user(addr, size);
+#ifndef __powerpc64__
+	if ((unsigned long)addr < TASK_SIZE) {
+		unsigned long over = (unsigned long)addr + size - TASK_SIZE;
+		return __clear_user(addr, size - over) + over;
+	}
+#endif /* __powerpc64__ */
+	return size;
+}
+
+extern int __strncpy_from_user(char *dst, const char __user *src, long count);
+
+static inline long strncpy_from_user(char *dst, const char __user *src,
+		long count)
+{
+	might_sleep();
+	if (likely(access_ok(VERIFY_READ, src, 1)))
+		return __strncpy_from_user(dst, src, count);
+	return -EFAULT;
+}
+
+/*
+ * Return the size of a string (including the ending 0)
+ *
+ * Return 0 for error
+ */
+#ifndef __powerpc64__
+extern int __strnlen_user(const char __user *str, long len, unsigned long top);
+#else /* __powerpc64__ */
+extern int __strnlen_user(const char __user *str, long len);
+#endif /* __powerpc64__ */
+
+/*
+ * Returns the length of the string at str (including the null byte),
+ * or 0 if we hit a page we can't access,
+ * or something > len if we didn't find a null byte.
+ *
+ * The `top' parameter to __strnlen_user is to make sure that
+ * we can never overflow from the user area into kernel space.
+ */
+static inline int strnlen_user(const char __user *str, long len)
+{
+#ifndef __powerpc64__
+	unsigned long top = current->thread.fs.seg;
+
+	if ((unsigned long)str > top)
+		return 0;
+	return __strnlen_user(str, len, top);
+#else /* __powerpc64__ */
+	might_sleep();
+	if (likely(access_ok(VERIFY_READ, str, 1)))
+		return __strnlen_user(str, len);
+	return 0;
+#endif /* __powerpc64__ */
+}
+
+#define strlen_user(str)	strnlen_user((str), 0x7ffffffe)
+
+#endif  /* __ASSEMBLY__ */
+#endif /* __KERNEL__ */
+
+#endif	/* _ARCH_POWERPC_UACCESS_H */