x86, um: ... and asm-x86 move

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

1 files changed, 454 insertions, 0 deletions

diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
new file mode 100644
index 000000000000..48ebc0ad40ec
--- /dev/null
+++ b/arch/x86/include/asm/uaccess.h
@@ -0,0 +1,454 @@
+#ifndef ASM_X86__UACCESS_H
+#define ASM_X86__UACCESS_H
+/*
+ * User space memory access functions
+ */
+#include <linux/errno.h>
+#include <linux/compiler.h>
+#include <linux/thread_info.h>
+#include <linux/prefetch.h>
+#include <linux/string.h>
+#include <asm/asm.h>
+#include <asm/page.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.
+ */
+
+#define MAKE_MM_SEG(s)	((mm_segment_t) { (s) })
+
+#define KERNEL_DS	MAKE_MM_SEG(-1UL)
+#define USER_DS		MAKE_MM_SEG(PAGE_OFFSET)
+
+#define get_ds()	(KERNEL_DS)
+#define get_fs()	(current_thread_info()->addr_limit)
+#define set_fs(x)	(current_thread_info()->addr_limit = (x))
+
+#define segment_eq(a, b)	((a).seg == (b).seg)
+
+#define __addr_ok(addr)					\
+	((unsigned long __force)(addr) <		\
+	 (current_thread_info()->addr_limit.seg))
+
+/*
+ * Test whether a block of memory is a valid user space address.
+ * Returns 0 if the range is valid, nonzero otherwise.
+ *
+ * This is equivalent to the following test:
+ * (u33)addr + (u33)size >= (u33)current->addr_limit.seg (u65 for x86_64)
+ *
+ * This needs 33-bit (65-bit for x86_64) arithmetic. We have a carry...
+ */
+
+#define __range_not_ok(addr, size)					\
+({									\
+	unsigned long flag, roksum;					\
+	__chk_user_ptr(addr);						\
+	asm("add %3,%1 ; sbb %0,%0 ; cmp %1,%4 ; sbb $0,%0"		\
+	    : "=&r" (flag), "=r" (roksum)				\
+	    : "1" (addr), "g" ((long)(size)),				\
+	      "rm" (current_thread_info()->addr_limit.seg));		\
+	flag;								\
+})
+
+/**
+ * access_ok: - Checks if a user space pointer is valid
+ * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE.  Note that
+ *        %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe
+ *        to write to a block, it is always safe to read from it.
+ * @addr: User space pointer to start of block to check
+ * @size: Size of block to check
+ *
+ * Context: User context only.  This function may sleep.
+ *
+ * Checks if a pointer to a block of memory in user space is valid.
+ *
+ * Returns true (nonzero) if the memory block may be valid, false (zero)
+ * if it is definitely invalid.
+ *
+ * Note that, depending on architecture, this function probably just
+ * checks that the pointer is in the user space range - after calling
+ * this function, memory access functions may still return -EFAULT.
+ */
+#define access_ok(type, addr, size) (likely(__range_not_ok(addr, size) == 0))
+
+/*
+ * 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, fixup;
+};
+
+extern int fixup_exception(struct pt_regs *regs);
+
+/*
+ * 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).
+ */
+
+extern int __get_user_1(void);
+extern int __get_user_2(void);
+extern int __get_user_4(void);
+extern int __get_user_8(void);
+extern int __get_user_bad(void);
+
+#define __get_user_x(size, ret, x, ptr)		      \
+	asm volatile("call __get_user_" #size	      \
+		     : "=a" (ret),"=d" (x)	      \
+		     : "0" (ptr))		      \
+
+/* Careful: we have to cast the result to the type of the pointer
+ * for sign reasons */
+
+/**
+ * get_user: - Get a simple variable from user space.
+ * @x:   Variable to store result.
+ * @ptr: Source address, in user space.
+ *
+ * Context: User context only.  This function may sleep.
+ *
+ * This macro copies a single simple variable from user space to kernel
+ * space.  It supports simple types like char and int, but not larger
+ * data types like structures or arrays.
+ *
+ * @ptr must have pointer-to-simple-variable type, and the result of
+ * dereferencing @ptr must be assignable to @x without a cast.
+ *
+ * Returns zero on success, or -EFAULT on error.
+ * On error, the variable @x is set to zero.
+ */
+#ifdef CONFIG_X86_32
+#define __get_user_8(__ret_gu, __val_gu, ptr)				\
+		__get_user_x(X, __ret_gu, __val_gu, ptr)
+#else
+#define __get_user_8(__ret_gu, __val_gu, ptr)				\
+		__get_user_x(8, __ret_gu, __val_gu, ptr)
+#endif
+
+#define get_user(x, ptr)						\
+({									\
+	int __ret_gu;							\
+	unsigned long __val_gu;						\
+	__chk_user_ptr(ptr);						\
+	switch (sizeof(*(ptr))) {					\
+	case 1:								\
+		__get_user_x(1, __ret_gu, __val_gu, ptr);		\
+		break;							\
+	case 2:								\
+		__get_user_x(2, __ret_gu, __val_gu, ptr);		\
+		break;							\
+	case 4:								\
+		__get_user_x(4, __ret_gu, __val_gu, ptr);		\
+		break;							\
+	case 8:								\
+		__get_user_8(__ret_gu, __val_gu, ptr);			\
+		break;							\
+	default:							\
+		__get_user_x(X, __ret_gu, __val_gu, ptr);		\
+		break;							\
+	}								\
+	(x) = (__typeof__(*(ptr)))__val_gu;				\
+	__ret_gu;							\
+})
+
+#define __put_user_x(size, x, ptr, __ret_pu)			\
+	asm volatile("call __put_user_" #size : "=a" (__ret_pu)	\
+		     :"0" ((typeof(*(ptr)))(x)), "c" (ptr) : "ebx")
+
+
+
+#ifdef CONFIG_X86_32
+#define __put_user_u64(x, addr, err)					\
+	asm volatile("1:	movl %%eax,0(%2)\n"			\
+		     "2:	movl %%edx,4(%2)\n"			\
+		     "3:\n"						\
+		     ".section .fixup,\"ax\"\n"				\
+		     "4:	movl %3,%0\n"				\
+		     "	jmp 3b\n"					\
+		     ".previous\n"					\
+		     _ASM_EXTABLE(1b, 4b)				\
+		     _ASM_EXTABLE(2b, 4b)				\
+		     : "=r" (err)					\
+		     : "A" (x), "r" (addr), "i" (-EFAULT), "0" (err))
+
+#define __put_user_x8(x, ptr, __ret_pu)				\
+	asm volatile("call __put_user_8" : "=a" (__ret_pu)	\
+		     : "A" ((typeof(*(ptr)))(x)), "c" (ptr) : "ebx")
+#else
+#define __put_user_u64(x, ptr, retval) \
+	__put_user_asm(x, ptr, retval, "q", "", "Zr", -EFAULT)
+#define __put_user_x8(x, ptr, __ret_pu) __put_user_x(8, x, ptr, __ret_pu)
+#endif
+
+extern void __put_user_bad(void);
+
+/*
+ * Strange magic calling convention: pointer in %ecx,
+ * value in %eax(:%edx), return value in %eax. clobbers %rbx
+ */
+extern void __put_user_1(void);
+extern void __put_user_2(void);
+extern void __put_user_4(void);
+extern void __put_user_8(void);
+
+#ifdef CONFIG_X86_WP_WORKS_OK
+
+/**
+ * put_user: - Write a simple value into user space.
+ * @x:   Value to copy to user space.
+ * @ptr: Destination address, in user space.
+ *
+ * Context: User context only.  This function may sleep.
+ *
+ * This macro copies a single simple value from kernel space to user
+ * space.  It supports simple types like char and int, but not larger
+ * data types like structures or arrays.
+ *
+ * @ptr must have pointer-to-simple-variable type, and @x must be assignable
+ * to the result of dereferencing @ptr.
+ *
+ * Returns zero on success, or -EFAULT on error.
+ */
+#define put_user(x, ptr)					\
+({								\
+	int __ret_pu;						\
+	__typeof__(*(ptr)) __pu_val;				\
+	__chk_user_ptr(ptr);					\
+	__pu_val = x;						\
+	switch (sizeof(*(ptr))) {				\
+	case 1:							\
+		__put_user_x(1, __pu_val, ptr, __ret_pu);	\
+		break;						\
+	case 2:							\
+		__put_user_x(2, __pu_val, ptr, __ret_pu);	\
+		break;						\
+	case 4:							\
+		__put_user_x(4, __pu_val, ptr, __ret_pu);	\
+		break;						\
+	case 8:							\
+		__put_user_x8(__pu_val, ptr, __ret_pu);		\
+		break;						\
+	default:						\
+		__put_user_x(X, __pu_val, ptr, __ret_pu);	\
+		break;						\
+	}							\
+	__ret_pu;						\
+})
+
+#define __put_user_size(x, ptr, size, retval, errret)			\
+do {									\
+	retval = 0;							\
+	__chk_user_ptr(ptr);						\
+	switch (size) {							\
+	case 1:								\
+		__put_user_asm(x, ptr, retval, "b", "b", "iq", errret);	\
+		break;							\
+	case 2:								\
+		__put_user_asm(x, ptr, retval, "w", "w", "ir", errret);	\
+		break;							\
+	case 4:								\
+		__put_user_asm(x, ptr, retval, "l", "k",  "ir", errret);\
+		break;							\
+	case 8:								\
+		__put_user_u64((__typeof__(*ptr))(x), ptr, retval);	\
+		break;							\
+	default:							\
+		__put_user_bad();					\
+	}								\
+} while (0)
+
+#else
+
+#define __put_user_size(x, ptr, size, retval, errret)			\
+do {									\
+	__typeof__(*(ptr))__pus_tmp = x;				\
+	retval = 0;							\
+									\
+	if (unlikely(__copy_to_user_ll(ptr, &__pus_tmp, size) != 0))	\
+		retval = errret;					\
+} while (0)
+
+#define put_user(x, ptr)					\
+({								\
+	int __ret_pu;						\
+	__typeof__(*(ptr))__pus_tmp = x;			\
+	__ret_pu = 0;						\
+	if (unlikely(__copy_to_user_ll(ptr, &__pus_tmp,		\
+				       sizeof(*(ptr))) != 0))	\
+		__ret_pu = -EFAULT;				\
+	__ret_pu;						\
+})
+#endif
+
+#ifdef CONFIG_X86_32
+#define __get_user_asm_u64(x, ptr, retval, errret)	(x) = __get_user_bad()
+#else
+#define __get_user_asm_u64(x, ptr, retval, errret) \
+	 __get_user_asm(x, ptr, retval, "q", "", "=r", errret)
+#endif
+
+#define __get_user_size(x, ptr, size, retval, errret)			\
+do {									\
+	retval = 0;							\
+	__chk_user_ptr(ptr);						\
+	switch (size) {							\
+	case 1:								\
+		__get_user_asm(x, ptr, retval, "b", "b", "=q", errret);	\
+		break;							\
+	case 2:								\
+		__get_user_asm(x, ptr, retval, "w", "w", "=r", errret);	\
+		break;							\
+	case 4:								\
+		__get_user_asm(x, ptr, retval, "l", "k", "=r", errret);	\
+		break;							\
+	case 8:								\
+		__get_user_asm_u64(x, ptr, retval, errret);		\
+		break;							\
+	default:							\
+		(x) = __get_user_bad();					\
+	}								\
+} while (0)
+
+#define __get_user_asm(x, addr, err, itype, rtype, ltype, errret)	\
+	asm volatile("1:	mov"itype" %2,%"rtype"1\n"		\
+		     "2:\n"						\
+		     ".section .fixup,\"ax\"\n"				\
+		     "3:	mov %3,%0\n"				\
+		     "	xor"itype" %"rtype"1,%"rtype"1\n"		\
+		     "	jmp 2b\n"					\
+		     ".previous\n"					\
+		     _ASM_EXTABLE(1b, 3b)				\
+		     : "=r" (err), ltype(x)				\
+		     : "m" (__m(addr)), "i" (errret), "0" (err))
+
+#define __put_user_nocheck(x, ptr, size)			\
+({								\
+	long __pu_err;						\
+	__put_user_size((x), (ptr), (size), __pu_err, -EFAULT);	\
+	__pu_err;						\
+})
+
+#define __get_user_nocheck(x, ptr, size)				\
+({									\
+	long __gu_err;							\
+	unsigned long __gu_val;						\
+	__get_user_size(__gu_val, (ptr), (size), __gu_err, -EFAULT);	\
+	(x) = (__force __typeof__(*(ptr)))__gu_val;			\
+	__gu_err;							\
+})
+
+/* FIXME: this hack is definitely wrong -AK */
+struct __large_struct { unsigned long buf[100]; };
+#define __m(x) (*(struct __large_struct __user *)(x))
+
+/*
+ * Tell gcc we read from memory instead of writing: this is because
+ * we do not write to any memory gcc knows about, so there are no
+ * aliasing issues.
+ */
+#define __put_user_asm(x, addr, err, itype, rtype, ltype, errret)	\
+	asm volatile("1:	mov"itype" %"rtype"1,%2\n"		\
+		     "2:\n"						\
+		     ".section .fixup,\"ax\"\n"				\
+		     "3:	mov %3,%0\n"				\
+		     "	jmp 2b\n"					\
+		     ".previous\n"					\
+		     _ASM_EXTABLE(1b, 3b)				\
+		     : "=r"(err)					\
+		     : ltype(x), "m" (__m(addr)), "i" (errret), "0" (err))
+/**
+ * __get_user: - Get a simple variable from user space, with less checking.
+ * @x:   Variable to store result.
+ * @ptr: Source address, in user space.
+ *
+ * Context: User context only.  This function may sleep.
+ *
+ * This macro copies a single simple variable from user space to kernel
+ * space.  It supports simple types like char and int, but not larger
+ * data types like structures or arrays.
+ *
+ * @ptr must have pointer-to-simple-variable type, and the result of
+ * dereferencing @ptr must be assignable to @x without a cast.
+ *
+ * Caller must check the pointer with access_ok() before calling this
+ * function.
+ *
+ * Returns zero on success, or -EFAULT on error.
+ * On error, the variable @x is set to zero.
+ */
+
+#define __get_user(x, ptr)						\
+	__get_user_nocheck((x), (ptr), sizeof(*(ptr)))
+/**
+ * __put_user: - Write a simple value into user space, with less checking.
+ * @x:   Value to copy to user space.
+ * @ptr: Destination address, in user space.
+ *
+ * Context: User context only.  This function may sleep.
+ *
+ * This macro copies a single simple value from kernel space to user
+ * space.  It supports simple types like char and int, but not larger
+ * data types like structures or arrays.
+ *
+ * @ptr must have pointer-to-simple-variable type, and @x must be assignable
+ * to the result of dereferencing @ptr.
+ *
+ * Caller must check the pointer with access_ok() before calling this
+ * function.
+ *
+ * Returns zero on success, or -EFAULT on error.
+ */
+
+#define __put_user(x, ptr)						\
+	__put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
+
+#define __get_user_unaligned __get_user
+#define __put_user_unaligned __put_user
+
+/*
+ * movsl can be slow when source and dest are not both 8-byte aligned
+ */
+#ifdef CONFIG_X86_INTEL_USERCOPY
+extern struct movsl_mask {
+	int mask;
+} ____cacheline_aligned_in_smp movsl_mask;
+#endif
+
+#define ARCH_HAS_NOCACHE_UACCESS 1
+
+#ifdef CONFIG_X86_32
+# include "uaccess_32.h"
+#else
+# define ARCH_HAS_SEARCH_EXTABLE
+# include "uaccess_64.h"
+#endif
+
+#endif /* ASM_X86__UACCESS_H */
+