Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
index aae77eb..61d93f0 100644
--- a/arch/x86/include/asm/uaccess.h
+++ b/arch/x86/include/asm/uaccess.h
@@ -25,7 +25,6 @@
 #define KERNEL_DS	MAKE_MM_SEG(-1UL)
 #define USER_DS 	MAKE_MM_SEG(TASK_SIZE_MAX)
 
-#define get_ds()	(KERNEL_DS)
 #define get_fs()	(current->thread.addr_limit)
 static inline void set_fs(mm_segment_t fs)
 {
@@ -35,10 +34,7 @@
 }
 
 #define segment_eq(a, b)	((a).seg == (b).seg)
-
 #define user_addr_max() (current->thread.addr_limit.seg)
-#define __addr_ok(addr) 	\
-	((unsigned long __force)(addr) < user_addr_max())
 
 /*
  * Test whether a block of memory is a valid user space address.
@@ -70,16 +66,15 @@
 })
 
 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
-# define WARN_ON_IN_IRQ()	WARN_ON_ONCE(!in_task())
+static inline bool pagefault_disabled(void);
+# define WARN_ON_IN_IRQ()	\
+	WARN_ON_ONCE(!in_task() && !pagefault_disabled())
 #else
 # define WARN_ON_IN_IRQ()
 #endif
 
 /**
- * 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.
+ * access_ok - Checks if a user space pointer is valid
  * @addr: User space pointer to start of block to check
  * @size: Size of block to check
  *
@@ -88,14 +83,14 @@
  *
  * 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.
+ *
+ * Return: true (nonzero) if the memory block may be valid, false (zero)
+ * if it is definitely invalid.
  */
-#define access_ok(type, addr, size)					\
+#define access_ok(addr, size)					\
 ({									\
 	WARN_ON_IN_IRQ();						\
 	likely(!__range_not_ok(addr, size, user_addr_max()));		\
@@ -138,7 +133,7 @@
 __typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL))
 
 /**
- * get_user: - Get a simple variable from user space.
+ * get_user - Get a simple variable from user space.
  * @x:   Variable to store result.
  * @ptr: Source address, in user space.
  *
@@ -152,7 +147,7 @@
  * @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.
+ * Return: zero on success, or -EFAULT on error.
  * On error, the variable @x is set to zero.
  */
 /*
@@ -189,19 +184,14 @@
 
 
 #ifdef CONFIG_X86_32
-#define __put_user_asm_u64(x, addr, err, errret)			\
-	asm volatile("\n"						\
-		     "1:	movl %%eax,0(%2)\n"			\
-		     "2:	movl %%edx,4(%2)\n"			\
-		     "3:"						\
-		     ".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" (errret), "0" (err))
+#define __put_user_goto_u64(x, addr, label)			\
+	asm_volatile_goto("\n"					\
+		     "1:	movl %%eax,0(%1)\n"		\
+		     "2:	movl %%edx,4(%1)\n"		\
+		     _ASM_EXTABLE_UA(1b, %l2)			\
+		     _ASM_EXTABLE_UA(2b, %l2)			\
+		     : : "A" (x), "r" (addr)			\
+		     : : label)
 
 #define __put_user_asm_ex_u64(x, addr)					\
 	asm volatile("\n"						\
@@ -216,8 +206,8 @@
 	asm volatile("call __put_user_8" : "=a" (__ret_pu)	\
 		     : "A" ((typeof(*(ptr)))(x)), "c" (ptr) : "ebx")
 #else
-#define __put_user_asm_u64(x, ptr, retval, errret) \
-	__put_user_asm(x, ptr, retval, "q", "", "er", errret)
+#define __put_user_goto_u64(x, ptr, label) \
+	__put_user_goto(x, ptr, "q", "", "er", label)
 #define __put_user_asm_ex_u64(x, addr)	\
 	__put_user_asm_ex(x, addr, "q", "", "er")
 #define __put_user_x8(x, ptr, __ret_pu) __put_user_x(8, x, ptr, __ret_pu)
@@ -235,7 +225,7 @@
 extern void __put_user_8(void);
 
 /**
- * put_user: - Write a simple value into user space.
+ * put_user - Write a simple value into user space.
  * @x:   Value to copy to user space.
  * @ptr: Destination address, in user space.
  *
@@ -249,7 +239,7 @@
  * @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.
+ * Return: zero on success, or -EFAULT on error.
  */
 #define put_user(x, ptr)					\
 ({								\
@@ -278,23 +268,21 @@
 	__builtin_expect(__ret_pu, 0);				\
 })
 
-#define __put_user_size(x, ptr, size, retval, errret)			\
+#define __put_user_size(x, ptr, size, label)				\
 do {									\
-	retval = 0;							\
 	__chk_user_ptr(ptr);						\
 	switch (size) {							\
 	case 1:								\
-		__put_user_asm(x, ptr, retval, "b", "b", "iq", errret);	\
+		__put_user_goto(x, ptr, "b", "b", "iq", label);	\
 		break;							\
 	case 2:								\
-		__put_user_asm(x, ptr, retval, "w", "w", "ir", errret);	\
+		__put_user_goto(x, ptr, "w", "w", "ir", label);		\
 		break;							\
 	case 4:								\
-		__put_user_asm(x, ptr, retval, "l", "k", "ir", errret);	\
+		__put_user_goto(x, ptr, "l", "k", "ir", label);		\
 		break;							\
 	case 8:								\
-		__put_user_asm_u64((__typeof__(*ptr))(x), ptr, retval,	\
-				   errret);				\
+		__put_user_goto_u64(x, ptr, label);			\
 		break;							\
 	default:							\
 		__put_user_bad();					\
@@ -340,8 +328,8 @@
 		     "	xorl %%edx,%%edx\n"				\
 		     "	jmp 3b\n"					\
 		     ".previous\n"					\
-		     _ASM_EXTABLE(1b, 4b)				\
-		     _ASM_EXTABLE(2b, 4b)				\
+		     _ASM_EXTABLE_UA(1b, 4b)				\
+		     _ASM_EXTABLE_UA(2b, 4b)				\
 		     : "=r" (retval), "=&A"(x)				\
 		     : "m" (__m(__ptr)), "m" __m(((u32 __user *)(__ptr)) + 1),	\
 		       "i" (errret), "0" (retval));			\
@@ -386,7 +374,7 @@
 		     "	xor"itype" %"rtype"1,%"rtype"1\n"		\
 		     "	jmp 2b\n"					\
 		     ".previous\n"					\
-		     _ASM_EXTABLE(1b, 3b)				\
+		     _ASM_EXTABLE_UA(1b, 3b)				\
 		     : "=r" (err), ltype(x)				\
 		     : "m" (__m(addr)), "i" (errret), "0" (err))
 
@@ -398,7 +386,7 @@
 		     "3:	mov %3,%0\n"				\
 		     "	jmp 2b\n"					\
 		     ".previous\n"					\
-		     _ASM_EXTABLE(1b, 3b)				\
+		     _ASM_EXTABLE_UA(1b, 3b)				\
 		     : "=r" (err), ltype(x)				\
 		     : "m" (__m(addr)), "i" (errret), "0" (err))
 
@@ -439,9 +427,15 @@
 
 #define __put_user_nocheck(x, ptr, size)			\
 ({								\
-	int __pu_err;						\
+	__label__ __pu_label;					\
+	int __pu_err = -EFAULT;					\
+	__typeof__(*(ptr)) __pu_val = (x);			\
+	__typeof__(ptr) __pu_ptr = (ptr);			\
+	__typeof__(size) __pu_size = (size);			\
 	__uaccess_begin();					\
-	__put_user_size((x), (ptr), (size), __pu_err, -EFAULT);	\
+	__put_user_size(__pu_val, __pu_ptr, __pu_size, __pu_label);	\
+	__pu_err = 0;						\
+__pu_label:							\
 	__uaccess_end();					\
 	__builtin_expect(__pu_err, 0);				\
 })
@@ -450,8 +444,10 @@
 ({									\
 	int __gu_err;							\
 	__inttype(*(ptr)) __gu_val;					\
+	__typeof__(ptr) __gu_ptr = (ptr);				\
+	__typeof__(size) __gu_size = (size);				\
 	__uaccess_begin_nospec();					\
-	__get_user_size(__gu_val, (ptr), (size), __gu_err, -EFAULT);	\
+	__get_user_size(__gu_val, __gu_ptr, __gu_size, __gu_err, -EFAULT);	\
 	__uaccess_end();						\
 	(x) = (__force __typeof__(*(ptr)))__gu_val;			\
 	__builtin_expect(__gu_err, 0);					\
@@ -466,17 +462,23 @@
  * 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("\n"						\
-		     "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))
+#define __put_user_goto(x, addr, itype, rtype, ltype, label)	\
+	asm_volatile_goto("\n"						\
+		"1:	mov"itype" %"rtype"0,%1\n"			\
+		_ASM_EXTABLE_UA(1b, %l2)					\
+		: : ltype(x), "m" (__m(addr))				\
+		: : label)
+
+#define __put_user_failed(x, addr, itype, rtype, ltype, errret)		\
+	({	__label__ __puflab;					\
+		int __pufret = errret;					\
+		__put_user_goto(x,addr,itype,rtype,ltype,__puflab);	\
+		__pufret = 0;						\
+	__puflab: __pufret; })
+
+#define __put_user_asm(x, addr, retval, itype, rtype, ltype, errret)	do {	\
+	retval = __put_user_failed(x, addr, itype, rtype, ltype, errret);	\
+} while (0)
 
 #define __put_user_asm_ex(x, addr, itype, rtype, ltype)			\
 	asm volatile("1:	mov"itype" %"rtype"0,%1\n"		\
@@ -502,7 +504,7 @@
 } while (0)
 
 /**
- * __get_user: - Get a simple variable from user space, with less checking.
+ * __get_user - Get a simple variable from user space, with less checking.
  * @x:   Variable to store result.
  * @ptr: Source address, in user space.
  *
@@ -519,7 +521,7 @@
  * Caller must check the pointer with access_ok() before calling this
  * function.
  *
- * Returns zero on success, or -EFAULT on error.
+ * Return: zero on success, or -EFAULT on error.
  * On error, the variable @x is set to zero.
  */
 
@@ -527,7 +529,7 @@
 	__get_user_nocheck((x), (ptr), sizeof(*(ptr)))
 
 /**
- * __put_user: - Write a simple value into user space, with less checking.
+ * __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.
  *
@@ -544,7 +546,7 @@
  * Caller must check the pointer with access_ok() before calling this
  * function.
  *
- * Returns zero on success, or -EFAULT on error.
+ * Return: zero on success, or -EFAULT on error.
  */
 
 #define __put_user(x, ptr)						\
@@ -588,7 +590,6 @@
 #define __user_atomic_cmpxchg_inatomic(uval, ptr, old, new, size)	\
 ({									\
 	int __ret = 0;							\
-	__typeof__(ptr) __uval = (uval);				\
 	__typeof__(*(ptr)) __old = (old);				\
 	__typeof__(*(ptr)) __new = (new);				\
 	__uaccess_begin_nospec();					\
@@ -602,7 +603,7 @@
 			"3:\tmov     %3, %0\n"				\
 			"\tjmp     2b\n"				\
 			"\t.previous\n"					\
-			_ASM_EXTABLE(1b, 3b)				\
+			_ASM_EXTABLE_UA(1b, 3b)				\
 			: "+r" (__ret), "=a" (__old), "+m" (*(ptr))	\
 			: "i" (-EFAULT), "q" (__new), "1" (__old)	\
 			: "memory"					\
@@ -618,7 +619,7 @@
 			"3:\tmov     %3, %0\n"				\
 			"\tjmp     2b\n"				\
 			"\t.previous\n"					\
-			_ASM_EXTABLE(1b, 3b)				\
+			_ASM_EXTABLE_UA(1b, 3b)				\
 			: "+r" (__ret), "=a" (__old), "+m" (*(ptr))	\
 			: "i" (-EFAULT), "r" (__new), "1" (__old)	\
 			: "memory"					\
@@ -634,7 +635,7 @@
 			"3:\tmov     %3, %0\n"				\
 			"\tjmp     2b\n"				\
 			"\t.previous\n"					\
-			_ASM_EXTABLE(1b, 3b)				\
+			_ASM_EXTABLE_UA(1b, 3b)				\
 			: "+r" (__ret), "=a" (__old), "+m" (*(ptr))	\
 			: "i" (-EFAULT), "r" (__new), "1" (__old)	\
 			: "memory"					\
@@ -653,7 +654,7 @@
 			"3:\tmov     %3, %0\n"				\
 			"\tjmp     2b\n"				\
 			"\t.previous\n"					\
-			_ASM_EXTABLE(1b, 3b)				\
+			_ASM_EXTABLE_UA(1b, 3b)				\
 			: "+r" (__ret), "=a" (__old), "+m" (*(ptr))	\
 			: "i" (-EFAULT), "r" (__new), "1" (__old)	\
 			: "memory"					\
@@ -664,13 +665,13 @@
 		__cmpxchg_wrong_size();					\
 	}								\
 	__uaccess_end();						\
-	*__uval = __old;						\
+	*(uval) = __old;						\
 	__ret;								\
 })
 
 #define user_atomic_cmpxchg_inatomic(uval, ptr, old, new)		\
 ({									\
-	access_ok(VERIFY_WRITE, (ptr), sizeof(*(ptr))) ?		\
+	access_ok((ptr), sizeof(*(ptr))) ?		\
 		__user_atomic_cmpxchg_inatomic((uval), (ptr),		\
 				(old), (new), sizeof(*(ptr))) :		\
 		-EFAULT;						\
@@ -708,16 +709,21 @@
  * checking before using them, but you have to surround them with the
  * user_access_begin/end() pair.
  */
-#define user_access_begin()	__uaccess_begin()
+static __must_check __always_inline bool user_access_begin(const void __user *ptr, size_t len)
+{
+	if (unlikely(!access_ok(ptr,len)))
+		return 0;
+	__uaccess_begin_nospec();
+	return 1;
+}
+#define user_access_begin(a,b)	user_access_begin(a,b)
 #define user_access_end()	__uaccess_end()
 
-#define unsafe_put_user(x, ptr, err_label)					\
-do {										\
-	int __pu_err;								\
-	__typeof__(*(ptr)) __pu_val = (x);					\
-	__put_user_size(__pu_val, (ptr), sizeof(*(ptr)), __pu_err, -EFAULT);	\
-	if (unlikely(__pu_err)) goto err_label;					\
-} while (0)
+#define user_access_save()	smap_save()
+#define user_access_restore(x)	smap_restore(x)
+
+#define unsafe_put_user(x, ptr, label)	\
+	__put_user_size((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)), label)
 
 #define unsafe_get_user(x, ptr, err_label)					\
 do {										\
@@ -728,5 +734,28 @@
 	if (unlikely(__gu_err)) goto err_label;					\
 } while (0)
 
+/*
+ * We want the unsafe accessors to always be inlined and use
+ * the error labels - thus the macro games.
+ */
+#define unsafe_copy_loop(dst, src, len, type, label)			\
+	while (len >= sizeof(type)) {					\
+		unsafe_put_user(*(type *)src,(type __user *)dst,label);	\
+		dst += sizeof(type);					\
+		src += sizeof(type);					\
+		len -= sizeof(type);					\
+	}
+
+#define unsafe_copy_to_user(_dst,_src,_len,label)			\
+do {									\
+	char __user *__ucu_dst = (_dst);				\
+	const char *__ucu_src = (_src);					\
+	size_t __ucu_len = (_len);					\
+	unsafe_copy_loop(__ucu_dst, __ucu_src, __ucu_len, u64, label);	\
+	unsafe_copy_loop(__ucu_dst, __ucu_src, __ucu_len, u32, label);	\
+	unsafe_copy_loop(__ucu_dst, __ucu_src, __ucu_len, u16, label);	\
+	unsafe_copy_loop(__ucu_dst, __ucu_src, __ucu_len, u8, label);	\
+} while (0)
+
 #endif /* _ASM_X86_UACCESS_H */