LoongArch: Adjust user accessors for 32BIT/64BIT

Adjust user accessors for both 32BIT and 64BIT, including: get_user(),
put_user(), copy_user(), clear_user(), etc.

Reviewed-by: Arnd Bergmann <[e-mail]>
Signed-off-by: Jiaxun Yang <[e-mail]>
Signed-off-by: Huacai Chen <[e-mail]>

arch/loongarch/include/asm/uaccess.h

···
 #include <asm/asm-extable.h>
 #include <asm-generic/access_ok.h>
 
+#define __LSW	0
+#define __MSW	1
+
 extern u64 __ua_limit;
 
-#define __UA_ADDR	".dword"
+#ifdef CONFIG_64BIT
 #define __UA_LIMIT	__ua_limit
+#else
+#define __UA_LIMIT	0x80000000UL
+#endif
 
 /*
  * get_user: - Get a simple variable from user space.
···
  *
  * Returns zero on success, or -EFAULT on error.
  */
+
 #define __put_user(x, ptr) \
 ({									\
 	int __pu_err = 0;						\
···
 	case 1: __get_data_asm(val, "ld.b", ptr); break;		\
 	case 2: __get_data_asm(val, "ld.h", ptr); break;		\
 	case 4: __get_data_asm(val, "ld.w", ptr); break;		\
-	case 8: __get_data_asm(val, "ld.d", ptr); break;		\
+	case 8: __get_data_asm_8(val, ptr); break;			\
 	default: BUILD_BUG(); break;					\
 	}								\
 } while (0)
···
 	(val) = (__typeof__(*(ptr))) __gu_tmp;				\
 }
 
+#ifdef CONFIG_64BIT
+#define __get_data_asm_8(val, ptr) \
+	__get_data_asm(val, "ld.d", ptr)
+#else /* !CONFIG_64BIT */
+#define __get_data_asm_8(val, ptr)					\
+{									\
+	u32 __lo, __hi;							\
+	u32 __user *__ptr = (u32 __user *)(ptr);			\
+									\
+	__asm__ __volatile__ (						\
+		"1:\n"							\
+		"	ld.w %1, %3				\n"	\
+		"2:\n"							\
+		"	ld.w %2, %4				\n"	\
+		"3:\n"							\
+		_ASM_EXTABLE_UACCESS_ERR_ZERO(1b, 3b, %0, %1)		\
+		_ASM_EXTABLE_UACCESS_ERR_ZERO(2b, 3b, %0, %1)		\
+		: "+r" (__gu_err), "=&r" (__lo), "=r" (__hi)		\
+		: "m" (__ptr[__LSW]), "m" (__ptr[__MSW]));		\
+	if (__gu_err)							\
+		__hi = 0;						\
+	(val) = (__typeof__(val))((__typeof__((val)-(val)))		\
+		((((u64)__hi << 32) | __lo)));				\
+}
+#endif /* CONFIG_64BIT */
+
 #define __put_user_common(ptr, size)					\
 do {									\
 	switch (size) {							\
 	case 1: __put_data_asm("st.b", ptr); break;			\
 	case 2: __put_data_asm("st.h", ptr); break;			\
 	case 4: __put_data_asm("st.w", ptr); break;			\
-	case 8: __put_data_asm("st.d", ptr); break;			\
+	case 8: __put_data_asm_8(ptr); break;				\
 	default: BUILD_BUG(); break;					\
 	}								\
 } while (0)
···
 	: "+r" (__pu_err), "=m" (__m(ptr))				\
 	: "Jr" (__pu_val));						\
 }
+
+#ifdef CONFIG_64BIT
+#define __put_data_asm_8(ptr) \
+	__put_data_asm("st.d", ptr)
+#else /* !CONFIG_64BIT */
+#define __put_data_asm_8(ptr)						\
+{									\
+	u32 __user *__ptr = (u32 __user *)(ptr);			\
+	u64 __x = (__typeof__((__pu_val)-(__pu_val)))(__pu_val);	\
+									\
+	__asm__ __volatile__ (						\
+		"1:\n"							\
+		"	st.w %z3, %1				\n"	\
+		"2:\n"							\
+		"	st.w %z4, %2				\n"	\
+		"3:\n"							\
+		_ASM_EXTABLE_UACCESS_ERR(1b, 3b, %0)			\
+		_ASM_EXTABLE_UACCESS_ERR(2b, 3b, %0)			\
+		: "+r" (__pu_err),					\
+			"=m" (__ptr[__LSW]),				\
+			"=m" (__ptr[__MSW])				\
+		: "rJ" (__x), "rJ" (__x >> 32));			\
+}
+#endif /* CONFIG_64BIT */
 
 #define __get_kernel_nofault(dst, src, type, err_label)			\
 do {									\

arch/loongarch/lib/clear_user.S

···
 #include <asm/unwind_hints.h>
 
 SYM_FUNC_START(__clear_user)
+#ifdef CONFIG_32BIT
+	b		__clear_user_generic
+#else
 	/*
 	 * Some CPUs support hardware unaligned access
 	 */
 	ALTERNATIVE	"b __clear_user_generic",	\
 			"b __clear_user_fast", CPU_FEATURE_UAL
+#endif
 SYM_FUNC_END(__clear_user)
 
 EXPORT_SYMBOL(__clear_user)
···
  * a1: size
  */
 SYM_FUNC_START(__clear_user_generic)
-	beqz	a1, 2f
+	beqz		a1, 2f
 
-1:	st.b	zero, a0, 0
-	addi.d	a0, a0, 1
-	addi.d	a1, a1, -1
-	bgtz	a1, 1b
+1:	st.b		zero, a0, 0
+	PTR_ADDI	a0, a0, 1
+	PTR_ADDI	a1, a1, -1
+	bgtz		a1, 1b
 
-2:	move	a0, a1
-	jr	ra
+2:	move		a0, a1
+	jr		ra
 
-	_asm_extable 1b, 2b
+	_asm_extable 	1b, 2b
 SYM_FUNC_END(__clear_user_generic)
 
+#ifdef CONFIG_64BIT
 /*
  * unsigned long __clear_user_fast(void *addr, unsigned long size)
  *
···
 SYM_FUNC_END(__clear_user_fast)
 
 STACK_FRAME_NON_STANDARD __clear_user_fast
+#endif

arch/loongarch/lib/copy_user.S

···
 #include <asm/unwind_hints.h>
 
 SYM_FUNC_START(__copy_user)
+#ifdef CONFIG_32BIT
+	b		__copy_user_generic
+#else
 	/*
 	 * Some CPUs support hardware unaligned access
 	 */
 	ALTERNATIVE	"b __copy_user_generic",	\
 			"b __copy_user_fast", CPU_FEATURE_UAL
+#endif
 SYM_FUNC_END(__copy_user)
 
 EXPORT_SYMBOL(__copy_user)
···
  * a2: n
  */
 SYM_FUNC_START(__copy_user_generic)
-	beqz	a2, 3f
+	beqz		a2, 3f
 
-1:	ld.b	t0, a1, 0
-2:	st.b	t0, a0, 0
-	addi.d	a0, a0, 1
-	addi.d	a1, a1, 1
-	addi.d	a2, a2, -1
-	bgtz	a2, 1b
+1:	ld.b		t0, a1, 0
+2:	st.b		t0, a0, 0
+	PTR_ADDI	a0, a0, 1
+	PTR_ADDI	a1, a1, 1
+	PTR_ADDI	a2, a2, -1
+	bgtz		a2, 1b
 
-3:	move	a0, a2
-	jr	ra
+3:	move		a0, a2
+	jr		ra
 
-	_asm_extable 1b, 3b
-	_asm_extable 2b, 3b
+	_asm_extable	1b, 3b
+	_asm_extable	2b, 3b
 SYM_FUNC_END(__copy_user_generic)
 
+#ifdef CONFIG_64BIT
 /*
  * unsigned long __copy_user_fast(void *to, const void *from, unsigned long n)
  *
···
 SYM_FUNC_END(__copy_user_fast)
 
 STACK_FRAME_NON_STANDARD __copy_user_fast
+#endif