nds32: Library functions

This patch add support for various library functions.

Signed-off-by: Vincent Chen <vincentc@andestech.com>
Signed-off-by: Greentime Hu <greentime@andestech.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>

1 files changed, 283 insertions, 0 deletions

diff --git a/arch/nds32/include/asm/uaccess.h b/arch/nds32/include/asm/uaccess.h
new file mode 100644
index 000000000000..18a009f3804d
--- /dev/null
+++ b/arch/nds32/include/asm/uaccess.h
@@ -0,0 +1,283 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2005-2017 Andes Technology Corporation
+
+#ifndef _ASMANDES_UACCESS_H
+#define _ASMANDES_UACCESS_H
+
+/*
+ * User space memory access functions
+ */
+#include <linux/sched.h>
+#include <asm/errno.h>
+#include <asm/memory.h>
+#include <asm/types.h>
+#include <linux/mm.h>
+
+#define VERIFY_READ	0
+#define VERIFY_WRITE	1
+
+#define __asmeq(x, y)  ".ifnc " x "," y " ; .err ; .endif\n\t"
+
+/*
+ * 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);
+
+#define KERNEL_DS 	((mm_segment_t) { ~0UL })
+#define USER_DS     	((mm_segment_t) {TASK_SIZE - 1})
+
+#define get_ds()	(KERNEL_DS)
+#define get_fs()	(current_thread_info()->addr_limit)
+#define user_addr_max	get_fs
+
+static inline void set_fs(mm_segment_t fs)
+{
+	current_thread_info()->addr_limit = fs;
+}
+
+#define segment_eq(a, b)    ((a) == (b))
+
+#define __range_ok(addr, size) (size <= get_fs() && addr <= (get_fs() -size))
+
+#define access_ok(type, addr, size)                 \
+	__range_ok((unsigned long)addr, (unsigned long)size)
+/*
+ * Single-value transfer routines.  They automatically use the right
+ * size if we just have the right pointer type.  Note that the functions
+ * which read from user space (*get_*) need to take care not to leak
+ * kernel data even if the calling code is buggy and fails to check
+ * the return value.  This means zeroing out the destination variable
+ * or buffer on error.  Normally this is done out of line by the
+ * fixup code, but there are a few places where it intrudes on the
+ * main code path.  When we only write to user space, there is no
+ * problem.
+ *
+ * The "__xxx" versions of the user access functions do not verify the
+ * address space - it must have been done previously with a separate
+ * "access_ok()" call.
+ *
+ * The "xxx_error" versions set the third argument to EFAULT if an
+ * error occurs, and leave it unchanged on success.  Note that these
+ * versions are void (ie, don't return a value as such).
+ */
+
+#define get_user(x,p)							\
+({									\
+	long __e = -EFAULT;						\
+	if(likely(access_ok(VERIFY_READ,  p, sizeof(*p)))) {		\
+		__e = __get_user(x,p);					\
+	} else								\
+		x = 0;							\
+	__e;								\
+})
+#define __get_user(x,ptr)						\
+({									\
+	long __gu_err = 0;						\
+	__get_user_err((x),(ptr),__gu_err);				\
+	__gu_err;							\
+})
+
+#define __get_user_error(x,ptr,err)					\
+({									\
+	__get_user_err((x),(ptr),err);					\
+	(void) 0;							\
+})
+
+#define __get_user_err(x,ptr,err)					\
+do {									\
+	unsigned long __gu_addr = (unsigned long)(ptr);			\
+	unsigned long __gu_val;						\
+	__chk_user_ptr(ptr);						\
+	switch (sizeof(*(ptr))) {					\
+	case 1:								\
+		__get_user_asm("lbi",__gu_val,__gu_addr,err);		\
+		break;							\
+	case 2:								\
+		__get_user_asm("lhi",__gu_val,__gu_addr,err);		\
+		break;							\
+	case 4:								\
+		__get_user_asm("lwi",__gu_val,__gu_addr,err);		\
+		break;							\
+	case 8:								\
+		__get_user_asm_dword(__gu_val,__gu_addr,err);		\
+		break;							\
+	default:							\
+		BUILD_BUG(); 						\
+		break;							\
+	}								\
+	(x) = (__typeof__(*(ptr)))__gu_val;				\
+} while (0)
+
+#define __get_user_asm(inst,x,addr,err)					\
+	asm volatile(							\
+	"1:	"inst"	%1,[%2]\n"					\
+	"2:\n"								\
+	"	.section .fixup,\"ax\"\n"				\
+	"	.align	2\n"						\
+	"3:	move %0, %3\n"						\
+	"	move %1, #0\n"						\
+	"	b	2b\n"						\
+	"	.previous\n"						\
+	"	.section __ex_table,\"a\"\n"				\
+	"	.align	3\n"						\
+	"	.long	1b, 3b\n"					\
+	"	.previous"						\
+	: "+r" (err), "=&r" (x)						\
+	: "r" (addr), "i" (-EFAULT)					\
+	: "cc")
+
+#ifdef __NDS32_EB__
+#define __gu_reg_oper0 "%H1"
+#define __gu_reg_oper1 "%L1"
+#else
+#define __gu_reg_oper0 "%L1"
+#define __gu_reg_oper1 "%H1"
+#endif
+
+#define __get_user_asm_dword(x, addr, err) 				\
+	asm volatile(			    				\
+	"\n1:\tlwi " __gu_reg_oper0 ",[%2]\n"				\
+	"\n2:\tlwi " __gu_reg_oper1 ",[%2+4]\n"				\
+	"3:\n"								\
+	"	.section .fixup,\"ax\"\n"				\
+	"	.align	2\n"						\
+	"4:	move	%0, %3\n"					\
+	"	b	3b\n"						\
+	"	.previous\n"						\
+	"	.section __ex_table,\"a\"\n"				\
+	"	.align	3\n"						\
+	"	.long	1b, 4b\n"					\
+	"	.long	2b, 4b\n"					\
+	"	.previous"						\
+	: "+r"(err), "=&r"(x)                				\
+	: "r"(addr), "i"(-EFAULT) 					\
+	: "cc")
+#define put_user(x,p)							\
+({									\
+	long __e = -EFAULT;						\
+	if(likely(access_ok(VERIFY_WRITE,  p, sizeof(*p)))) {		\
+		__e = __put_user(x,p);					\
+	}								\
+	__e;								\
+})
+#define __put_user(x,ptr)						\
+({									\
+	long __pu_err = 0;						\
+	__put_user_err((x),(ptr),__pu_err);				\
+	__pu_err;							\
+})
+
+#define __put_user_error(x,ptr,err)					\
+({									\
+	__put_user_err((x),(ptr),err);					\
+	(void) 0;							\
+})
+
+#define __put_user_err(x,ptr,err)					\
+do {									\
+	unsigned long __pu_addr = (unsigned long)(ptr);			\
+	__typeof__(*(ptr)) __pu_val = (x);				\
+	__chk_user_ptr(ptr);						\
+	switch (sizeof(*(ptr))) {					\
+	case 1:								\
+		__put_user_asm("sbi",__pu_val,__pu_addr,err);		\
+		break;							\
+	case 2: 							\
+		__put_user_asm("shi",__pu_val,__pu_addr,err);		\
+		break;							\
+	case 4: 							\
+		__put_user_asm("swi",__pu_val,__pu_addr,err);		\
+		break;							\
+	case 8:								\
+		__put_user_asm_dword(__pu_val,__pu_addr,err);		\
+		break;							\
+	default:							\
+		BUILD_BUG(); 						\
+		break;							\
+	}								\
+} while (0)
+
+#define __put_user_asm(inst,x,addr,err)					\
+	asm volatile(							\
+	"1:	"inst"	%1,[%2]\n"					\
+	"2:\n"								\
+	"	.section .fixup,\"ax\"\n"				\
+	"	.align	2\n"						\
+	"3:	move	%0, %3\n"					\
+	"	b	2b\n"						\
+	"	.previous\n"						\
+	"	.section __ex_table,\"a\"\n"				\
+	"	.align	3\n"						\
+	"	.long	1b, 3b\n"					\
+	"	.previous"						\
+	: "+r" (err)							\
+	: "r" (x), "r" (addr), "i" (-EFAULT)				\
+	: "cc")
+
+#ifdef __NDS32_EB__
+#define __pu_reg_oper0 "%H2"
+#define __pu_reg_oper1 "%L2"
+#else
+#define __pu_reg_oper0 "%L2"
+#define __pu_reg_oper1 "%H2"
+#endif
+
+#define __put_user_asm_dword(x, addr, err) 				\
+	asm volatile(			    				\
+	"\n1:\tswi " __pu_reg_oper0 ",[%1]\n"				\
+	"\n2:\tswi " __pu_reg_oper1 ",[%1+4]\n"				\
+	"3:\n"								\
+	"	.section .fixup,\"ax\"\n"				\
+	"	.align	2\n"						\
+	"4:	move	%0, %3\n"					\
+	"	b	3b\n"						\
+	"	.previous\n"						\
+	"	.section __ex_table,\"a\"\n"				\
+	"	.align	3\n"						\
+	"	.long	1b, 4b\n"					\
+	"	.long	2b, 4b\n"					\
+	"	.previous"						\
+	: "+r"(err)                					\
+	: "r"(addr), "r"(x), "i"(-EFAULT) 				\
+	: "cc")
+extern unsigned long __arch_clear_user(void __user * addr, unsigned long n);
+extern long strncpy_from_user(char *dest, const char __user * src, long count);
+extern __must_check long strlen_user(const char __user * str);
+extern __must_check long strnlen_user(const char __user * str, long n);
+extern unsigned long __arch_copy_from_user(void *to, const void __user * from,
+                                           unsigned long n);
+extern unsigned long __arch_copy_to_user(void __user * to, const void *from,
+                                         unsigned long n);
+
+#define raw_copy_from_user __arch_copy_from_user
+#define raw_copy_to_user __arch_copy_to_user
+
+#define INLINE_COPY_FROM_USER
+#define INLINE_COPY_TO_USER
+static inline unsigned long clear_user(void __user * to, unsigned long n)
+{
+	if (access_ok(VERIFY_WRITE, to, n))
+		n = __arch_clear_user(to, n);
+	return n;
+}
+
+static inline unsigned long __clear_user(void __user * to, unsigned long n)
+{
+	return __arch_clear_user(to, n);
+}
+
+#endif /* _ASMNDS32_UACCESS_H */