Commit 8ade8339 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Geert Uytterhoeven
Browse files

m68k: Provide __{get,put}_kernel_nofault 



Allow non-faulting access to kernel addresses without overriding the
address space.  Implemented by passing the instruction name to the
low-level assembly macros as an argument, and force the use of the
normal move instructions for kernel access.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarMichael Schmitz <schmitzmic@gmail.com>
Tested-by: default avatarMichael Schmitz <schmitzmic@gmail.com>
Link: https://lore.kernel.org/r/20210916070405.52750-6-hch@lst.de


Signed-off-by: default avatarGeert Uytterhoeven <geert@linux-m68k.org>
parent 01eec1af

arch/m68k/include/asm/uaccess.h

+84 −21
Original line number Diff line number Diff line
@@ -39,9 +39,9 @@ static inline int access_ok(const void __user *addr, 
#define	MOVES	"move"

#endif



#define __put_user_asm(res, x, ptr, bwl, reg, err)	\

#define __put_user_asm(inst, res, x, ptr, bwl, reg, err) \

asm volatile ("\n"					\

	"1:	"MOVES"."#bwl"	%2,%1\n"		\

	"1:	"inst"."#bwl"	%2,%1\n"		\

	"2:\n"						\

	"	.section .fixup,\"ax\"\n"		\

	"	.even\n"				\
@@ -57,13 +57,13 @@ asm volatile ("\n" \ 
	: "+d" (res), "=m" (*(ptr))			\

	: #reg (x), "i" (err))



#define __put_user_asm8(res, x, ptr)				\

#define __put_user_asm8(inst, res, x, ptr)			\

do {								\

	const void *__pu_ptr = (const void __force *)(ptr);	\

								\

	asm volatile ("\n"					\

		"1:	"MOVES".l %2,(%1)+\n"			\

		"2:	"MOVES".l %R2,(%1)\n"			\

		"1:	"inst".l %2,(%1)+\n"			\

		"2:	"inst".l %R2,(%1)\n"			\

		"3:\n"						\

		"	.section .fixup,\"ax\"\n"		\

		"	.even\n"				\
@@ -94,16 +94,16 @@ do { \ 
	__chk_user_ptr(ptr);						\

	switch (sizeof (*(ptr))) {					\

	case 1:								\

		__put_user_asm(__pu_err, __pu_val, ptr, b, d, -EFAULT);	\

		__put_user_asm(MOVES, __pu_err, __pu_val, ptr, b, d, -EFAULT); \

		break;							\

	case 2:								\

		__put_user_asm(__pu_err, __pu_val, ptr, w, r, -EFAULT);	\

		__put_user_asm(MOVES, __pu_err, __pu_val, ptr, w, r, -EFAULT); \

		break;							\

	case 4:								\

		__put_user_asm(__pu_err, __pu_val, ptr, l, r, -EFAULT);	\

		__put_user_asm(MOVES, __pu_err, __pu_val, ptr, l, r, -EFAULT); \

		break;							\

	case 8:								\

		__put_user_asm8(__pu_err, __pu_val, ptr);		\

		__put_user_asm8(MOVES, __pu_err, __pu_val, ptr);	\

		break;							\

	default:							\

		BUILD_BUG();						\
@@ -113,10 +113,10 @@ do { \ 
#define put_user(x, ptr)	__put_user(x, ptr)





#define __get_user_asm(res, x, ptr, type, bwl, reg, err) ({		\

#define __get_user_asm(inst, res, x, ptr, type, bwl, reg, err) ({	\

	type __gu_val;							\

	asm volatile ("\n"						\

		"1:	"MOVES"."#bwl"	%2,%1\n"			\

		"1:	"inst"."#bwl"	%2,%1\n"			\

		"2:\n"							\

		"	.section .fixup,\"ax\"\n"			\

		"	.even\n"					\
@@ -134,7 +134,7 @@ do { \ 
	(x) = (__force typeof(*(ptr)))(__force unsigned long)__gu_val;	\

})



#define __get_user_asm8(res, x, ptr)					\

#define __get_user_asm8(inst, res, x, ptr) 				\

do {									\

	const void *__gu_ptr = (const void __force *)(ptr);		\

	union {								\
@@ -143,8 +143,8 @@ do { \ 
	} __gu_val;							\

									\

	asm volatile ("\n"						\

		"1:	"MOVES".l	(%2)+,%1\n"			\

		"2:	"MOVES".l	(%2),%R1\n"			\

		"1:	"inst".l (%2)+,%1\n"				\

		"2:	"inst".l (%2),%R1\n"				\

		"3:\n"							\

		"	.section .fixup,\"ax\"\n"			\

		"	.even\n"					\
@@ -172,16 +172,16 @@ do { \ 
	__chk_user_ptr(ptr);						\

	switch (sizeof(*(ptr))) {					\

	case 1:								\

		__get_user_asm(__gu_err, x, ptr, u8, b, d, -EFAULT);	\

		__get_user_asm(MOVES, __gu_err, x, ptr, u8, b, d, -EFAULT); \

		break;							\

	case 2:								\

		__get_user_asm(__gu_err, x, ptr, u16, w, r, -EFAULT);	\

		__get_user_asm(MOVES, __gu_err, x, ptr, u16, w, r, -EFAULT); \

		break;							\

	case 4:								\

		__get_user_asm(__gu_err, x, ptr, u32, l, r, -EFAULT);	\

		__get_user_asm(MOVES, __gu_err, x, ptr, u32, l, r, -EFAULT); \

		break;							\

	case 8:								\

		__get_user_asm8(__gu_err, x, ptr);			\

		__get_user_asm8(MOVES, __gu_err, x, ptr);		\

		break;							\

	default:							\

		BUILD_BUG();						\
@@ -330,16 +330,19 @@ __constant_copy_to_user(void __user *to, const void *from, unsigned long n) 


	switch (n) {

	case 1:

		__put_user_asm(res, *(u8 *)from, (u8 __user *)to, b, d, 1);

		__put_user_asm(MOVES, res, *(u8 *)from, (u8 __user *)to,

				b, d, 1);

		break;

	case 2:

		__put_user_asm(res, *(u16 *)from, (u16 __user *)to, w, r, 2);

		__put_user_asm(MOVES, res, *(u16 *)from, (u16 __user *)to,

				w, r, 2);

		break;

	case 3:

		__constant_copy_to_user_asm(res, to, from, tmp, 3, w, b,);

		break;

	case 4:

		__put_user_asm(res, *(u32 *)from, (u32 __user *)to, l, r, 4);

		__put_user_asm(MOVES, res, *(u32 *)from, (u32 __user *)to,

				l, r, 4);

		break;

	case 5:

		__constant_copy_to_user_asm(res, to, from, tmp, 5, l, b,);
@@ -388,6 +391,66 @@ raw_copy_to_user(void __user *to, const void *from, unsigned long n) 
#define INLINE_COPY_FROM_USER

#define INLINE_COPY_TO_USER



#define HAVE_GET_KERNEL_NOFAULT



#define __get_kernel_nofault(dst, src, type, err_label)			\

do {									\

	type *__gk_dst = (type *)(dst);					\

	type *__gk_src = (type *)(src);					\

	int __gk_err = 0;						\

									\

	switch (sizeof(type)) {						\

	case 1:								\

		__get_user_asm("move", __gk_err, *__gk_dst, __gk_src,	\

				u8, b, d, -EFAULT);			\

		break;							\

	case 2:								\

		__get_user_asm("move", __gk_err, *__gk_dst, __gk_src,	\

				u16, w, r, -EFAULT);			\

		break;							\

	case 4:								\

		__get_user_asm("move", __gk_err, *__gk_dst, __gk_src,	\

				u32, l, r, -EFAULT);			\

		break;							\

	case 8:								\

		__get_user_asm8("move", __gk_err, *__gk_dst, __gk_src);	\

		break;							\

	default:							\

		BUILD_BUG();						\

	}								\

	if (unlikely(__gk_err))						\

		goto err_label;						\

} while (0)



#define __put_kernel_nofault(dst, src, type, err_label)			\

do {									\

	type __pk_src = *(type *)(src);					\

	type *__pk_dst = (type *)(dst);					\

	int __pk_err = 0;						\

									\

	switch (sizeof(type)) {						\

	case 1:								\

		__put_user_asm("move", __pk_err, __pk_src, __pk_dst,	\

				b, d, -EFAULT);				\

		break;							\

	case 2:								\

		__put_user_asm("move", __pk_err, __pk_src, __pk_dst,	\

				w, r, -EFAULT);				\

		break;							\

	case 4:								\

		__put_user_asm("move", __pk_err, __pk_src, __pk_dst,	\

				l, r, -EFAULT);				\

		break;							\

	case 8:								\

		__put_user_asm8("move", __pk_err, __pk_src, __pk_dst);	\

		break;							\

	default:							\

		BUILD_BUG();						\

	}								\

	if (unlikely(__pk_err))						\

		goto err_label;						\

} while (0)



#define user_addr_max() \

	(uaccess_kernel() ? ~0UL : TASK_SIZE)