diff mbox series

[v2,02/18] uaccess: fix nios2 and microblaze get_user_8()

Message ID 20220216131332.1489939-3-arnd@kernel.org (mailing list archive)
State New
Headers show
Series clean up asm/uaccess.h, kill set_fs for good | expand

Commit Message

Arnd Bergmann Feb. 16, 2022, 1:13 p.m. UTC
From: Arnd Bergmann <arnd@arndb.de>

These two architectures implement 8-byte get_user() through
a memcpy() into a four-byte variable, which won't fit.

Use a temporary 64-bit variable instead here, and use a double
cast the way that risc-v and openrisc do to avoid compile-time
warnings.

Fixes: 6a090e97972d ("arch/microblaze: support get_user() of size 8 bytes")
Fixes: 5ccc6af5e88e ("nios2: Memory management")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 arch/microblaze/include/asm/uaccess.h | 18 +++++++++---------
 arch/nios2/include/asm/uaccess.h      | 26 ++++++++++++++++----------
 2 files changed, 25 insertions(+), 19 deletions(-)

Comments

David Laight Feb. 16, 2022, 1:35 p.m. UTC | #1
From: Arnd Bergmann
> Sent: 16 February 2022 13:13
> 
> These two architectures implement 8-byte get_user() through
> a memcpy() into a four-byte variable, which won't fit.
> 
> Use a temporary 64-bit variable instead here, and use a double
> cast the way that risc-v and openrisc do to avoid compile-time
> warnings.
> 
...
>  	case 4:								\
> -		__get_user_asm("lw", (ptr), __gu_val, __gu_err);	\
> +		__get_user_asm("lw", (ptr), x, __gu_err);		\
>  		break;							\
> -	case 8:								\
> -		__gu_err = __copy_from_user(&__gu_val, ptr, 8);		\
> -		if (__gu_err)						\
> -			__gu_err = -EFAULT;				\
> +	case 8: {							\
> +		__u64 __x = 0;						\
> +		__gu_err = raw_copy_from_user(&__x, ptr, 8) ?		\
> +							-EFAULT : 0;	\
> +		(x) = (typeof(x))(typeof((x) - (x)))__x;		\
>  		break;							\

Wouldn't it be better to just fetch two 32bit values:
Something like (for LE - nios2 is definitely LE:
		__u32 val_lo, val_hi;
		__get_user_asm("lw", (ptr), val_lo, __gu_err);
		__get_user_asm("lw", (ptr) + 4, val_hi, __gu_err);
		x = val_lo | val_hi << 32;
		break;

	David

-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
Christoph Hellwig Feb. 18, 2022, 6:25 a.m. UTC | #2
Looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>
Dinh Nguyen Feb. 25, 2022, 4:28 a.m. UTC | #3
On 2/16/22 07:13, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
> 
> These two architectures implement 8-byte get_user() through
> a memcpy() into a four-byte variable, which won't fit.
> 
> Use a temporary 64-bit variable instead here, and use a double
> cast the way that risc-v and openrisc do to avoid compile-time
> warnings.
> 
> Fixes: 6a090e97972d ("arch/microblaze: support get_user() of size 8 bytes")
> Fixes: 5ccc6af5e88e ("nios2: Memory management")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>   arch/microblaze/include/asm/uaccess.h | 18 +++++++++---------
>   arch/nios2/include/asm/uaccess.h      | 26 ++++++++++++++++----------
>   2 files changed, 25 insertions(+), 19 deletions(-)
> 
> diff --git a/arch/microblaze/include/asm/uaccess.h b/arch/microblaze/include/asm/uaccess.h
> index 5b6e0e7788f4..3fe96979d2c6 100644
> --- a/arch/microblaze/include/asm/uaccess.h
> +++ b/arch/microblaze/include/asm/uaccess.h
> @@ -130,27 +130,27 @@ extern long __user_bad(void);
>   
>   #define __get_user(x, ptr)						\
>   ({									\
> -	unsigned long __gu_val = 0;					\
>   	long __gu_err;							\
>   	switch (sizeof(*(ptr))) {					\
>   	case 1:								\
> -		__get_user_asm("lbu", (ptr), __gu_val, __gu_err);	\
> +		__get_user_asm("lbu", (ptr), x, __gu_err);		\
>   		break;							\
>   	case 2:								\
> -		__get_user_asm("lhu", (ptr), __gu_val, __gu_err);	\
> +		__get_user_asm("lhu", (ptr), x, __gu_err);		\
>   		break;							\
>   	case 4:								\
> -		__get_user_asm("lw", (ptr), __gu_val, __gu_err);	\
> +		__get_user_asm("lw", (ptr), x, __gu_err);		\
>   		break;							\
> -	case 8:								\
> -		__gu_err = __copy_from_user(&__gu_val, ptr, 8);		\
> -		if (__gu_err)						\
> -			__gu_err = -EFAULT;				\
> +	case 8: {							\
> +		__u64 __x = 0;						\
> +		__gu_err = raw_copy_from_user(&__x, ptr, 8) ?		\
> +							-EFAULT : 0;	\
> +		(x) = (typeof(x))(typeof((x) - (x)))__x;		\
>   		break;							\
> +	}								\
>   	default:							\
>   		/* __gu_val = 0; __gu_err = -EINVAL;*/ __gu_err = __user_bad();\
>   	}								\
> -	x = (__force __typeof__(*(ptr))) __gu_val;			\
>   	__gu_err;							\
>   })
>   
> diff --git a/arch/nios2/include/asm/uaccess.h b/arch/nios2/include/asm/uaccess.h
> index ba9340e96fd4..ca9285a915ef 100644
> --- a/arch/nios2/include/asm/uaccess.h
> +++ b/arch/nios2/include/asm/uaccess.h
> @@ -88,6 +88,7 @@ extern __must_check long strnlen_user(const char __user *s, long n);
>   /* Optimized macros */
>   #define __get_user_asm(val, insn, addr, err)				\
>   {									\
> +	unsigned long __gu_val;						\
>   	__asm__ __volatile__(						\
>   	"       movi    %0, %3\n"					\
>   	"1:   " insn " %1, 0(%2)\n"					\
> @@ -96,14 +97,20 @@ extern __must_check long strnlen_user(const char __user *s, long n);
>   	"       .section __ex_table,\"a\"\n"				\
>   	"       .word 1b, 2b\n"						\
>   	"       .previous"						\
> -	: "=&r" (err), "=r" (val)					\
> +	: "=&r" (err), "=r" (__gu_val)					\
>   	: "r" (addr), "i" (-EFAULT));					\
> +	val = (__force __typeof__(*(addr)))__gu_val;			\
>   }
>   
> -#define __get_user_unknown(val, size, ptr, err) do {			\
> +extern void __get_user_unknown(void);
> +
> +#define __get_user_8(val, ptr, err) do {				\
> +	u64 __val = 0;							\
>   	err = 0;							\
> -	if (__copy_from_user(&(val), ptr, size)) {			\
> +	if (raw_copy_from_user(&(__val), ptr, sizeof(val))) {		\
>   		err = -EFAULT;						\
> +	} else {							\
> +		val = (typeof(val))(typeof((val) - (val)))__val;	\
>   	}								\
>   	} while (0)
>   
> @@ -119,8 +126,11 @@ do {									\
>   	case 4:								\
>   		__get_user_asm(val, "ldw", ptr, err);			\
>   		break;							\
> +	case 8:								\
> +		__get_user_8(val, ptr, err);				\
> +		break;							\
>   	default:							\
> -		__get_user_unknown(val, size, ptr, err);		\
> +		__get_user_unknown();					\
>   		break;							\
>   	}								\
>   } while (0)
> @@ -129,9 +139,7 @@ do {									\
>   	({								\
>   	long __gu_err = -EFAULT;					\
>   	const __typeof__(*(ptr)) __user *__gu_ptr = (ptr);		\
> -	unsigned long __gu_val = 0;					\
> -	__get_user_common(__gu_val, sizeof(*(ptr)), __gu_ptr, __gu_err);\
> -	(x) = (__force __typeof__(x))__gu_val;				\
> +	__get_user_common(x, sizeof(*(ptr)), __gu_ptr, __gu_err);	\
>   	__gu_err;							\
>   	})
>   
> @@ -139,11 +147,9 @@ do {									\
>   ({									\
>   	long __gu_err = -EFAULT;					\
>   	const __typeof__(*(ptr)) __user *__gu_ptr = (ptr);		\
> -	unsigned long __gu_val = 0;					\
>   	if (access_ok( __gu_ptr, sizeof(*__gu_ptr)))	\
> -		__get_user_common(__gu_val, sizeof(*__gu_ptr),		\
> +		__get_user_common(x, sizeof(*__gu_ptr),			\
>   			__gu_ptr, __gu_err);				\
> -	(x) = (__force __typeof__(x))__gu_val;				\
>   	__gu_err;							\
>   })
>   

Acked-by: Dinh Nguyen <dinguyen@kernel.org>
diff mbox series

Patch

diff --git a/arch/microblaze/include/asm/uaccess.h b/arch/microblaze/include/asm/uaccess.h
index 5b6e0e7788f4..3fe96979d2c6 100644
--- a/arch/microblaze/include/asm/uaccess.h
+++ b/arch/microblaze/include/asm/uaccess.h
@@ -130,27 +130,27 @@  extern long __user_bad(void);
 
 #define __get_user(x, ptr)						\
 ({									\
-	unsigned long __gu_val = 0;					\
 	long __gu_err;							\
 	switch (sizeof(*(ptr))) {					\
 	case 1:								\
-		__get_user_asm("lbu", (ptr), __gu_val, __gu_err);	\
+		__get_user_asm("lbu", (ptr), x, __gu_err);		\
 		break;							\
 	case 2:								\
-		__get_user_asm("lhu", (ptr), __gu_val, __gu_err);	\
+		__get_user_asm("lhu", (ptr), x, __gu_err);		\
 		break;							\
 	case 4:								\
-		__get_user_asm("lw", (ptr), __gu_val, __gu_err);	\
+		__get_user_asm("lw", (ptr), x, __gu_err);		\
 		break;							\
-	case 8:								\
-		__gu_err = __copy_from_user(&__gu_val, ptr, 8);		\
-		if (__gu_err)						\
-			__gu_err = -EFAULT;				\
+	case 8: {							\
+		__u64 __x = 0;						\
+		__gu_err = raw_copy_from_user(&__x, ptr, 8) ?		\
+							-EFAULT : 0;	\
+		(x) = (typeof(x))(typeof((x) - (x)))__x;		\
 		break;							\
+	}								\
 	default:							\
 		/* __gu_val = 0; __gu_err = -EINVAL;*/ __gu_err = __user_bad();\
 	}								\
-	x = (__force __typeof__(*(ptr))) __gu_val;			\
 	__gu_err;							\
 })
 
diff --git a/arch/nios2/include/asm/uaccess.h b/arch/nios2/include/asm/uaccess.h
index ba9340e96fd4..ca9285a915ef 100644
--- a/arch/nios2/include/asm/uaccess.h
+++ b/arch/nios2/include/asm/uaccess.h
@@ -88,6 +88,7 @@  extern __must_check long strnlen_user(const char __user *s, long n);
 /* Optimized macros */
 #define __get_user_asm(val, insn, addr, err)				\
 {									\
+	unsigned long __gu_val;						\
 	__asm__ __volatile__(						\
 	"       movi    %0, %3\n"					\
 	"1:   " insn " %1, 0(%2)\n"					\
@@ -96,14 +97,20 @@  extern __must_check long strnlen_user(const char __user *s, long n);
 	"       .section __ex_table,\"a\"\n"				\
 	"       .word 1b, 2b\n"						\
 	"       .previous"						\
-	: "=&r" (err), "=r" (val)					\
+	: "=&r" (err), "=r" (__gu_val)					\
 	: "r" (addr), "i" (-EFAULT));					\
+	val = (__force __typeof__(*(addr)))__gu_val;			\
 }
 
-#define __get_user_unknown(val, size, ptr, err) do {			\
+extern void __get_user_unknown(void);
+
+#define __get_user_8(val, ptr, err) do {				\
+	u64 __val = 0;							\
 	err = 0;							\
-	if (__copy_from_user(&(val), ptr, size)) {			\
+	if (raw_copy_from_user(&(__val), ptr, sizeof(val))) {		\
 		err = -EFAULT;						\
+	} else {							\
+		val = (typeof(val))(typeof((val) - (val)))__val;	\
 	}								\
 	} while (0)
 
@@ -119,8 +126,11 @@  do {									\
 	case 4:								\
 		__get_user_asm(val, "ldw", ptr, err);			\
 		break;							\
+	case 8:								\
+		__get_user_8(val, ptr, err);				\
+		break;							\
 	default:							\
-		__get_user_unknown(val, size, ptr, err);		\
+		__get_user_unknown();					\
 		break;							\
 	}								\
 } while (0)
@@ -129,9 +139,7 @@  do {									\
 	({								\
 	long __gu_err = -EFAULT;					\
 	const __typeof__(*(ptr)) __user *__gu_ptr = (ptr);		\
-	unsigned long __gu_val = 0;					\
-	__get_user_common(__gu_val, sizeof(*(ptr)), __gu_ptr, __gu_err);\
-	(x) = (__force __typeof__(x))__gu_val;				\
+	__get_user_common(x, sizeof(*(ptr)), __gu_ptr, __gu_err);	\
 	__gu_err;							\
 	})
 
@@ -139,11 +147,9 @@  do {									\
 ({									\
 	long __gu_err = -EFAULT;					\
 	const __typeof__(*(ptr)) __user *__gu_ptr = (ptr);		\
-	unsigned long __gu_val = 0;					\
 	if (access_ok( __gu_ptr, sizeof(*__gu_ptr)))	\
-		__get_user_common(__gu_val, sizeof(*__gu_ptr),		\
+		__get_user_common(x, sizeof(*__gu_ptr),			\
 			__gu_ptr, __gu_err);				\
-	(x) = (__force __typeof__(x))__gu_val;				\
 	__gu_err;							\
 })