[PATCH 1/2] tile: fix put_user sparse errors

[PATCH 1/2] tile: fix put_user sparse errors

[Chris Metcalf]

Use x86's __inttype macro instead of using the typeof(x-x) trick to
generate a suitable integer size type.  This avoids a sparse warning
when examining the x-x type with a bitwise type.

Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com>
---
 arch/tile/include/asm/uaccess.h | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/arch/tile/include/asm/uaccess.h b/arch/tile/include/asm/uaccess.h
index b6cde3209b96..b81b24a8489b 100644
--- a/arch/tile/include/asm/uaccess.h
+++ b/arch/tile/include/asm/uaccess.h
@@ -114,14 +114,14 @@ struct exception_table_entry {
 extern int fixup_exception(struct pt_regs *regs);
 
 /*
+ * This is a type: either unsigned long, if the argument fits into
+ * that type, or otherwise unsigned long long.
+ */
+#define __inttype(x) \
+	__typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL))
+
+/*
  * Support macros for __get_user().
- *
- * Implementation note: The "case 8" logic of casting to the type of
- * the result of subtracting the value from itself is basically a way
- * of keeping all integer types the same, but casting any pointers to
- * ptrdiff_t, i.e. also an integer type.  This way there are no
- * questionable casts seen by the compiler on an ILP32 platform.
- *
  * Note that __get_user() and __put_user() assume proper alignment.
  */
 
@@ -178,7 +178,7 @@ extern int fixup_exception(struct pt_regs *regs);
 			     "9:"					\
 			     : "=r" (ret), "=r" (__a), "=&r" (__b)	\
 			     : "r" (ptr), "i" (-EFAULT));		\
-		(x) = (__typeof(x))(__typeof((x)-(x)))			\
+		(x) = (__force __typeof(x))(__inttype(x))		\
 			(((u64)__hi32(__a, __b) << 32) |		\
 			 __lo32(__a, __b));				\
 	})
@@ -246,7 +246,7 @@ extern int __get_user_bad(void)
 #define __put_user_4(x, ptr, ret) __put_user_asm(sw, x, ptr, ret)
 #define __put_user_8(x, ptr, ret)					\
 	({								\
-		u64 __x = (__typeof((x)-(x)))(x);			\
+		u64 __x = (__force __inttype(x))(x);			\
 		int __lo = (int) __x, __hi = (int) (__x >> 32);		\
 		asm volatile("1: { sw %1, %2; addi %0, %1, 4 }\n"	\
 			     "2: { sw %0, %3; movei %0, 0 }\n"		\
-- 
2.1.2

[PATCH 1/2] tile: fix put_user sparse errors

[Chris Metcalf]

Use x86's __inttype macro instead of using the typeof(x-x) trick to
generate a suitable integer size type.  This avoids a sparse warning
when examining the x-x type with a bitwise type.

Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com>
---
 arch/tile/include/asm/uaccess.h | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/arch/tile/include/asm/uaccess.h b/arch/tile/include/asm/uaccess.h
index b6cde3209b96..b81b24a8489b 100644
--- a/arch/tile/include/asm/uaccess.h
+++ b/arch/tile/include/asm/uaccess.h
@@ -114,14 +114,14 @@ struct exception_table_entry {
 extern int fixup_exception(struct pt_regs *regs);
 
 /*
+ * This is a type: either unsigned long, if the argument fits into
+ * that type, or otherwise unsigned long long.
+ */
+#define __inttype(x) \
+	__typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL))
+
+/*
  * Support macros for __get_user().
- *
- * Implementation note: The "case 8" logic of casting to the type of
- * the result of subtracting the value from itself is basically a way
- * of keeping all integer types the same, but casting any pointers to
- * ptrdiff_t, i.e. also an integer type.  This way there are no
- * questionable casts seen by the compiler on an ILP32 platform.
- *
  * Note that __get_user() and __put_user() assume proper alignment.
  */
 
@@ -178,7 +178,7 @@ extern int fixup_exception(struct pt_regs *regs);
 			     "9:"					\
 			     : "=r" (ret), "=r" (__a), "=&r" (__b)	\
 			     : "r" (ptr), "i" (-EFAULT));		\
-		(x) = (__typeof(x))(__typeof((x)-(x)))			\
+		(x) = (__force __typeof(x))(__inttype(x))		\
 			(((u64)__hi32(__a, __b) << 32) |		\
 			 __lo32(__a, __b));				\
 	})
@@ -246,7 +246,7 @@ extern int __get_user_bad(void)
 #define __put_user_4(x, ptr, ret) __put_user_asm(sw, x, ptr, ret)
 #define __put_user_8(x, ptr, ret)					\
 	({								\
-		u64 __x = (__typeof((x)-(x)))(x);			\
+		u64 __x = (__force __inttype(x))(x);			\
 		int __lo = (int) __x, __hi = (int) (__x >> 32);		\
 		asm volatile("1: { sw %1, %2; addi %0, %1, 4 }\n"	\
 			     "2: { sw %0, %3; movei %0, 0 }\n"		\
-- 
2.1.2

[PATCH 2/2] tile: enable sparse checks for get/put_user

[Chris Metcalf]

Add an extra intermediate variable to __get_user and __put_user
to give sparse an opportunity to detect mismatches.

Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com>
---
 arch/tile/include/asm/uaccess.h | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/arch/tile/include/asm/uaccess.h b/arch/tile/include/asm/uaccess.h
index b81b24a8489b..f41cb53cf645 100644
--- a/arch/tile/include/asm/uaccess.h
+++ b/arch/tile/include/asm/uaccess.h
@@ -210,14 +210,16 @@ extern int __get_user_bad(void)
 #define __get_user(x, ptr)						\
 	({								\
 		int __ret;						\
+		typeof(x) _x;						\
 		__chk_user_ptr(ptr);					\
 		switch (sizeof(*(ptr))) {				\
-		case 1: __get_user_1(x, ptr, __ret); break;		\
-		case 2: __get_user_2(x, ptr, __ret); break;		\
-		case 4: __get_user_4(x, ptr, __ret); break;		\
-		case 8: __get_user_8(x, ptr, __ret); break;		\
+		case 1: __get_user_1(_x, ptr, __ret); break;		\
+		case 2: __get_user_2(_x, ptr, __ret); break;		\
+		case 4: __get_user_4(_x, ptr, __ret); break;		\
+		case 8: __get_user_8(_x, ptr, __ret); break;		\
 		default: __ret = __get_user_bad(); break;		\
 		}							\
+		(x) = (typeof(*(ptr))) _x;				\
 		__ret;							\
 	})
 
@@ -289,12 +291,13 @@ extern int __put_user_bad(void)
 #define __put_user(x, ptr)						\
 ({									\
 	int __ret;							\
+	typeof(*(ptr)) _x = (x);					\
 	__chk_user_ptr(ptr);						\
 	switch (sizeof(*(ptr))) {					\
-	case 1: __put_user_1(x, ptr, __ret); break;			\
-	case 2: __put_user_2(x, ptr, __ret); break;			\
-	case 4: __put_user_4(x, ptr, __ret); break;			\
-	case 8: __put_user_8(x, ptr, __ret); break;			\
+	case 1: __put_user_1(_x, ptr, __ret); break;			\
+	case 2: __put_user_2(_x, ptr, __ret); break;			\
+	case 4: __put_user_4(_x, ptr, __ret); break;			\
+	case 8: __put_user_8(_x, ptr, __ret); break;			\
 	default: __ret = __put_user_bad(); break;			\
 	}								\
 	__ret;								\
-- 
2.1.2

[PATCH 2/2] tile: enable sparse checks for get/put_user

[Chris Metcalf]

Add an extra intermediate variable to __get_user and __put_user
to give sparse an opportunity to detect mismatches.

Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com>
---
 arch/tile/include/asm/uaccess.h | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/arch/tile/include/asm/uaccess.h b/arch/tile/include/asm/uaccess.h
index b81b24a8489b..f41cb53cf645 100644
--- a/arch/tile/include/asm/uaccess.h
+++ b/arch/tile/include/asm/uaccess.h
@@ -210,14 +210,16 @@ extern int __get_user_bad(void)
 #define __get_user(x, ptr)						\
 	({								\
 		int __ret;						\
+		typeof(x) _x;						\
 		__chk_user_ptr(ptr);					\
 		switch (sizeof(*(ptr))) {				\
-		case 1: __get_user_1(x, ptr, __ret); break;		\
-		case 2: __get_user_2(x, ptr, __ret); break;		\
-		case 4: __get_user_4(x, ptr, __ret); break;		\
-		case 8: __get_user_8(x, ptr, __ret); break;		\
+		case 1: __get_user_1(_x, ptr, __ret); break;		\
+		case 2: __get_user_2(_x, ptr, __ret); break;		\
+		case 4: __get_user_4(_x, ptr, __ret); break;		\
+		case 8: __get_user_8(_x, ptr, __ret); break;		\
 		default: __ret = __get_user_bad(); break;		\
 		}							\
+		(x) = (typeof(*(ptr))) _x;				\
 		__ret;							\
 	})
 
@@ -289,12 +291,13 @@ extern int __put_user_bad(void)
 #define __put_user(x, ptr)						\
 ({									\
 	int __ret;							\
+	typeof(*(ptr)) _x = (x);					\
 	__chk_user_ptr(ptr);						\
 	switch (sizeof(*(ptr))) {					\
-	case 1: __put_user_1(x, ptr, __ret); break;			\
-	case 2: __put_user_2(x, ptr, __ret); break;			\
-	case 4: __put_user_4(x, ptr, __ret); break;			\
-	case 8: __put_user_8(x, ptr, __ret); break;			\
+	case 1: __put_user_1(_x, ptr, __ret); break;			\
+	case 2: __put_user_2(_x, ptr, __ret); break;			\
+	case 4: __put_user_4(_x, ptr, __ret); break;			\
+	case 8: __put_user_8(_x, ptr, __ret); break;			\
 	default: __ret = __put_user_bad(); break;			\
 	}								\
 	__ret;								\
-- 
2.1.2

Re: [PATCH 1/2] tile: fix put_user sparse errors

[Michael S. Tsirkin]

On Tue, Jan 13, 2015 at 02:39:05PM -0500, Chris Metcalf wrote:
> Use x86's __inttype macro instead of using the typeof(x-x) trick to
> generate a suitable integer size type.  This avoids a sparse warning
> when examining the x-x type with a bitwise type.
> 
> Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com>

Reviewed-by: Michael S. Tsirkin <mst@redhat.com>

> ---
>  arch/tile/include/asm/uaccess.h | 18 +++++++++---------
>  1 file changed, 9 insertions(+), 9 deletions(-)
> 
> diff --git a/arch/tile/include/asm/uaccess.h b/arch/tile/include/asm/uaccess.h
> index b6cde3209b96..b81b24a8489b 100644
> --- a/arch/tile/include/asm/uaccess.h
> +++ b/arch/tile/include/asm/uaccess.h
> @@ -114,14 +114,14 @@ struct exception_table_entry {
>  extern int fixup_exception(struct pt_regs *regs);
>  
>  /*
> + * This is a type: either unsigned long, if the argument fits into
> + * that type, or otherwise unsigned long long.
> + */
> +#define __inttype(x) \
> +	__typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL))
> +
> +/*
>   * Support macros for __get_user().
> - *
> - * Implementation note: The "case 8" logic of casting to the type of
> - * the result of subtracting the value from itself is basically a way
> - * of keeping all integer types the same, but casting any pointers to
> - * ptrdiff_t, i.e. also an integer type.  This way there are no
> - * questionable casts seen by the compiler on an ILP32 platform.
> - *
>   * Note that __get_user() and __put_user() assume proper alignment.
>   */
>  
> @@ -178,7 +178,7 @@ extern int fixup_exception(struct pt_regs *regs);
>  			     "9:"					\
>  			     : "=r" (ret), "=r" (__a), "=&r" (__b)	\
>  			     : "r" (ptr), "i" (-EFAULT));		\
> -		(x) = (__typeof(x))(__typeof((x)-(x)))			\
> +		(x) = (__force __typeof(x))(__inttype(x))		\
>  			(((u64)__hi32(__a, __b) << 32) |		\
>  			 __lo32(__a, __b));				\
>  	})
> @@ -246,7 +246,7 @@ extern int __get_user_bad(void)
>  #define __put_user_4(x, ptr, ret) __put_user_asm(sw, x, ptr, ret)
>  #define __put_user_8(x, ptr, ret)					\
>  	({								\
> -		u64 __x = (__typeof((x)-(x)))(x);			\
> +		u64 __x = (__force __inttype(x))(x);			\
>  		int __lo = (int) __x, __hi = (int) (__x >> 32);		\
>  		asm volatile("1: { sw %1, %2; addi %0, %1, 4 }\n"	\
>  			     "2: { sw %0, %3; movei %0, 0 }\n"		\
> -- 
> 2.1.2

Re: [PATCH 1/2] tile: fix put_user sparse errors

[Michael S. Tsirkin]

On Tue, Jan 13, 2015 at 02:39:05PM -0500, Chris Metcalf wrote:
> Use x86's __inttype macro instead of using the typeof(x-x) trick to
> generate a suitable integer size type.  This avoids a sparse warning
> when examining the x-x type with a bitwise type.
> 
> Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com>

Reviewed-by: Michael S. Tsirkin <mst@redhat.com>

> ---
>  arch/tile/include/asm/uaccess.h | 18 +++++++++---------
>  1 file changed, 9 insertions(+), 9 deletions(-)
> 
> diff --git a/arch/tile/include/asm/uaccess.h b/arch/tile/include/asm/uaccess.h
> index b6cde3209b96..b81b24a8489b 100644
> --- a/arch/tile/include/asm/uaccess.h
> +++ b/arch/tile/include/asm/uaccess.h
> @@ -114,14 +114,14 @@ struct exception_table_entry {
>  extern int fixup_exception(struct pt_regs *regs);
>  
>  /*
> + * This is a type: either unsigned long, if the argument fits into
> + * that type, or otherwise unsigned long long.
> + */
> +#define __inttype(x) \
> +	__typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL))
> +
> +/*
>   * Support macros for __get_user().
> - *
> - * Implementation note: The "case 8" logic of casting to the type of
> - * the result of subtracting the value from itself is basically a way
> - * of keeping all integer types the same, but casting any pointers to
> - * ptrdiff_t, i.e. also an integer type.  This way there are no
> - * questionable casts seen by the compiler on an ILP32 platform.
> - *
>   * Note that __get_user() and __put_user() assume proper alignment.
>   */
>  
> @@ -178,7 +178,7 @@ extern int fixup_exception(struct pt_regs *regs);
>  			     "9:"					\
>  			     : "=r" (ret), "=r" (__a), "=&r" (__b)	\
>  			     : "r" (ptr), "i" (-EFAULT));		\
> -		(x) = (__typeof(x))(__typeof((x)-(x)))			\
> +		(x) = (__force __typeof(x))(__inttype(x))		\
>  			(((u64)__hi32(__a, __b) << 32) |		\
>  			 __lo32(__a, __b));				\
>  	})
> @@ -246,7 +246,7 @@ extern int __get_user_bad(void)
>  #define __put_user_4(x, ptr, ret) __put_user_asm(sw, x, ptr, ret)
>  #define __put_user_8(x, ptr, ret)					\
>  	({								\
> -		u64 __x = (__typeof((x)-(x)))(x);			\
> +		u64 __x = (__force __inttype(x))(x);			\
>  		int __lo = (int) __x, __hi = (int) (__x >> 32);		\
>  		asm volatile("1: { sw %1, %2; addi %0, %1, 4 }\n"	\
>  			     "2: { sw %0, %3; movei %0, 0 }\n"		\
> -- 
> 2.1.2

Re: [PATCH 2/2] tile: enable sparse checks for get/put_user

[Michael S. Tsirkin]

On Tue, Jan 13, 2015 at 02:41:20PM -0500, Chris Metcalf wrote:
> Add an extra intermediate variable to __get_user and __put_user
> to give sparse an opportunity to detect mismatches.
> 
> Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com>

Reviewed-by: Michael S. Tsirkin <mst@redhat.com>

> ---
>  arch/tile/include/asm/uaccess.h | 19 +++++++++++--------
>  1 file changed, 11 insertions(+), 8 deletions(-)
> 
> diff --git a/arch/tile/include/asm/uaccess.h b/arch/tile/include/asm/uaccess.h
> index b81b24a8489b..f41cb53cf645 100644
> --- a/arch/tile/include/asm/uaccess.h
> +++ b/arch/tile/include/asm/uaccess.h
> @@ -210,14 +210,16 @@ extern int __get_user_bad(void)
>  #define __get_user(x, ptr)						\
>  	({								\
>  		int __ret;						\
> +		typeof(x) _x;						\
>  		__chk_user_ptr(ptr);					\
>  		switch (sizeof(*(ptr))) {				\
> -		case 1: __get_user_1(x, ptr, __ret); break;		\
> -		case 2: __get_user_2(x, ptr, __ret); break;		\
> -		case 4: __get_user_4(x, ptr, __ret); break;		\
> -		case 8: __get_user_8(x, ptr, __ret); break;		\
> +		case 1: __get_user_1(_x, ptr, __ret); break;		\
> +		case 2: __get_user_2(_x, ptr, __ret); break;		\
> +		case 4: __get_user_4(_x, ptr, __ret); break;		\
> +		case 8: __get_user_8(_x, ptr, __ret); break;		\
>  		default: __ret = __get_user_bad(); break;		\
>  		}							\
> +		(x) = (typeof(*(ptr))) _x;				\
>  		__ret;							\
>  	})
>  
> @@ -289,12 +291,13 @@ extern int __put_user_bad(void)
>  #define __put_user(x, ptr)						\
>  ({									\
>  	int __ret;							\
> +	typeof(*(ptr)) _x = (x);					\
>  	__chk_user_ptr(ptr);						\
>  	switch (sizeof(*(ptr))) {					\
> -	case 1: __put_user_1(x, ptr, __ret); break;			\
> -	case 2: __put_user_2(x, ptr, __ret); break;			\
> -	case 4: __put_user_4(x, ptr, __ret); break;			\
> -	case 8: __put_user_8(x, ptr, __ret); break;			\
> +	case 1: __put_user_1(_x, ptr, __ret); break;			\
> +	case 2: __put_user_2(_x, ptr, __ret); break;			\
> +	case 4: __put_user_4(_x, ptr, __ret); break;			\
> +	case 8: __put_user_8(_x, ptr, __ret); break;			\
>  	default: __ret = __put_user_bad(); break;			\
>  	}								\
>  	__ret;								\
> -- 
> 2.1.2