[tip: x86/cleanups] x86/uaccess: Add missing __force to casts in __access_ok() and valid_user_address()

[tip-bot2 for Thomas Gleixner]

The following commit has been merged into the x86/cleanups branch of tip:

Commit-ID:     ae6b0195f5c503f22673a4acf21111822305c1e0
Gitweb:        https://git.kernel.org/tip/ae6b0195f5c503f22673a4acf21111822305c1e0
Author:        Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate:    Mon, 04 Mar 2024 11:12:25 +01:00
Committer:     Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Mon, 04 Mar 2024 12:09:12 +01:00

x86/uaccess: Add missing __force to casts in __access_ok() and valid_user_address()

Sparse complains about losing the __user address space due to the cast to
long:

  uaccess_64.h:88:24: sparse: warning: cast removes address space '__user' of expression

Annotate it with __force to tell sparse that this is intentional.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20240304005104.677606054@xxxxxxxxxxxxx
---
 arch/x86/include/asm/uaccess_64.h | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/arch/x86/include/asm/uaccess_64.h b/arch/x86/include/asm/uaccess_64.h
index f2c02e4..d2a0c2a 100644
--- a/arch/x86/include/asm/uaccess_64.h
+++ b/arch/x86/include/asm/uaccess_64.h
@@ -54,7 +54,7 @@ static inline unsigned long __untagged_addr_remote(struct mm_struct *mm,
  * half and a user half.  When cast to a signed type, user pointers
  * are positive and kernel pointers are negative.
  */
-#define valid_user_address(x) ((long)(x) >= 0)
+#define valid_user_address(x) ((__force long)(x) >= 0)
 
 /*
  * User pointers can have tag bits on x86-64.  This scheme tolerates
@@ -87,8 +87,9 @@ static inline bool __access_ok(const void __user *ptr, unsigned long size)
 	if (__builtin_constant_p(size <= PAGE_SIZE) && size <= PAGE_SIZE) {
 		return valid_user_address(ptr);
 	} else {
-		unsigned long sum = size + (unsigned long)ptr;
-		return valid_user_address(sum) && sum >= (unsigned long)ptr;
+		unsigned long sum = size + (__force unsigned long)ptr;
+
+		return valid_user_address(sum) && sum >= (__force unsigned long)ptr;
 	}
 }
 #define __access_ok __access_ok