x86: remove __range_not_ok()

The __range_not_ok() helper is an x86 (and sparc64) specific interface
that does roughly the same thing as __access_ok(), but with different
calling conventions.

Change this to use the normal interface in order for consistency as we
clean up all access_ok() implementations.

This changes the limit from TASK_SIZE to TASK_SIZE_MAX, which Al points
out is the right thing do do here anyway.

The callers have to use __access_ok() instead of the normal access_ok()
though, because on x86 that contains a WARN_ON_IN_IRQ() check that cannot
be used inside of NMI context while tracing.

The check in copy_code() is not needed any more, because this one is
already done by copy_from_user_nmi().

Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Suggested-by: Christoph Hellwig <hch@infradead.org>
Link: https://lore.kernel.org/lkml/YgsUKcXGR7r4nINj@zeniv-ca.linux.org.uk/
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

1 files changed, 6 insertions, 4 deletions

diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
index ac96f9b2d64b..79c4869ccdd6 100644
--- a/arch/x86/include/asm/uaccess.h
+++ b/arch/x86/include/asm/uaccess.h
@@ -16,8 +16,10 @@
  * Test whether a block of memory is a valid user space address.
  * Returns 0 if the range is valid, nonzero otherwise.
  */
-static inline bool __chk_range_not_ok(unsigned long addr, unsigned long size, unsigned long limit)
+static inline bool __chk_range_not_ok(unsigned long addr, unsigned long size)
 {
+	unsigned long limit = TASK_SIZE_MAX;
+
 	/*
 	 * If we have used "sizeof()" for the size,
 	 * we know it won't overflow the limit (but
@@ -35,10 +37,10 @@ static inline bool __chk_range_not_ok(unsigned long addr, unsigned long size, un
 	return unlikely(addr > limit);
 }
 
-#define __range_not_ok(addr, size, limit)				\
+#define __access_ok(addr, size)						\
 ({									\
 	__chk_user_ptr(addr);						\
-	__chk_range_not_ok((unsigned long __force)(addr), size, limit); \
+	!__chk_range_not_ok((unsigned long __force)(addr), size);	\
 })
 
 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
@@ -69,7 +71,7 @@ static inline bool pagefault_disabled(void);
 #define access_ok(addr, size)					\
 ({									\
 	WARN_ON_IN_IRQ();						\
-	likely(!__range_not_ok(addr, size, TASK_SIZE_MAX));		\
+	likely(__access_ok(addr, size));				\
 })
 
 extern int __get_user_1(void);