kasan: support instrumented bitops combined with generic bitops

Currently bitops-instrumented.h assumes that the architecture provides
atomic, non-atomic and locking bitops (e.g. both set_bit and __set_bit).
This is true on x86 and s390, but is not always true: there is a
generic bitops/non-atomic.h header that provides generic non-atomic
operations, and also a generic bitops/lock.h for locking operations.

powerpc uses the generic non-atomic version, so it does not have it's
own e.g. __set_bit that could be renamed arch___set_bit.

Split up bitops-instrumented.h to mirror the atomic/non-atomic/lock
split. This allows arches to only include the headers where they
have arch-specific versions to rename. Update x86 and s390.

(The generic operations are automatically instrumented because they're
written in C, not asm.)
Suggested-by: Christophe Leroy <christophe.leroy@c-s.fr>
Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Daniel Axtens <dja@axtens.net>
Acked-by: Marco Elver <elver@google.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190820024941.12640-1-dja@axtens.net

Documentation/core-api/kernel-api.rst

@@ -57,7 +57,22 @@ The Linux kernel provides more basic utility functions.
 Bit Operations
 --------------
 
-.. kernel-doc:: include/asm-generic/bitops-instrumented.h
+Atomic Operations
+~~~~~~~~~~~~~~~~~
+
+.. kernel-doc:: include/asm-generic/bitops/instrumented-atomic.h
+   :internal:
+
+Non-atomic Operations
+~~~~~~~~~~~~~~~~~~~~~
+
+.. kernel-doc:: include/asm-generic/bitops/instrumented-non-atomic.h
+   :internal:
+
+Locking Operations
+~~~~~~~~~~~~~~~~~~
+
+.. kernel-doc:: include/asm-generic/bitops/instrumented-lock.h
    :internal:
 
 Bitmap Operations

arch/s390/include/asm/bitops.h

@@ -241,7 +241,9 @@ static inline void arch___clear_bit_unlock(unsigned long nr,
 	arch___clear_bit(nr, ptr);
 }
 
-#include <asm-generic/bitops-instrumented.h>
+#include <asm-generic/bitops/instrumented-atomic.h>
+#include <asm-generic/bitops/instrumented-non-atomic.h>
+#include <asm-generic/bitops/instrumented-lock.h>
 
 /*
  * Functions which use MSB0 bit numbering.

arch/x86/include/asm/bitops.h

@@ -388,7 +388,9 @@ static __always_inline int fls64(__u64 x)
 
 #include <asm-generic/bitops/const_hweight.h>
 
-#include <asm-generic/bitops-instrumented.h>
+#include <asm-generic/bitops/instrumented-atomic.h>
+#include <asm-generic/bitops/instrumented-non-atomic.h>
+#include <asm-generic/bitops/instrumented-lock.h>
 
 #include <asm-generic/bitops/le.h>
 

include/asm-generic/bitops/instrumented-atomic.h

+/* SPDX-License-Identifier: GPL-2.0 */
+
+/*
+ * This file provides wrappers with sanitizer instrumentation for atomic bit
+ * operations.
+ *
+ * To use this functionality, an arch's bitops.h file needs to define each of
+ * the below bit operations with an arch_ prefix (e.g. arch_set_bit(),
+ * arch___set_bit(), etc.).
+ */
+#ifndef _ASM_GENERIC_BITOPS_INSTRUMENTED_ATOMIC_H
+#define _ASM_GENERIC_BITOPS_INSTRUMENTED_ATOMIC_H
+
+#include <linux/kasan-checks.h>
+
+/**
+ * set_bit - Atomically set a bit in memory
+ * @nr: the bit to set
+ * @addr: the address to start counting from
+ *
+ * This is a relaxed atomic operation (no implied memory barriers).
+ *
+ * Note that @nr may be almost arbitrarily large; this function is not
+ * restricted to acting on a single-word quantity.
+ */
+static inline void set_bit(long nr, volatile unsigned long *addr)
+{
+	kasan_check_write(addr + BIT_WORD(nr), sizeof(long));
+	arch_set_bit(nr, addr);
+}
+
+/**
+ * clear_bit - Clears a bit in memory
+ * @nr: Bit to clear
+ * @addr: Address to start counting from
+ *
+ * This is a relaxed atomic operation (no implied memory barriers).
+ */
+static inline void clear_bit(long nr, volatile unsigned long *addr)
+{
+	kasan_check_write(addr + BIT_WORD(nr), sizeof(long));
+	arch_clear_bit(nr, addr);
+}
+
+/**
+ * change_bit - Toggle a bit in memory
+ * @nr: Bit to change
+ * @addr: Address to start counting from
+ *
+ * This is a relaxed atomic operation (no implied memory barriers).
+ *
+ * Note that @nr may be almost arbitrarily large; this function is not
+ * restricted to acting on a single-word quantity.
+ */
+static inline void change_bit(long nr, volatile unsigned long *addr)
+{
+	kasan_check_write(addr + BIT_WORD(nr), sizeof(long));
+	arch_change_bit(nr, addr);
+}
+
+/**
+ * test_and_set_bit - Set a bit and return its old value
+ * @nr: Bit to set
+ * @addr: Address to count from
+ *
+ * This is an atomic fully-ordered operation (implied full memory barrier).
+ */
+static inline bool test_and_set_bit(long nr, volatile unsigned long *addr)
+{
+	kasan_check_write(addr + BIT_WORD(nr), sizeof(long));
+	return arch_test_and_set_bit(nr, addr);
+}
+
+/**
+ * test_and_clear_bit - Clear a bit and return its old value
+ * @nr: Bit to clear
+ * @addr: Address to count from
+ *
+ * This is an atomic fully-ordered operation (implied full memory barrier).
+ */
+static inline bool test_and_clear_bit(long nr, volatile unsigned long *addr)
+{
+	kasan_check_write(addr + BIT_WORD(nr), sizeof(long));
+	return arch_test_and_clear_bit(nr, addr);
+}
+
+/**
+ * test_and_change_bit - Change a bit and return its old value
+ * @nr: Bit to change
+ * @addr: Address to count from
+ *
+ * This is an atomic fully-ordered operation (implied full memory barrier).
+ */
+static inline bool test_and_change_bit(long nr, volatile unsigned long *addr)
+{
+	kasan_check_write(addr + BIT_WORD(nr), sizeof(long));
+	return arch_test_and_change_bit(nr, addr);
+}
+
+#endif /* _ASM_GENERIC_BITOPS_INSTRUMENTED_NON_ATOMIC_H */

include/asm-generic/bitops/instrumented-lock.h

+/* SPDX-License-Identifier: GPL-2.0 */
+
+/*
+ * This file provides wrappers with sanitizer instrumentation for bit
+ * locking operations.
+ *
+ * To use this functionality, an arch's bitops.h file needs to define each of
+ * the below bit operations with an arch_ prefix (e.g. arch_set_bit(),
+ * arch___set_bit(), etc.).
+ */
+#ifndef _ASM_GENERIC_BITOPS_INSTRUMENTED_LOCK_H
+#define _ASM_GENERIC_BITOPS_INSTRUMENTED_LOCK_H
+
+#include <linux/kasan-checks.h>
+
+/**
+ * clear_bit_unlock - Clear a bit in memory, for unlock
+ * @nr: the bit to set
+ * @addr: the address to start counting from
+ *
+ * This operation is atomic and provides release barrier semantics.
+ */
+static inline void clear_bit_unlock(long nr, volatile unsigned long *addr)
+{
+	kasan_check_write(addr + BIT_WORD(nr), sizeof(long));
+	arch_clear_bit_unlock(nr, addr);
+}
+
+/**
+ * __clear_bit_unlock - Clears a bit in memory
+ * @nr: Bit to clear
+ * @addr: Address to start counting from
+ *
+ * This is a non-atomic operation but implies a release barrier before the
+ * memory operation. It can be used for an unlock if no other CPUs can
+ * concurrently modify other bits in the word.
+ */
+static inline void __clear_bit_unlock(long nr, volatile unsigned long *addr)
+{
+	kasan_check_write(addr + BIT_WORD(nr), sizeof(long));
+	arch___clear_bit_unlock(nr, addr);
+}
+
+/**
+ * test_and_set_bit_lock - Set a bit and return its old value, for lock
+ * @nr: Bit to set
+ * @addr: Address to count from
+ *
+ * This operation is atomic and provides acquire barrier semantics if
+ * the returned value is 0.
+ * It can be used to implement bit locks.
+ */
+static inline bool test_and_set_bit_lock(long nr, volatile unsigned long *addr)
+{
+	kasan_check_write(addr + BIT_WORD(nr), sizeof(long));
+	return arch_test_and_set_bit_lock(nr, addr);
+}
+
+#if defined(arch_clear_bit_unlock_is_negative_byte)
+/**
+ * clear_bit_unlock_is_negative_byte - Clear a bit in memory and test if bottom
+ *                                     byte is negative, for unlock.
+ * @nr: the bit to clear
+ * @addr: the address to start counting from
+ *
+ * This operation is atomic and provides release barrier semantics.
+ *
+ * This is a bit of a one-trick-pony for the filemap code, which clears
+ * PG_locked and tests PG_waiters,
+ */
+static inline bool
+clear_bit_unlock_is_negative_byte(long nr, volatile unsigned long *addr)
+{
+	kasan_check_write(addr + BIT_WORD(nr), sizeof(long));
+	return arch_clear_bit_unlock_is_negative_byte(nr, addr);
+}
+/* Let everybody know we have it. */
+#define clear_bit_unlock_is_negative_byte clear_bit_unlock_is_negative_byte
+#endif
+
+#endif /* _ASM_GENERIC_BITOPS_INSTRUMENTED_LOCK_H */

include/asm-generic/bitops-instrumented.h → include/asm-generic/bitops/instrumented-non-atomic.h

 /* SPDX-License-Identifier: GPL-2.0 */
 
 /*
- * This file provides wrappers with sanitizer instrumentation for bit
- * operations.
+ * This file provides wrappers with sanitizer instrumentation for non-atomic
+ * bit operations.
  *
  * To use this functionality, an arch's bitops.h file needs to define each of
  * the below bit operations with an arch_ prefix (e.g. arch_set_bit(),
  * arch___set_bit(), etc.).
  */
-#ifndef _ASM_GENERIC_BITOPS_INSTRUMENTED_H
-#define _ASM_GENERIC_BITOPS_INSTRUMENTED_H
+#ifndef _ASM_GENERIC_BITOPS_INSTRUMENTED_NON_ATOMIC_H
+#define _ASM_GENERIC_BITOPS_INSTRUMENTED_NON_ATOMIC_H
 
 #include <linux/kasan-checks.h>
 
-/**
- * set_bit - Atomically set a bit in memory
- * @nr: the bit to set
- * @addr: the address to start counting from
- *
- * This is a relaxed atomic operation (no implied memory barriers).
- *
- * Note that @nr may be almost arbitrarily large; this function is not
- * restricted to acting on a single-word quantity.
- */
-static inline void set_bit(long nr, volatile unsigned long *addr)
-{
-	kasan_check_write(addr + BIT_WORD(nr), sizeof(long));
-	arch_set_bit(nr, addr);
-}
-
 /**
  * __set_bit - Set a bit in memory
  * @nr: the bit to set
@@ -44,19 +28,6 @@ static inline void __set_bit(long nr, volatile unsigned long *addr)
 	arch___set_bit(nr, addr);
 }
 
-/**
- * clear_bit - Clears a bit in memory
- * @nr: Bit to clear
- * @addr: Address to start counting from
- *
- * This is a relaxed atomic operation (no implied memory barriers).
- */
-static inline void clear_bit(long nr, volatile unsigned long *addr)
-{
-	kasan_check_write(addr + BIT_WORD(nr), sizeof(long));
-	arch_clear_bit(nr, addr);
-}
-
 /**
  * __clear_bit - Clears a bit in memory
  * @nr: the bit to clear
@@ -72,50 +43,6 @@ static inline void __clear_bit(long nr, volatile unsigned long *addr)
 	arch___clear_bit(nr, addr);
 }
 
-/**
- * clear_bit_unlock - Clear a bit in memory, for unlock
- * @nr: the bit to set
- * @addr: the address to start counting from
- *
- * This operation is atomic and provides release barrier semantics.
- */
-static inline void clear_bit_unlock(long nr, volatile unsigned long *addr)
-{
-	kasan_check_write(addr + BIT_WORD(nr), sizeof(long));
-	arch_clear_bit_unlock(nr, addr);
-}
-
-/**
- * __clear_bit_unlock - Clears a bit in memory
- * @nr: Bit to clear
- * @addr: Address to start counting from
- *
- * This is a non-atomic operation but implies a release barrier before the
- * memory operation. It can be used for an unlock if no other CPUs can
- * concurrently modify other bits in the word.
- */
-static inline void __clear_bit_unlock(long nr, volatile unsigned long *addr)
-{
-	kasan_check_write(addr + BIT_WORD(nr), sizeof(long));
-	arch___clear_bit_unlock(nr, addr);
-}
-
-/**
- * change_bit - Toggle a bit in memory
- * @nr: Bit to change
- * @addr: Address to start counting from
- *
- * This is a relaxed atomic operation (no implied memory barriers).
- *
- * Note that @nr may be almost arbitrarily large; this function is not
- * restricted to acting on a single-word quantity.
- */
-static inline void change_bit(long nr, volatile unsigned long *addr)
-{
-	kasan_check_write(addr + BIT_WORD(nr), sizeof(long));
-	arch_change_bit(nr, addr);
-}
-
 /**
  * __change_bit - Toggle a bit in memory
  * @nr: the bit to change
@@ -131,19 +58,6 @@ static inline void __change_bit(long nr, volatile unsigned long *addr)
 	arch___change_bit(nr, addr);
 }
 
-/**
- * test_and_set_bit - Set a bit and return its old value
- * @nr: Bit to set
- * @addr: Address to count from
- *
- * This is an atomic fully-ordered operation (implied full memory barrier).
- */
-static inline bool test_and_set_bit(long nr, volatile unsigned long *addr)
-{
-	kasan_check_write(addr + BIT_WORD(nr), sizeof(long));
-	return arch_test_and_set_bit(nr, addr);
-}
-
 /**
  * __test_and_set_bit - Set a bit and return its old value
  * @nr: Bit to set
@@ -158,34 +72,6 @@ static inline bool __test_and_set_bit(long nr, volatile unsigned long *addr)
 	return arch___test_and_set_bit(nr, addr);
 }
 
-/**
- * test_and_set_bit_lock - Set a bit and return its old value, for lock
- * @nr: Bit to set
- * @addr: Address to count from
- *
- * This operation is atomic and provides acquire barrier semantics if
- * the returned value is 0.
- * It can be used to implement bit locks.
- */
-static inline bool test_and_set_bit_lock(long nr, volatile unsigned long *addr)
-{
-	kasan_check_write(addr + BIT_WORD(nr), sizeof(long));
-	return arch_test_and_set_bit_lock(nr, addr);
-}
-
-/**
- * test_and_clear_bit - Clear a bit and return its old value
- * @nr: Bit to clear
- * @addr: Address to count from
- *
- * This is an atomic fully-ordered operation (implied full memory barrier).
- */
-static inline bool test_and_clear_bit(long nr, volatile unsigned long *addr)
-{
-	kasan_check_write(addr + BIT_WORD(nr), sizeof(long));
-	return arch_test_and_clear_bit(nr, addr);
-}
-
 /**
  * __test_and_clear_bit - Clear a bit and return its old value
  * @nr: Bit to clear
@@ -200,19 +86,6 @@ static inline bool __test_and_clear_bit(long nr, volatile unsigned long *addr)
 	return arch___test_and_clear_bit(nr, addr);
 }
 
-/**
- * test_and_change_bit - Change a bit and return its old value
- * @nr: Bit to change
- * @addr: Address to count from
- *
- * This is an atomic fully-ordered operation (implied full memory barrier).
- */
-static inline bool test_and_change_bit(long nr, volatile unsigned long *addr)
-{
-	kasan_check_write(addr + BIT_WORD(nr), sizeof(long));
-	return arch_test_and_change_bit(nr, addr);
-}
-
 /**
  * __test_and_change_bit - Change a bit and return its old value
  * @nr: Bit to change
@@ -238,26 +111,4 @@ static inline bool test_bit(long nr, const volatile unsigned long *addr)
 	return arch_test_bit(nr, addr);
 }
 
-#if defined(arch_clear_bit_unlock_is_negative_byte)
-/**
- * clear_bit_unlock_is_negative_byte - Clear a bit in memory and test if bottom
- *                                     byte is negative, for unlock.
- * @nr: the bit to clear
- * @addr: the address to start counting from
- *
- * This operation is atomic and provides release barrier semantics.
- *
- * This is a bit of a one-trick-pony for the filemap code, which clears
- * PG_locked and tests PG_waiters,
- */
-static inline bool
-clear_bit_unlock_is_negative_byte(long nr, volatile unsigned long *addr)
-{
-	kasan_check_write(addr + BIT_WORD(nr), sizeof(long));
-	return arch_clear_bit_unlock_is_negative_byte(nr, addr);
-}
-/* Let everybody know we have it. */
-#define clear_bit_unlock_is_negative_byte clear_bit_unlock_is_negative_byte
-#endif
-
-#endif /* _ASM_GENERIC_BITOPS_INSTRUMENTED_H */
+#endif /* _ASM_GENERIC_BITOPS_INSTRUMENTED_NON_ATOMIC_H */