[PATCH 2/2] riscv: Enable bitops instrumentation

From: Samuel Holland
Date: Wed Jul 31 2024 - 23:37:53 EST


Instead of implementing the bitops functions directly in assembly,
provide the arch_-prefixed versions and use the wrappers from
asm-generic to add instrumentation. This improves KASAN coverage and
fixes the kasan_bitops_generic() unit test.

Signed-off-by: Samuel Holland <samuel.holland@xxxxxxxxxx>
---

arch/riscv/include/asm/bitops.h | 43 ++++++++++++++++++---------------
1 file changed, 23 insertions(+), 20 deletions(-)

diff --git a/arch/riscv/include/asm/bitops.h b/arch/riscv/include/asm/bitops.h
index 71af9ecfcfcb..fae152ea0508 100644
--- a/arch/riscv/include/asm/bitops.h
+++ b/arch/riscv/include/asm/bitops.h
@@ -222,44 +222,44 @@ static __always_inline int variable_fls(unsigned int x)
#define __NOT(x) (~(x))

/**
- * test_and_set_bit - Set a bit and return its old value
+ * arch_test_and_set_bit - Set a bit and return its old value
* @nr: Bit to set
* @addr: Address to count from
*
* This operation may be reordered on other architectures than x86.
*/
-static inline int test_and_set_bit(int nr, volatile unsigned long *addr)
+static inline int arch_test_and_set_bit(int nr, volatile unsigned long *addr)
{
return __test_and_op_bit(or, __NOP, nr, addr);
}

/**
- * test_and_clear_bit - Clear a bit and return its old value
+ * arch_test_and_clear_bit - Clear a bit and return its old value
* @nr: Bit to clear
* @addr: Address to count from
*
* This operation can be reordered on other architectures other than x86.
*/
-static inline int test_and_clear_bit(int nr, volatile unsigned long *addr)
+static inline int arch_test_and_clear_bit(int nr, volatile unsigned long *addr)
{
return __test_and_op_bit(and, __NOT, nr, addr);
}

/**
- * test_and_change_bit - Change a bit and return its old value
+ * arch_test_and_change_bit - Change a bit and return its old value
* @nr: Bit to change
* @addr: Address to count from
*
* This operation is atomic and cannot be reordered.
* It also implies a memory barrier.
*/
-static inline int test_and_change_bit(int nr, volatile unsigned long *addr)
+static inline int arch_test_and_change_bit(int nr, volatile unsigned long *addr)
{
return __test_and_op_bit(xor, __NOP, nr, addr);
}

/**
- * set_bit - Atomically set a bit in memory
+ * arch_set_bit - Atomically set a bit in memory
* @nr: the bit to set
* @addr: the address to start counting from
*
@@ -270,13 +270,13 @@ static inline int test_and_change_bit(int nr, volatile unsigned long *addr)
* 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(int nr, volatile unsigned long *addr)
+static inline void arch_set_bit(int nr, volatile unsigned long *addr)
{
__op_bit(or, __NOP, nr, addr);
}

/**
- * clear_bit - Clears a bit in memory
+ * arch_clear_bit - Clears a bit in memory
* @nr: Bit to clear
* @addr: Address to start counting from
*
@@ -284,13 +284,13 @@ static inline void set_bit(int nr, volatile unsigned long *addr)
* on non x86 architectures, so if you are writing portable code,
* make sure not to rely on its reordering guarantees.
*/
-static inline void clear_bit(int nr, volatile unsigned long *addr)
+static inline void arch_clear_bit(int nr, volatile unsigned long *addr)
{
__op_bit(and, __NOT, nr, addr);
}

/**
- * change_bit - Toggle a bit in memory
+ * arch_change_bit - Toggle a bit in memory
* @nr: Bit to change
* @addr: Address to start counting from
*
@@ -298,40 +298,40 @@ static inline void clear_bit(int nr, volatile unsigned long *addr)
* 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(int nr, volatile unsigned long *addr)
+static inline void arch_change_bit(int nr, volatile unsigned long *addr)
{
__op_bit(xor, __NOP, nr, addr);
}

/**
- * test_and_set_bit_lock - Set a bit and return its old value, for lock
+ * arch_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.
* It can be used to implement bit locks.
*/
-static inline int test_and_set_bit_lock(
+static inline int arch_test_and_set_bit_lock(
unsigned long nr, volatile unsigned long *addr)
{
return __test_and_op_bit_ord(or, __NOP, nr, addr, .aq);
}

/**
- * clear_bit_unlock - Clear a bit in memory, for unlock
+ * arch_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(
+static inline void arch_clear_bit_unlock(
unsigned long nr, volatile unsigned long *addr)
{
__op_bit_ord(and, __NOT, nr, addr, .rl);
}

/**
- * __clear_bit_unlock - Clear a bit in memory, for unlock
+ * arch___clear_bit_unlock - Clear a bit in memory, for unlock
* @nr: the bit to set
* @addr: the address to start counting from
*
@@ -345,13 +345,13 @@ static inline void clear_bit_unlock(
* non-atomic property here: it's a lot more instructions and we still have to
* provide release semantics anyway.
*/
-static inline void __clear_bit_unlock(
+static inline void arch___clear_bit_unlock(
unsigned long nr, volatile unsigned long *addr)
{
- clear_bit_unlock(nr, addr);
+ arch_clear_bit_unlock(nr, addr);
}

-static inline bool xor_unlock_is_negative_byte(unsigned long mask,
+static inline bool arch_xor_unlock_is_negative_byte(unsigned long mask,
volatile unsigned long *addr)
{
unsigned long res;
@@ -369,6 +369,9 @@ static inline bool xor_unlock_is_negative_byte(unsigned long mask,
#undef __NOT
#undef __AMO

+#include <asm-generic/bitops/instrumented-atomic.h>
+#include <asm-generic/bitops/instrumented-lock.h>
+
#include <asm-generic/bitops/non-atomic.h>
#include <asm-generic/bitops/le.h>
#include <asm-generic/bitops/ext2-atomic.h>
--
2.45.1