Merge patch series "riscv: Improve KASAN coverage to fix unit tests"

Samuel Holland <samuel.holland@sifive.com> says:

This series fixes two areas where uninstrumented assembly routines
caused gaps in KASAN coverage on RISC-V, which were caught by KUnit
tests. The KASAN KUnit test suite passes after applying this series.

This series fixes the following test failures:
  # kasan_strings: EXPECTATION FAILED at mm/kasan/kasan_test.c:1520
  KASAN failure expected in "kasan_int_result = strcmp(ptr, "2")", but none occurred
  # kasan_strings: EXPECTATION FAILED at mm/kasan/kasan_test.c:1524
  KASAN failure expected in "kasan_int_result = strlen(ptr)", but none occurred
  not ok 60 kasan_strings
  # kasan_bitops_generic: EXPECTATION FAILED at mm/kasan/kasan_test.c:1531
  KASAN failure expected in "set_bit(nr, addr)", but none occurred
  # kasan_bitops_generic: EXPECTATION FAILED at mm/kasan/kasan_test.c:1533
  KASAN failure expected in "clear_bit(nr, addr)", but none occurred
  # kasan_bitops_generic: EXPECTATION FAILED at mm/kasan/kasan_test.c:1535
  KASAN failure expected in "clear_bit_unlock(nr, addr)", but none occurred
  # kasan_bitops_generic: EXPECTATION FAILED at mm/kasan/kasan_test.c:1536
  KASAN failure expected in "__clear_bit_unlock(nr, addr)", but none occurred
  # kasan_bitops_generic: EXPECTATION FAILED at mm/kasan/kasan_test.c:1537
  KASAN failure expected in "change_bit(nr, addr)", but none occurred
  # kasan_bitops_generic: EXPECTATION FAILED at mm/kasan/kasan_test.c:1543
  KASAN failure expected in "test_and_set_bit(nr, addr)", but none occurred
  # kasan_bitops_generic: EXPECTATION FAILED at mm/kasan/kasan_test.c:1545
  KASAN failure expected in "test_and_set_bit_lock(nr, addr)", but none occurred
  # kasan_bitops_generic: EXPECTATION FAILED at mm/kasan/kasan_test.c:1546
  KASAN failure expected in "test_and_clear_bit(nr, addr)", but none occurred
  # kasan_bitops_generic: EXPECTATION FAILED at mm/kasan/kasan_test.c:1548
  KASAN failure expected in "test_and_change_bit(nr, addr)", but none occurred
  not ok 61 kasan_bitops_generic

Samuel Holland (2):
  riscv: Omit optimized string routines when using KASAN
  riscv: Enable bitops instrumentation

arch/riscv/include/asm/bitops.h | 43 ++++++++++++++++++---------------
 arch/riscv/include/asm/string.h |  2 ++
 arch/riscv/kernel/riscv_ksyms.c |  3 ---
 arch/riscv/lib/Makefile         |  2 ++
 arch/riscv/lib/strcmp.S         |  1 +
 arch/riscv/lib/strlen.S         |  1 +
 arch/riscv/lib/strncmp.S        |  1 +
 arch/riscv/purgatory/Makefile   |  2 ++
 8 files changed, 32 insertions(+), 23 deletions(-)

* b4-shazam-merge:
  riscv: Enable bitops instrumentation
  riscv: Omit optimized string routines when using KASAN

Link: https://lore.kernel.org/r/20240801033725.28816-1-samuel.holland@sifive.comSigned-off-by: Palmer Dabbelt <palmer@rivosinc.com>

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>

arch/riscv/include/asm/string.h

@@ -19,6 +19,7 @@ extern asmlinkage void *__memcpy(void *, const void *, size_t);
 extern asmlinkage void *memmove(void *, const void *, size_t);
 extern asmlinkage void *__memmove(void *, const void *, size_t);
 
+#if !(defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS))
 #define __HAVE_ARCH_STRCMP
 extern asmlinkage int strcmp(const char *cs, const char *ct);
 
@@ -27,6 +28,7 @@ extern asmlinkage __kernel_size_t strlen(const char *);
 
 #define __HAVE_ARCH_STRNCMP
 extern asmlinkage int strncmp(const char *cs, const char *ct, size_t count);
+#endif
 
 /* For those files which don't want to check by kasan. */
 #if defined(CONFIG_KASAN) && !defined(__SANITIZE_ADDRESS__)

arch/riscv/kernel/riscv_ksyms.c

@@ -12,9 +12,6 @@
 EXPORT_SYMBOL(memset);
 EXPORT_SYMBOL(memcpy);
 EXPORT_SYMBOL(memmove);
-EXPORT_SYMBOL(strcmp);
-EXPORT_SYMBOL(strlen);
-EXPORT_SYMBOL(strncmp);
 EXPORT_SYMBOL(__memset);
 EXPORT_SYMBOL(__memcpy);
 EXPORT_SYMBOL(__memmove);

arch/riscv/lib/Makefile

@@ -3,9 +3,11 @@ lib-y			+= delay.o
 lib-y			+= memcpy.o
 lib-y			+= memset.o
 lib-y			+= memmove.o
+ifeq ($(CONFIG_KASAN_GENERIC)$(CONFIG_KASAN_SW_TAGS),)
 lib-y			+= strcmp.o
 lib-y			+= strlen.o
 lib-y			+= strncmp.o
+endif
 lib-y			+= csum.o
 ifeq ($(CONFIG_MMU), y)
 lib-$(CONFIG_RISCV_ISA_V)	+= uaccess_vector.o

arch/riscv/lib/strcmp.S

@@ -121,3 +121,4 @@ strcmp_zbb:
 #endif
 SYM_FUNC_END(strcmp)
 SYM_FUNC_ALIAS(__pi_strcmp, strcmp)
+EXPORT_SYMBOL(strcmp)

arch/riscv/lib/strlen.S

@@ -131,3 +131,4 @@ strlen_zbb:
 #endif
 SYM_FUNC_END(strlen)
 SYM_FUNC_ALIAS(__pi_strlen, strlen)
+EXPORT_SYMBOL(strlen)

arch/riscv/lib/strncmp.S

@@ -137,3 +137,4 @@ strncmp_zbb:
 #endif
 SYM_FUNC_END(strncmp)
 SYM_FUNC_ALIAS(__pi_strncmp, strncmp)
+EXPORT_SYMBOL(strncmp)

arch/riscv/purgatory/Makefile

 # SPDX-License-Identifier: GPL-2.0
 
 purgatory-y := purgatory.o sha256.o entry.o string.o ctype.o memcpy.o memset.o
+ifeq ($(CONFIG_KASAN_GENERIC)$(CONFIG_KASAN_SW_TAGS),)
 purgatory-y += strcmp.o strlen.o strncmp.o
+endif
 
 targets += $(purgatory-y)
 PURGATORY_OBJS = $(addprefix $(obj)/,$(purgatory-y))