[PATCH 0/2] riscv: Improve KASAN coverage to fix unit tests

[PATCH 0/2] riscv: Improve KASAN coverage to fix unit tests

[Samuel Holland]

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(-)

-- 
2.45.1


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[PATCH 1/2] riscv: Omit optimized string routines when using KASAN

[Samuel Holland]

The optimized string routines are implemented in assembly, so they are
not instrumented for use with KASAN. Fall back to the C version of the
routines in order to improve KASAN coverage. This fixes the
kasan_strings() unit test.

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

 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 ++
 7 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/arch/riscv/include/asm/string.h b/arch/riscv/include/asm/string.h
index a96b1fea24fe..5ba77f60bf0b 100644
--- a/arch/riscv/include/asm/string.h
+++ b/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__)
diff --git a/arch/riscv/kernel/riscv_ksyms.c b/arch/riscv/kernel/riscv_ksyms.c
index a72879b4249a..5ab1c7e1a6ed 100644
--- a/arch/riscv/kernel/riscv_ksyms.c
+++ b/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);
diff --git a/arch/riscv/lib/Makefile b/arch/riscv/lib/Makefile
index 2b369f51b0a5..8eec6b69a875 100644
--- a/arch/riscv/lib/Makefile
+++ b/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
diff --git a/arch/riscv/lib/strcmp.S b/arch/riscv/lib/strcmp.S
index 687b2bea5c43..542301a67a2f 100644
--- a/arch/riscv/lib/strcmp.S
+++ b/arch/riscv/lib/strcmp.S
@@ -120,3 +120,4 @@ strcmp_zbb:
 .option pop
 #endif
 SYM_FUNC_END(strcmp)
+EXPORT_SYMBOL(strcmp)
diff --git a/arch/riscv/lib/strlen.S b/arch/riscv/lib/strlen.S
index 8ae3064e45ff..962983b73251 100644
--- a/arch/riscv/lib/strlen.S
+++ b/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)
diff --git a/arch/riscv/lib/strncmp.S b/arch/riscv/lib/strncmp.S
index aba5b3148621..0f359ea2f55b 100644
--- a/arch/riscv/lib/strncmp.S
+++ b/arch/riscv/lib/strncmp.S
@@ -136,3 +136,4 @@ strncmp_zbb:
 .option pop
 #endif
 SYM_FUNC_END(strncmp)
+EXPORT_SYMBOL(strncmp)
diff --git a/arch/riscv/purgatory/Makefile b/arch/riscv/purgatory/Makefile
index f11945ee2490..fb9c917c9b45 100644
--- a/arch/riscv/purgatory/Makefile
+++ b/arch/riscv/purgatory/Makefile
@@ -1,7 +1,9 @@
 # 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))
-- 
2.45.1


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[PATCH 2/2] riscv: Enable bitops instrumentation

[Samuel Holland]

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@sifive.com>
---

 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


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Re: [PATCH 1/2] riscv: Omit optimized string routines when using KASAN

[Alexandre Ghiti]

Hi Samuel,

On 01/08/2024 05:36, Samuel Holland wrote:
> The optimized string routines are implemented in assembly, so they are
> not instrumented for use with KASAN. Fall back to the C version of the
> routines in order to improve KASAN coverage. This fixes the
> kasan_strings() unit test.
>
> Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
> ---
>
>   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 ++
>   7 files changed, 9 insertions(+), 3 deletions(-)
>
> diff --git a/arch/riscv/include/asm/string.h b/arch/riscv/include/asm/string.h
> index a96b1fea24fe..5ba77f60bf0b 100644
> --- a/arch/riscv/include/asm/string.h
> +++ b/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))


We do not support KASAN_SW_TAGS so there is no need for this #ifdef.


>   #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__)
> diff --git a/arch/riscv/kernel/riscv_ksyms.c b/arch/riscv/kernel/riscv_ksyms.c
> index a72879b4249a..5ab1c7e1a6ed 100644
> --- a/arch/riscv/kernel/riscv_ksyms.c
> +++ b/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);
> diff --git a/arch/riscv/lib/Makefile b/arch/riscv/lib/Makefile
> index 2b369f51b0a5..8eec6b69a875 100644
> --- a/arch/riscv/lib/Makefile
> +++ b/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
> diff --git a/arch/riscv/lib/strcmp.S b/arch/riscv/lib/strcmp.S
> index 687b2bea5c43..542301a67a2f 100644
> --- a/arch/riscv/lib/strcmp.S
> +++ b/arch/riscv/lib/strcmp.S
> @@ -120,3 +120,4 @@ strcmp_zbb:
>   .option pop
>   #endif
>   SYM_FUNC_END(strcmp)
> +EXPORT_SYMBOL(strcmp)
> diff --git a/arch/riscv/lib/strlen.S b/arch/riscv/lib/strlen.S
> index 8ae3064e45ff..962983b73251 100644
> --- a/arch/riscv/lib/strlen.S
> +++ b/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)
> diff --git a/arch/riscv/lib/strncmp.S b/arch/riscv/lib/strncmp.S
> index aba5b3148621..0f359ea2f55b 100644
> --- a/arch/riscv/lib/strncmp.S
> +++ b/arch/riscv/lib/strncmp.S
> @@ -136,3 +136,4 @@ strncmp_zbb:
>   .option pop
>   #endif
>   SYM_FUNC_END(strncmp)
> +EXPORT_SYMBOL(strncmp)
> diff --git a/arch/riscv/purgatory/Makefile b/arch/riscv/purgatory/Makefile
> index f11945ee2490..fb9c917c9b45 100644
> --- a/arch/riscv/purgatory/Makefile
> +++ b/arch/riscv/purgatory/Makefile
> @@ -1,7 +1,9 @@
>   # 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))


With the removal of KASAN_SW_TAGS, you can add:

Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>

And since I have this testsuite in my CI, I gave it a try and it works so:

Tested-by: Alexandre Ghiti <alexghiti@rivosinc.com>

Thanks,

Alex




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Re: [PATCH 2/2] riscv: Enable bitops instrumentation

[Alexandre Ghiti]

On 01/08/2024 05:37, Samuel Holland wrote:
> 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@sifive.com>
> ---
>
>   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
>    *


Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Tested-by: Alexandre Ghiti <alexghiti@rivosinc.com>

Thanks,

Alex


> @@ -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>

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Re: [PATCH 1/2] riscv: Omit optimized string routines when using KASAN

[Samuel Holland]

Hi Alex,

On 2024-08-01 5:26 AM, Alexandre Ghiti wrote:
> Hi Samuel,
> 
> On 01/08/2024 05:36, Samuel Holland wrote:
>> The optimized string routines are implemented in assembly, so they are
>> not instrumented for use with KASAN. Fall back to the C version of the
>> routines in order to improve KASAN coverage. This fixes the
>> kasan_strings() unit test.
>>
>> Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
>> ---
>>
>>   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 ++
>>   7 files changed, 9 insertions(+), 3 deletions(-)
>>
>> diff --git a/arch/riscv/include/asm/string.h b/arch/riscv/include/asm/string.h
>> index a96b1fea24fe..5ba77f60bf0b 100644
>> --- a/arch/riscv/include/asm/string.h
>> +++ b/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))
> 
> 
> We do not support KASAN_SW_TAGS so there is no need for this #ifdef.

I just sent an RFC implementation of KASAN_SW_TAGS[1] (which you wouldn't have
known I was working on at the time :) ). Since these changes will be needed for
both modes, it made sense to me to go ahead and cover both at once.

Regards,
Samuel

[1]: https://lore.kernel.org/all/20240814085618.968833-1-samuel.holland@sifive.com/

>>   #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__)
>> diff --git a/arch/riscv/kernel/riscv_ksyms.c b/arch/riscv/kernel/riscv_ksyms.c
>> index a72879b4249a..5ab1c7e1a6ed 100644
>> --- a/arch/riscv/kernel/riscv_ksyms.c
>> +++ b/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);
>> diff --git a/arch/riscv/lib/Makefile b/arch/riscv/lib/Makefile
>> index 2b369f51b0a5..8eec6b69a875 100644
>> --- a/arch/riscv/lib/Makefile
>> +++ b/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
>> diff --git a/arch/riscv/lib/strcmp.S b/arch/riscv/lib/strcmp.S
>> index 687b2bea5c43..542301a67a2f 100644
>> --- a/arch/riscv/lib/strcmp.S
>> +++ b/arch/riscv/lib/strcmp.S
>> @@ -120,3 +120,4 @@ strcmp_zbb:
>>   .option pop
>>   #endif
>>   SYM_FUNC_END(strcmp)
>> +EXPORT_SYMBOL(strcmp)
>> diff --git a/arch/riscv/lib/strlen.S b/arch/riscv/lib/strlen.S
>> index 8ae3064e45ff..962983b73251 100644
>> --- a/arch/riscv/lib/strlen.S
>> +++ b/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)
>> diff --git a/arch/riscv/lib/strncmp.S b/arch/riscv/lib/strncmp.S
>> index aba5b3148621..0f359ea2f55b 100644
>> --- a/arch/riscv/lib/strncmp.S
>> +++ b/arch/riscv/lib/strncmp.S
>> @@ -136,3 +136,4 @@ strncmp_zbb:
>>   .option pop
>>   #endif
>>   SYM_FUNC_END(strncmp)
>> +EXPORT_SYMBOL(strncmp)
>> diff --git a/arch/riscv/purgatory/Makefile b/arch/riscv/purgatory/Makefile
>> index f11945ee2490..fb9c917c9b45 100644
>> --- a/arch/riscv/purgatory/Makefile
>> +++ b/arch/riscv/purgatory/Makefile
>> @@ -1,7 +1,9 @@
>>   # 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))
> 
> 
> With the removal of KASAN_SW_TAGS, you can add:
> 
> Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
> 
> And since I have this testsuite in my CI, I gave it a try and it works so:
> 
> Tested-by: Alexandre Ghiti <alexghiti@rivosinc.com>
> 
> Thanks,
> 
> Alex
> 
> 
> 


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Re: [PATCH 0/2] riscv: Improve KASAN coverage to fix unit tests

[patchwork-bot+linux-riscv]

Hello:

This series was applied to riscv/linux.git (for-next)
by Palmer Dabbelt <palmer@rivosinc.com>:

On Wed, 31 Jul 2024 20:36:58 -0700 you wrote:
> 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
> 
> [...]

Here is the summary with links:
  - [1/2] riscv: Omit optimized string routines when using KASAN
    https://git.kernel.org/riscv/c/58ff537109ac
  - [2/2] riscv: Enable bitops instrumentation
    https://git.kernel.org/riscv/c/77514915b72c

You are awesome, thank you!
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