[PATCH] compiler: Use __typeof_unqual__() for __unqual_scalar_typeof()

Thomas Gleixner posted 1 patch 3 weeks, 4 days ago
There is a newer version of this series
Makefile                       |    8 ++++++++
include/linux/compiler.h       |   10 ----------
include/linux/compiler_types.h |   11 +++++++++++
scripts/checker-valid.sh       |   19 +++++++++++++++++++
4 files changed, 38 insertions(+), 10 deletions(-)
[PATCH] compiler: Use __typeof_unqual__() for __unqual_scalar_typeof()
Posted by Thomas Gleixner 3 weeks, 4 days ago
From: Peter Zijlstra <peterz@infradead.org>

The recent changes to get_unaligned() resulted in a new sparse warning:

   net/rds/ib_cm.c:96:35: sparse: sparse: incorrect type in argument 1 (different modifiers) @@     expected void * @@     got restricted __be64 const * @@
   net/rds/ib_cm.c:96:35: sparse:     expected void *
   net/rds/ib_cm.c:96:35: sparse:     got restricted __be64 const *
 
The updated get_unaligned_t() uses __unqual_scalar_typeof() to get an
unqualified type. This works correctly for the compilers, but fails for
sparse when the data type is __be64 (or any other __beNN variant).

On sparse runs (C=[12]) __beNN types are annotated with
__attribute__((bitwise)).

That annotation allows sparse to detect incompatible operations on __beNN
variables, but it also prevents sparse from evaluating the _Generic() in
__unqual_scalar_typeof() and map __beNN to a unqualified scalar type, so it
ends up with the default, i.e. the original qualified type of a 'const
__beNN' pointer. That then ends up as the first pointer argument to
builtin_memcpy(), which obviously causes the above sparse warnings.

The sparse git tree supports typeof_unqual() now, which allows to use it
instead of the _Generic() based __unqual_scalar_typeof(). With that sparse
correctly evaluates the unqualified type and keeps the __beNN logic intact.

The downside is that this requires a top of tree sparse build and an old
sparse version will emit a metric ton of incomprehensible error messages
before it dies with a segfault.

Therefore implement a sanity check which validates that the checker is
available and capable of handling typeof_unqual(). Emit a warning if not so
the user can take informed action.

[ tglx: Move the evaluation of USE_TYPEOF_UNQUAL to compiler_types.h so it is
  	set before use and implement the sanity checker ]

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Closes: https://lore.kernel.org/oe-kbuild-all/202601150001.sKSN644a-lkp@intel.com/
---
 Makefile                       |    8 ++++++++
 include/linux/compiler.h       |   10 ----------
 include/linux/compiler_types.h |   11 +++++++++++
 scripts/checker-valid.sh       |   19 +++++++++++++++++++
 4 files changed, 38 insertions(+), 10 deletions(-)

--- a/Makefile
+++ b/Makefile
@@ -1178,6 +1178,14 @@ ifdef CONFIG_CC_IS_CLANG
 KBUILD_USERLDFLAGS += --ld-path=$(LD)
 endif
 
+# Validate the checker is available and functional
+ifneq ($(KBUILD_CHECKSRC), 0)
+  ifneq ($(shell $(srctree)/scripts/checker-valid.sh $(CHECK)), 1)
+    $(warning C=$(KBUILD_CHECKSRC) specified, but $(CHECK) is not available or not up to date)
+    KBUILD_CHECKSRC = 0
+  endif
+endif
+
 # make the checker run with the right architecture
 CHECKFLAGS += --arch=$(ARCH)
 
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -231,16 +231,6 @@ void ftrace_likely_update(struct ftrace_
 				"must be non-C-string (not NUL-terminated)")
 
 /*
- * Use __typeof_unqual__() when available.
- *
- * XXX: Remove test for __CHECKER__ once
- * sparse learns about __typeof_unqual__().
- */
-#if CC_HAS_TYPEOF_UNQUAL && !defined(__CHECKER__)
-# define USE_TYPEOF_UNQUAL 1
-#endif
-
-/*
  * Define TYPEOF_UNQUAL() to use __typeof_unqual__() as typeof
  * operator when available, to return an unqualified type of the exp.
  */
--- a/include/linux/compiler_types.h
+++ b/include/linux/compiler_types.h
@@ -562,6 +562,13 @@ struct ftrace_likely_data {
 #define asm_inline asm
 #endif
 
+/*
+ * Use __typeof_unqual__() when available.
+ */
+#if CC_HAS_TYPEOF_UNQUAL || defined(__CHECKER__)
+# define USE_TYPEOF_UNQUAL 1
+#endif
+
 /* Are two types/vars the same type (ignoring qualifiers)? */
 #define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
 
@@ -569,6 +576,7 @@ struct ftrace_likely_data {
  * __unqual_scalar_typeof(x) - Declare an unqualified scalar type, leaving
  *			       non-scalar types unchanged.
  */
+#ifndef USE_TYPEOF_UNQUAL
 /*
  * Prefer C11 _Generic for better compile-times and simpler code. Note: 'char'
  * is not type-compatible with 'signed char', and we define a separate case.
@@ -586,6 +594,9 @@ struct ftrace_likely_data {
 			 __scalar_type_to_expr_cases(long),		\
 			 __scalar_type_to_expr_cases(long long),	\
 			 default: (x)))
+#else
+#define __unqual_scalar_typeof(x) __typeof_unqual__(x)
+#endif
 
 /* Is this type a native word size -- useful for atomic operations */
 #define __native_word(t) \
--- /dev/null
+++ b/scripts/checker-valid.sh
@@ -0,0 +1,19 @@
+#!/bin/sh -eu
+# SPDX-License-Identifier: GPL-2.0
+
+[ ! -x "$(command -v "$1")" ] && exit 1
+
+tmp_file=$(mktemp)
+trap "rm -f $tmp_file" EXIT
+
+cat << EOF >$tmp_file
+static inline int u(const int *q)
+{
+	__typeof_unqual__(*q) v = *q;
+	return v;
+}
+EOF
+
+# sparse happily exits with 0 on error so validate
+# there is none on stderr. Use awk as grep is a pain with sh -e
+$1 $tmp_file 2>&1 | awk -v c=1 '/error/{c=0}END{print c}'
Re: [PATCH] compiler: Use __typeof_unqual__() for __unqual_scalar_typeof()
Posted by Ian Rogers 3 weeks, 3 days ago
On Fri, Jan 16, 2026 at 10:18 AM Thomas Gleixner <tglx@kernel.org> wrote:
>
> From: Peter Zijlstra <peterz@infradead.org>
>
> The recent changes to get_unaligned() resulted in a new sparse warning:
>
>    net/rds/ib_cm.c:96:35: sparse: sparse: incorrect type in argument 1 (different modifiers) @@     expected void * @@     got restricted __be64 const * @@
>    net/rds/ib_cm.c:96:35: sparse:     expected void *
>    net/rds/ib_cm.c:96:35: sparse:     got restricted __be64 const *
>
> The updated get_unaligned_t() uses __unqual_scalar_typeof() to get an
> unqualified type. This works correctly for the compilers, but fails for
> sparse when the data type is __be64 (or any other __beNN variant).
>
> On sparse runs (C=[12]) __beNN types are annotated with
> __attribute__((bitwise)).
>
> That annotation allows sparse to detect incompatible operations on __beNN
> variables, but it also prevents sparse from evaluating the _Generic() in
> __unqual_scalar_typeof() and map __beNN to a unqualified scalar type, so it
> ends up with the default, i.e. the original qualified type of a 'const
> __beNN' pointer. That then ends up as the first pointer argument to
> builtin_memcpy(), which obviously causes the above sparse warnings.
>
> The sparse git tree supports typeof_unqual() now, which allows to use it
> instead of the _Generic() based __unqual_scalar_typeof(). With that sparse
> correctly evaluates the unqualified type and keeps the __beNN logic intact.

Wow, that's painful. Congratulations on finding the root case.

Acked-by: Ian Rogers <irogers@google.com>

Thanks,
Ian

> The downside is that this requires a top of tree sparse build and an old
> sparse version will emit a metric ton of incomprehensible error messages
> before it dies with a segfault.
>
> Therefore implement a sanity check which validates that the checker is
> available and capable of handling typeof_unqual(). Emit a warning if not so
> the user can take informed action.
>
> [ tglx: Move the evaluation of USE_TYPEOF_UNQUAL to compiler_types.h so it is
>         set before use and implement the sanity checker ]
>
> Reported-by: kernel test robot <lkp@intel.com>
> Signed-off-by: Peter Zijlstra <peterz@infradead.org>
> Signed-off-by: Thomas Gleixner <tglx@kernel.org>
> Closes: https://lore.kernel.org/oe-kbuild-all/202601150001.sKSN644a-lkp@intel.com/
> ---
>  Makefile                       |    8 ++++++++
>  include/linux/compiler.h       |   10 ----------
>  include/linux/compiler_types.h |   11 +++++++++++
>  scripts/checker-valid.sh       |   19 +++++++++++++++++++
>  4 files changed, 38 insertions(+), 10 deletions(-)
>
> --- a/Makefile
> +++ b/Makefile
> @@ -1178,6 +1178,14 @@ ifdef CONFIG_CC_IS_CLANG
>  KBUILD_USERLDFLAGS += --ld-path=$(LD)
>  endif
>
> +# Validate the checker is available and functional
> +ifneq ($(KBUILD_CHECKSRC), 0)
> +  ifneq ($(shell $(srctree)/scripts/checker-valid.sh $(CHECK)), 1)
> +    $(warning C=$(KBUILD_CHECKSRC) specified, but $(CHECK) is not available or not up to date)
> +    KBUILD_CHECKSRC = 0
> +  endif
> +endif
> +
>  # make the checker run with the right architecture
>  CHECKFLAGS += --arch=$(ARCH)
>
> --- a/include/linux/compiler.h
> +++ b/include/linux/compiler.h
> @@ -231,16 +231,6 @@ void ftrace_likely_update(struct ftrace_
>                                 "must be non-C-string (not NUL-terminated)")
>
>  /*
> - * Use __typeof_unqual__() when available.
> - *
> - * XXX: Remove test for __CHECKER__ once
> - * sparse learns about __typeof_unqual__().
> - */
> -#if CC_HAS_TYPEOF_UNQUAL && !defined(__CHECKER__)
> -# define USE_TYPEOF_UNQUAL 1
> -#endif
> -
> -/*
>   * Define TYPEOF_UNQUAL() to use __typeof_unqual__() as typeof
>   * operator when available, to return an unqualified type of the exp.
>   */
> --- a/include/linux/compiler_types.h
> +++ b/include/linux/compiler_types.h
> @@ -562,6 +562,13 @@ struct ftrace_likely_data {
>  #define asm_inline asm
>  #endif
>
> +/*
> + * Use __typeof_unqual__() when available.
> + */
> +#if CC_HAS_TYPEOF_UNQUAL || defined(__CHECKER__)
> +# define USE_TYPEOF_UNQUAL 1
> +#endif
> +
>  /* Are two types/vars the same type (ignoring qualifiers)? */
>  #define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
>
> @@ -569,6 +576,7 @@ struct ftrace_likely_data {
>   * __unqual_scalar_typeof(x) - Declare an unqualified scalar type, leaving
>   *                            non-scalar types unchanged.
>   */
> +#ifndef USE_TYPEOF_UNQUAL
>  /*
>   * Prefer C11 _Generic for better compile-times and simpler code. Note: 'char'
>   * is not type-compatible with 'signed char', and we define a separate case.
> @@ -586,6 +594,9 @@ struct ftrace_likely_data {
>                          __scalar_type_to_expr_cases(long),             \
>                          __scalar_type_to_expr_cases(long long),        \
>                          default: (x)))
> +#else
> +#define __unqual_scalar_typeof(x) __typeof_unqual__(x)
> +#endif
>
>  /* Is this type a native word size -- useful for atomic operations */
>  #define __native_word(t) \
> --- /dev/null
> +++ b/scripts/checker-valid.sh
> @@ -0,0 +1,19 @@
> +#!/bin/sh -eu
> +# SPDX-License-Identifier: GPL-2.0
> +
> +[ ! -x "$(command -v "$1")" ] && exit 1
> +
> +tmp_file=$(mktemp)
> +trap "rm -f $tmp_file" EXIT
> +
> +cat << EOF >$tmp_file
> +static inline int u(const int *q)
> +{
> +       __typeof_unqual__(*q) v = *q;
> +       return v;
> +}
> +EOF
> +
> +# sparse happily exits with 0 on error so validate
> +# there is none on stderr. Use awk as grep is a pain with sh -e
> +$1 $tmp_file 2>&1 | awk -v c=1 '/error/{c=0}END{print c}'
[tip: timers/vdso] compiler: Use __typeof_unqual__() for __unqual_scalar_typeof()
Posted by tip-bot2 for Peter Zijlstra 3 weeks, 2 days ago
The following commit has been merged into the timers/vdso branch of tip:

Commit-ID:     fd69b2f7d5f4e1d89cea4cdfa6f15e7fa53d8358
Gitweb:        https://git.kernel.org/tip/fd69b2f7d5f4e1d89cea4cdfa6f15e7fa53d8358
Author:        Peter Zijlstra <peterz@infradead.org>
AuthorDate:    Fri, 16 Jan 2026 19:18:16 +01:00
Committer:     Thomas Gleixner <tglx@kernel.org>
CommitterDate: Sun, 18 Jan 2026 10:32:03 +01:00

compiler: Use __typeof_unqual__() for __unqual_scalar_typeof()

The recent changes to get_unaligned() resulted in a new sparse warning:

   net/rds/ib_cm.c:96:35: sparse: sparse: incorrect type in argument 1 (different modifiers) @@     expected void * @@     got restricted __be64 const * @@
   net/rds/ib_cm.c:96:35: sparse:     expected void *
   net/rds/ib_cm.c:96:35: sparse:     got restricted __be64 const *

The updated get_unaligned_t() uses __unqual_scalar_typeof() to get an
unqualified type. This works correctly for the compilers, but fails for
sparse when the data type is __be64 (or any other __beNN variant).

On sparse runs (C=[12]) __beNN types are annotated with
__attribute__((bitwise)).

That annotation allows sparse to detect incompatible operations on __beNN
variables, but it also prevents sparse from evaluating the _Generic() in
__unqual_scalar_typeof() and map __beNN to a unqualified scalar type, so it
ends up with the default, i.e. the original qualified type of a 'const
__beNN' pointer. That then ends up as the first pointer argument to
builtin_memcpy(), which obviously causes the above sparse warnings.

The sparse git tree supports typeof_unqual() now, which allows to use it
instead of the _Generic() based __unqual_scalar_typeof(). With that sparse
correctly evaluates the unqualified type and keeps the __beNN logic intact.

The downside is that this requires a top of tree sparse build and an old
sparse version will emit a metric ton of incomprehensible error messages
before it dies with a segfault.

Therefore implement a sanity check which validates that the checker is
available and capable of handling typeof_unqual(). Emit a warning if not so
the user can take informed action.

[ tglx: Move the evaluation of USE_TYPEOF_UNQUAL to compiler_types.h so it is
  	set before use and implement the sanity checker ]

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Acked-by: Ian Rogers <irogers@google.com>
Link: https://patch.msgid.link/87ecnp2zh3.ffs@tglx
Closes: https://lore.kernel.org/oe-kbuild-all/202601150001.sKSN644a-lkp@intel.com/
---
 Makefile                       |  8 ++++++++
 include/linux/compiler.h       | 10 ----------
 include/linux/compiler_types.h | 13 +++++++++++++
 scripts/checker-valid.sh       | 19 +++++++++++++++++++
 4 files changed, 40 insertions(+), 10 deletions(-)
 create mode 100755 scripts/checker-valid.sh

diff --git a/Makefile b/Makefile
index 9d38125..179c9d9 100644
--- a/Makefile
+++ b/Makefile
@@ -1187,6 +1187,14 @@ CHECKFLAGS += $(if $(CONFIG_CPU_BIG_ENDIAN),-mbig-endian,-mlittle-endian)
 # the checker needs the correct machine size
 CHECKFLAGS += $(if $(CONFIG_64BIT),-m64,-m32)
 
+# Validate the checker is available and functional
+ifneq ($(KBUILD_CHECKSRC), 0)
+  ifneq ($(shell $(srctree)/scripts/checker-valid.sh $(CHECK) $(CHECKFLAGS)), 1)
+    $(warning C=$(KBUILD_CHECKSRC) specified, but $(CHECK) is not available or not up to date)
+    KBUILD_CHECKSRC = 0
+  endif
+endif
+
 # Default kernel image to build when no specific target is given.
 # KBUILD_IMAGE may be overruled on the command line or
 # set in the environment
diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index 04487c9..c601222 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -231,16 +231,6 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
 				"must be non-C-string (not NUL-terminated)")
 
 /*
- * Use __typeof_unqual__() when available.
- *
- * XXX: Remove test for __CHECKER__ once
- * sparse learns about __typeof_unqual__().
- */
-#if CC_HAS_TYPEOF_UNQUAL && !defined(__CHECKER__)
-# define USE_TYPEOF_UNQUAL 1
-#endif
-
-/*
  * Define TYPEOF_UNQUAL() to use __typeof_unqual__() as typeof
  * operator when available, to return an unqualified type of the exp.
  */
diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h
index d3318a3..377df1e 100644
--- a/include/linux/compiler_types.h
+++ b/include/linux/compiler_types.h
@@ -562,6 +562,14 @@ struct ftrace_likely_data {
 #define asm_inline asm
 #endif
 
+#ifndef __ASSEMBLY__
+/*
+ * Use __typeof_unqual__() when available.
+ */
+#if CC_HAS_TYPEOF_UNQUAL || defined(__CHECKER__)
+# define USE_TYPEOF_UNQUAL 1
+#endif
+
 /* Are two types/vars the same type (ignoring qualifiers)? */
 #define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
 
@@ -569,6 +577,7 @@ struct ftrace_likely_data {
  * __unqual_scalar_typeof(x) - Declare an unqualified scalar type, leaving
  *			       non-scalar types unchanged.
  */
+#ifndef USE_TYPEOF_UNQUAL
 /*
  * Prefer C11 _Generic for better compile-times and simpler code. Note: 'char'
  * is not type-compatible with 'signed char', and we define a separate case.
@@ -586,6 +595,10 @@ struct ftrace_likely_data {
 			 __scalar_type_to_expr_cases(long),		\
 			 __scalar_type_to_expr_cases(long long),	\
 			 default: (x)))
+#else
+#define __unqual_scalar_typeof(x) __typeof_unqual__(x)
+#endif
+#endif /* !__ASSEMBLY__ */
 
 /* Is this type a native word size -- useful for atomic operations */
 #define __native_word(t) \
diff --git a/scripts/checker-valid.sh b/scripts/checker-valid.sh
new file mode 100755
index 0000000..625a789
--- /dev/null
+++ b/scripts/checker-valid.sh
@@ -0,0 +1,19 @@
+#!/bin/sh -eu
+# SPDX-License-Identifier: GPL-2.0
+
+[ ! -x "$(command -v "$1")" ] && exit 1
+
+tmp_file=$(mktemp)
+trap "rm -f $tmp_file" EXIT
+
+cat << EOF >$tmp_file
+static inline int u(const int *q)
+{
+	__typeof_unqual__(*q) v = *q;
+	return v;
+}
+EOF
+
+# sparse happily exits with 0 on error so validate
+# there is none on stderr. Use awk as grep is a pain with sh -e
+$@ $tmp_file 2>&1 | awk -v c=1 '/error/{c=0}END{print c}'
[tip: timers/vdso] compiler: Use __typeof_unqual__() for __unqual_scalar_typeof()
Posted by tip-bot2 for Peter Zijlstra 3 weeks, 3 days ago
The following commit has been merged into the timers/vdso branch of tip:

Commit-ID:     adc00a0daf1bb08915bceee9ae73cca682e7d5bb
Gitweb:        https://git.kernel.org/tip/adc00a0daf1bb08915bceee9ae73cca682e7d5bb
Author:        Peter Zijlstra <peterz@infradead.org>
AuthorDate:    Fri, 16 Jan 2026 19:18:16 +01:00
Committer:     Thomas Gleixner <tglx@kernel.org>
CommitterDate: Sat, 17 Jan 2026 22:18:40 +01:00

compiler: Use __typeof_unqual__() for __unqual_scalar_typeof()

The recent changes to get_unaligned() resulted in a new sparse warning:

   net/rds/ib_cm.c:96:35: sparse: sparse: incorrect type in argument 1 (different modifiers) @@     expected void * @@     got restricted __be64 const * @@
   net/rds/ib_cm.c:96:35: sparse:     expected void *
   net/rds/ib_cm.c:96:35: sparse:     got restricted __be64 const *

The updated get_unaligned_t() uses __unqual_scalar_typeof() to get an
unqualified type. This works correctly for the compilers, but fails for
sparse when the data type is __be64 (or any other __beNN variant).

On sparse runs (C=[12]) __beNN types are annotated with
__attribute__((bitwise)).

That annotation allows sparse to detect incompatible operations on __beNN
variables, but it also prevents sparse from evaluating the _Generic() in
__unqual_scalar_typeof() and map __beNN to a unqualified scalar type, so it
ends up with the default, i.e. the original qualified type of a 'const
__beNN' pointer. That then ends up as the first pointer argument to
builtin_memcpy(), which obviously causes the above sparse warnings.

The sparse git tree supports typeof_unqual() now, which allows to use it
instead of the _Generic() based __unqual_scalar_typeof(). With that sparse
correctly evaluates the unqualified type and keeps the __beNN logic intact.

The downside is that this requires a top of tree sparse build and an old
sparse version will emit a metric ton of incomprehensible error messages
before it dies with a segfault.

Therefore implement a sanity check which validates that the checker is
available and capable of handling typeof_unqual(). Emit a warning if not so
the user can take informed action.

[ tglx: Move the evaluation of USE_TYPEOF_UNQUAL to compiler_types.h so it is
  	set before use and implement the sanity checker ]

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Acked-by: Ian Rogers <irogers@google.com>
Link: https://patch.msgid.link/87ecnp2zh3.ffs@tglx
Closes: https://lore.kernel.org/oe-kbuild-all/202601150001.sKSN644a-lkp@intel.com/
---
 Makefile                       |  8 ++++++++
 include/linux/compiler.h       | 10 ----------
 include/linux/compiler_types.h | 11 +++++++++++
 scripts/checker-valid.sh       | 19 +++++++++++++++++++
 4 files changed, 38 insertions(+), 10 deletions(-)
 create mode 100755 scripts/checker-valid.sh

diff --git a/Makefile b/Makefile
index 9d38125..179c9d9 100644
--- a/Makefile
+++ b/Makefile
@@ -1187,6 +1187,14 @@ CHECKFLAGS += $(if $(CONFIG_CPU_BIG_ENDIAN),-mbig-endian,-mlittle-endian)
 # the checker needs the correct machine size
 CHECKFLAGS += $(if $(CONFIG_64BIT),-m64,-m32)
 
+# Validate the checker is available and functional
+ifneq ($(KBUILD_CHECKSRC), 0)
+  ifneq ($(shell $(srctree)/scripts/checker-valid.sh $(CHECK) $(CHECKFLAGS)), 1)
+    $(warning C=$(KBUILD_CHECKSRC) specified, but $(CHECK) is not available or not up to date)
+    KBUILD_CHECKSRC = 0
+  endif
+endif
+
 # Default kernel image to build when no specific target is given.
 # KBUILD_IMAGE may be overruled on the command line or
 # set in the environment
diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index 04487c9..c601222 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -231,16 +231,6 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
 				"must be non-C-string (not NUL-terminated)")
 
 /*
- * Use __typeof_unqual__() when available.
- *
- * XXX: Remove test for __CHECKER__ once
- * sparse learns about __typeof_unqual__().
- */
-#if CC_HAS_TYPEOF_UNQUAL && !defined(__CHECKER__)
-# define USE_TYPEOF_UNQUAL 1
-#endif
-
-/*
  * Define TYPEOF_UNQUAL() to use __typeof_unqual__() as typeof
  * operator when available, to return an unqualified type of the exp.
  */
diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h
index d3318a3..9cf4dcf 100644
--- a/include/linux/compiler_types.h
+++ b/include/linux/compiler_types.h
@@ -562,6 +562,13 @@ struct ftrace_likely_data {
 #define asm_inline asm
 #endif
 
+/*
+ * Use __typeof_unqual__() when available.
+ */
+#if CC_HAS_TYPEOF_UNQUAL || defined(__CHECKER__)
+# define USE_TYPEOF_UNQUAL 1
+#endif
+
 /* Are two types/vars the same type (ignoring qualifiers)? */
 #define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
 
@@ -569,6 +576,7 @@ struct ftrace_likely_data {
  * __unqual_scalar_typeof(x) - Declare an unqualified scalar type, leaving
  *			       non-scalar types unchanged.
  */
+#ifndef USE_TYPEOF_UNQUAL
 /*
  * Prefer C11 _Generic for better compile-times and simpler code. Note: 'char'
  * is not type-compatible with 'signed char', and we define a separate case.
@@ -586,6 +594,9 @@ struct ftrace_likely_data {
 			 __scalar_type_to_expr_cases(long),		\
 			 __scalar_type_to_expr_cases(long long),	\
 			 default: (x)))
+#else
+#define __unqual_scalar_typeof(x) __typeof_unqual__(x)
+#endif
 
 /* Is this type a native word size -- useful for atomic operations */
 #define __native_word(t) \
diff --git a/scripts/checker-valid.sh b/scripts/checker-valid.sh
new file mode 100755
index 0000000..625a789
--- /dev/null
+++ b/scripts/checker-valid.sh
@@ -0,0 +1,19 @@
+#!/bin/sh -eu
+# SPDX-License-Identifier: GPL-2.0
+
+[ ! -x "$(command -v "$1")" ] && exit 1
+
+tmp_file=$(mktemp)
+trap "rm -f $tmp_file" EXIT
+
+cat << EOF >$tmp_file
+static inline int u(const int *q)
+{
+	__typeof_unqual__(*q) v = *q;
+	return v;
+}
+EOF
+
+# sparse happily exits with 0 on error so validate
+# there is none on stderr. Use awk as grep is a pain with sh -e
+$@ $tmp_file 2>&1 | awk -v c=1 '/error/{c=0}END{print c}'