[PATCH 1/3] drm/i915: rename range_overflows_end() to range_end_overflows()

[PATCH 1/3] drm/i915: rename range_overflows_end() to range_end_overflows()

[Jani Nikula]

Rename range_overflows_end() to range_end_overflows(), along with the _t
variant.

It's all rather subjective, but I think range_end_overflows() reads
better.

Cc: Kees Cook <kees@kernel.org>
Cc: Gustavo A. R. Silva <gustavoars@kernel.org>
Cc: linux-hardening@vger.kernel.org
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
---
 drivers/gpu/drm/i915/display/intel_fbc.c | 4 ++--
 drivers/gpu/drm/i915/gt/intel_rc6.c      | 2 +-
 drivers/gpu/drm/i915/i915_utils.h        | 6 +++---
 3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_fbc.c b/drivers/gpu/drm/i915/display/intel_fbc.c
index d4c5deff9cbe..446e2ad28a70 100644
--- a/drivers/gpu/drm/i915/display/intel_fbc.c
+++ b/drivers/gpu/drm/i915/display/intel_fbc.c
@@ -383,11 +383,11 @@ static void i8xx_fbc_program_cfb(struct intel_fbc *fbc)
 	struct drm_i915_private *i915 = to_i915(display->drm);
 
 	drm_WARN_ON(display->drm,
-		    range_overflows_end_t(u64, i915_gem_stolen_area_address(i915),
+		    range_end_overflows_t(u64, i915_gem_stolen_area_address(i915),
 					  i915_gem_stolen_node_offset(&fbc->compressed_fb),
 					  U32_MAX));
 	drm_WARN_ON(display->drm,
-		    range_overflows_end_t(u64, i915_gem_stolen_area_address(i915),
+		    range_end_overflows_t(u64, i915_gem_stolen_area_address(i915),
 					  i915_gem_stolen_node_offset(&fbc->compressed_llb),
 					  U32_MAX));
 	intel_de_write(display, FBC_CFB_BASE,
diff --git a/drivers/gpu/drm/i915/gt/intel_rc6.c b/drivers/gpu/drm/i915/gt/intel_rc6.c
index 9ca42589da4d..bf38cc5fe872 100644
--- a/drivers/gpu/drm/i915/gt/intel_rc6.c
+++ b/drivers/gpu/drm/i915/gt/intel_rc6.c
@@ -341,7 +341,7 @@ static int vlv_rc6_init(struct intel_rc6 *rc6)
 		return PTR_ERR(pctx);
 	}
 
-	GEM_BUG_ON(range_overflows_end_t(u64,
+	GEM_BUG_ON(range_end_overflows_t(u64,
 					 i915->dsm.stolen.start,
 					 pctx->stolen->start,
 					 U32_MAX));
diff --git a/drivers/gpu/drm/i915/i915_utils.h b/drivers/gpu/drm/i915/i915_utils.h
index 9cb40c2c4b12..fdac9a158b53 100644
--- a/drivers/gpu/drm/i915/i915_utils.h
+++ b/drivers/gpu/drm/i915/i915_utils.h
@@ -79,7 +79,7 @@ bool i915_error_injected(void);
 #define range_overflows_t(type, start, size, max) \
 	range_overflows((type)(start), (type)(size), (type)(max))
 
-#define range_overflows_end(start, size, max) ({ \
+#define range_end_overflows(start, size, max) ({ \
 	typeof(start) start__ = (start); \
 	typeof(size) size__ = (size); \
 	typeof(max) max__ = (max); \
@@ -88,8 +88,8 @@ bool i915_error_injected(void);
 	start__ > max__ || size__ > max__ - start__; \
 })
 
-#define range_overflows_end_t(type, start, size, max) \
-	range_overflows_end((type)(start), (type)(size), (type)(max))
+#define range_end_overflows_t(type, start, size, max) \
+	range_end_overflows((type)(start), (type)(size), (type)(max))
 
 #define ptr_mask_bits(ptr, n) ({					\
 	unsigned long __v = (unsigned long)(ptr);			\
-- 
2.47.2

[PATCH 2/3] drm/i915: document range_overflows() and range_end_overflows() macros

[Jani Nikula]

Document the macros in preparation for making them more generally
available.

Cc: Kees Cook <kees@kernel.org>
Cc: Gustavo A. R. Silva <gustavoars@kernel.org>
Cc: linux-hardening@vger.kernel.org
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
---
 drivers/gpu/drm/i915/i915_utils.h | 46 +++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_utils.h b/drivers/gpu/drm/i915/i915_utils.h
index fdac9a158b53..968dae941532 100644
--- a/drivers/gpu/drm/i915/i915_utils.h
+++ b/drivers/gpu/drm/i915/i915_utils.h
@@ -67,6 +67,18 @@ bool i915_error_injected(void);
 		drm_err(&(i915)->drm, fmt, ##__VA_ARGS__); \
 })
 
+/**
+ * range_overflows() - Check if a range is out of bounds
+ * @start: Start of the range.
+ * @size:  Size of the range.
+ * @max:   Exclusive upper boundary.
+ *
+ * A strict check to determine if the range [@start, @start + @size) is
+ * invalid with respect to the allowable range [0, @max). Any range
+ * starting at or beyond @max is considered an overflow, even if @size is 0.
+ *
+ * Returns: true if the range is out of bounds.
+ */
 #define range_overflows(start, size, max) ({ \
 	typeof(start) start__ = (start); \
 	typeof(size) size__ = (size); \
@@ -76,9 +88,32 @@ bool i915_error_injected(void);
 	start__ >= max__ || size__ > max__ - start__; \
 })
 
+/**
+ * range_overflows_t() - Check if a range is out of bounds
+ * @type:  Data type to use.
+ * @start: Start of the range.
+ * @size:  Size of the range.
+ * @max:   Exclusive upper boundary.
+ *
+ * Same as range_overflows() but forcing the parameters to @type.
+ *
+ * Returns: true if the range is out of bounds.
+ */
 #define range_overflows_t(type, start, size, max) \
 	range_overflows((type)(start), (type)(size), (type)(max))
 
+/**
+ * range_end_overflows() - Check if a range's endpoint is out of bounds
+ * @start: Start of the range.
+ * @size:  Size of the range.
+ * @max:   Exclusive upper boundary.
+ *
+ * Checks only if the endpoint of a range (@start + @size) exceeds @max.
+ * Unlike range_overflows(), a zero-sized range at the boundary (@start == @max)
+ * is not considered an overflow. Useful for iterator-style checks.
+ *
+ * Returns: true if the endpoint exceeds the boundary.
+ */
 #define range_end_overflows(start, size, max) ({ \
 	typeof(start) start__ = (start); \
 	typeof(size) size__ = (size); \
@@ -88,6 +123,17 @@ bool i915_error_injected(void);
 	start__ > max__ || size__ > max__ - start__; \
 })
 
+/**
+ * range_end_overflows_t() - Check if a range's endpoint is out of bounds
+ * @type:  Data type to use.
+ * @start: Start of the range.
+ * @size:  Size of the range.
+ * @max:   Exclusive upper boundary.
+ *
+ * Same as range_end_overflows() but forcing the parameters to @type.
+ *
+ * Returns: true if the endpoint exceeds the boundary.
+ */
 #define range_end_overflows_t(type, start, size, max) \
 	range_end_overflows((type)(start), (type)(size), (type)(max))
 
-- 
2.47.2

[PATCH 3/3] overflow: add range_overflows() and range_end_overflows()

[Jani Nikula]

Move the range_overflows() and range_end_overflows() along with the _t
variants over from drm/i915 and drm/buddy to overflow.h.

Cc: Kees Cook <kees@kernel.org>
Cc: Gustavo A. R. Silva <gustavoars@kernel.org>
Cc: linux-hardening@vger.kernel.org
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
---
 drivers/gpu/drm/i915/i915_utils.h | 70 -------------------------------
 include/drm/drm_buddy.h           |  9 ----
 include/linux/overflow.h          | 70 +++++++++++++++++++++++++++++++
 3 files changed, 70 insertions(+), 79 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_utils.h b/drivers/gpu/drm/i915/i915_utils.h
index 968dae941532..eb4d43c40009 100644
--- a/drivers/gpu/drm/i915/i915_utils.h
+++ b/drivers/gpu/drm/i915/i915_utils.h
@@ -67,76 +67,6 @@ bool i915_error_injected(void);
 		drm_err(&(i915)->drm, fmt, ##__VA_ARGS__); \
 })
 
-/**
- * range_overflows() - Check if a range is out of bounds
- * @start: Start of the range.
- * @size:  Size of the range.
- * @max:   Exclusive upper boundary.
- *
- * A strict check to determine if the range [@start, @start + @size) is
- * invalid with respect to the allowable range [0, @max). Any range
- * starting at or beyond @max is considered an overflow, even if @size is 0.
- *
- * Returns: true if the range is out of bounds.
- */
-#define range_overflows(start, size, max) ({ \
-	typeof(start) start__ = (start); \
-	typeof(size) size__ = (size); \
-	typeof(max) max__ = (max); \
-	(void)(&start__ == &size__); \
-	(void)(&start__ == &max__); \
-	start__ >= max__ || size__ > max__ - start__; \
-})
-
-/**
- * range_overflows_t() - Check if a range is out of bounds
- * @type:  Data type to use.
- * @start: Start of the range.
- * @size:  Size of the range.
- * @max:   Exclusive upper boundary.
- *
- * Same as range_overflows() but forcing the parameters to @type.
- *
- * Returns: true if the range is out of bounds.
- */
-#define range_overflows_t(type, start, size, max) \
-	range_overflows((type)(start), (type)(size), (type)(max))
-
-/**
- * range_end_overflows() - Check if a range's endpoint is out of bounds
- * @start: Start of the range.
- * @size:  Size of the range.
- * @max:   Exclusive upper boundary.
- *
- * Checks only if the endpoint of a range (@start + @size) exceeds @max.
- * Unlike range_overflows(), a zero-sized range at the boundary (@start == @max)
- * is not considered an overflow. Useful for iterator-style checks.
- *
- * Returns: true if the endpoint exceeds the boundary.
- */
-#define range_end_overflows(start, size, max) ({ \
-	typeof(start) start__ = (start); \
-	typeof(size) size__ = (size); \
-	typeof(max) max__ = (max); \
-	(void)(&start__ == &size__); \
-	(void)(&start__ == &max__); \
-	start__ > max__ || size__ > max__ - start__; \
-})
-
-/**
- * range_end_overflows_t() - Check if a range's endpoint is out of bounds
- * @type:  Data type to use.
- * @start: Start of the range.
- * @size:  Size of the range.
- * @max:   Exclusive upper boundary.
- *
- * Same as range_end_overflows() but forcing the parameters to @type.
- *
- * Returns: true if the endpoint exceeds the boundary.
- */
-#define range_end_overflows_t(type, start, size, max) \
-	range_end_overflows((type)(start), (type)(size), (type)(max))
-
 #define ptr_mask_bits(ptr, n) ({					\
 	unsigned long __v = (unsigned long)(ptr);			\
 	(typeof(ptr))(__v & -BIT(n));					\
diff --git a/include/drm/drm_buddy.h b/include/drm/drm_buddy.h
index 513837632b7d..04afd7c21a82 100644
--- a/include/drm/drm_buddy.h
+++ b/include/drm/drm_buddy.h
@@ -13,15 +13,6 @@
 
 #include <drm/drm_print.h>
 
-#define range_overflows(start, size, max) ({ \
-	typeof(start) start__ = (start); \
-	typeof(size) size__ = (size); \
-	typeof(max) max__ = (max); \
-	(void)(&start__ == &size__); \
-	(void)(&start__ == &max__); \
-	start__ >= max__ || size__ > max__ - start__; \
-})
-
 #define DRM_BUDDY_RANGE_ALLOCATION		BIT(0)
 #define DRM_BUDDY_TOPDOWN_ALLOCATION		BIT(1)
 #define DRM_BUDDY_CONTIGUOUS_ALLOCATION		BIT(2)
diff --git a/include/linux/overflow.h b/include/linux/overflow.h
index 154ed0dbb43f..725f95f7e416 100644
--- a/include/linux/overflow.h
+++ b/include/linux/overflow.h
@@ -238,6 +238,76 @@ static inline bool __must_check __must_check_overflow(bool overflow)
 			      __overflows_type_constexpr(n, T),	\
 			      __overflows_type(n, T))
 
+/**
+ * range_overflows() - Check if a range is out of bounds
+ * @start: Start of the range.
+ * @size:  Size of the range.
+ * @max:   Exclusive upper boundary.
+ *
+ * A strict check to determine if the range [@start, @start + @size) is
+ * invalid with respect to the allowable range [0, @max). Any range
+ * starting at or beyond @max is considered an overflow, even if @size is 0.
+ *
+ * Returns: true if the range is out of bounds.
+ */
+#define range_overflows(start, size, max) ({ \
+	typeof(start) start__ = (start); \
+	typeof(size) size__ = (size); \
+	typeof(max) max__ = (max); \
+	(void)(&start__ == &size__); \
+	(void)(&start__ == &max__); \
+	start__ >= max__ || size__ > max__ - start__; \
+})
+
+/**
+ * range_overflows_t() - Check if a range is out of bounds
+ * @type:  Data type to use.
+ * @start: Start of the range.
+ * @size:  Size of the range.
+ * @max:   Exclusive upper boundary.
+ *
+ * Same as range_overflows() but forcing the parameters to @type.
+ *
+ * Returns: true if the range is out of bounds.
+ */
+#define range_overflows_t(type, start, size, max) \
+	range_overflows((type)(start), (type)(size), (type)(max))
+
+/**
+ * range_end_overflows() - Check if a range's endpoint is out of bounds
+ * @start: Start of the range.
+ * @size:  Size of the range.
+ * @max:   Exclusive upper boundary.
+ *
+ * Checks only if the endpoint of a range (@start + @size) exceeds @max.
+ * Unlike range_overflows(), a zero-sized range at the boundary (@start == @max)
+ * is not considered an overflow. Useful for iterator-style checks.
+ *
+ * Returns: true if the endpoint exceeds the boundary.
+ */
+#define range_end_overflows(start, size, max) ({ \
+	typeof(start) start__ = (start); \
+	typeof(size) size__ = (size); \
+	typeof(max) max__ = (max); \
+	(void)(&start__ == &size__); \
+	(void)(&start__ == &max__); \
+	start__ > max__ || size__ > max__ - start__; \
+})
+
+/**
+ * range_end_overflows_t() - Check if a range's endpoint is out of bounds
+ * @type:  Data type to use.
+ * @start: Start of the range.
+ * @size:  Size of the range.
+ * @max:   Exclusive upper boundary.
+ *
+ * Same as range_end_overflows() but forcing the parameters to @type.
+ *
+ * Returns: true if the endpoint exceeds the boundary.
+ */
+#define range_end_overflows_t(type, start, size, max) \
+	range_end_overflows((type)(start), (type)(size), (type)(max))
+
 /**
  * castable_to_type - like __same_type(), but also allows for casted literals
  *
-- 
2.47.2

Re: [PATCH 1/3] drm/i915: rename range_overflows_end() to range_end_overflows()

[Hogander, Jouni]

On Fri, 2025-08-29 at 20:45 +0300, Jani Nikula wrote:
> Rename range_overflows_end() to range_end_overflows(), along with the
> _t
> variant.
> 
> It's all rather subjective, but I think range_end_overflows() reads
> better.
> 
> Cc: Kees Cook <kees@kernel.org>
> Cc: Gustavo A. R. Silva <gustavoars@kernel.org>
> Cc: linux-hardening@vger.kernel.org
> Signed-off-by: Jani Nikula <jani.nikula@intel.com>

Reviewed-by: Jouni Högander <jouni.hogander@intel.com>

> ---
>  drivers/gpu/drm/i915/display/intel_fbc.c | 4 ++--
>  drivers/gpu/drm/i915/gt/intel_rc6.c      | 2 +-
>  drivers/gpu/drm/i915/i915_utils.h        | 6 +++---
>  3 files changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_fbc.c
> b/drivers/gpu/drm/i915/display/intel_fbc.c
> index d4c5deff9cbe..446e2ad28a70 100644
> --- a/drivers/gpu/drm/i915/display/intel_fbc.c
> +++ b/drivers/gpu/drm/i915/display/intel_fbc.c
> @@ -383,11 +383,11 @@ static void i8xx_fbc_program_cfb(struct
> intel_fbc *fbc)
>  	struct drm_i915_private *i915 = to_i915(display->drm);
>  
>  	drm_WARN_ON(display->drm,
> -		    range_overflows_end_t(u64,
> i915_gem_stolen_area_address(i915),
> +		    range_end_overflows_t(u64,
> i915_gem_stolen_area_address(i915),
>  					 
> i915_gem_stolen_node_offset(&fbc->compressed_fb),
>  					  U32_MAX));
>  	drm_WARN_ON(display->drm,
> -		    range_overflows_end_t(u64,
> i915_gem_stolen_area_address(i915),
> +		    range_end_overflows_t(u64,
> i915_gem_stolen_area_address(i915),
>  					 
> i915_gem_stolen_node_offset(&fbc->compressed_llb),
>  					  U32_MAX));
>  	intel_de_write(display, FBC_CFB_BASE,
> diff --git a/drivers/gpu/drm/i915/gt/intel_rc6.c
> b/drivers/gpu/drm/i915/gt/intel_rc6.c
> index 9ca42589da4d..bf38cc5fe872 100644
> --- a/drivers/gpu/drm/i915/gt/intel_rc6.c
> +++ b/drivers/gpu/drm/i915/gt/intel_rc6.c
> @@ -341,7 +341,7 @@ static int vlv_rc6_init(struct intel_rc6 *rc6)
>  		return PTR_ERR(pctx);
>  	}
>  
> -	GEM_BUG_ON(range_overflows_end_t(u64,
> +	GEM_BUG_ON(range_end_overflows_t(u64,
>  					 i915->dsm.stolen.start,
>  					 pctx->stolen->start,
>  					 U32_MAX));
> diff --git a/drivers/gpu/drm/i915/i915_utils.h
> b/drivers/gpu/drm/i915/i915_utils.h
> index 9cb40c2c4b12..fdac9a158b53 100644
> --- a/drivers/gpu/drm/i915/i915_utils.h
> +++ b/drivers/gpu/drm/i915/i915_utils.h
> @@ -79,7 +79,7 @@ bool i915_error_injected(void);
>  #define range_overflows_t(type, start, size, max) \
>  	range_overflows((type)(start), (type)(size), (type)(max))
>  
> -#define range_overflows_end(start, size, max) ({ \
> +#define range_end_overflows(start, size, max) ({ \
>  	typeof(start) start__ = (start); \
>  	typeof(size) size__ = (size); \
>  	typeof(max) max__ = (max); \
> @@ -88,8 +88,8 @@ bool i915_error_injected(void);
>  	start__ > max__ || size__ > max__ - start__; \
>  })
>  
> -#define range_overflows_end_t(type, start, size, max) \
> -	range_overflows_end((type)(start), (type)(size),
> (type)(max))
> +#define range_end_overflows_t(type, start, size, max) \
> +	range_end_overflows((type)(start), (type)(size),
> (type)(max))
>  
>  #define ptr_mask_bits(ptr, n)
> ({					\
>  	unsigned long __v = (unsigned
> long)(ptr);			\

Re: [PATCH 3/3] overflow: add range_overflows() and range_end_overflows()

[Kees Cook]

On Fri, Aug 29, 2025 at 08:46:01PM +0300, Jani Nikula wrote:
> Move the range_overflows() and range_end_overflows() along with the _t
> variants over from drm/i915 and drm/buddy to overflow.h.
> 
> Cc: Kees Cook <kees@kernel.org>
> Cc: Gustavo A. R. Silva <gustavoars@kernel.org>
> Cc: linux-hardening@vger.kernel.org
> Signed-off-by: Jani Nikula <jani.nikula@intel.com>

Looks good to me! :)

Reviewed-by: Kees Cook <kees@kernel.org>

-- 
Kees Cook

Re: [PATCH 3/3] overflow: add range_overflows() and range_end_overflows()

[Jani Nikula]

On Wed, 03 Sep 2025, Kees Cook <kees@kernel.org> wrote:
> On Fri, Aug 29, 2025 at 08:46:01PM +0300, Jani Nikula wrote:
>> Move the range_overflows() and range_end_overflows() along with the _t
>> variants over from drm/i915 and drm/buddy to overflow.h.
>> 
>> Cc: Kees Cook <kees@kernel.org>
>> Cc: Gustavo A. R. Silva <gustavoars@kernel.org>
>> Cc: linux-hardening@vger.kernel.org
>> Signed-off-by: Jani Nikula <jani.nikula@intel.com>
>
> Looks good to me! :)
>
> Reviewed-by: Kees Cook <kees@kernel.org>

Cool, thanks! How do you want to handle merging this?

BR,
Jani.


-- 
Jani Nikula, Intel

Re: [PATCH 3/3] overflow: add range_overflows() and range_end_overflows()

[Kees Cook]

On Thu, Sep 04, 2025 at 10:34:04AM +0300, Jani Nikula wrote:
> On Wed, 03 Sep 2025, Kees Cook <kees@kernel.org> wrote:
> > On Fri, Aug 29, 2025 at 08:46:01PM +0300, Jani Nikula wrote:
> >> Move the range_overflows() and range_end_overflows() along with the _t
> >> variants over from drm/i915 and drm/buddy to overflow.h.
> >> 
> >> Cc: Kees Cook <kees@kernel.org>
> >> Cc: Gustavo A. R. Silva <gustavoars@kernel.org>
> >> Cc: linux-hardening@vger.kernel.org
> >> Signed-off-by: Jani Nikula <jani.nikula@intel.com>
> >
> > Looks good to me! :)
> >
> > Reviewed-by: Kees Cook <kees@kernel.org>
> 
> Cool, thanks! How do you want to handle merging this?

Since it's touching drm, feel free to take it there. I'm not worried
about conflict resolution in overflow.h.

-- 
Kees Cook