[PATCH v2 3/3] limits.h: provide all limit macros for standard [u]intNN_t types

Rasmus Villemoes ravi at prevas.dk
Mon Jul 7 22:36:55 CEST 2025


Currently, we only have UINT32_MAX and UINT64_MAX in limits.h, and
then stdint.h and kernel.h somewhat randomly define UINT8_MAX and
INT32_MAX, respectively.

Provide a full set of definitions in terms of the min/max macros for
the types that [u]intNN_t are defined in terms of, namely the {s,u}NN
ones.

Try to avoid breaking whatever depended on getting UINT8_MAX from our
compat stdint.h by replacing it with an include of limits.h.

Signed-off-by: Rasmus Villemoes <ravi at prevas.dk>
---
 include/limits.h       | 15 +++++++++++++--
 include/linux/kernel.h |  2 --
 include/stdint.h       |  2 +-
 3 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/include/limits.h b/include/limits.h
index c2e3d0302b7..a032bc5b84d 100644
--- a/include/limits.h
+++ b/include/limits.h
@@ -44,9 +44,20 @@
 #define S64_MAX     LLONG_MAX
 #define S64_MIN     LLONG_MIN
 
+#define UINT8_MAX   U8_MAX
+#define INT8_MAX    S8_MAX
+#define INT8_MIN    S8_MIN
+#define UINT16_MAX  U16_MAX
+#define INT16_MAX   S16_MAX
+#define INT16_MIN   S16_MIN
+#define UINT32_MAX  U32_MAX
+#define INT32_MAX   S32_MAX
+#define INT32_MIN   S32_MIN
+#define UINT64_MAX  U64_MAX
+#define INT64_MAX   S64_MAX
+#define INT64_MIN   S64_MIN
+
 #define CHAR_BIT    8
-#define UINT32_MAX  0xffffffffU
-#define UINT64_MAX  0xffffffffffffffffULL
 
 #if (defined(CONFIG_64BIT) && !defined(CONFIG_SPL_BUILD)) || \
 	(defined(CONFIG_SPL_64BIT) && defined(CONFIG_SPL_BUILD))
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index d3d979834ae..e0443ecac84 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -5,8 +5,6 @@
 #include <linux/printk.h> /* for printf/pr_* utilities */
 #include <limits.h>
 
-#define INT32_MAX	S32_MAX
-
 #define STACK_MAGIC	0xdeadbeef
 
 #define REPEAT_BYTE(x)	((~0ul / 0xff) * (x))
diff --git a/include/stdint.h b/include/stdint.h
index dea83c8226a..90fd2bdee08 100644
--- a/include/stdint.h
+++ b/include/stdint.h
@@ -9,6 +9,6 @@
 #ifndef __UB_STDINT_H
 #define __UB_STDINT_H
 
-#define UINT8_MAX	0xff
+#include <limits.h>
 
 #endif
-- 
2.50.0



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