3 files changed, 23 insertions, 5 deletions
diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h
index ac3fa37a84f9..bbaa39e98f9f 100644
--- a/include/linux/compiler_types.h
+++ b/include/linux/compiler_types.h
@@ -64,6 +64,17 @@ static inline void __chk_io_ptr(const volatile void __iomem *ptr) { }
 /* Attributes */
 #include <linux/compiler_attributes.h>
 
+/* Builtins */
+
+/*
+ * __has_builtin is supported on gcc >= 10, clang >= 3 and icc >= 21.
+ * In the meantime, to support gcc < 10, we implement __has_builtin
+ * by hand.
+ */
+#ifndef __has_builtin
+#define __has_builtin(x) (0)
+#endif
+
 /* Compiler specific macros. */
 #ifdef __clang__
 #include <linux/compiler-clang.h>
diff --git a/include/linux/ctype.h b/include/linux/ctype.h
index 363b004426db..bc95aef2219c 100644
--- a/include/linux/ctype.h
+++ b/include/linux/ctype.h
@@ -2,6 +2,8 @@
 #ifndef _LINUX_CTYPE_H
 #define _LINUX_CTYPE_H
 
+#include <linux/compiler.h>
+
 /*
  * NOTE! This ctype does not handle EOF like the standard C
  * library is required to.
@@ -23,10 +25,6 @@ extern const unsigned char _ctype[];
 #define isalnum(c)	((__ismask(c)&(_U|_L|_D)) != 0)
 #define isalpha(c)	((__ismask(c)&(_U|_L)) != 0)
 #define iscntrl(c)	((__ismask(c)&(_C)) != 0)
-static inline int isdigit(int c)
-{
-	return '0' <= c && c <= '9';
-}
 #define isgraph(c)	((__ismask(c)&(_P|_U|_L|_D)) != 0)
 #define islower(c)	((__ismask(c)&(_L)) != 0)
 #define isprint(c)	((__ismask(c)&(_P|_U|_L|_D|_SP)) != 0)
@@ -39,6 +37,15 @@ static inline int isdigit(int c)
 #define isascii(c) (((unsigned char)(c))<=0x7f)
 #define toascii(c) (((unsigned char)(c))&0x7f)
 
+#if __has_builtin(__builtin_isdigit)
+#define  isdigit(c) __builtin_isdigit(c)
+#else
+static inline int isdigit(int c)
+{
+	return '0' <= c && c <= '9';
+}
+#endif
+
 static inline unsigned char __tolower(unsigned char c)
 {
 	if (isupper(c))
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 0f72f380db72..17ac91876544 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -744,7 +744,7 @@ asmlinkage long sys_settimeofday(struct __kernel_old_timeval __user *tv,
 asmlinkage long sys_adjtimex(struct __kernel_timex __user *txc_p);
 asmlinkage long sys_adjtimex_time32(struct old_timex32 __user *txc_p);
 
-/* kernel/timer.c */
+/* kernel/sys.c */
 asmlinkage long sys_getpid(void);
 asmlinkage long sys_getppid(void);
 asmlinkage long sys_getuid(void);