[PATCH v3 1/2] x86: add kstrtoul() converter func to boot code

[Vamshi K Sthambamkadi]

add str to unsigned long converter function to boot code.

Signed-off-by: Vamshi K Sthambamkadi <vamshi.k.sthambamkadi@xxxxxxxxx>
---
 arch/x86/boot/string.c | 43 +++++++++++++++++++++++++++++++++++++++++++
 arch/x86/boot/string.h |  1 +
 2 files changed, 44 insertions(+)

diff --git a/arch/x86/boot/string.c b/arch/x86/boot/string.c
index 8272a44..e06ebe1 100644
--- a/arch/x86/boot/string.c
+++ b/arch/x86/boot/string.c
@@ -335,3 +335,46 @@ int kstrtoull(const char *s, unsigned int base, unsigned long long *res)
 		s++;
 	return _kstrtoull(s, base, res);
 }
+
+/* Internal, do not use. */
+int _kstrtoul(const char *s, unsigned int base, unsigned long *res)
+{
+	unsigned long long tmp;
+	int rv;
+
+	rv = kstrtoull(s, base, &tmp);
+	if (rv < 0)
+		return rv;
+	if (tmp != (unsigned long)tmp)
+		return -ERANGE;
+	*res = tmp;
+	return 0;
+}
+
+/**
+ * kstrtoul - convert a string to an unsigned long
+ * @s: The start of the string. The string must be null-terminated, and may also
+ *  include a single newline before its terminating null. The first character
+ *  may also be a plus sign, but not a minus sign.
+ * @base: The number base to use. The maximum supported base is 16. If base is
+ *  given as 0, then the base of the string is automatically detected with the
+ *  conventional semantics - If it begins with 0x the number will be parsed as a
+ *  hexadecimal (case insensitive), if it otherwise begins with 0, it will be
+ *  parsed as an octal number. Otherwise it will be parsed as a decimal.
+ * @res: Where to write the result of the conversion on success.
+ *
+ * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
+ * Used as a replacement for the simple_strtoull.
+ */
+int kstrtoul(const char *s, unsigned int base, unsigned long *res)
+{
+	/*
+	 * We want to shortcut function call, but
+	 * __builtin_types_compatible_p(unsigned long, unsigned long long) = 0.
+	 */
+	if (sizeof(unsigned long) == sizeof(unsigned long long) &&
+	    __alignof__(unsigned long) == __alignof__(unsigned long long))
+		return kstrtoull(s, base, (unsigned long long *)res);
+	else
+		return _kstrtoul(s, base, res);
+}
diff --git a/arch/x86/boot/string.h b/arch/x86/boot/string.h
index 38d8f2f..e8dd239 100644
--- a/arch/x86/boot/string.h
+++ b/arch/x86/boot/string.h
@@ -30,4 +30,5 @@ extern unsigned long long simple_strtoull(const char *cp, char **endp,
 					  unsigned int base);
 
 int kstrtoull(const char *s, unsigned int base, unsigned long long *res);
+int kstrtoul(const char *s, unsigned int base, unsigned long *res);
 #endif /* BOOT_STRING_H */
-- 
2.7.4