kconfig: use unsigned integers for hex range checks

While 'hex' values should use the bounds of 64-bit unsigned integers, the
range values are treated as signed (checks use strtoll).

For example:

  config HEX_RANGE
    hex
    range 0 0xfffffffffffffffe
    default 0xffffffffffffffff

the default value should adjust down to the upper bound of
0xfffffffffffffffe, but since the check incorrectly parses both as
LLONG_MAX, the value stays at the out-of-range default of
0xffffffffffffffff.

To fix this, let's use a union of signed and unsigned integers to
represent both 'int' and 'hex' range values, then use both strtoll and
strtoull where appropriate.

Assisted-by: LLM
Signed-off-by: Julian Braha <julianbraha@gmail.com>
Reviewed-by: Nicolas Schier <n.schier@fritz.com>
Link: https://patch.msgid.link/20260915211508.291790-6-julianbraha@gmail.com
Signed-off-by: Nathan Chancellor <nathan@kernel.org>

3 files changed, 36 insertions, 11 deletions

diff --git a/scripts/kconfig/symbol.c b/scripts/kconfig/symbol.c
index 8ccd9e7e2cf0..dcb4b45e674b 100644
--- a/scripts/kconfig/symbol.c
+++ b/scripts/kconfig/symbol.c
@@ -142,8 +142,15 @@ struct property *sym_get_range_prop(struct symbol *sym)
 	return NULL;
 }
 
-static long long sym_get_range_val(struct symbol *sym, int base)
+union range_value {
+	long long s;
+	unsigned long long u;
+};
+
+static union range_value sym_get_range_val(struct symbol *sym, int base)
 {
+	union range_value val;
+
 	sym_calc_value(sym);
 	switch (sym->type) {
 	case S_INT:
@@ -155,7 +162,12 @@ static long long sym_get_range_val(struct symbol *sym, int base)
 	default:
 		break;
 	}
-	return strtoll(sym->curr.val, NULL, base);
+	if (base == 10)
+		val.s = strtoll(sym->curr.val, NULL, base);
+	else
+		/* HEX */
+		val.u = strtoull(sym->curr.val, NULL, base);
+	return val;
 }
 
 /*
@@ -168,7 +180,7 @@ static struct symbol *sym_get_near_range_bound(struct symbol *sym,
 	struct property *prop;
 	struct symbol *range_sym;
 	int base;
-	long long val, val2;
+	union range_value val, val2;
 
 	switch (sym->type) {
 	case S_INT:
@@ -183,13 +195,19 @@ static struct symbol *sym_get_near_range_bound(struct symbol *sym,
 	prop = sym_get_range_prop(sym);
 	if (!prop)
 		return NULL;
-	val = strtoll(value, NULL, base);
+	val = sym_get_range_val(sym, base);
 	range_sym = prop->expr->left.sym;
 	val2 = sym_get_range_val(range_sym, base);
-	if (val >= val2) {
+
+	if (base == 10 && val.s >= val2.s) {
+		range_sym = prop->expr->right.sym;
+		val2 = sym_get_range_val(range_sym, base);
+		if (val.s <= val2.s)
+			return NULL;
+	} else if (base == 16 && val.u >= val2.u) {
 		range_sym = prop->expr->right.sym;
 		val2 = sym_get_range_val(range_sym, base);
-		if (val <= val2)
+		if (val.u <= val2.u)
 			return NULL;
 	}
 
@@ -746,6 +764,7 @@ bool sym_string_within_range(struct symbol *sym, const char *str)
 {
 	struct property *prop;
 	long long val;
+	unsigned long long uval;
 
 	switch (sym->type) {
 	case S_STRING:
@@ -759,8 +778,8 @@ bool sym_string_within_range(struct symbol *sym, const char *str)
 		if (!prop)
 			return true;
 		val = strtoll(str, NULL, 10);
-		return val >= sym_get_range_val(prop->expr->left.sym, 10) &&
-		       val <= sym_get_range_val(prop->expr->right.sym, 10);
+		return val >= sym_get_range_val(prop->expr->left.sym, 10).s &&
+		       val <= sym_get_range_val(prop->expr->right.sym, 10).s;
 	case S_HEX:
 		if (!sym_string_valid(sym, str))
 			return false;
@@ -769,9 +788,9 @@ bool sym_string_within_range(struct symbol *sym, const char *str)
 		prop = sym_get_range_prop(sym);
 		if (!prop)
 			return true;
-		val = strtoll(str, NULL, 16);
-		return val >= sym_get_range_val(prop->expr->left.sym, 16) &&
-		       val <= sym_get_range_val(prop->expr->right.sym, 16);
+		uval = strtoull(str, NULL, 16);
+		return uval >= sym_get_range_val(prop->expr->left.sym, 16).u &&
+		       uval <= sym_get_range_val(prop->expr->right.sym, 16).u;
 	case S_BOOLEAN:
 	case S_TRISTATE:
 		switch (str[0]) {
diff --git a/scripts/kconfig/tests/warn_changed_input/Kconfig b/scripts/kconfig/tests/warn_changed_input/Kconfig
index 69845e2f3fb3..df4183a08420 100644
--- a/scripts/kconfig/tests/warn_changed_input/Kconfig
+++ b/scripts/kconfig/tests/warn_changed_input/Kconfig
@@ -26,6 +26,11 @@ config NUM
 	  Kconfig resolves it to the constrained in-range value.
 	  The warning should report that adjustment.
 
+config HEX_RANGE
+	hex
+	range 0 0xfffffffffffffffe
+	default 0xffffffffffffffff
+
 config DUP
 	bool "DUP"
 	depends on DEP
diff --git a/scripts/kconfig/tests/warn_changed_input/expected_config b/scripts/kconfig/tests/warn_changed_input/expected_config
index fe8bbec66c53..6a8d98a69b7e 100644
--- a/scripts/kconfig/tests/warn_changed_input/expected_config
+++ b/scripts/kconfig/tests/warn_changed_input/expected_config
@@ -4,3 +4,4 @@
 #
 # CONFIG_DEP is not set
 CONFIG_NUM=20
+CONFIG_HEX_RANGE=0xfffffffffffffffe