diff --git a/Makefile b/Makefile
index 997b67722292..5ad42c712182 100644
--- a/Makefile
+++ b/Makefile
@@ -562,7 +562,7 @@ KBUILD_AFLAGS   := -D__ASSEMBLY__ -fno-PIE
 KBUILD_CFLAGS   := -Wall -Wundef -Werror=strict-prototypes -Wno-trigraphs \
 		   -fno-strict-aliasing -fno-common -fshort-wchar -fno-PIE \
 		   -Werror=implicit-function-declaration -Werror=implicit-int \
-		   -Werror=return-type -Wno-format-security \
+		   -Werror=return-type -Wno-format-security -funsigned-char \
 		   -std=gnu11
 KBUILD_CPPFLAGS := -D__KERNEL__
 KBUILD_RUSTFLAGS := $(rust_common_flags) \
diff --git a/arch/x86/events/intel/p4.c b/arch/x86/events/intel/p4.c
index 03bbcc2fa2ff..35936188db01 100644
--- a/arch/x86/events/intel/p4.c
+++ b/arch/x86/events/intel/p4.c
@@ -24,7 +24,7 @@ struct p4_event_bind {
 	unsigned int escr_msr[2];		/* ESCR MSR for this event */
 	unsigned int escr_emask;		/* valid ESCR EventMask bits */
 	unsigned int shared;			/* event is shared across threads */
-	char cntr[2][P4_CNTR_LIMIT];		/* counter index (offset), -1 on absence */
+	signed char cntr[2][P4_CNTR_LIMIT];	/* counter index (offset), -1 on absence */
 };
 
 struct p4_pebs_bind {
diff --git a/drivers/media/dvb-frontends/stv0288.c b/drivers/media/dvb-frontends/stv0288.c
index 3d54a0ec86af..3ae1f3a2f142 100644
--- a/drivers/media/dvb-frontends/stv0288.c
+++ b/drivers/media/dvb-frontends/stv0288.c
@@ -440,9 +440,8 @@ static int stv0288_set_frontend(struct dvb_frontend *fe)
 	struct stv0288_state *state = fe->demodulator_priv;
 	struct dtv_frontend_properties *c = &fe->dtv_property_cache;
 
-	char tm;
-	unsigned char tda[3];
-	u8 reg, time_out = 0;
+	u8 tda[3], reg, time_out = 0;
+	s8 tm;
 
 	dprintk("%s : FE_SET_FRONTEND\n", __func__);
 
diff --git a/drivers/sbus/char/envctrl.c b/drivers/sbus/char/envctrl.c
index 843e830b5f87..ea914a7eaa7f 100644
--- a/drivers/sbus/char/envctrl.c
+++ b/drivers/sbus/char/envctrl.c
@@ -363,8 +363,8 @@ static int envctrl_read_cpu_info(int cpu, struct i2c_child_t *pchild,
 				 char mon_type, unsigned char *bufdata)
 {
 	unsigned char data;
-	int i;
-	char *tbl, j = -1;
+	int i, j = -1;
+	char *tbl;
 
 	/* Find the right monitor type and channel. */
 	for (i = 0; i < PCF8584_MAX_CHANNELS; i++) {
diff --git a/drivers/staging/media/atomisp/pci/hive_types.h b/drivers/staging/media/atomisp/pci/hive_types.h
index 4b8a679fb672..55d36931f079 100644
--- a/drivers/staging/media/atomisp/pci/hive_types.h
+++ b/drivers/staging/media/atomisp/pci/hive_types.h
@@ -42,7 +42,7 @@ typedef unsigned int hive_bool;
 #define hive_false 0
 #define hive_true  1
 
-typedef char                 hive_int8;
+typedef signed char          hive_int8;
 typedef short                hive_int16;
 typedef int                  hive_int32;
 typedef long long            hive_int64;
diff --git a/lib/is_signed_type_kunit.c b/lib/is_signed_type_kunit.c
index 207207522925..0a7f6ae62839 100644
--- a/lib/is_signed_type_kunit.c
+++ b/lib/is_signed_type_kunit.c
@@ -21,11 +21,7 @@ static void is_signed_type_test(struct kunit *test)
 	KUNIT_EXPECT_EQ(test, is_signed_type(bool), false);
 	KUNIT_EXPECT_EQ(test, is_signed_type(signed char), true);
 	KUNIT_EXPECT_EQ(test, is_signed_type(unsigned char), false);
-#ifdef __CHAR_UNSIGNED__
 	KUNIT_EXPECT_EQ(test, is_signed_type(char), false);
-#else
-	KUNIT_EXPECT_EQ(test, is_signed_type(char), true);
-#endif
 	KUNIT_EXPECT_EQ(test, is_signed_type(int), true);
 	KUNIT_EXPECT_EQ(test, is_signed_type(unsigned int), false);
 	KUNIT_EXPECT_EQ(test, is_signed_type(long), true);
diff --git a/lib/test_printf.c b/lib/test_printf.c
index 4bd15a593fbd..5eb889679e4f 100644
--- a/lib/test_printf.c
+++ b/lib/test_printf.c
@@ -179,18 +179,6 @@ test_number(void)
 	 * behaviour.
 	 */
 	test("00|0|0|0|0", "%.2d|%.1d|%.0d|%.*d|%1.0d", 0, 0, 0, 0, 0, 0);
-#ifndef __CHAR_UNSIGNED__
-	{
-		/*
-		 * Passing a 'char' to a %02x specifier doesn't do
-		 * what was presumably the intention when char is
-		 * signed and the value is negative. One must either &
-		 * with 0xff or cast to u8.
-		 */
-		char val = -16;
-		test("0xfffffff0|0xf0|0xf0", "%#02x|%#02x|%#02x", val, val & 0xff, (u8)val);
-	}
-#endif
 }
 
 static void __init