Enable -funsigned-char and fix code affected by that flag.

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Merge tag 'unsigned-char-6.2-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/zx2c4/linux

Pull unsigned-char conversion from Jason Donenfeld:
 "Enable -funsigned-char and fix code affected by that flag.

  During the 6.1 cycle, several patches already made it into the tree,
  which were for code that was already broken on at least one
  architecture, where the naked char had a different sign than the code
  author anticipated, or were part of some bug fix for an existing bug
  that this initiative unearthed.

  These 6.1-era fixes are:

    648060902a ("MIPS: pic32: treat port as signed integer")
    5c26159c97 ("ipvs: use explicitly signed chars")
    e6cb876945 ("wifi: airo: do not assign -1 to unsigned char")
    937ec9f7d5 ("staging: rtl8192e: remove bogus ssid character sign test")
    6770473832 ("misc: sgi-gru: use explicitly signed char")
    50895a55bc ("ALSA: rme9652: use explicitly signed char")
    ee03c0f200 ("ALSA: au88x0: use explicitly signed char")
    835bed1b83 ("fbdev: sisfb: use explicitly signed char")
    50f19697dd ("parisc: Use signed char for hardware path in pdc.h")
    66063033f7 ("wifi: rt2x00: use explicitly signed or unsigned types")

  Regarding patches in this pull:

   - There is one patch in this pull that should have made it to you
     during 6.1 ("media: stv0288: use explicitly signed char"), but the
     maintainer was MIA during the cycle, so it's in here instead.

   - Two patches fix single architecture code affected by unsigned char
     ("perf/x86: Make struct p4_event_bind::cntr signed array" and
     "sparc: sbus: treat CPU index as integer"), while one patch fixes
     an unused typedef, in case it's ever used in the future ("media:
     atomisp: make hive_int8 explictly signed").

   - Finally, there's the change to actually enable -funsigned-char
     ("kbuild: treat char as always unsigned") and then the removal of
     some no longer useful !__CHAR_UNSIGNED__ selftest code ("lib:
     assume char is unsigned").

  The various fixes were found with a combination of diffing objdump
  output, a large variety of Coccinelle scripts, and plain old grep. In
  the end, things didn't seem as bad as I feared they would. But of
  course, it's also possible I missed things.

  However, this has been in linux-next for basically an entire cycle
  now, so I'm not overly worried. I've also been daily driving this on
  my laptop for all of 6.1. Still, this series, and the ones sent for
  6.1 don't total in quantity to what I thought it'd be, so I will be on
  the lookout for breakage.

  We could receive a few reports that are quickly fixable. Hopefully we
  won't receive a barrage of reports that would result in a revert. And
  just maybe we won't receive any reports at all and nobody will even
  notice. Knock on wood"

* tag 'unsigned-char-6.2-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/zx2c4/linux:
  lib: assume char is unsigned
  kbuild: treat char as always unsigned
  media: atomisp: make hive_int8 explictly signed
  media: stv0288: use explicitly signed char
  sparc: sbus: treat CPU index as integer
  perf/x86: Make struct p4_event_bind::cntr signed array

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) \

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 {

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__);
 

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++) {

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;

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);

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