s390/facilities: move stfl information from lowcore to global data

With gcc-11, there are a lot of warnings because the facility functions
are accessing lowcore through a null pointer. Fix this by moving the
facility arrays away from lowcore.

Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

Author: svens-s390

arch/s390/boot/als.c

@@ -68,7 +68,7 @@ void print_missing_facilities(void)
 
 	first = 1;
 	for (i = 0; i < ARRAY_SIZE(als); i++) {
-		val = ~S390_lowcore.stfle_fac_list[i] & als[i];
+		val = ~stfle_fac_list[i] & als[i];
 		for (j = 0; j < BITS_PER_LONG; j++) {
 			if (!(val & (1UL << (BITS_PER_LONG - 1 - j))))
 				continue;
@@ -106,9 +106,9 @@ void verify_facilities(void)
 {
 	int i;
 
-	__stfle(S390_lowcore.stfle_fac_list, ARRAY_SIZE(S390_lowcore.stfle_fac_list));
+	__stfle(stfle_fac_list, ARRAY_SIZE(stfle_fac_list));
 	for (i = 0; i < ARRAY_SIZE(als); i++) {
-		if ((S390_lowcore.stfle_fac_list[i] & als[i]) != als[i])
+		if ((stfle_fac_list[i] & als[i]) != als[i])
 			facility_mismatch();
 	}
 }

arch/s390/boot/ipl_parm.c

@@ -180,9 +180,9 @@ void setup_boot_command_line(void)
 static void modify_facility(unsigned long nr, bool clear)
 {
 	if (clear)
-		__clear_facility(nr, S390_lowcore.stfle_fac_list);
+		__clear_facility(nr, stfle_fac_list);
 	else
-		__set_facility(nr, S390_lowcore.stfle_fac_list);
+		__set_facility(nr, stfle_fac_list);
 }
 
 static void check_cleared_facilities(void)
@@ -191,7 +191,7 @@ static void check_cleared_facilities(void)
 	int i;
 
 	for (i = 0; i < ARRAY_SIZE(als); i++) {
-		if ((S390_lowcore.stfle_fac_list[i] & als[i]) != als[i]) {
+		if ((stfle_fac_list[i] & als[i]) != als[i]) {
 			sclp_early_printk("Warning: The Linux kernel requires facilities cleared via command line option\n");
 			print_missing_facilities();
 			break;

arch/s390/boot/startup.c

@@ -17,6 +17,9 @@ extern char __boot_data_preserved_start[], __boot_data_preserved_end[];
 unsigned long __bootdata_preserved(__kaslr_offset);
 unsigned long __bootdata(ident_map_size);
 
+u64 __bootdata_preserved(stfle_fac_list[16]);
+u64 __bootdata_preserved(alt_stfle_fac_list[16]);
+
 /*
  * Some code and data needs to stay below 2 GB, even when the kernel would be
  * relocated above 2 GB, because it has to use 31 bit addresses.

arch/s390/include/asm/facility.h

@@ -13,7 +13,10 @@
 #include <linux/preempt.h>
 #include <asm/lowcore.h>
 
-#define MAX_FACILITY_BIT (sizeof(((struct lowcore *)0)->stfle_fac_list) * 8)
+#define MAX_FACILITY_BIT (sizeof(stfle_fac_list) * 8)
+
+extern u64 stfle_fac_list[16];
+extern u64 alt_stfle_fac_list[16];
 
 static inline void __set_facility(unsigned long nr, void *facilities)
 {
@@ -56,7 +59,7 @@ static inline int test_facility(unsigned long nr)
 		if (__test_facility(nr, &facilities_als))
 			return 1;
 	}
-	return __test_facility(nr, &S390_lowcore.stfle_fac_list);
+	return __test_facility(nr, &stfle_fac_list);
 }
 
 static inline unsigned long __stfle_asm(u64 *stfle_fac_list, int size)
@@ -79,13 +82,15 @@ static inline unsigned long __stfle_asm(u64 *stfle_fac_list, int size)
 static inline void __stfle(u64 *stfle_fac_list, int size)
 {
 	unsigned long nr;
+	u32 stfl_fac_list;
 
 	asm volatile(
 		"	stfl	0(0)\n"
 		: "=m" (S390_lowcore.stfl_fac_list));
+	stfl_fac_list = S390_lowcore.stfl_fac_list;
+	memcpy(stfle_fac_list, &stfl_fac_list, 4);
 	nr = 4; /* bytes stored by stfl */
-	memcpy(stfle_fac_list, &S390_lowcore.stfl_fac_list, 4);
-	if (S390_lowcore.stfl_fac_list & 0x01000000) {
+	if (stfl_fac_list & 0x01000000) {
 		/* More facility bits available with stfle */
 		nr = __stfle_asm(stfle_fac_list, size);
 		nr = min_t(unsigned long, (nr + 1) * 8, size * 8);

arch/s390/include/asm/lowcore.h

@@ -153,12 +153,7 @@ struct lowcore {
 	__u64	vmcore_info;			/* 0x0e0c */
 	__u8	pad_0x0e14[0x0e18-0x0e14];	/* 0x0e14 */
 	__u64	os_info;			/* 0x0e18 */
-	__u8	pad_0x0e20[0x0f00-0x0e20];	/* 0x0e20 */
-
-	/* Extended facility list */
-	__u64	stfle_fac_list[16];		/* 0x0f00 */
-	__u64	alt_stfle_fac_list[16];		/* 0x0f80 */
-	__u8	pad_0x1000[0x11b0-0x1000];	/* 0x1000 */
+	__u8	pad_0x0e20[0x11b0-0x0e20];	/* 0x0e20 */
 
 	/* Pointer to the machine check extended save area */
 	__u64	mcesad;				/* 0x11b0 */

arch/s390/kernel/alternative.c

@@ -76,8 +76,7 @@ static void __init_or_module __apply_alternatives(struct alt_instr *start,
 		instr = (u8 *)&a->instr_offset + a->instr_offset;
 		replacement = (u8 *)&a->repl_offset + a->repl_offset;
 
-		if (!__test_facility(a->facility,
-				     S390_lowcore.alt_stfle_fac_list))
+		if (!__test_facility(a->facility, alt_stfle_fac_list))
 			continue;
 
 		if (unlikely(a->instrlen % 2 || a->replacementlen % 2)) {

arch/s390/kernel/asm-offsets.c

@@ -75,8 +75,6 @@ int main(void)
 	OFFSET(__LC_SUBCHANNEL_NR, lowcore, subchannel_nr);
 	OFFSET(__LC_IO_INT_PARM, lowcore, io_int_parm);
 	OFFSET(__LC_IO_INT_WORD, lowcore, io_int_word);
-	OFFSET(__LC_STFL_FAC_LIST, lowcore, stfl_fac_list);
-	OFFSET(__LC_STFLE_FAC_LIST, lowcore, stfle_fac_list);
 	OFFSET(__LC_MCCK_CODE, lowcore, mcck_interruption_code);
 	OFFSET(__LC_EXT_DAMAGE_CODE, lowcore, external_damage_code);
 	OFFSET(__LC_MCCK_FAIL_STOR_ADDR, lowcore, failing_storage_address);

arch/s390/kernel/early.c

@@ -180,11 +180,9 @@ static noinline __init void setup_lowcore_early(void)
 
 static noinline __init void setup_facility_list(void)
 {
-	memcpy(S390_lowcore.alt_stfle_fac_list,
-	       S390_lowcore.stfle_fac_list,
-	       sizeof(S390_lowcore.alt_stfle_fac_list));
+	memcpy(alt_stfle_fac_list, stfle_fac_list, sizeof(alt_stfle_fac_list));
 	if (!IS_ENABLED(CONFIG_KERNEL_NOBP))
-		__clear_facility(82, S390_lowcore.alt_stfle_fac_list);
+		__clear_facility(82, alt_stfle_fac_list);
 }
 
 static __init void detect_diag9c(void)

arch/s390/kernel/nospec-branch.c

@@ -17,19 +17,19 @@ static int __init nobp_setup_early(char *str)
 		 * The user explicitely requested nobp=1, enable it and
 		 * disable the expoline support.
 		 */
-		__set_facility(82, S390_lowcore.alt_stfle_fac_list);
+		__set_facility(82, alt_stfle_fac_list);
 		if (IS_ENABLED(CONFIG_EXPOLINE))
 			nospec_disable = 1;
 	} else {
-		__clear_facility(82, S390_lowcore.alt_stfle_fac_list);
+		__clear_facility(82, alt_stfle_fac_list);
 	}
 	return 0;
 }
 early_param("nobp", nobp_setup_early);
 
 static int __init nospec_setup_early(char *str)
 {
-	__clear_facility(82, S390_lowcore.alt_stfle_fac_list);
+	__clear_facility(82, alt_stfle_fac_list);
 	return 0;
 }
 early_param("nospec", nospec_setup_early);
@@ -40,7 +40,7 @@ static int __init nospec_report(void)
 		pr_info("Spectre V2 mitigation: etokens\n");
 	if (__is_defined(CC_USING_EXPOLINE) && !nospec_disable)
 		pr_info("Spectre V2 mitigation: execute trampolines\n");
-	if (__test_facility(82, S390_lowcore.alt_stfle_fac_list))
+	if (__test_facility(82, alt_stfle_fac_list))
 		pr_info("Spectre V2 mitigation: limited branch prediction\n");
 	return 0;
 }
@@ -66,14 +66,14 @@ void __init nospec_auto_detect(void)
 		 */
 		if (__is_defined(CC_USING_EXPOLINE))
 			nospec_disable = 1;
-		__clear_facility(82, S390_lowcore.alt_stfle_fac_list);
+		__clear_facility(82, alt_stfle_fac_list);
 	} else if (__is_defined(CC_USING_EXPOLINE)) {
 		/*
 		 * The kernel has been compiled with expolines.
 		 * Keep expolines enabled and disable nobp.
 		 */
 		nospec_disable = 0;
-		__clear_facility(82, S390_lowcore.alt_stfle_fac_list);
+		__clear_facility(82, alt_stfle_fac_list);
 	}
 	/*
 	 * If the kernel has not been compiled with expolines the
@@ -86,7 +86,7 @@ static int __init spectre_v2_setup_early(char *str)
 {
 	if (str && !strncmp(str, "on", 2)) {
 		nospec_disable = 0;
-		__clear_facility(82, S390_lowcore.alt_stfle_fac_list);
+		__clear_facility(82, alt_stfle_fac_list);
 	}
 	if (str && !strncmp(str, "off", 3))
 		nospec_disable = 1;

arch/s390/kernel/nospec-sysfs.c

@@ -17,7 +17,7 @@ ssize_t cpu_show_spectre_v2(struct device *dev,
 		return sprintf(buf, "Mitigation: etokens\n");
 	if (__is_defined(CC_USING_EXPOLINE) && !nospec_disable)
 		return sprintf(buf, "Mitigation: execute trampolines\n");
-	if (__test_facility(82, S390_lowcore.alt_stfle_fac_list))
+	if (__test_facility(82, alt_stfle_fac_list))
 		return sprintf(buf, "Mitigation: limited branch prediction\n");
 	return sprintf(buf, "Vulnerable\n");
 }