[S390] cleanup facility list handling

Store the facility list once at system startup with stfl/stfle and
reuse the result for all facility tests.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 29 insertions, 11 deletions

diff --git a/arch/s390/kernel/early.c b/arch/s390/kernel/early.c
index 0badc63..d2455d4 100644
--- a/arch/s390/kernel/early.c
+++ b/arch/s390/kernel/early.c
@@ -256,13 +256,35 @@ static noinline __init void setup_lowcore_early(void)
 	s390_base_pgm_handler_fn = early_pgm_check_handler;
 }
 
+static noinline __init void setup_facility_list(void)
+{
+	unsigned long nr;
+
+	S390_lowcore.stfl_fac_list = 0;
+	asm volatile(
+		"	.insn	s,0xb2b10000,0(0)\n" /* stfl */
+		"0:\n"
+		EX_TABLE(0b,0b) : "=m" (S390_lowcore.stfl_fac_list));
+	memcpy(&S390_lowcore.stfle_fac_list, &S390_lowcore.stfl_fac_list, 4);
+	nr = 4;				/* # bytes stored by stfl */
+	if (test_facility(7)) {
+		/* More facility bits available with stfle */
+		register unsigned long reg0 asm("0") = MAX_FACILITY_BIT/64 - 1;
+		asm volatile(".insn s,0xb2b00000,%0" /* stfle */
+			     : "=m" (S390_lowcore.stfle_fac_list), "+d" (reg0)
+			     : : "cc");
+		nr = (reg0 + 1) * 8;	/* # bytes stored by stfle */
+	}
+	memset((char *) S390_lowcore.stfle_fac_list + nr, 0,
+	       MAX_FACILITY_BIT/8 - nr);
+}
+
 static noinline __init void setup_hpage(void)
 {
 #ifndef CONFIG_DEBUG_PAGEALLOC
 	unsigned int facilities;
 
-	facilities = stfl();
-	if (!(facilities & (1UL << 23)) || !(facilities & (1UL << 29)))
+	if (!test_facility(2) || !test_facility(8))
 		return;
 	S390_lowcore.machine_flags |= MACHINE_FLAG_HPAGE;
 	__ctl_set_bit(0, 23);
@@ -356,18 +378,13 @@ static __init void detect_diag44(void)
 static __init void detect_machine_facilities(void)
 {
 #ifdef CONFIG_64BIT
-	unsigned int facilities;
-	unsigned long long facility_bits;
-
-	facilities = stfl();
-	if (facilities & (1 << 28))
+	if (test_facility(3))
 		S390_lowcore.machine_flags |= MACHINE_FLAG_IDTE;
-	if (facilities & (1 << 23))
+	if (test_facility(8))
 		S390_lowcore.machine_flags |= MACHINE_FLAG_PFMF;
-	if (facilities & (1 << 4))
+	if (test_facility(27))
 		S390_lowcore.machine_flags |= MACHINE_FLAG_MVCOS;
-	if ((stfle(&facility_bits, 1) > 0) &&
-	    (facility_bits & (1ULL << (63 - 40))))
+	if (test_facility(40))
 		S390_lowcore.machine_flags |= MACHINE_FLAG_SPP;
 #endif
 }
@@ -448,6 +465,7 @@ void __init startup_init(void)
 	lockdep_off();
 	sort_main_extable();
 	setup_lowcore_early();
+	setup_facility_list();
 	detect_machine_type();
 	ipl_update_parameters();
 	setup_boot_command_line();