[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 0badc6344eb4..d2455d44d99a 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();