[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>

2 files changed, 20 insertions, 24 deletions

diff --git a/arch/s390/include/asm/lowcore.h b/arch/s390/include/asm/lowcore.h
index 0f97ef2d92ac..65e172f8209d 100644
--- a/arch/s390/include/asm/lowcore.h
+++ b/arch/s390/include/asm/lowcore.h
@@ -150,9 +150,10 @@ struct _lowcore {
          */
         __u32   ipib;                           /* 0x0e00 */
         __u32   ipib_checksum;                  /* 0x0e04 */
+        __u8    pad_0x0e08[0x0f00-0x0e08];      /* 0x0e08 */
 
-        /* Align to the top 1k of prefix area */
-        __u8    pad_0x0e08[0x1000-0x0e08];      /* 0x0e08 */
+        /* Extended facility list */
+        __u64   stfle_fac_list[32];             /* 0x0f00 */
 } __packed;
 
 #else /* CONFIG_32BIT */
@@ -285,7 +286,11 @@ struct _lowcore {
          */
         __u64   ipib;                           /* 0x0e00 */
         __u32   ipib_checksum;                  /* 0x0e08 */
-        __u8    pad_0x0e0c[0x11b8-0x0e0c];      /* 0x0e0c */
+        __u8    pad_0x0e0c[0x0f00-0x0e0c];      /* 0x0e0c */
+
+        /* Extended facility list */
+        __u64   stfle_fac_list[32];             /* 0x0f00 */
+        __u8    pad_0x1000[0x11b8-0x1000];      /* 0x1000 */
 
         /* 64 bit extparam used for pfault/diag 250: defined by architecture */
         __u64   ext_params2;                    /* 0x11B8 */
diff --git a/arch/s390/include/asm/system.h b/arch/s390/include/asm/system.h
index 3c079dd5ee79..3ad16dbf622e 100644
--- a/arch/s390/include/asm/system.h
+++ b/arch/s390/include/asm/system.h
@@ -420,30 +420,21 @@ extern void smp_ctl_clear_bit(int cr, int bit);
 
 #endif /* CONFIG_SMP */
 
-static inline unsigned int stfl(void)
-{
-        asm volatile(
-                "       .insn   s,0xb2b10000,0(0)\n" /* stfl */
-                "0:\n"
-                EX_TABLE(0b,0b));
-        return S390_lowcore.stfl_fac_list;
-}
+#define MAX_FACILITY_BIT (256*8)        /* stfle_fac_list has 256 bytes */
 
-static inline int __stfle(unsigned long long *list, int doublewords)
+/*
+ * The test_facility function uses the bit odering where the MSB is bit 0.
+ * That makes it easier to query facility bits with the bit number as
+ * documented in the Principles of Operation.
+ */
+static inline int test_facility(unsigned long nr)
 {
-        typedef struct { unsigned long long _[doublewords]; } addrtype;
-        register unsigned long __nr asm("0") = doublewords - 1;
-
-        asm volatile(".insn s,0xb2b00000,%0" /* stfle */
-                     : "=m" (*(addrtype *) list), "+d" (__nr) : : "cc");
-        return __nr + 1;
-}
+        unsigned char *ptr;
 
-static inline int stfle(unsigned long long *list, int doublewords)
-{
-        if (!(stfl() & (1UL << 24)))
-                return -EOPNOTSUPP;
-        return __stfle(list, doublewords);
+        if (nr >= MAX_FACILITY_BIT)
+                return 0;
+        ptr = (unsigned char *) &S390_lowcore.stfle_fac_list + (nr >> 3);
+        return (*ptr & (0x80 >> (nr & 7))) != 0;
 }
 
 static inline unsigned short stap(void)