[S390] Convert machine feature detection code to C.

From: Heiko Carstens <heiko.carstens@de.ibm.com>
From: Carsten Otte <cotte@de.ibm.com>

This lets us use defines for the magic bits in machine flags instead
of using plain numbers all over the place.
In addition on newer machines features/facilities are indicated by the
result of the stfl instruction. So we use these bits instead of trying
to execute new instructions and check wether we get an exception or
not.
Also the mvpg instruction is always available when in zArch mode,
whereas the idte instruction is only available in zArch mode. This
results in some minor optimizations.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Carsten Otte <cotte@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 106 insertions, 3 deletions

diff --git a/arch/s390/kernel/early.c b/arch/s390/kernel/early.c
index 68ec4083bf73..bd188f6bd0e2 100644
--- a/arch/s390/kernel/early.c
+++ b/arch/s390/kernel/early.c
@@ -139,15 +139,15 @@ static noinline __init void detect_machine_type(void)
 
         /* Running under z/VM ? */
         if (cpuinfo->cpu_id.version == 0xff)
-                machine_flags |= 1;
+                machine_flags |= MACHINE_FLAG_VM;
 
         /* Running on a P/390 ? */
         if (cpuinfo->cpu_id.machine == 0x7490)
-                machine_flags |= 4;
+                machine_flags |= MACHINE_FLAG_P390;
 
         /* Running under KVM ? */
         if (cpuinfo->cpu_id.version == 0xfe)
-                machine_flags |= 64;
+                machine_flags |= MACHINE_FLAG_KVM;
 }
 
 #ifdef CONFIG_64BIT
@@ -268,6 +268,103 @@ static noinline __init void setup_lowcore_early(void)
         s390_base_pgm_handler_fn = early_pgm_check_handler;
 }
 
+static __init void detect_mvpg(void)
+{
+#ifndef CONFIG_64BIT
+        int rc;
+
+        asm volatile(
+                "       la      0,0\n"
+                "       mvpg    %2,%2\n"
+                "0:     la      %0,0\n"
+                "1:\n"
+                EX_TABLE(0b,1b)
+                : "=d" (rc) : "0" (-EOPNOTSUPP), "a" (0) : "memory", "cc", "0");
+        if (!rc)
+                machine_flags |= MACHINE_FLAG_MVPG;
+#endif
+}
+
+static __init void detect_ieee(void)
+{
+#ifndef CONFIG_64BIT
+        int rc, tmp;
+
+        asm volatile(
+                "       efpc    %1,0\n"
+                "0:     la      %0,0\n"
+                "1:\n"
+                EX_TABLE(0b,1b)
+                : "=d" (rc), "=d" (tmp): "0" (-EOPNOTSUPP) : "cc");
+        if (!rc)
+                machine_flags |= MACHINE_FLAG_IEEE;
+#endif
+}
+
+static __init void detect_csp(void)
+{
+#ifndef CONFIG_64BIT
+        int rc;
+
+        asm volatile(
+                "       la      0,0\n"
+                "       la      1,0\n"
+                "       la      2,4\n"
+                "       csp     0,2\n"
+                "0:     la      %0,0\n"
+                "1:\n"
+                EX_TABLE(0b,1b)
+                : "=d" (rc) : "0" (-EOPNOTSUPP) : "cc", "0", "1", "2");
+        if (!rc)
+                machine_flags |= MACHINE_FLAG_CSP;
+#endif
+}
+
+static __init void detect_diag9c(void)
+{
+        unsigned int cpu_address;
+        int rc;
+
+        cpu_address = stap();
+        asm volatile(
+                "       diag    %2,0,0x9c\n"
+                "0:     la      %0,0\n"
+                "1:\n"
+                EX_TABLE(0b,1b)
+                : "=d" (rc) : "0" (-EOPNOTSUPP), "d" (cpu_address) : "cc");
+        if (!rc)
+                machine_flags |= MACHINE_FLAG_DIAG9C;
+}
+
+static __init void detect_diag44(void)
+{
+#ifdef CONFIG_64BIT
+        int rc;
+
+        asm volatile(
+                "       diag    0,0,0x44\n"
+                "0:     la      %0,0\n"
+                "1:\n"
+                EX_TABLE(0b,1b)
+                : "=d" (rc) : "0" (-EOPNOTSUPP) : "cc");
+        if (!rc)
+                machine_flags |= MACHINE_FLAG_DIAG44;
+#endif
+}
+
+static __init void detect_machine_facilities(void)
+{
+#ifdef CONFIG_64BIT
+        unsigned int facilities;
+
+        facilities = stfl();
+        if (facilities & (1 << 28))
+                machine_flags |= MACHINE_FLAG_IDTE;
+        if (facilities & (1 << 4))
+                machine_flags |= MACHINE_FLAG_MVCOS;
+#endif
+}
+
 /*
  * Save ipl parameters, clear bss memory, initialize storage keys
  * and create a kernel NSS at startup if the SAVESYS= parm is defined
@@ -285,6 +382,12 @@ void __init startup_init(void)
         create_kernel_nss();
         sort_main_extable();
         setup_lowcore_early();
+        detect_mvpg();
+        detect_ieee();
+        detect_csp();
+        detect_diag9c();
+        detect_diag44();
+        detect_machine_facilities();
         sclp_read_info_early();
         sclp_facilities_detect();
         memsize = sclp_memory_detect();