pc-bios/s390-ccw: Get device address via diag 308/6

To IPL from a device, pc-bios receives from qemu a device address via
general register 7. The better way to do it is to use diag308/6
instruction which returns so called
"IplParameterBlock". IplParameterBlock contains the device address for
IPL and additional parameters that can be used by pc-bios.

This patch allows pc-bios to get device address via diag308/6 and
doesn't use gr7 passed boot information anymore.

Signed-off-by: Alexander Yarygin <yarygin@linux.vnet.ibm.com>
Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>

4 files changed, 95 insertions, 13 deletions

diff --git a/pc-bios/s390-ccw/iplb.h b/pc-bios/s390-ccw/iplb.h
new file mode 100644
index 0000000000..1cf509f497
--- /dev/null
+++ b/pc-bios/s390-ccw/iplb.h
@@ -0,0 +1,79 @@
+/*
+ * QEMU S390 IPL Block
+ *
+ * Copyright 2015 IBM Corp.
+ * Author(s): Alexander Yarygin <yarygin@linux.vnet.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or (at
+ * your option) any later version. See the COPYING file in the top-level
+ * directory.
+ */
+
+#ifndef IPLB_H
+#define IPLB_H
+
+struct IplBlockCcw {
+    uint8_t  reserved0[85];
+    uint8_t  ssid;
+    uint16_t devno;
+    uint8_t  vm_flags;
+    uint8_t  reserved3[3];
+    uint32_t vm_parm_len;
+    uint8_t  nss_name[8];
+    uint8_t  vm_parm[64];
+    uint8_t  reserved4[8];
+} __attribute__ ((packed));
+typedef struct IplBlockCcw IplBlockCcw;
+
+struct IplBlockFcp {
+    uint8_t  reserved1[305 - 1];
+    uint8_t  opt;
+    uint8_t  reserved2[3];
+    uint16_t reserved3;
+    uint16_t devno;
+    uint8_t  reserved4[4];
+    uint64_t wwpn;
+    uint64_t lun;
+    uint32_t bootprog;
+    uint8_t  reserved5[12];
+    uint64_t br_lba;
+    uint32_t scp_data_len;
+    uint8_t  reserved6[260];
+    uint8_t  scp_data[];
+} __attribute__ ((packed));
+typedef struct IplBlockFcp IplBlockFcp;
+
+struct IplParameterBlock {
+    uint32_t len;
+    uint8_t  reserved0[3];
+    uint8_t  version;
+    uint32_t blk0_len;
+    uint8_t  pbt;
+    uint8_t  flags;
+    uint16_t reserved01;
+    uint8_t  loadparm[8];
+    union {
+        IplBlockCcw ccw;
+        IplBlockFcp fcp;
+    };
+} __attribute__ ((packed));
+typedef struct IplParameterBlock IplParameterBlock;
+
+extern IplParameterBlock iplb __attribute__((__aligned__(PAGE_SIZE)));
+
+#define S390_IPL_TYPE_FCP 0x00
+#define S390_IPL_TYPE_CCW 0x02
+
+static inline bool store_iplb(IplParameterBlock *iplb)
+{
+    register unsigned long addr asm("0") = (unsigned long) iplb;
+    register unsigned long rc asm("1") = 0;
+
+    asm volatile ("diag %0,%2,0x308\n"
+                  : "+d" (addr), "+d" (rc)
+                  : "d" (6)
+                  : "memory", "cc");
+    return rc == 0x01;
+}
+
+#endif /* IPLB_H */
diff --git a/pc-bios/s390-ccw/main.c b/pc-bios/s390-ccw/main.c
index 1c9e0791ab..9446ecc235 100644
--- a/pc-bios/s390-ccw/main.c
+++ b/pc-bios/s390-ccw/main.c
@@ -12,8 +12,8 @@
 #include "virtio.h"
 
 char stack[PAGE_SIZE * 8] __attribute__((__aligned__(PAGE_SIZE)));
-uint64_t boot_value;
 static SubChannelId blk_schid = { .one = 1 };
+IplParameterBlock iplb __attribute__((__aligned__(PAGE_SIZE)));
 
 /*
  * Priniciples of Operations (SA22-7832-09) chapter 17 requires that
@@ -61,7 +61,7 @@ static bool find_dev(Schib *schib, int dev_no)
     return false;
 }
 
-static void virtio_setup(uint64_t dev_info)
+static void virtio_setup(void)
 {
     Schib schib;
     int ssid;
@@ -75,12 +75,18 @@ static void virtio_setup(uint64_t dev_info)
      */
     enable_mss_facility();
 
-    if (dev_info != -1) {
-        dev_no = dev_info & 0xffff;
-        debug_print_int("device no. ", dev_no);
-        blk_schid.ssid = (dev_info >> 16) & 0x3;
-        debug_print_int("ssid ", blk_schid.ssid);
-        found = find_dev(&schib, dev_no);
+    if (store_iplb(&iplb)) {
+        switch (iplb.pbt) {
+        case S390_IPL_TYPE_CCW:
+            dev_no = iplb.ccw.devno;
+            debug_print_int("device no. ", dev_no);
+            blk_schid.ssid = iplb.ccw.ssid & 0x3;
+            debug_print_int("ssid ", blk_schid.ssid);
+            found = find_dev(&schib, dev_no);
+            break;
+        default:
+            panic("List-directed IPL not supported yet!\n");
+        }
     } else {
         for (ssid = 0; ssid < 0x3; ssid++) {
             blk_schid.ssid = ssid;
@@ -101,8 +107,7 @@ static void virtio_setup(uint64_t dev_info)
 int main(void)
 {
     sclp_setup();
-    debug_print_int("boot reg[7] ", boot_value);
-    virtio_setup(boot_value);
+    virtio_setup();
 
     zipl_load(); /* no return */
 
diff --git a/pc-bios/s390-ccw/s390-ccw.h b/pc-bios/s390-ccw/s390-ccw.h
index 616d96738d..ded67bcbc6 100644
--- a/pc-bios/s390-ccw/s390-ccw.h
+++ b/pc-bios/s390-ccw/s390-ccw.h
@@ -44,6 +44,7 @@ typedef unsigned long long __u64;
 #endif
 
 #include "cio.h"
+#include "iplb.h"
 
 typedef struct irb Irb;
 typedef struct ccw1 Ccw1;
@@ -61,7 +62,6 @@ void consume_sclp_int(void);
 void panic(const char *string);
 void write_subsystem_identification(void);
 extern char stack[PAGE_SIZE * 8] __attribute__((__aligned__(PAGE_SIZE)));
-extern uint64_t boot_value;
 
 /* sclp-ascii.c */
 void sclp_print(const char *string);
diff --git a/pc-bios/s390-ccw/start.S b/pc-bios/s390-ccw/start.S
index b6dd8c2fbe..43f9bd243e 100644
--- a/pc-bios/s390-ccw/start.S
+++ b/pc-bios/s390-ccw/start.S
@@ -14,8 +14,6 @@
 _start:
 
 larl	%r15, stack + 0x8000    /* Set up stack */
-larl    %r6, boot_value
-stg     %r7, 0(%r6)     /* save the boot_value before any function calls */
 j	main                    /* And call C */
 
 /*