[S390] reipl: move dump_prefix_page out of text section.

Reipl doesn't work on older machines were s390_reset_machine() gets
called. The reason is that the text section is read-only but the
variable dump_prefix_page is there. Since s390_reset_machine() writes
to it we get a protection exception.
Therefore move dump_prefix_page to the bss section.

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

4 files changed, 19 insertions, 12 deletions

diff --git a/arch/s390/kernel/ipl.c b/arch/s390/kernel/ipl.c
index 5a863a3bf10c..d125a4ead08d 100644
--- a/arch/s390/kernel/ipl.c
+++ b/arch/s390/kernel/ipl.c
@@ -1066,7 +1066,7 @@ static void do_reset_calls(void)
                 reset->fn();
 }
 
-extern __u32 dump_prefix_page;
+u32 dump_prefix_page;
 
 void s390_reset_system(void)
 {
@@ -1078,7 +1078,7 @@ void s390_reset_system(void)
         lc->panic_stack = S390_lowcore.panic_stack;
 
         /* Save prefix page address for dump case */
-        dump_prefix_page = (unsigned long) lc;
+        dump_prefix_page = (u32)(unsigned long) lc;
 
         /* Disable prefixing */
         set_prefix(0);
diff --git a/arch/s390/kernel/reipl.S b/arch/s390/kernel/reipl.S
index c3f4d9b95083..2f481cc3d1c9 100644
--- a/arch/s390/kernel/reipl.S
+++ b/arch/s390/kernel/reipl.S
@@ -8,6 +8,10 @@
 
 #include <asm/lowcore.h>
 
+#
+# do_reipl_asm
+# Parameter: r2 = schid of reipl device
+#
                 .globl  do_reipl_asm
 do_reipl_asm:   basr    %r13,0
 .Lpg0:          lpsw    .Lnewpsw-.Lpg0(%r13)
@@ -16,12 +20,12 @@ do_reipl_asm:	basr	%r13,0
                 stm     %r0,%r15,__LC_GPREGS_SAVE_AREA
                 stctl   %c0,%c15,__LC_CREGS_SAVE_AREA
                 stam    %a0,%a15,__LC_AREGS_SAVE_AREA
-                mvc     __LC_PREFIX_SAVE_AREA(4),dump_prefix_page-.Lpg0(%r13)
+                l       %r10,.Ldump_pfx-.Lpg0(%r13)
+                mvc     __LC_PREFIX_SAVE_AREA(4),0(%r10)
                 stckc   .Lclkcmp-.Lpg0(%r13)
                 mvc     __LC_CLOCK_COMP_SAVE_AREA(8),.Lclkcmp-.Lpg0(%r13)
                 stpt    __LC_CPU_TIMER_SAVE_AREA
                 st      %r13, __LC_PSW_SAVE_AREA+4
-
                 lctl    %c6,%c6,.Lall-.Lpg0(%r13)
                 lr      %r1,%r2
                 mvc     __LC_PGM_NEW_PSW(8),.Lpcnew-.Lpg0(%r13)
@@ -55,6 +59,7 @@ do_reipl_asm:	basr	%r13,0
                 .align  8
 .Lclkcmp:       .quad   0x0000000000000000
 .Lall:          .long   0xff000000
+.Ldump_pfx:     .long   dump_prefix_page
                 .align  8
 .Lnewpsw:       .long   0x00080000,0x80000000+.Lpg1
 .Lpcnew:        .long   0x00080000,0x80000000+.Lecs
@@ -79,7 +84,3 @@ do_reipl_asm:	basr	%r13,0
                 .long   0x00000000,0x00000000
                 .long   0x00000000,0x00000000
                 .long   0x00000000,0x00000000
-        .globl dump_prefix_page
-dump_prefix_page:
-        .long 0x00000000
-
diff --git a/arch/s390/kernel/reipl64.S b/arch/s390/kernel/reipl64.S
index dbb3eed38865..c41930499a5f 100644
--- a/arch/s390/kernel/reipl64.S
+++ b/arch/s390/kernel/reipl64.S
@@ -8,6 +8,12 @@
  */
 
 #include <asm/lowcore.h>
+
+#
+# do_reipl_asm
+# Parameter: r2 = schid of reipl device
+#
+
                 .globl  do_reipl_asm
 do_reipl_asm:   basr    %r13,0
 .Lpg0:          lpswe   .Lnewpsw-.Lpg0(%r13)
@@ -20,7 +26,8 @@ do_reipl_asm:	basr	%r13,0
                 stg     %r0,__LC_GPREGS_SAVE_AREA-0x1000+8(%r1)
                 stctg   %c0,%c15,__LC_CREGS_SAVE_AREA-0x1000(%r1)
                 stam    %a0,%a15,__LC_AREGS_SAVE_AREA-0x1000(%r1)
-                mvc     __LC_PREFIX_SAVE_AREA-0x1000(4,%r1),dump_prefix_page-.Lpg0(%r13)
+                lg      %r10,.Ldump_pfx-.Lpg0(%r13)
+                mvc     __LC_PREFIX_SAVE_AREA-0x1000(4,%r1),0(%r10)
                 stfpc   __LC_FP_CREG_SAVE_AREA-0x1000(%r1)
                 stckc   .Lclkcmp-.Lpg0(%r13)
                 mvc     __LC_CLOCK_COMP_SAVE_AREA-0x1000(8,%r1),.Lclkcmp-.Lpg0(%r13)
@@ -64,6 +71,7 @@ do_reipl_asm:	basr	%r13,0
                 .align  8
 .Lclkcmp:       .quad   0x0000000000000000
 .Lall:          .quad   0x00000000ff000000
+.Ldump_pfx:     .quad   dump_prefix_page
 .Lregsave:      .quad   0x0000000000000000
                 .align  16
 /*
@@ -103,6 +111,3 @@ do_reipl_asm:	basr	%r13,0
                 .long   0x00000000,0x00000000
                 .long   0x00000000,0x00000000
                 .long   0x00000000,0x00000000
-        .globl dump_prefix_page
-dump_prefix_page:
-        .long 0x00000000
diff --git a/include/asm-s390/ipl.h b/include/asm-s390/ipl.h
index 5650d3d4ae46..660f78271a93 100644
--- a/include/asm-s390/ipl.h
+++ b/include/asm-s390/ipl.h
@@ -74,6 +74,7 @@ struct ipl_parameter_block {
 extern u32 ipl_flags;
 extern u16 ipl_devno;
 
+extern u32 dump_prefix_page;
 extern void do_reipl(void);
 extern void ipl_save_parameters(void);