[S390] nss: Free unused memory in kernel image.

With CONFIG_SHARED_KERNEL the kernel text segment that might be in a
read only memory sections starts at 1MB. Memory between 0x12000 and
0x100000 is unused then. Free this, so we have appr. an extra MB
of memory available.

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

4 files changed, 17 insertions, 28 deletions

diff --git a/arch/s390/kernel/head31.S b/arch/s390/kernel/head31.S
index 453fd3b4edea..da7c8bb80982 100644
--- a/arch/s390/kernel/head31.S
+++ b/arch/s390/kernel/head31.S
@@ -148,20 +148,9 @@ startup_continue:
 .Lstartup_init:
             .long startup_init
 
-        .globl ipl_schib
-ipl_schib:
-        .rept 13
-        .long 0
-        .endr
-
-        .globl ipl_flags
-ipl_flags:
-        .long 0
-        .globl ipl_devno
-ipl_devno:
-        .word 0
-
         .org    0x12000
+        .globl  _ehead
+_ehead:
 #ifdef CONFIG_SHARED_KERNEL
         .org    0x100000
 #endif
diff --git a/arch/s390/kernel/head64.S b/arch/s390/kernel/head64.S
index b8fec4e5c5d4..af09e18cc5d0 100644
--- a/arch/s390/kernel/head64.S
+++ b/arch/s390/kernel/head64.S
@@ -154,21 +154,9 @@ startup_continue:
 .Lparmaddr:
         .quad   PARMAREA
 
-        .globl  ipl_schib
-ipl_schib:
-        .rept 13
-        .long 0
-        .endr
-
-        .globl  ipl_flags
-ipl_flags:
-        .long   0
-        .globl  ipl_devno
-ipl_devno:
-        .word 0
-
         .org    0x12000
-
+        .globl  _ehead
+_ehead:
 #ifdef CONFIG_SHARED_KERNEL
         .org    0x100000
 #endif
diff --git a/arch/s390/kernel/ipl.c b/arch/s390/kernel/ipl.c
index ee6826a52d26..5a863a3bf10c 100644
--- a/arch/s390/kernel/ipl.c
+++ b/arch/s390/kernel/ipl.c
@@ -43,6 +43,13 @@ enum ipl_type {
 #define IPL_FCP_STR      "fcp"
 #define IPL_NSS_STR      "nss"
 
+/*
+ * Must be in data section since the bss section
+ * is not cleared when these are accessed.
+ */
+u16 ipl_devno __attribute__((__section__(".data"))) = 0;
+u32 ipl_flags __attribute__((__section__(".data"))) = 0;
+
 static char *ipl_type_str(enum ipl_type type)
 {
         switch (type) {
diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
index fced022dc58d..863c8d08c026 100644
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -690,9 +690,14 @@ setup_memory(void)
         psw_set_key(PAGE_DEFAULT_KEY);
 
         free_bootmem_with_active_regions(0, max_pfn);
-        reserve_bootmem(0, PFN_PHYS(start_pfn));
 
         /*
+         * Reserve memory used for lowcore/command line/kernel image.
+         */
+        reserve_bootmem(0, (unsigned long)_ehead);
+        reserve_bootmem((unsigned long)_stext,
+                        PFN_PHYS(start_pfn) - (unsigned long)_stext);
+        /*
          * Reserve the bootmem bitmap itself as well. We do this in two
          * steps (first step was init_bootmem()) because this catches
          * the (very unlikely) case of us accidentally initializing the