[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