s390: move vmalloc option parsing to startup code

Few other crucial memory setup options are already handled in
the startup code. Those values are needed by kaslr and kasan
implementations. "vmalloc" is the last piece required for future
improvements such as early decision on kernel page levels depth required
for actual memory setup, as well as vmalloc memory area access monitoring
in kasan.

Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
diff --git a/arch/s390/boot/ipl_parm.c b/arch/s390/boot/ipl_parm.c
index 3c49bde..449d26a 100644
--- a/arch/s390/boot/ipl_parm.c
+++ b/arch/s390/boot/ipl_parm.c
@@ -7,6 +7,7 @@
 #include <asm/sections.h>
 #include <asm/boot_data.h>
 #include <asm/facility.h>
+#include <asm/pgtable.h>
 #include <asm/uv.h>
 #include "boot.h"
 
@@ -14,6 +15,7 @@ char __bootdata(early_command_line)[COMMAND_LINE_SIZE];
 struct ipl_parameter_block __bootdata_preserved(ipl_block);
 int __bootdata_preserved(ipl_block_valid);
 
+unsigned long __bootdata(vmalloc_size) = VMALLOC_DEFAULT_SIZE;
 unsigned long __bootdata(memory_end);
 int __bootdata(memory_end_set);
 int __bootdata(noexec_disabled);
@@ -226,6 +228,9 @@ void parse_boot_command_line(void)
 			memory_end_set = 1;
 		}
 
+		if (!strcmp(param, "vmalloc"))
+			vmalloc_size = round_up(memparse(val, NULL), PAGE_SIZE);
+
 		if (!strcmp(param, "noexec")) {
 			rc = kstrtobool(val, &enabled);
 			if (!rc && !enabled)