s390/boot: block uncompressed vmlinux booting attempts
Since the plain vmlinux ELF file no longer carries all necessary parts
for starting up (like the entry point and decompressor), add a check
which would block boot process and encourage users to use bzImage or
arch/s390/boot/compressed/vmlinux instead.
The check relies on s390 linux entry point ABI definition, which is only
present in bzImage and arch/s390/boot/compressed/vmlinux.
Reported-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Cornelia Huck <cohuck@redhat.com>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/boot/head.S b/arch/s390/boot/head.S
index f09e792..f721913b 100644
--- a/arch/s390/boot/head.S
+++ b/arch/s390/boot/head.S
@@ -272,14 +272,14 @@
.org 0x10000
ENTRY(startup)
j .Lep_startup_normal
- .org 0x10008
+ .org EP_OFFSET
#
# This is a list of s390 kernel entry points. At address 0x1000f the number of
# valid entry points is stored.
#
# IMPORTANT: Do not change this table, it is s390 kernel ABI!
#
- .ascii "S390EP"
+ .ascii EP_STRING
.byte 0x00,0x01
#
# kdump startup-code at 0x10010, running in 64 bit absolute addressing mode
diff --git a/arch/s390/include/asm/setup.h b/arch/s390/include/asm/setup.h
index be02f05..1d66016 100644
--- a/arch/s390/include/asm/setup.h
+++ b/arch/s390/include/asm/setup.h
@@ -9,7 +9,8 @@
#include <linux/const.h>
#include <uapi/asm/setup.h>
-
+#define EP_OFFSET 0x10008
+#define EP_STRING "S390EP"
#define PARMAREA 0x10400
#define PARMAREA_END 0x11000
diff --git a/arch/s390/kernel/early.c b/arch/s390/kernel/early.c
index 827699e..5b28b43 100644
--- a/arch/s390/kernel/early.c
+++ b/arch/s390/kernel/early.c
@@ -331,8 +331,20 @@ static void __init setup_boot_command_line(void)
append_to_cmdline(append_ipl_scpdata);
}
+static void __init check_image_bootable(void)
+{
+ if (!memcmp(EP_STRING, (void *)EP_OFFSET, strlen(EP_STRING)))
+ return;
+
+ sclp_early_printk("Linux kernel boot failure: An attempt to boot a vmlinux ELF image failed.\n");
+ sclp_early_printk("This image does not contain all parts necessary for starting up. Use\n");
+ sclp_early_printk("bzImage or arch/s390/boot/compressed/vmlinux instead.\n");
+ disabled_wait(0xbadb007);
+}
+
void __init startup_init(void)
{
+ check_image_bootable();
time_early_init();
init_kernel_storage_key();
lockdep_off();