From 627c9b62058ebfd368b7411e7ea5a27df48486c8 Mon Sep 17 00:00:00 2001 From: Vasily Gorbik Date: Mon, 25 Jun 2018 13:59:35 +0200 Subject: [PATCH] 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 Tested-by: Guenter Roeck Acked-by: Cornelia Huck Acked-by: Christian Borntraeger Reviewed-by: Heiko Carstens Signed-off-by: Vasily Gorbik Signed-off-by: Martin Schwidefsky --- arch/s390/boot/head.S | 4 ++-- arch/s390/include/asm/setup.h | 3 ++- arch/s390/kernel/early.c | 12 ++++++++++++ 3 files changed, 16 insertions(+), 3 deletions(-) diff --git a/arch/s390/boot/head.S b/arch/s390/boot/head.S index f09e792df495..f721913b73f1 100644 --- a/arch/s390/boot/head.S +++ b/arch/s390/boot/head.S @@ -272,14 +272,14 @@ iplstart: .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 be02f0558048..1d66016f4170 100644 --- a/arch/s390/include/asm/setup.h +++ b/arch/s390/include/asm/setup.h @@ -9,7 +9,8 @@ #include #include - +#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 827699eb48fa..5b28b434f8a1 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(); -- 2.30.2