s390: clean .bss before running uncompressed kernel

Clean uncompressed kernel .bss section in the startup code before
the uncompressed kernel is executed. At this point of time initrd and
certificates have been already rescued. Uncompressed kernel .bss size
is known from vmlinux_info. It is also taken into consideration during
uncompressed kernel positioning by kaslr (so it is safe to clean it).

With that uncompressed kernel is starting with .bss section zeroed and
no .bss section usage restrictions apply. Which makes chkbss checks for
uncompressed kernel objects obsolete and they can be removed.

early_nobss.c is also not needed anymore. Parts of it which are still
relevant are moved to early.c. Kasan initialization code is now called
directly from head64 (early.c is instrumented and should not be
executed before kasan shadow memory is set up).

Reviewed-by: Philipp Rudo <prudo@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

1 files changed, 0 insertions, 45 deletions

diff --git a/arch/s390/kernel/early_nobss.c b/arch/s390/kernel/early_nobss.c
deleted file mode 100644
index 52a3ef959341..000000000000
--- a/arch/s390/kernel/early_nobss.c
+++ /dev/null
@@ -1,45 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- *    Copyright IBM Corp. 2007, 2018
- */
-
-/*
- * Early setup functions which may not rely on an initialized bss
- * section. The last thing that is supposed to happen here is
- * initialization of the bss section.
- */
-
-#include <linux/processor.h>
-#include <linux/string.h>
-#include <asm/sections.h>
-#include <asm/lowcore.h>
-#include <asm/timex.h>
-#include <asm/kasan.h>
-#include "entry.h"
-
-static void __init reset_tod_clock(void)
-{
-	u64 time;
-
-	if (store_tod_clock(&time) == 0)
-		return;
-	/* TOD clock not running. Set the clock to Unix Epoch. */
-	if (set_tod_clock(TOD_UNIX_EPOCH) != 0 || store_tod_clock(&time) != 0)
-		disabled_wait();
-
-	memset(tod_clock_base, 0, 16);
-	*(__u64 *) &tod_clock_base[1] = TOD_UNIX_EPOCH;
-	S390_lowcore.last_update_clock = TOD_UNIX_EPOCH;
-}
-
-static void __init clear_bss_section(void)
-{
-	memset(__bss_start, 0, __bss_stop - __bss_start);
-}
-
-void __init startup_init_nobss(void)
-{
-	reset_tod_clock();
-	clear_bss_section();
-	kasan_early_init();
-}