arch/s390/kernel/early_nobss.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *    Copyright IBM Corp. 2007, 2018
   4  */
   5
   6 /*
   7  * Early setup functions which may not rely on an initialized bss
   8  * section. The last thing that is supposed to happen here is
   9  * initialization of the bss section.
  10  */
  11
  12 #include <linux/processor.h>
  13 #include <linux/string.h>
  14 #include <asm/sections.h>
  15 #include <asm/lowcore.h>
  16 #include <asm/timex.h>
  17 #include <asm/kasan.h>
  18 #include "entry.h"
  19
  20 static void __init reset_tod_clock(void)
  21 {
  22         u64 time;
  23
  24         if (store_tod_clock(&time) == 0)
  25                 return;
  26         /* TOD clock not running. Set the clock to Unix Epoch. */
  27         if (set_tod_clock(TOD_UNIX_EPOCH) != 0 || store_tod_clock(&time) != 0)
  28                 disabled_wait(0);
  29
  30         memset(tod_clock_base, 0, 16);
  31         *(__u64 *) &tod_clock_base[1] = TOD_UNIX_EPOCH;
  32         S390_lowcore.last_update_clock = TOD_UNIX_EPOCH;
  33 }
  34
  35 static void __init clear_bss_section(void)
  36 {
  37         memset(__bss_start, 0, __bss_stop - __bss_start);
  38 }
  39
  40 void __init startup_init_nobss(void)
  41 {
  42         reset_tod_clock();
  43         clear_bss_section();
  44         kasan_early_init();
  45 }