Commit 3053cb97 authored by Martin Schwidefsky's avatar Martin Schwidefsky Committed by Greg Kroah-Hartman

s390/setup: fix boot crash for machine without EDAT-1

commit 86a86804 upstream.

The fix to make WARN work in the early boot code created a problem
on older machines without EDAT-1. The setup_lowcore_dat_on function
uses the pointer from lowcore_ptr[0] to set the DAT bit in the new
PSWs. That does not work if the kernel page table is set up with
4K pages as the prefix address maps to absolute zero.

To make this work the PSWs need to be changed with via address 0 in
form of the S390_lowcore definition.
Reported-by: default avatarGuenter Roeck <linux@roeck-us.net>
Tested-by: default avatarCornelia Huck <cohuck@redhat.com>
Fixes: 94f85ed3e2f8 ("s390/setup: fix early warning messages")
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent e578f90d
...@@ -387,13 +387,12 @@ static void __init setup_lowcore_dat_off(void) ...@@ -387,13 +387,12 @@ static void __init setup_lowcore_dat_off(void)
static void __init setup_lowcore_dat_on(void) static void __init setup_lowcore_dat_on(void)
{ {
struct lowcore *lc; __ctl_clear_bit(0, 28);
S390_lowcore.external_new_psw.mask |= PSW_MASK_DAT;
lc = lowcore_ptr[0]; S390_lowcore.svc_new_psw.mask |= PSW_MASK_DAT;
lc->external_new_psw.mask |= PSW_MASK_DAT; S390_lowcore.program_new_psw.mask |= PSW_MASK_DAT;
lc->svc_new_psw.mask |= PSW_MASK_DAT; S390_lowcore.io_new_psw.mask |= PSW_MASK_DAT;
lc->program_new_psw.mask |= PSW_MASK_DAT; __ctl_set_bit(0, 28);
lc->io_new_psw.mask |= PSW_MASK_DAT;
} }
static struct resource code_resource = { static struct resource code_resource = {
......
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