s390/facilities: always use lowcore's stfle field for storing facility bits

BugLink: http://bugs.launchpad.net/bugs/1555344

head.s contains an stfle instruction which stores it result at the
storage location that is assigned to the stfl instruction.

This is currently no problem, since we only care about one double
word. However if the number of double words in the ALS bitfield grows
the current code is not very stable.

E.g. before issuing the stfle command the memory to which it stores
must be cleared, since the instruction may or may not clear memory
contents where no bits are set.

In order to simplify the code a bit always use the storage location
that we reserved for the stfle result.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
(cherry picked from commit 76cdd44c)
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

arch/s390/kernel/asm-offsets.c

@@ -120,6 +120,7 @@ int main(void)
 	OFFSET(__LC_IO_INT_PARM, _lowcore, io_int_parm);
 	OFFSET(__LC_IO_INT_WORD, _lowcore, io_int_word);
 	OFFSET(__LC_STFL_FAC_LIST, _lowcore, stfl_fac_list);
+	OFFSET(__LC_STFLE_FAC_LIST, _lowcore, stfle_fac_list);
 	OFFSET(__LC_MCCK_CODE, _lowcore, mcck_interruption_code);
 	OFFSET(__LC_MCCK_FAIL_STOR_ADDR, _lowcore, failing_storage_address);
 	OFFSET(__LC_LAST_BREAK, _lowcore, breaking_event_addr);

arch/s390/kernel/head.S

@@ -300,19 +300,19 @@ ENTRY(startup_kdump)
 	xc	0x200(256),0x200	# partially clear lowcore
 	xc	0x300(256),0x300
 	xc	0xe00(256),0xe00
+	xc	0xf00(256),0xf00
 	lctlg	%c0,%c15,0x200(%r0)	# initialize control registers
 	stck	__LC_LAST_UPDATE_CLOCK
 	spt	6f-.LPG0(%r13)
 	mvc	__LC_LAST_UPDATE_TIMER(8),6f-.LPG0(%r13)
-	xc	__LC_STFL_FAC_LIST(8),__LC_STFL_FAC_LIST
-	# check capabilities against MARCH_{G5,Z900,Z990,Z9_109,Z10}
 	stfl	0(%r0)			# store facilities @ __LC_STFL_FAC_LIST
-	tm	__LC_STFL_FAC_LIST,0x01	# stfle available ?
+	mvc	__LC_STFLE_FAC_LIST(4),__LC_STFL_FAC_LIST
+	tm	__LC_STFLE_FAC_LIST,0x01	# stfle available ?
 	jz	0f
 	la	%r0,1
-	.insn	s,0xb2b00000,__LC_STFL_FAC_LIST	# store facility list extended
+	.insn	s,0xb2b00000,__LC_STFLE_FAC_LIST # store facility list extended
 	# verify if all required facilities are supported by the machine
-0:	la	%r1,__LC_STFL_FAC_LIST
+0:	la	%r1,__LC_STFLE_FAC_LIST
 	la	%r2,3f+8-.LPG0(%r13)
 	l	%r3,0(%r2)
 1:	l	%r0,0(%r1)

arch/s390/kernel/head64.S

@@ -16,7 +16,7 @@
 
 __HEAD
 ENTRY(startup_continue)
-	tm	__LC_STFL_FAC_LIST+6,0x80	# LPP available ?
+	tm	__LC_STFLE_FAC_LIST+6,0x80	# LPP available ?
 	jz	0f
 	xc	__LC_LPP+1(7,0),__LC_LPP+1	# clear lpp and current_pid
 	mvi	__LC_LPP,0x80			#   and set LPP_MAGIC