[S390] Reset infrastructure for re-IPL.

In case of re-IPL and diag308 doesn't work we have to reset all devices
manually and wait synchronously that each reset finished.
This patch adds the necessary infrastucture and the first exploiter of it.

Subsystems that need to add a function that needs to be called at re-IPL
may register/unregister this function via

struct reset_call {
	struct reset_call *next;
	void (*fn)(void);
};

void register_reset_call(struct reset_call *reset);
void unregister_reset_call(struct reset_call *reset);

When the registered function get called the context is:

- all cpus beside the current one are stopped
- all machine checks and interrupts are disabled
- prefixing is disabled
- a default machine check handler is available for use

The registered functions may not take any locks are sleep.

For the common I/O layer part of this patch:

Introduce a reset_call css_reset that does the following:
- clear all subchannels
- perform a rchp on all channel paths and wait for the resulting
  machine checks
This replaces the calls to clear_all_subchannels() and
cio_reset_channel_paths() for kexec and ccw reipl. reipl_ccw_dev() now
uses reipl_find_schid() to determine the subchannel id for a given
device id.
Also remove cio_reset_channel_paths() and friends since they are not
needed anymore.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 2 insertions, 15 deletions

diff --git a/arch/s390/kernel/reipl.S b/arch/s390/kernel/reipl.S
index 0340477f3b08..f9434d42ce9f 100644
--- a/arch/s390/kernel/reipl.S
+++ b/arch/s390/kernel/reipl.S
@@ -11,19 +11,10 @@
 		.globl	do_reipl_asm
 do_reipl_asm:	basr	%r13,0
 .Lpg0:		lpsw	.Lnewpsw-.Lpg0(%r13)
-
-		# switch off lowcore protection
-
-.Lpg1:		stctl	%c0,%c0,.Lctlsave1-.Lpg0(%r13)
-		stctl	%c0,%c0,.Lctlsave2-.Lpg0(%r13)
-		ni	.Lctlsave1-.Lpg0(%r13),0xef
-		lctl	%c0,%c0,.Lctlsave1-.Lpg0(%r13)
-
-		# do store status of all registers
+.Lpg1:		# do store status of all registers
 
 		stm	%r0,%r15,__LC_GPREGS_SAVE_AREA
 		stctl	%c0,%c15,__LC_CREGS_SAVE_AREA
-		mvc	__LC_CREGS_SAVE_AREA(4),.Lctlsave2-.Lpg0(%r13)
 		stam	%a0,%a15,__LC_AREGS_SAVE_AREA
 		stpx	__LC_PREFIX_SAVE_AREA
 		stckc	.Lclkcmp-.Lpg0(%r13)
@@ -56,8 +47,7 @@ do_reipl_asm:	basr	%r13,0
 .L002:		tm	.Liplirb+8-.Lpg0(%r13),0xf3
 		jz	.L003
 		bas	%r14,.Ldisab-.Lpg0(%r13)
-.L003:		spx	.Lnull-.Lpg0(%r13)
-		st	%r1,__LC_SUBCHANNEL_ID
+.L003:		st	%r1,__LC_SUBCHANNEL_ID
 		lpsw	0
 		sigp	0,0,0(6)
 .Ldisab:	st	%r14,.Ldispsw+4-.Lpg0(%r13)
@@ -65,9 +55,6 @@ do_reipl_asm:	basr	%r13,0
 		.align	8
 .Lclkcmp:	.quad	0x0000000000000000
 .Lall:		.long	0xff000000
-.Lnull:		.long	0x00000000
-.Lctlsave1:	.long	0x00000000
-.Lctlsave2:	.long	0x00000000
 		.align	8
 .Lnewpsw:	.long	0x00080000,0x80000000+.Lpg1
 .Lpcnew:	.long	0x00080000,0x80000000+.Lecs