[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>

8 files changed, 115 insertions, 41 deletions

diff --git a/arch/s390/kernel/Makefile b/arch/s390/kernel/Makefile
index aa97897..a81881c 100644
--- a/arch/s390/kernel/Makefile
+++ b/arch/s390/kernel/Makefile
@@ -4,7 +4,7 @@
 
 EXTRA_AFLAGS	:= -traditional
 
-obj-y	:=  bitmap.o traps.o time.o process.o \
+obj-y	:=  bitmap.o traps.o time.o process.o reset.o \
             setup.o sys_s390.o ptrace.o signal.o cpcmd.o ebcdic.o \
 	    semaphore.o s390_ext.o debug.o profile.o irq.o ipl.o
 
diff --git a/arch/s390/kernel/ipl.c b/arch/s390/kernel/ipl.c
index ec12782..77f4aff 100644
--- a/arch/s390/kernel/ipl.c
+++ b/arch/s390/kernel/ipl.c
@@ -19,6 +19,7 @@
 #include <asm/cpcmd.h>
 #include <asm/cio.h>
 #include <asm/ebcdic.h>
+#include <asm/reset.h>
 
 #define IPL_PARM_BLOCK_VERSION 0
 #define LOADPARM_LEN 8
@@ -1024,3 +1025,56 @@ static int __init s390_ipl_init(void)
 }
 
 __initcall(s390_ipl_init);
+
+static LIST_HEAD(rcall);
+static DEFINE_MUTEX(rcall_mutex);
+
+void register_reset_call(struct reset_call *reset)
+{
+	mutex_lock(&rcall_mutex);
+	list_add(&reset->list, &rcall);
+	mutex_unlock(&rcall_mutex);
+}
+EXPORT_SYMBOL_GPL(register_reset_call);
+
+void unregister_reset_call(struct reset_call *reset)
+{
+	mutex_lock(&rcall_mutex);
+	list_del(&reset->list);
+	mutex_unlock(&rcall_mutex);
+}
+EXPORT_SYMBOL_GPL(unregister_reset_call);
+
+static void do_reset_calls(void)
+{
+	struct reset_call *reset;
+
+	list_for_each_entry(reset, &rcall, list)
+		reset->fn();
+}
+
+extern void reset_mcck_handler(void);
+
+void s390_reset_system(void)
+{
+	struct _lowcore *lc;
+
+	/* Disable all interrupts/machine checks */
+	__load_psw_mask(PSW_KERNEL_BITS & ~PSW_MASK_MCHECK);
+
+	/* Stack for interrupt/machine check handler */
+	lc = (struct _lowcore *)(unsigned long) store_prefix();
+	lc->panic_stack = S390_lowcore.panic_stack;
+
+	/* Disable prefixing */
+	set_prefix(0);
+
+	/* Disable lowcore protection */
+	__ctl_clear_bit(0,28);
+
+	/* Set new machine check handler */
+	S390_lowcore.mcck_new_psw.mask = PSW_KERNEL_BITS & ~PSW_MASK_MCHECK;
+	S390_lowcore.mcck_new_psw.addr =
+		PSW_ADDR_AMODE | (unsigned long) &reset_mcck_handler;
+	do_reset_calls();
+}
diff --git a/arch/s390/kernel/machine_kexec.c b/arch/s390/kernel/machine_kexec.c
index 60b1ea9..202bf1fd 100644
--- a/arch/s390/kernel/machine_kexec.c
+++ b/arch/s390/kernel/machine_kexec.c
@@ -22,6 +22,7 @@
 #include <asm/pgalloc.h>
 #include <asm/system.h>
 #include <asm/smp.h>
+#include <asm/reset.h>
 
 static void kexec_halt_all_cpus(void *);
 
@@ -62,12 +63,6 @@ machine_shutdown(void)
 NORET_TYPE void
 machine_kexec(struct kimage *image)
 {
-	clear_all_subchannels();
-	cio_reset_channel_paths();
-
-	/* Disable lowcore protection */
-	ctl_clear_bit(0,28);
-
 	on_each_cpu(kexec_halt_all_cpus, image, 0, 0);
 	for (;;);
 }
@@ -98,6 +93,8 @@ kexec_halt_all_cpus(void *kernel_image)
 			cpu_relax();
 	}
 
+	s390_reset_system();
+
 	image = (struct kimage *) kernel_image;
 	data_mover = (relocate_kernel_t)
 		(page_to_pfn(image->control_code_page) << PAGE_SHIFT);
diff --git a/arch/s390/kernel/reipl.S b/arch/s390/kernel/reipl.S
index 0340477..f9434d4 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
diff --git a/arch/s390/kernel/reipl64.S b/arch/s390/kernel/reipl64.S
index de74350..f18ef26 100644
--- a/arch/s390/kernel/reipl64.S
+++ b/arch/s390/kernel/reipl64.S
@@ -10,10 +10,10 @@
 #include <asm/lowcore.h>
 		.globl	do_reipl_asm
 do_reipl_asm:	basr	%r13,0
+.Lpg0:		lpswe	.Lnewpsw-.Lpg0(%r13)
+.Lpg1:		# do store status of all registers
 
-		# do store status of all registers
-
-.Lpg0:		stg	%r1,.Lregsave-.Lpg0(%r13)
+		stg	%r1,.Lregsave-.Lpg0(%r13)
 		lghi	%r1,0x1000
 		stmg	%r0,%r15,__LC_GPREGS_SAVE_AREA-0x1000(%r1)
 		lg	%r0,.Lregsave-.Lpg0(%r13)
@@ -27,11 +27,7 @@ do_reipl_asm:	basr	%r13,0
 		stpt	__LC_CPU_TIMER_SAVE_AREA-0x1000(%r1)
 		stg	%r13, __LC_PSW_SAVE_AREA-0x1000+8(%r1)
 
-		lpswe	.Lnewpsw-.Lpg0(%r13)
-.Lpg1:		lctlg	%c6,%c6,.Lall-.Lpg0(%r13)
-		stctg	%c0,%c0,.Lregsave-.Lpg0(%r13)
-		ni	.Lregsave+4-.Lpg0(%r13),0xef
-		lctlg	%c0,%c0,.Lregsave-.Lpg0(%r13)
+		lctlg	%c6,%c6,.Lall-.Lpg0(%r13)
 		lgr	%r1,%r2
 		mvc	__LC_PGM_NEW_PSW(16),.Lpcnew-.Lpg0(%r13)
 		stsch	.Lschib-.Lpg0(%r13)
@@ -56,8 +52,7 @@ 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
 		lhi	%r1,0		 # mode 0 = esa
 		slr	%r0,%r0 	 # set cpuid to zero
 		sigp	%r1,%r0,0x12	 # switch to esa mode
@@ -70,7 +65,6 @@ do_reipl_asm:	basr	%r13,0
 .Lclkcmp:	.quad	0x0000000000000000
 .Lall:		.quad	0x00000000ff000000
 .Lregsave:	.quad	0x0000000000000000
-.Lnull:		.long	0x0000000000000000
 		.align	16
 /*
  * These addresses have to be 31 bit otherwise
diff --git a/arch/s390/kernel/relocate_kernel.S b/arch/s390/kernel/relocate_kernel.S
index f9899ff..3b456b8 100644
--- a/arch/s390/kernel/relocate_kernel.S
+++ b/arch/s390/kernel/relocate_kernel.S
@@ -26,8 +26,7 @@
 	relocate_kernel:
 		basr	%r13,0		# base address
 	.base:
-		stnsm	sys_msk-.base(%r13),0xf8	# disable DAT and IRQ (external)
-		spx	zero64-.base(%r13)	# absolute addressing mode
+		stnsm	sys_msk-.base(%r13),0xfb	# disable DAT
 		stctl	%c0,%c15,ctlregs-.base(%r13)
 		stm	%r0,%r15,gprregs-.base(%r13)
 		la	%r1,load_psw-.base(%r13)
@@ -97,8 +96,6 @@
 		lpsw	0		# hopefully start new kernel...
 
 		.align	8
-	zero64:
-		.quad	0
 	load_psw:
 		.long	0x00080000,0x80000000
 	sys_msk:
diff --git a/arch/s390/kernel/relocate_kernel64.S b/arch/s390/kernel/relocate_kernel64.S
index 4fb4430..1f9ea20 100644
--- a/arch/s390/kernel/relocate_kernel64.S
+++ b/arch/s390/kernel/relocate_kernel64.S
@@ -27,8 +27,7 @@
 	relocate_kernel:
 		basr	%r13,0		# base address
 	.base:
-		stnsm	sys_msk-.base(%r13),0xf8	# disable DAT and IRQs
-		spx	zero64-.base(%r13)	# absolute addressing mode
+		stnsm	sys_msk-.base(%r13),0xfb	# disable DAT
 		stctg	%c0,%c15,ctlregs-.base(%r13)
 		stmg	%r0,%r15,gprregs-.base(%r13)
 		lghi	%r0,3
@@ -100,8 +99,6 @@
 		lpsw	0		# hopefully start new kernel...
 
 		.align	8
-	zero64:
-		.quad	0
 	load_psw:
 		.long	0x00080000,0x80000000
 	sys_msk:
diff --git a/arch/s390/kernel/reset.S b/arch/s390/kernel/reset.S
new file mode 100644
index 0000000..be8688c
--- /dev/null
+++ b/arch/s390/kernel/reset.S
@@ -0,0 +1,48 @@
+/*
+ *  arch/s390/kernel/reset.S
+ *
+ *    Copyright (C) IBM Corp. 2006
+ *    Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
+ */
+
+#include <asm/ptrace.h>
+#include <asm/lowcore.h>
+
+#ifdef CONFIG_64BIT
+
+	.globl	reset_mcck_handler
+reset_mcck_handler:
+	basr	%r13,0
+0:	lg	%r15,__LC_PANIC_STACK	# load panic stack
+	aghi	%r15,-STACK_FRAME_OVERHEAD
+	lg	%r1,s390_reset_mcck_handler-0b(%r13)
+	ltgr	%r1,%r1
+	jz	1f
+	basr	%r14,%r1
+1:	la	%r1,4095
+	lmg	%r0,%r15,__LC_GPREGS_SAVE_AREA-4095(%r1)
+	lpswe	__LC_MCK_OLD_PSW
+
+	.globl	s390_reset_mcck_handler
+s390_reset_mcck_handler:
+	.quad	0
+
+#else /* CONFIG_64BIT */
+
+	.globl	reset_mcck_handler
+reset_mcck_handler:
+	basr	%r13,0
+0:	l	%r15,__LC_PANIC_STACK	# load panic stack
+	ahi	%r15,-STACK_FRAME_OVERHEAD
+	l	%r1,s390_reset_mcck_handler-0b(%r13)
+	ltr	%r1,%r1
+	jz	1f
+	basr	%r14,%r1
+1:	lm	%r0,%r15,__LC_GPREGS_SAVE_AREA
+	lpsw	__LC_MCK_OLD_PSW
+
+	.globl	s390_reset_mcck_handler
+s390_reset_mcck_handler:
+	.long	0
+
+#endif /* CONFIG_64BIT */