[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 aa978978d3d1..a81881c9b297 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 ec127826f221..77f4aff630fe 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 60b1ea9f946b..202bf1fdfe39 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 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
diff --git a/arch/s390/kernel/reipl64.S b/arch/s390/kernel/reipl64.S
index de7435054f7c..f18ef260ca23 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 f9899ff2e5b0..3b456b80bcee 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 4fb443042d9c..1f9ea2067b59 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 000000000000..be8688c0665c
--- /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 */