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Subject[S390] cpu shutdown rework
From: Heiko Carstens <heiko.carstens@de.ibm.com>

[S390] cpu shutdown rework

Let one master cpu kill all other cpus instead of sending an external
interrupt to all other cpus so they can kill themselves.
Simplifies reipl/shutdown functions a lot.

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

arch/s390/kernel/ipl.c | 24 ---------
arch/s390/kernel/machine_kexec.c | 65 ++++++------------------
arch/s390/kernel/smp.c | 104 +++++++++++----------------------------
drivers/s390/char/sclp_quiesce.c | 37 -------------
include/asm-s390/smp.h | 8 +++
5 files changed, 58 insertions(+), 180 deletions(-)

diff -urpN linux-2.6/arch/s390/kernel/ipl.c linux-2.6-patched/arch/s390/kernel/ipl.c
--- linux-2.6/arch/s390/kernel/ipl.c 2006-12-04 14:50:50.000000000 +0100
+++ linux-2.6-patched/arch/s390/kernel/ipl.c 2006-12-04 14:50:50.000000000 +0100
@@ -576,23 +576,6 @@ static struct subsys_attribute dump_type

static decl_subsys(dump, NULL, NULL);

-#ifdef CONFIG_SMP
-static void dump_smp_stop_all(void)
-{
- int cpu;
- preempt_disable();
- for_each_online_cpu(cpu) {
- if (cpu == smp_processor_id())
- continue;
- while (signal_processor(cpu, sigp_stop) == sigp_busy)
- udelay(10);
- }
- preempt_enable();
-}
-#else
-#define dump_smp_stop_all() do { } while (0)
-#endif
-
/*
* Shutdown actions section
*/
@@ -724,13 +707,13 @@ static void do_dump(void)

switch (dump_method) {
case IPL_METHOD_CCW_CIO:
- dump_smp_stop_all();
+ smp_send_stop();
devid.devno = dump_block_ccw->ipl_info.ccw.devno;
devid.ssid = 0;
reipl_ccw_dev(&devid);
break;
case IPL_METHOD_CCW_VM:
- dump_smp_stop_all();
+ smp_send_stop();
sprintf(buf, "STORE STATUS");
__cpcmd(buf, NULL, 0, NULL);
sprintf(buf, "IPL %X", dump_block_ccw->ipl_info.ccw.devno);
@@ -1059,9 +1042,6 @@ 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;
diff -urpN linux-2.6/arch/s390/kernel/machine_kexec.c linux-2.6-patched/arch/s390/kernel/machine_kexec.c
--- linux-2.6/arch/s390/kernel/machine_kexec.c 2006-12-04 14:50:48.000000000 +0100
+++ linux-2.6-patched/arch/s390/kernel/machine_kexec.c 2006-12-04 14:50:50.000000000 +0100
@@ -1,15 +1,10 @@
/*
* arch/s390/kernel/machine_kexec.c
*
- * (C) Copyright IBM Corp. 2005
+ * Copyright IBM Corp. 2005,2006
*
- * Author(s): Rolf Adelsberger <adelsberger@de.ibm.com>
- *
- */
-
-/*
- * s390_machine_kexec.c - handle the transition of Linux booting another kernel
- * on the S390 architecture.
+ * Author(s): Rolf Adelsberger,
+ * Heiko Carstens <heiko.carstens@de.ibm.com>
*/

#include <linux/device.h>
@@ -24,81 +19,53 @@
#include <asm/smp.h>
#include <asm/reset.h>

-static void kexec_halt_all_cpus(void *);
-
-typedef void (*relocate_kernel_t) (kimage_entry_t *, unsigned long);
+typedef void (*relocate_kernel_t)(kimage_entry_t *, unsigned long);

extern const unsigned char relocate_kernel[];
extern const unsigned long long relocate_kernel_len;

-int
-machine_kexec_prepare(struct kimage *image)
+int machine_kexec_prepare(struct kimage *image)
{
- unsigned long reboot_code_buffer;
+ void *reboot_code_buffer;

/* We don't support anything but the default image type for now. */
if (image->type != KEXEC_TYPE_DEFAULT)
return -EINVAL;

/* Get the destination where the assembler code should be copied to.*/
- reboot_code_buffer = page_to_pfn(image->control_code_page)<<PAGE_SHIFT;
+ reboot_code_buffer = (void *) page_to_phys(image->control_code_page);

/* Then copy it */
- memcpy((void *) reboot_code_buffer, relocate_kernel,
- relocate_kernel_len);
+ memcpy(reboot_code_buffer, relocate_kernel, relocate_kernel_len);
return 0;
}

-void
-machine_kexec_cleanup(struct kimage *image)
+void machine_kexec_cleanup(struct kimage *image)
{
}

-void
-machine_shutdown(void)
+void machine_shutdown(void)
{
printk(KERN_INFO "kexec: machine_shutdown called\n");
}

-NORET_TYPE void
-machine_kexec(struct kimage *image)
-{
- on_each_cpu(kexec_halt_all_cpus, image, 0, 0);
- for (;;);
-}
-
extern void pfault_fini(void);

-static void
-kexec_halt_all_cpus(void *kernel_image)
+void machine_kexec(struct kimage *image)
{
- static atomic_t cpuid = ATOMIC_INIT(-1);
- int cpu;
- struct kimage *image;
relocate_kernel_t data_mover;

+ preempt_disable();
#ifdef CONFIG_PFAULT
if (MACHINE_IS_VM)
pfault_fini();
#endif
-
- if (atomic_cmpxchg(&cpuid, -1, smp_processor_id()) != -1)
- signal_processor(smp_processor_id(), sigp_stop);
-
- /* Wait for all other cpus to enter stopped state */
- for_each_online_cpu(cpu) {
- if (cpu == smp_processor_id())
- continue;
- while (!smp_cpu_not_running(cpu))
- cpu_relax();
- }
-
+ smp_send_stop();
s390_reset_system();

- image = (struct kimage *) kernel_image;
- data_mover = (relocate_kernel_t)
- (page_to_pfn(image->control_code_page) << PAGE_SHIFT);
+ data_mover = (relocate_kernel_t) page_to_phys(image->control_code_page);

/* Call the moving routine */
- (*data_mover) (&image->head, image->start);
+ (*data_mover)(&image->head, image->start);
+ for (;;);
}
diff -urpN linux-2.6/arch/s390/kernel/smp.c linux-2.6-patched/arch/s390/kernel/smp.c
--- linux-2.6/arch/s390/kernel/smp.c 2006-11-29 22:57:37.000000000 +0100
+++ linux-2.6-patched/arch/s390/kernel/smp.c 2006-12-04 14:50:50.000000000 +0100
@@ -230,18 +230,37 @@ static inline void do_store_status(void)
}
}

+static inline void do_wait_for_stop(void)
+{
+ int cpu;
+
+ /* Wait for all other cpus to enter stopped state */
+ for_each_online_cpu(cpu) {
+ if (cpu == smp_processor_id())
+ continue;
+ while(!smp_cpu_not_running(cpu))
+ cpu_relax();
+ }
+}
+
/*
* this function sends a 'stop' sigp to all other CPUs in the system.
* it goes straight through.
*/
void smp_send_stop(void)
{
+ /* Disable all interrupts/machine checks */
+ __load_psw_mask(PSW_KERNEL_BITS & ~PSW_MASK_MCHECK);
+
/* write magic number to zero page (absolute 0) */
lowcore_ptr[smp_processor_id()]->panic_magic = __PANIC_MAGIC;

/* stop other processors. */
do_send_stop();

+ /* wait until other processors are stopped */
+ do_wait_for_stop();
+
/* store status of other processors. */
do_store_status();
}
@@ -250,88 +269,28 @@ void smp_send_stop(void)
* Reboot, halt and power_off routines for SMP.
*/

-static void do_machine_restart(void * __unused)
-{
- int cpu;
- static atomic_t cpuid = ATOMIC_INIT(-1);
-
- if (atomic_cmpxchg(&cpuid, -1, smp_processor_id()) != -1)
- signal_processor(smp_processor_id(), sigp_stop);
-
- /* Wait for all other cpus to enter stopped state */
- for_each_online_cpu(cpu) {
- if (cpu == smp_processor_id())
- continue;
- while(!smp_cpu_not_running(cpu))
- cpu_relax();
- }
-
- /* Store status of other cpus. */
- do_store_status();
-
- /*
- * Finally call reipl. Because we waited for all other
- * cpus to enter this function we know that they do
- * not hold any s390irq-locks (the cpus have been
- * interrupted by an external interrupt and s390irq
- * locks are always held disabled).
- */
- do_reipl();
-}
-
void machine_restart_smp(char * __unused)
{
- on_each_cpu(do_machine_restart, NULL, 0, 0);
-}
-
-static void do_wait_for_stop(void)
-{
- unsigned long cr[16];
-
- __ctl_store(cr, 0, 15);
- cr[0] &= ~0xffff;
- cr[6] = 0;
- __ctl_load(cr, 0, 15);
- for (;;)
- enabled_wait();
-}
-
-static void do_machine_halt(void * __unused)
-{
- static atomic_t cpuid = ATOMIC_INIT(-1);
-
- if (atomic_cmpxchg(&cpuid, -1, smp_processor_id()) == -1) {
- smp_send_stop();
- if (MACHINE_IS_VM && strlen(vmhalt_cmd) > 0)
- cpcmd(vmhalt_cmd, NULL, 0, NULL);
- signal_processor(smp_processor_id(),
- sigp_stop_and_store_status);
- }
- do_wait_for_stop();
+ smp_send_stop();
+ do_reipl();
}

void machine_halt_smp(void)
{
- on_each_cpu(do_machine_halt, NULL, 0, 0);
-}
-
-static void do_machine_power_off(void * __unused)
-{
- static atomic_t cpuid = ATOMIC_INIT(-1);
-
- if (atomic_cmpxchg(&cpuid, -1, smp_processor_id()) == -1) {
- smp_send_stop();
- if (MACHINE_IS_VM && strlen(vmpoff_cmd) > 0)
- cpcmd(vmpoff_cmd, NULL, 0, NULL);
- signal_processor(smp_processor_id(),
- sigp_stop_and_store_status);
- }
- do_wait_for_stop();
+ smp_send_stop();
+ if (MACHINE_IS_VM && strlen(vmhalt_cmd) > 0)
+ __cpcmd(vmhalt_cmd, NULL, 0, NULL);
+ signal_processor(smp_processor_id(), sigp_stop_and_store_status);
+ for (;;);
}

void machine_power_off_smp(void)
{
- on_each_cpu(do_machine_power_off, NULL, 0, 0);
+ smp_send_stop();
+ if (MACHINE_IS_VM && strlen(vmpoff_cmd) > 0)
+ __cpcmd(vmpoff_cmd, NULL, 0, NULL);
+ signal_processor(smp_processor_id(), sigp_stop_and_store_status);
+ for (;;);
}

/*
@@ -860,4 +819,3 @@ EXPORT_SYMBOL(smp_ctl_clear_bit);
EXPORT_SYMBOL(smp_call_function);
EXPORT_SYMBOL(smp_get_cpu);
EXPORT_SYMBOL(smp_put_cpu);
-
diff -urpN linux-2.6/drivers/s390/char/sclp_quiesce.c linux-2.6-patched/drivers/s390/char/sclp_quiesce.c
--- linux-2.6/drivers/s390/char/sclp_quiesce.c 2006-11-29 22:57:37.000000000 +0100
+++ linux-2.6-patched/drivers/s390/char/sclp_quiesce.c 2006-12-04 14:50:50.000000000 +0100
@@ -19,52 +19,17 @@

#include "sclp.h"

-
-#ifdef CONFIG_SMP
-/* Signal completion of shutdown process. All CPUs except the first to enter
- * this function: go to stopped state. First CPU: wait until all other
- * CPUs are in stopped or check stop state. Afterwards, load special PSW
- * to indicate completion. */
-static void
-do_load_quiesce_psw(void * __unused)
-{
- static atomic_t cpuid = ATOMIC_INIT(-1);
- psw_t quiesce_psw;
- int cpu;
-
- if (atomic_cmpxchg(&cpuid, -1, smp_processor_id()) != -1)
- signal_processor(smp_processor_id(), sigp_stop);
- /* Wait for all other cpus to enter stopped state */
- for_each_online_cpu(cpu) {
- if (cpu == smp_processor_id())
- continue;
- while(!smp_cpu_not_running(cpu))
- cpu_relax();
- }
- /* Quiesce the last cpu with the special psw */
- quiesce_psw.mask = PSW_BASE_BITS | PSW_MASK_WAIT;
- quiesce_psw.addr = 0xfff;
- __load_psw(quiesce_psw);
-}
-
-/* Shutdown handler. Perform shutdown function on all CPUs. */
-static void
-do_machine_quiesce(void)
-{
- on_each_cpu(do_load_quiesce_psw, NULL, 0, 0);
-}
-#else
/* Shutdown handler. Signal completion of shutdown by loading special PSW. */
static void
do_machine_quiesce(void)
{
psw_t quiesce_psw;

+ smp_send_stop();
quiesce_psw.mask = PSW_BASE_BITS | PSW_MASK_WAIT;
quiesce_psw.addr = 0xfff;
__load_psw(quiesce_psw);
}
-#endif

/* Handler for quiesce event. Start shutdown procedure. */
static void
diff -urpN linux-2.6/include/asm-s390/smp.h linux-2.6-patched/include/asm-s390/smp.h
--- linux-2.6/include/asm-s390/smp.h 2006-11-29 22:57:37.000000000 +0100
+++ linux-2.6-patched/include/asm-s390/smp.h 2006-12-04 14:50:50.000000000 +0100
@@ -18,6 +18,7 @@

#include <asm/lowcore.h>
#include <asm/sigp.h>
+#include <asm/ptrace.h>

/*
s390 specific smp.c headers
@@ -101,6 +102,13 @@ smp_call_function_on(void (*func) (void
func(info);
return 0;
}
+
+static inline void smp_send_stop(void)
+{
+ /* Disable all interrupts/machine checks */
+ __load_psw_mask(PSW_KERNEL_BITS & ~PSW_MASK_MCHECK);
+}
+
#define smp_cpu_not_running(cpu) 1
#define smp_get_cpu(cpu) ({ 0; })
#define smp_put_cpu(cpu) ({ 0; })
-
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