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authorHeiko Carstens <heiko.carstens@de.ibm.com>2009-09-11 10:29:03 +0200
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2009-09-11 10:29:55 +0200
commit4bb5e07b68565d7983108993aa23eccf5f1b35fe (patch)
treea76f2d5933cc8d90878f3df2d29f09fbd952daca
parent53f8c573ea3b54b7e1b81d2cd403373b08103736 (diff)
[S390] Limit cpu detection to 256 physical cpus.
Saves us more than 65k pointless IPIs. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
-rw-r--r--arch/s390/include/asm/cpu.h6
-rw-r--r--arch/s390/kernel/head.S1
-rw-r--r--arch/s390/kernel/head64.S8
-rw-r--r--arch/s390/kernel/smp.c5
4 files changed, 13 insertions, 7 deletions
diff --git a/arch/s390/include/asm/cpu.h b/arch/s390/include/asm/cpu.h
new file mode 100644
index 000000000000..702ad46841cf
--- /dev/null
+++ b/arch/s390/include/asm/cpu.h
@@ -0,0 +1,6 @@
+#ifndef _ASM_S390_CPU_H
+#define _ASM_S390_CPU_H
+
+#define MAX_CPU_ADDRESS 255
+
+#endif /* _ASM_S390_CPU_H */
diff --git a/arch/s390/kernel/head.S b/arch/s390/kernel/head.S
index ec6882348520..c52b4f7742fa 100644
--- a/arch/s390/kernel/head.S
+++ b/arch/s390/kernel/head.S
@@ -27,6 +27,7 @@
#include <asm/asm-offsets.h>
#include <asm/thread_info.h>
#include <asm/page.h>
+#include <asm/cpu.h>
#ifdef CONFIG_64BIT
#define ARCH_OFFSET 4
diff --git a/arch/s390/kernel/head64.S b/arch/s390/kernel/head64.S
index bdcb3f05bcd1..6a250808092b 100644
--- a/arch/s390/kernel/head64.S
+++ b/arch/s390/kernel/head64.S
@@ -62,9 +62,9 @@ startup_continue:
clr %r11,%r12
je 5f # no more space in prefix array
4:
- ahi %r8,1 # next cpu (r8 += 1)
- cl %r8,.Llast_cpu-.LPG1(%r13) # is last possible cpu ?
- jl 1b # jump if not last cpu
+ ahi %r8,1 # next cpu (r8 += 1)
+ chi %r8,MAX_CPU_ADDRESS # is last possible cpu ?
+ jle 1b # jump if not last cpu
5:
lhi %r1,2 # mode 2 = esame (dump)
j 6f
@@ -130,8 +130,6 @@ startup_continue:
#ifdef CONFIG_ZFCPDUMP
.Lcurrent_cpu:
.long 0x0
-.Llast_cpu:
- .long 0x0000ffff
.Lpref_arr_ptr:
.long zfcpdump_prefix_array
#endif /* CONFIG_ZFCPDUMP */
diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index be2cae083406..9261495ca2c3 100644
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -49,6 +49,7 @@
#include <asm/sclp.h>
#include <asm/cputime.h>
#include <asm/vdso.h>
+#include <asm/cpu.h>
#include "entry.h"
static struct task_struct *current_set[NR_CPUS];
@@ -300,7 +301,7 @@ static int smp_rescan_cpus_sigp(cpumask_t avail)
logical_cpu = cpumask_first(&avail);
if (logical_cpu >= nr_cpu_ids)
return 0;
- for (cpu_id = 0; cpu_id <= 65535; cpu_id++) {
+ for (cpu_id = 0; cpu_id <= MAX_CPU_ADDRESS; cpu_id++) {
if (cpu_known(cpu_id))
continue;
__cpu_logical_map[logical_cpu] = cpu_id;
@@ -379,7 +380,7 @@ static void __init smp_detect_cpus(void)
/* Use sigp detection algorithm if sclp doesn't work. */
if (sclp_get_cpu_info(info)) {
smp_use_sigp_detection = 1;
- for (cpu = 0; cpu <= 65535; cpu++) {
+ for (cpu = 0; cpu <= MAX_CPU_ADDRESS; cpu++) {
if (cpu == boot_cpu_addr)
continue;
__cpu_logical_map[CPU_INIT_NO] = cpu;

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