From: Anton Blanchard <anton@samba.org>
Also add cpu_relax() to several spinloops in xmon which wait for other cpus.
---
arch/ppc64/xmon/xmon.c | 14 +++++++++-----
drivers/char/hvc_console.c | 9 +++++----
2 files changed, 14 insertions(+), 9 deletions(-)
diff -puN arch/ppc64/xmon/xmon.c~ppc64-xmon-cpumask arch/ppc64/xmon/xmon.c
--- 25/arch/ppc64/xmon/xmon.c~ppc64-xmon-cpumask 2004-02-04 02:24:54.000000000 -0800
+++ 25-akpm/arch/ppc64/xmon/xmon.c 2004-02-04 02:24:54.000000000 -0800
@@ -16,6 +16,7 @@
#include <linux/reboot.h>
#include <linux/delay.h>
#include <linux/kallsyms.h>
+#include <linux/cpumask.h>
#include <asm/ptrace.h>
#include <asm/string.h>
@@ -37,7 +38,7 @@
#define skipbl xmon_skipbl
#ifdef CONFIG_SMP
-volatile unsigned long cpus_in_xmon = 0;
+volatile cpumask_t cpus_in_xmon = CPU_MASK_NONE;
static unsigned long got_xmon = 0;
static volatile int take_xmon = -1;
static volatile int leaving_xmon = 0;
@@ -288,17 +289,18 @@ xmon(struct pt_regs *excp)
leaving_xmon = 0;
/* possible race condition here if a CPU is held up and gets
* here while we are exiting */
- if (test_and_set_bit(smp_processor_id(), &cpus_in_xmon)) {
+ if (cpu_test_and_set(smp_processor_id(), cpus_in_xmon)) {
/* xmon probably caused an exception itself */
printf("We are already in xmon\n");
for (;;)
- ;
+ cpu_relax();
}
while (test_and_set_bit(0, &got_xmon)) {
if (take_xmon == smp_processor_id()) {
take_xmon = -1;
break;
}
+ cpu_relax();
}
/*
* XXX: breakpoints are removed while any cpu is in xmon
@@ -325,7 +327,7 @@ xmon(struct pt_regs *excp)
leaving_xmon = 1;
if (cmd != 's')
clear_bit(0, &got_xmon);
- clear_bit(smp_processor_id(), &cpus_in_xmon);
+ cpu_clear(smp_processor_id(), cpus_in_xmon);
#endif /* CONFIG_SMP */
set_msrd(msr); /* restore interrupt enable */
}
@@ -602,6 +604,7 @@ cmds(struct pt_regs *excp)
printf(" (type ? for help)\n");
break;
}
+ cpu_relax();
}
}
@@ -638,7 +641,7 @@ static void cpu_cmd(void)
/* print cpus waiting or in xmon */
printf("cpus stopped:");
for (cpu = 0; cpu < NR_CPUS; ++cpu) {
- if (test_bit(cpu, &cpus_in_xmon)) {
+ if (cpu_isset(cpu, cpus_in_xmon)) {
printf(" %x", cpu);
if (cpu == smp_processor_id())
printf("*", cpu);
@@ -664,6 +667,7 @@ static void cpu_cmd(void)
take_xmon = -1;
break;
}
+ cpu_relax();
}
}
#endif /* CONFIG_SMP */
diff -puN drivers/char/hvc_console.c~ppc64-xmon-cpumask drivers/char/hvc_console.c
--- 25/drivers/char/hvc_console.c~ppc64-xmon-cpumask 2004-02-04 02:24:54.000000000 -0800
+++ 25-akpm/drivers/char/hvc_console.c 2004-02-04 02:24:54.000000000 -0800
@@ -29,6 +29,7 @@
#include <linux/kbd_kern.h>
#include <asm/uaccess.h>
#include <linux/spinlock.h>
+#include <linux/cpumask.h>
extern int hvc_count(int *);
extern int hvc_get_chars(int index, char *buf, int count);
@@ -223,10 +224,10 @@ static void hvc_poll(int index)
spin_unlock_irqrestore(&hp->lock, flags);
}
-#if defined (CONFIG_XMON)
-extern unsigned long cpus_in_xmon;
+#if defined(CONFIG_XMON) && defined(CONFIG_SMP)
+extern cpumask_t cpus_in_xmon;
#else
-unsigned long cpus_in_xmon=0;
+static const cpumask_t cpus_in_xmon = CPU_MASK_NONE;
#endif
@@ -237,7 +238,7 @@ int khvcd(void *unused)
daemonize("khvcd");
for (;;) {
- if (!cpus_in_xmon) {
+ if (cpus_empty(cpus_in_xmon)) {
for (i = 0; i < MAX_NR_HVC_CONSOLES; ++i)
hvc_poll(i);
}
_