Hi
when I tried to hot plug a cpu on IBM bladecentre JS20 system,it dropped
in to xmon. On analyzing the problem,I found out that "self-stop" token
is not exported
to the OS through rtas(Could be verified by looking in to
/proc/device-tree/rtas file).
1:mon> e
cpu 0x1: Vector: 700 (Program Check) at [c00000000ff1bab0]
pc: c00000000001b144: .rtas_stop_self+0x34/0x70
lr: c0000000000439c0: .pSeries_mach_cpu_die+0x34/0x40
sp: c00000000ff1bd30
msr: 8000000000021032
current = 0xc00000000ff050b0
paca = 0xc0000000005ec500
pid = 0, comm = swapper
kernel BUG in rtas_stop_self at arch/powerpc/kernel/rtas.c:829!
===========================================
void rtas_stop_self(void)
{
struct rtas_args *rtas_args = &rtas_stop_self_args;
local_irq_disable();
BUG_ON(rtas_args->token == RTAS_UNKNOWN_SERVICE);
===================================================
#ifdef CONFIG_HOTPLUG_CPU
rtas_stop_self_args.token = rtas_token("stop-self");
#endif /* CONFIG_HOTPLUG_CPU */
#ifdef CONFIG_RTAS_ERROR_LOGGING
rtas_last_error_token = rtas_token("rtas-last-error");
===================================================
Since we are not supported by hardware for cpu hotplug. I have developed
the patch which will disable cpu hotplug on IBM bladecentre JS20. Please
let me know your comments on this please.
Signed-off-by: Srinivasa DS <[email protected]>
Thanks
Srinivasa DS
arch/powerpc/kernel/rtas.c | 9 +++++++++
kernel/cpu.c | 4 ++--
2 files changed, 11 insertions(+), 2 deletions(-)
Index: linux-2.6.19-rc5/arch/powerpc/kernel/rtas.c
===================================================================
--- linux-2.6.19-rc5.orig/arch/powerpc/kernel/rtas.c 2006-11-08 07:54:20.000000000 +0530
+++ linux-2.6.19-rc5/arch/powerpc/kernel/rtas.c 2006-11-13 17:39:10.000000000 +0530
@@ -53,6 +53,9 @@
unsigned long rtas_rmo_buf;
+extern int cpu_hotplug_disabled;
+extern struct mutex cpu_add_remove_lock;
+
/*
* If non-NULL, this gets called when the kernel terminates.
* This is done like this so rtas_flash can be a module.
@@ -881,6 +884,12 @@
#ifdef CONFIG_HOTPLUG_CPU
rtas_stop_self_args.token = rtas_token("stop-self");
+ if(rtas_stop_self_args.token == RTAS_UNKNOWN_SERVICE) {
+ mutex_lock(&cpu_add_remove_lock);
+ cpu_hotplug_disabled = 1;
+ mutex_unlock(&cpu_add_remove_lock);
+ }
+
#endif /* CONFIG_HOTPLUG_CPU */
#ifdef CONFIG_RTAS_ERROR_LOGGING
rtas_last_error_token = rtas_token("rtas-last-error");
Index: linux-2.6.19-rc5/kernel/cpu.c
===================================================================
--- linux-2.6.19-rc5.orig/kernel/cpu.c 2006-11-08 07:54:20.000000000 +0530
+++ linux-2.6.19-rc5/kernel/cpu.c 2006-11-13 17:36:22.000000000 +0530
@@ -16,7 +16,7 @@
#include <linux/mutex.h>
/* This protects CPUs going up and down... */
-static DEFINE_MUTEX(cpu_add_remove_lock);
+DEFINE_MUTEX(cpu_add_remove_lock);
static DEFINE_MUTEX(cpu_bitmask_lock);
static __cpuinitdata RAW_NOTIFIER_HEAD(cpu_chain);
@@ -24,7 +24,7 @@
/* If set, cpu_up and cpu_down will return -EBUSY and do nothing.
* Should always be manipulated under cpu_add_remove_lock
*/
-static int cpu_hotplug_disabled;
+int cpu_hotplug_disabled;
#ifdef CONFIG_HOTPLUG_CPU
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