From: Greg Kurz <gkurz@linux.vnet.ibm.com>
To: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Michael Roth <mdroth@linux.vnet.ibm.com>,
linux-kernel@vger.kernel.org, Paul Mackerras <paulus@samba.org>,
qemu-ppc@nongnu.org, linuxppc-dev@lists.ozlabs.org,
David Gibson <david@gibson.dropbear.id.au>
Subject: [PATCH] powerpc/pseries: start rtasd before PCI probing
Date: Mon, 23 May 2016 10:28:28 +0200 [thread overview]
Message-ID: <146399210850.26372.5857516772891352049.stgit@bahia.huguette.org> (raw)
A strange behaviour is observed when comparing PCI hotplug in QEMU, between
x86 and pseries. If you consider the following steps:
- start a VM
- add a PCI device via the QEMU monitor before the rtasd has started (for
example starting the VM in paused state, or hotplug during FW or boot
loader)
- resume the VM execution
The x86 kernel detects the PCI device, but the pseries one does not.
This happens because the rtasd kernel worker is currently started under
device_initcall, while PCI probing happens earlier under subsys_initcall.
As a consequence, if we have a pending RTAS event at boot time, a message
is printed and the event is dropped.
This patch moves all the initialization of rtasd to arch_initcall, which is
run before subsys_call: this way, logging_enabled is true when the RTAS
event pops up and it is not lost anymore.
The proc fs bits stay at device_initcall because they cannot be run before
fs_initcall.
Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
---
arch/powerpc/kernel/rtasd.c | 19 ++++++++++++++-----
1 file changed, 14 insertions(+), 5 deletions(-)
diff --git a/arch/powerpc/kernel/rtasd.c b/arch/powerpc/kernel/rtasd.c
index e864b7c5884e..ad9e4e1a2d5d 100644
--- a/arch/powerpc/kernel/rtasd.c
+++ b/arch/powerpc/kernel/rtasd.c
@@ -526,10 +526,8 @@ void rtas_cancel_event_scan(void)
}
EXPORT_SYMBOL_GPL(rtas_cancel_event_scan);
-static int __init rtas_init(void)
+static int __init rtas_event_scan_init(void)
{
- struct proc_dir_entry *entry;
-
if (!machine_is(pseries) && !machine_is(chrp))
return 0;
@@ -562,13 +560,24 @@ static int __init rtas_init(void)
return -ENOMEM;
}
+ start_event_scan();
+
+ return 0;
+}
+arch_initcall(rtas_event_scan_init);
+
+static int __init rtas_init(void)
+{
+ struct proc_dir_entry *entry;
+
+ if (!machine_is(pseries) && !machine_is(chrp))
+ return 0;
+
entry = proc_create("powerpc/rtas/error_log", S_IRUSR, NULL,
&proc_rtas_log_operations);
if (!entry)
printk(KERN_ERR "Failed to create error_log proc entry\n");
- start_event_scan();
-
return 0;
}
__initcall(rtas_init);
next reply other threads:[~2016-05-23 8:28 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-23 8:28 Greg Kurz [this message]
2016-05-23 18:23 ` powerpc/pseries: start rtasd before PCI probing Thomas Huth
2016-05-23 18:39 ` Greg Kurz
2016-05-30 7:37 ` [Qemu-ppc] [PATCH] " Greg Kurz
2016-06-10 5:18 ` Michael Ellerman
2016-06-10 6:41 ` Greg Kurz
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