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Subject[tip:smp/hotplug] x86/pci/amd-bus: Convert to hotplug state machine
Commit-ID:  57b85d6eb29b289722d2c85c0ff025618c7fe700
Gitweb: http://git.kernel.org/tip/57b85d6eb29b289722d2c85c0ff025618c7fe700
Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
AuthorDate: Thu, 17 Nov 2016 19:35:41 +0100
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitDate: Mon, 21 Nov 2016 16:37:09 +0100

x86/pci/amd-bus: Convert to hotplug state machine

Install the callbacks via the state machine and let the core invoke
the callbacks on the already online CPUs.

The smp_call_function_single() is dropped because the ONLINE callback is
invoked on the target CPU since commit 1cf4f629d9d2 ("cpu/hotplug: Move
online calls to hotplugged cpu"). smp_call_function_single() invokes the
invoked function with interrupts disabled, but this calling convention is
not preserved as the MSR is not modified by anything else than this code.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: linux-pci@vger.kernel.org
Cc: rt@linuxtronix.de
Link: http://lkml.kernel.org/r/20161117183541.8588-21-bigeasy@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

---
arch/x86/pci/amd_bus.c | 34 +++++++---------------------------
1 file changed, 7 insertions(+), 27 deletions(-)

diff --git a/arch/x86/pci/amd_bus.c b/arch/x86/pci/amd_bus.c
index c20d2cc..ae387e5 100644
--- a/arch/x86/pci/amd_bus.c
+++ b/arch/x86/pci/amd_bus.c
@@ -327,35 +327,18 @@ static int __init early_root_info_init(void)

#define ENABLE_CF8_EXT_CFG (1ULL << 46)

-static void enable_pci_io_ecs(void *unused)
+static int amd_bus_cpu_online(unsigned int cpu)
{
u64 reg;
+
rdmsrl(MSR_AMD64_NB_CFG, reg);
if (!(reg & ENABLE_CF8_EXT_CFG)) {
reg |= ENABLE_CF8_EXT_CFG;
wrmsrl(MSR_AMD64_NB_CFG, reg);
}
+ return 0;
}

-static int amd_cpu_notify(struct notifier_block *self, unsigned long action,
- void *hcpu)
-{
- int cpu = (long)hcpu;
- switch (action) {
- case CPU_ONLINE:
- case CPU_ONLINE_FROZEN:
- smp_call_function_single(cpu, enable_pci_io_ecs, NULL, 0);
- break;
- default:
- break;
- }
- return NOTIFY_OK;
-}
-
-static struct notifier_block amd_cpu_notifier = {
- .notifier_call = amd_cpu_notify,
-};
-
static void __init pci_enable_pci_io_ecs(void)
{
#ifdef CONFIG_AMD_NB
@@ -385,7 +368,7 @@ static void __init pci_enable_pci_io_ecs(void)

static int __init pci_io_ecs_init(void)
{
- int cpu;
+ int ret;

/* assume all cpus from fam10h have IO ECS */
if (boot_cpu_data.x86 < 0x10)
@@ -395,12 +378,9 @@ static int __init pci_io_ecs_init(void)
if (early_pci_allowed())
pci_enable_pci_io_ecs();

- cpu_notifier_register_begin();
- for_each_online_cpu(cpu)
- amd_cpu_notify(&amd_cpu_notifier, (unsigned long)CPU_ONLINE,
- (void *)(long)cpu);
- __register_cpu_notifier(&amd_cpu_notifier);
- cpu_notifier_register_done();
+ ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "pci/amd_bus:online",
+ amd_bus_cpu_online, NULL);
+ WARN_ON(ret < 0);

pci_probe |= PCI_HAS_IO_ECS;

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