From c9f11c30374329a0d2a88cf05281ca49d8eca9ab Mon Sep 17 00:00:00 2001 From: Jia Hongtao Date: Fri, 3 Aug 2012 18:14:09 +0800 Subject: powerpc/fsl-pci: Only scan PCI bus if configured as a host We change fsl_add_bridge to return -ENODEV if the controller is working in agent mode. Then check the return value of fsl_add_bridge to guarantee that only successfully added host bus will be scanned. Signed-off-by: Jia Hongtao Signed-off-by: Li Yang Signed-off-by: Kumar Gala --- arch/powerpc/sysdev/fsl_pci.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) (limited to 'arch/powerpc/sysdev') diff --git a/arch/powerpc/sysdev/fsl_pci.c b/arch/powerpc/sysdev/fsl_pci.c index a7b2a600d0a4..c37f46136321 100644 --- a/arch/powerpc/sysdev/fsl_pci.c +++ b/arch/powerpc/sysdev/fsl_pci.c @@ -465,7 +465,7 @@ int __init fsl_add_bridge(struct device_node *dev, int is_primary) iounmap(hose->cfg_data); iounmap(hose->cfg_addr); pcibios_free_controller(hose); - return 0; + return -ENODEV; } setup_pci_cmd(hose); @@ -827,6 +827,7 @@ struct device_node *fsl_pci_primary; void __devinit fsl_pci_init(void) { + int ret; struct device_node *node; struct pci_controller *hose; dma_addr_t max = 0xffffffff; @@ -855,10 +856,12 @@ void __devinit fsl_pci_init(void) if (!fsl_pci_primary) fsl_pci_primary = node; - fsl_add_bridge(node, fsl_pci_primary == node); - hose = pci_find_hose_for_OF_device(node); - max = min(max, hose->dma_window_base_cur + - hose->dma_window_size); + ret = fsl_add_bridge(node, fsl_pci_primary == node); + if (ret == 0) { + hose = pci_find_hose_for_OF_device(node); + max = min(max, hose->dma_window_base_cur + + hose->dma_window_size); + } } } -- cgit v1.2.3 From 46c5c59e6902855b61a31be1b8e26bfffcae1e07 Mon Sep 17 00:00:00 2001 From: Scott Wood Date: Wed, 22 Aug 2012 15:35:47 +0000 Subject: powerpc/mpic_msgr: Add missing includes Add several #includes that mpic_msgr relies on being pulled implicitly, which only happens on certain configs. Signed-off-by: Scott Wood Cc: Meador Inge Cc: Jia Hongtao Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/include/asm/mpic_msgr.h | 1 + arch/powerpc/sysdev/mpic_msgr.c | 3 +++ 2 files changed, 4 insertions(+) (limited to 'arch/powerpc/sysdev') diff --git a/arch/powerpc/include/asm/mpic_msgr.h b/arch/powerpc/include/asm/mpic_msgr.h index 326d33ca55cd..d4f471fb1031 100644 --- a/arch/powerpc/include/asm/mpic_msgr.h +++ b/arch/powerpc/include/asm/mpic_msgr.h @@ -14,6 +14,7 @@ #include #include #include +#include struct mpic_msgr { u32 __iomem *base; diff --git a/arch/powerpc/sysdev/mpic_msgr.c b/arch/powerpc/sysdev/mpic_msgr.c index 483d8fa72e8b..e961f8c4a8f0 100644 --- a/arch/powerpc/sysdev/mpic_msgr.c +++ b/arch/powerpc/sysdev/mpic_msgr.c @@ -14,6 +14,9 @@ #include #include #include +#include +#include +#include #include #include #include -- cgit v1.2.3 From 9fb1b36ca1234e64a5d1cc573175303395e3354d Mon Sep 17 00:00:00 2001 From: Paul Mackerras Date: Tue, 4 Sep 2012 18:33:08 +0000 Subject: powerpc: Make sure IPI handlers see data written by IPI senders We have been observing hangs, both of KVM guest vcpu tasks and more generally, where a process that is woken doesn't properly wake up and continue to run, but instead sticks in TASK_WAKING state. This happens because the update of rq->wake_list in ttwu_queue_remote() is not ordered with the update of ipi_message in smp_muxed_ipi_message_pass(), and the reading of rq->wake_list in scheduler_ipi() is not ordered with the reading of ipi_message in smp_ipi_demux(). Thus it is possible for the IPI receiver not to see the updated rq->wake_list and therefore conclude that there is nothing for it to do. In order to make sure that anything done before smp_send_reschedule() is ordered before anything done in the resulting call to scheduler_ipi(), this adds barriers in smp_muxed_message_pass() and smp_ipi_demux(). The barrier in smp_muxed_message_pass() is a full barrier to ensure that there is a full ordering between the smp_send_reschedule() caller and scheduler_ipi(). In smp_ipi_demux(), we use xchg() rather than xchg_local() because xchg() includes release and acquire barriers. Using xchg() rather than xchg_local() makes sense given that ipi_message is not just accessed locally. This moves the barrier between setting the message and calling the cause_ipi() function into the individual cause_ipi implementations. Most of them -- those that used outb, out_8 or similar -- already had a full barrier because out_8 etc. include a sync before the MMIO store. This adds an explicit barrier in the two remaining cases. These changes made no measurable difference to the speed of IPIs as measured using a simple ping-pong latency test across two CPUs on different cores of a POWER7 machine. The analysis of the reason why processes were not waking up properly is due to Milton Miller. Cc: stable@vger.kernel.org # v3.0+ Reported-by: Milton Miller Signed-off-by: Paul Mackerras Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/kernel/dbell.c | 2 ++ arch/powerpc/kernel/smp.c | 11 +++++++++-- arch/powerpc/sysdev/xics/icp-hv.c | 6 +++++- 3 files changed, 16 insertions(+), 3 deletions(-) (limited to 'arch/powerpc/sysdev') diff --git a/arch/powerpc/kernel/dbell.c b/arch/powerpc/kernel/dbell.c index 5b25c8060fd6..a892680668d8 100644 --- a/arch/powerpc/kernel/dbell.c +++ b/arch/powerpc/kernel/dbell.c @@ -28,6 +28,8 @@ void doorbell_setup_this_cpu(void) void doorbell_cause_ipi(int cpu, unsigned long data) { + /* Order previous accesses vs. msgsnd, which is treated as a store */ + mb(); ppc_msgsnd(PPC_DBELL, 0, data); } diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c index 0321007086f7..8d4214afc21d 100644 --- a/arch/powerpc/kernel/smp.c +++ b/arch/powerpc/kernel/smp.c @@ -198,8 +198,15 @@ void smp_muxed_ipi_message_pass(int cpu, int msg) struct cpu_messages *info = &per_cpu(ipi_message, cpu); char *message = (char *)&info->messages; + /* + * Order previous accesses before accesses in the IPI handler. + */ + smp_mb(); message[msg] = 1; - mb(); + /* + * cause_ipi functions are required to include a full barrier + * before doing whatever causes the IPI. + */ smp_ops->cause_ipi(cpu, info->data); } @@ -211,7 +218,7 @@ irqreturn_t smp_ipi_demux(void) mb(); /* order any irq clear */ do { - all = xchg_local(&info->messages, 0); + all = xchg(&info->messages, 0); #ifdef __BIG_ENDIAN if (all & (1 << (24 - 8 * PPC_MSG_CALL_FUNCTION))) diff --git a/arch/powerpc/sysdev/xics/icp-hv.c b/arch/powerpc/sysdev/xics/icp-hv.c index 14469cf9df68..df0fc5821469 100644 --- a/arch/powerpc/sysdev/xics/icp-hv.c +++ b/arch/powerpc/sysdev/xics/icp-hv.c @@ -65,7 +65,11 @@ static inline void icp_hv_set_xirr(unsigned int value) static inline void icp_hv_set_qirr(int n_cpu , u8 value) { int hw_cpu = get_hard_smp_processor_id(n_cpu); - long rc = plpar_hcall_norets(H_IPI, hw_cpu, value); + long rc; + + /* Make sure all previous accesses are ordered before IPI sending */ + mb(); + rc = plpar_hcall_norets(H_IPI, hw_cpu, value); if (rc != H_SUCCESS) { pr_err("%s: bad return code qirr cpu=%d hw_cpu=%d mfrr=0x%x " "returned %ld\n", __func__, n_cpu, hw_cpu, value, rc); -- cgit v1.2.3