OpenCloudOS-Kernel/drivers/pci/hotplug/pciehp_ctrl.c

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/*
* PCI Express Hot Plug Controller Driver
*
* Copyright (C) 1995,2001 Compaq Computer Corporation
* Copyright (C) 2001 Greg Kroah-Hartman (greg@kroah.com)
* Copyright (C) 2001 IBM Corp.
* Copyright (C) 2003-2004 Intel Corporation
*
* All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or (at
* your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
* NON INFRINGEMENT. See the GNU General Public License for more
* details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
* Send feedback to <greg@kroah.com>, <kristen.c.accardi@intel.com>
*
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/types.h>
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 16:04:11 +08:00
#include <linux/slab.h>
#include <linux/pci.h>
#include "../pci.h"
#include "pciehp.h"
static void interrupt_event_handler(struct work_struct *work);
static int queue_interrupt_event(struct slot *p_slot, u32 event_type)
{
struct event_info *info;
info = kmalloc(sizeof(*info), GFP_ATOMIC);
if (!info)
return -ENOMEM;
info->event_type = event_type;
info->p_slot = p_slot;
INIT_WORK(&info->work, interrupt_event_handler);
PCI: pciehp: Use per-slot workqueues to avoid deadlock When we have a hotplug-capable PCIe port with a second hotplug-capable PCIe port below it, removing the device below the upstream port causes a deadlock. The deadlock happens because we use the pciehp_wq workqueue to run pciehp_power_thread(), which uses pciehp_disable_slot() to remove devices below the upstream port. When we remove the downstream PCIe port, we call pciehp_remove(), the pciehp driver's .remove() method. That calls flush_workqueue(pciehp_wq), which deadlocks because the pciehp_power_thread() work item is still running. This patch avoids the deadlock by creating a workqueue for every PCIe port and removing the single shared workqueue. Here's the call path that leads to the deadlock: pciehp_queue_pushbutton_work queue_work(pciehp_wq) # queue pciehp_power_thread ... pciehp_power_thread pciehp_disable_slot remove_board pciehp_unconfigure_device pci_stop_and_remove_bus_device ... pciehp_remove # pciehp driver .remove method pciehp_release_ctrl pcie_cleanup_slot flush_workqueue(pciehp_wq) This is fairly urgent because it can be caused by simply unplugging a Thunderbolt adapter, as reported by Daniel below. [bhelgaas: changelog] Reference: http://lkml.kernel.org/r/CAMVG2ssiRgcTD1bej2tkUUfsWmpL5eNtPcNif9va2-Gzb2u8nQ@mail.gmail.com Reported-and-tested-by: Daniel J Blueman <daniel@quora.org> Reviewed-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> Signed-off-by: Yijing Wang <wangyijing@huawei.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> CC: stable@vger.kernel.org
2013-01-11 10:15:54 +08:00
queue_work(p_slot->wq, &info->work);
return 0;
}
pciehp: fix NULL dereference in interrupt handler Fix the following NULL dereference problem reported from Pierre Ossman and Ingo Molnar. pciehp: HPC vendor_id 8086 device_id 27d0 ss_vid 0 ss_did 0 pciehp: pciehp_find_slot: slot (device=0x0) not found BUG: unable to handle kernel NULL pointer dereference at 0000000000000070 IP: [<ffffffff80494a8b>] pciehp_handle_presence_change+0x7e/0x113 PGD 0 Oops: 0000 [1] CPU 0 Modules linked in: Pid: 1, comm: swapper Tainted: G W 2.6.26-rc3-sched-devel.git-00001-g2b99b26-dirty #170 RIP: 0010:[<ffffffff80494a8b>] [<ffffffff80494a8b>] pciehp_handle_presence_change+0x7e/0x113 RSP: 0000:ffff81003f83fbb0 EFLAGS: 00010046 RAX: 0000000000000039 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000046 RBP: ffff81003f83fbd0 R08: 0000000000000001 R09: ffffffff80245103 R10: 0000000000000020 R11: 0000000000000000 R12: ffff81003ea53a30 R13: 0000000000000000 R14: 0000000000000011 R15: ffffffff80495926 FS: 0000000000000000(0000) GS:ffffffff80be7400(0000) knlGS:0000000000000000 CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b CR2: 0000000000000070 CR3: 0000000000201000 CR4: 00000000000006a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process swapper (pid: 1, threadinfo ffff81003f83e000, task ffff81003f840000) Stack: 0000000000000008 ffff81003f83fbf6 ffff81003ea53a30 0000000000000008 ffff81003f83fc10 ffffffff80495ab4 0000000000000011 0000000000000002 0000000000000202 0000000000000202 00000000fffffff4 ffff81003ea53a30 Call Trace: [<ffffffff80495ab4>] pcie_isr+0x18e/0x1bc [<ffffffff80260831>] request_irq+0x106/0x12f [<ffffffff80495fb6>] pcie_init+0x15e/0x6cc [<ffffffff804933a3>] pciehp_probe+0x64/0x541 [<ffffffff8048f4e7>] pcie_port_probe_service+0x4c/0x76 [<ffffffff8054af70>] driver_probe_device+0xd4/0x1f0 [<ffffffff8054b108>] __driver_attach+0x7c/0x7e [<ffffffff8054b08c>] ? __driver_attach+0x0/0x7e [<ffffffff8054a4b6>] bus_for_each_dev+0x53/0x7d [<ffffffff8054ad3c>] driver_attach+0x1c/0x1e [<ffffffff8054a9c2>] bus_add_driver+0xdd/0x25b [<ffffffff80c09d3d>] ? pcied_init+0x0/0x8b [<ffffffff8054b288>] driver_register+0x5f/0x13e [<ffffffff80c09d3d>] ? pcied_init+0x0/0x8b [<ffffffff8048f441>] pcie_port_service_register+0x47/0x49 [<ffffffff80c09d52>] pcied_init+0x15/0x8b [<ffffffff80bf3938>] kernel_init+0x75/0x243 [<ffffffff808639d2>] ? _spin_unlock_irq+0x2b/0x3a [<ffffffff80228d1f>] ? finish_task_switch+0x57/0x9a [<ffffffff8020c258>] child_rip+0xa/0x12 [<ffffffff8020bcec>] ? restore_args+0x0/0x30 [<ffffffff80bf38c3>] ? kernel_init+0x0/0x243 [<ffffffff8020c24e>] ? child_rip+0x0/0x12 Code: 83 80 00 00 00 48 39 f0 75 e1 0f b6 c9 48 c7 c2 00 0e 8d 80 48 c7 c6 8a 60 a6 80 48 c7 c7 10 db a8 80 31 c0 e8 3f 8d d9 ff 31 db <48> 8b 43 70 48 8d 75 ef 48 89 df ff 50 30 80 7d ef 00 74 37 48 RIP [<ffffffff80494a8b>] pciehp_handle_presence_change+0x7e/0x113 RSP <ffff81003f83fbb0> CR2: 0000000000000070 Kernel panic - not syncing: Fatal exception The situation under which it occurs is hw and timing related: it appears to happen on a system that has PCI hotplug hardware but with no active hotplug cards, and another interrupt in the same (shared) IRQ line arrives too early, before the hotplug-slot entry has been set up - as triggered by CONFIG_DEBUG_SHIRQ=y: This patch contains the following two fixes. (1) Clear all events bits in Slot Status register to prevent the pciehp driver from detecting the spurious events that would have been occur before pciehp loading. (2) Add check whether slot initialization had been already done. This is short term fix. We need more structural fixes to install interrupt handler after slot initialization is done. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2008-05-27 18:03:16 +08:00
u8 pciehp_handle_attention_button(struct slot *p_slot)
{
u32 event_type;
struct controller *ctrl = p_slot->ctrl;
/* Attention Button Change */
ctrl_dbg(ctrl, "Attention button interrupt received\n");
/*
* Button pressed - See if need to TAKE ACTION!!!
*/
ctrl_info(ctrl, "Button pressed on Slot(%s)\n", slot_name(p_slot));
event_type = INT_BUTTON_PRESS;
queue_interrupt_event(p_slot, event_type);
return 0;
}
pciehp: fix NULL dereference in interrupt handler Fix the following NULL dereference problem reported from Pierre Ossman and Ingo Molnar. pciehp: HPC vendor_id 8086 device_id 27d0 ss_vid 0 ss_did 0 pciehp: pciehp_find_slot: slot (device=0x0) not found BUG: unable to handle kernel NULL pointer dereference at 0000000000000070 IP: [<ffffffff80494a8b>] pciehp_handle_presence_change+0x7e/0x113 PGD 0 Oops: 0000 [1] CPU 0 Modules linked in: Pid: 1, comm: swapper Tainted: G W 2.6.26-rc3-sched-devel.git-00001-g2b99b26-dirty #170 RIP: 0010:[<ffffffff80494a8b>] [<ffffffff80494a8b>] pciehp_handle_presence_change+0x7e/0x113 RSP: 0000:ffff81003f83fbb0 EFLAGS: 00010046 RAX: 0000000000000039 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000046 RBP: ffff81003f83fbd0 R08: 0000000000000001 R09: ffffffff80245103 R10: 0000000000000020 R11: 0000000000000000 R12: ffff81003ea53a30 R13: 0000000000000000 R14: 0000000000000011 R15: ffffffff80495926 FS: 0000000000000000(0000) GS:ffffffff80be7400(0000) knlGS:0000000000000000 CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b CR2: 0000000000000070 CR3: 0000000000201000 CR4: 00000000000006a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process swapper (pid: 1, threadinfo ffff81003f83e000, task ffff81003f840000) Stack: 0000000000000008 ffff81003f83fbf6 ffff81003ea53a30 0000000000000008 ffff81003f83fc10 ffffffff80495ab4 0000000000000011 0000000000000002 0000000000000202 0000000000000202 00000000fffffff4 ffff81003ea53a30 Call Trace: [<ffffffff80495ab4>] pcie_isr+0x18e/0x1bc [<ffffffff80260831>] request_irq+0x106/0x12f [<ffffffff80495fb6>] pcie_init+0x15e/0x6cc [<ffffffff804933a3>] pciehp_probe+0x64/0x541 [<ffffffff8048f4e7>] pcie_port_probe_service+0x4c/0x76 [<ffffffff8054af70>] driver_probe_device+0xd4/0x1f0 [<ffffffff8054b108>] __driver_attach+0x7c/0x7e [<ffffffff8054b08c>] ? __driver_attach+0x0/0x7e [<ffffffff8054a4b6>] bus_for_each_dev+0x53/0x7d [<ffffffff8054ad3c>] driver_attach+0x1c/0x1e [<ffffffff8054a9c2>] bus_add_driver+0xdd/0x25b [<ffffffff80c09d3d>] ? pcied_init+0x0/0x8b [<ffffffff8054b288>] driver_register+0x5f/0x13e [<ffffffff80c09d3d>] ? pcied_init+0x0/0x8b [<ffffffff8048f441>] pcie_port_service_register+0x47/0x49 [<ffffffff80c09d52>] pcied_init+0x15/0x8b [<ffffffff80bf3938>] kernel_init+0x75/0x243 [<ffffffff808639d2>] ? _spin_unlock_irq+0x2b/0x3a [<ffffffff80228d1f>] ? finish_task_switch+0x57/0x9a [<ffffffff8020c258>] child_rip+0xa/0x12 [<ffffffff8020bcec>] ? restore_args+0x0/0x30 [<ffffffff80bf38c3>] ? kernel_init+0x0/0x243 [<ffffffff8020c24e>] ? child_rip+0x0/0x12 Code: 83 80 00 00 00 48 39 f0 75 e1 0f b6 c9 48 c7 c2 00 0e 8d 80 48 c7 c6 8a 60 a6 80 48 c7 c7 10 db a8 80 31 c0 e8 3f 8d d9 ff 31 db <48> 8b 43 70 48 8d 75 ef 48 89 df ff 50 30 80 7d ef 00 74 37 48 RIP [<ffffffff80494a8b>] pciehp_handle_presence_change+0x7e/0x113 RSP <ffff81003f83fbb0> CR2: 0000000000000070 Kernel panic - not syncing: Fatal exception The situation under which it occurs is hw and timing related: it appears to happen on a system that has PCI hotplug hardware but with no active hotplug cards, and another interrupt in the same (shared) IRQ line arrives too early, before the hotplug-slot entry has been set up - as triggered by CONFIG_DEBUG_SHIRQ=y: This patch contains the following two fixes. (1) Clear all events bits in Slot Status register to prevent the pciehp driver from detecting the spurious events that would have been occur before pciehp loading. (2) Add check whether slot initialization had been already done. This is short term fix. We need more structural fixes to install interrupt handler after slot initialization is done. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2008-05-27 18:03:16 +08:00
u8 pciehp_handle_switch_change(struct slot *p_slot)
{
u8 getstatus;
u32 event_type;
struct controller *ctrl = p_slot->ctrl;
/* Switch Change */
ctrl_dbg(ctrl, "Switch interrupt received\n");
pciehp_get_latch_status(p_slot, &getstatus);
if (getstatus) {
/*
* Switch opened
*/
ctrl_info(ctrl, "Latch open on Slot(%s)\n", slot_name(p_slot));
event_type = INT_SWITCH_OPEN;
} else {
/*
* Switch closed
*/
ctrl_info(ctrl, "Latch close on Slot(%s)\n", slot_name(p_slot));
event_type = INT_SWITCH_CLOSE;
}
queue_interrupt_event(p_slot, event_type);
return 1;
}
pciehp: fix NULL dereference in interrupt handler Fix the following NULL dereference problem reported from Pierre Ossman and Ingo Molnar. pciehp: HPC vendor_id 8086 device_id 27d0 ss_vid 0 ss_did 0 pciehp: pciehp_find_slot: slot (device=0x0) not found BUG: unable to handle kernel NULL pointer dereference at 0000000000000070 IP: [<ffffffff80494a8b>] pciehp_handle_presence_change+0x7e/0x113 PGD 0 Oops: 0000 [1] CPU 0 Modules linked in: Pid: 1, comm: swapper Tainted: G W 2.6.26-rc3-sched-devel.git-00001-g2b99b26-dirty #170 RIP: 0010:[<ffffffff80494a8b>] [<ffffffff80494a8b>] pciehp_handle_presence_change+0x7e/0x113 RSP: 0000:ffff81003f83fbb0 EFLAGS: 00010046 RAX: 0000000000000039 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000046 RBP: ffff81003f83fbd0 R08: 0000000000000001 R09: ffffffff80245103 R10: 0000000000000020 R11: 0000000000000000 R12: ffff81003ea53a30 R13: 0000000000000000 R14: 0000000000000011 R15: ffffffff80495926 FS: 0000000000000000(0000) GS:ffffffff80be7400(0000) knlGS:0000000000000000 CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b CR2: 0000000000000070 CR3: 0000000000201000 CR4: 00000000000006a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process swapper (pid: 1, threadinfo ffff81003f83e000, task ffff81003f840000) Stack: 0000000000000008 ffff81003f83fbf6 ffff81003ea53a30 0000000000000008 ffff81003f83fc10 ffffffff80495ab4 0000000000000011 0000000000000002 0000000000000202 0000000000000202 00000000fffffff4 ffff81003ea53a30 Call Trace: [<ffffffff80495ab4>] pcie_isr+0x18e/0x1bc [<ffffffff80260831>] request_irq+0x106/0x12f [<ffffffff80495fb6>] pcie_init+0x15e/0x6cc [<ffffffff804933a3>] pciehp_probe+0x64/0x541 [<ffffffff8048f4e7>] pcie_port_probe_service+0x4c/0x76 [<ffffffff8054af70>] driver_probe_device+0xd4/0x1f0 [<ffffffff8054b108>] __driver_attach+0x7c/0x7e [<ffffffff8054b08c>] ? __driver_attach+0x0/0x7e [<ffffffff8054a4b6>] bus_for_each_dev+0x53/0x7d [<ffffffff8054ad3c>] driver_attach+0x1c/0x1e [<ffffffff8054a9c2>] bus_add_driver+0xdd/0x25b [<ffffffff80c09d3d>] ? pcied_init+0x0/0x8b [<ffffffff8054b288>] driver_register+0x5f/0x13e [<ffffffff80c09d3d>] ? pcied_init+0x0/0x8b [<ffffffff8048f441>] pcie_port_service_register+0x47/0x49 [<ffffffff80c09d52>] pcied_init+0x15/0x8b [<ffffffff80bf3938>] kernel_init+0x75/0x243 [<ffffffff808639d2>] ? _spin_unlock_irq+0x2b/0x3a [<ffffffff80228d1f>] ? finish_task_switch+0x57/0x9a [<ffffffff8020c258>] child_rip+0xa/0x12 [<ffffffff8020bcec>] ? restore_args+0x0/0x30 [<ffffffff80bf38c3>] ? kernel_init+0x0/0x243 [<ffffffff8020c24e>] ? child_rip+0x0/0x12 Code: 83 80 00 00 00 48 39 f0 75 e1 0f b6 c9 48 c7 c2 00 0e 8d 80 48 c7 c6 8a 60 a6 80 48 c7 c7 10 db a8 80 31 c0 e8 3f 8d d9 ff 31 db <48> 8b 43 70 48 8d 75 ef 48 89 df ff 50 30 80 7d ef 00 74 37 48 RIP [<ffffffff80494a8b>] pciehp_handle_presence_change+0x7e/0x113 RSP <ffff81003f83fbb0> CR2: 0000000000000070 Kernel panic - not syncing: Fatal exception The situation under which it occurs is hw and timing related: it appears to happen on a system that has PCI hotplug hardware but with no active hotplug cards, and another interrupt in the same (shared) IRQ line arrives too early, before the hotplug-slot entry has been set up - as triggered by CONFIG_DEBUG_SHIRQ=y: This patch contains the following two fixes. (1) Clear all events bits in Slot Status register to prevent the pciehp driver from detecting the spurious events that would have been occur before pciehp loading. (2) Add check whether slot initialization had been already done. This is short term fix. We need more structural fixes to install interrupt handler after slot initialization is done. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2008-05-27 18:03:16 +08:00
u8 pciehp_handle_presence_change(struct slot *p_slot)
{
u32 event_type;
u8 presence_save;
struct controller *ctrl = p_slot->ctrl;
/* Presence Change */
ctrl_dbg(ctrl, "Presence/Notify input change\n");
/* Switch is open, assume a presence change
* Save the presence state
*/
pciehp_get_adapter_status(p_slot, &presence_save);
if (presence_save) {
/*
* Card Present
*/
ctrl_info(ctrl, "Card present on Slot(%s)\n", slot_name(p_slot));
event_type = INT_PRESENCE_ON;
} else {
/*
* Not Present
*/
ctrl_info(ctrl, "Card not present on Slot(%s)\n",
slot_name(p_slot));
event_type = INT_PRESENCE_OFF;
}
queue_interrupt_event(p_slot, event_type);
return 1;
}
pciehp: fix NULL dereference in interrupt handler Fix the following NULL dereference problem reported from Pierre Ossman and Ingo Molnar. pciehp: HPC vendor_id 8086 device_id 27d0 ss_vid 0 ss_did 0 pciehp: pciehp_find_slot: slot (device=0x0) not found BUG: unable to handle kernel NULL pointer dereference at 0000000000000070 IP: [<ffffffff80494a8b>] pciehp_handle_presence_change+0x7e/0x113 PGD 0 Oops: 0000 [1] CPU 0 Modules linked in: Pid: 1, comm: swapper Tainted: G W 2.6.26-rc3-sched-devel.git-00001-g2b99b26-dirty #170 RIP: 0010:[<ffffffff80494a8b>] [<ffffffff80494a8b>] pciehp_handle_presence_change+0x7e/0x113 RSP: 0000:ffff81003f83fbb0 EFLAGS: 00010046 RAX: 0000000000000039 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000046 RBP: ffff81003f83fbd0 R08: 0000000000000001 R09: ffffffff80245103 R10: 0000000000000020 R11: 0000000000000000 R12: ffff81003ea53a30 R13: 0000000000000000 R14: 0000000000000011 R15: ffffffff80495926 FS: 0000000000000000(0000) GS:ffffffff80be7400(0000) knlGS:0000000000000000 CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b CR2: 0000000000000070 CR3: 0000000000201000 CR4: 00000000000006a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process swapper (pid: 1, threadinfo ffff81003f83e000, task ffff81003f840000) Stack: 0000000000000008 ffff81003f83fbf6 ffff81003ea53a30 0000000000000008 ffff81003f83fc10 ffffffff80495ab4 0000000000000011 0000000000000002 0000000000000202 0000000000000202 00000000fffffff4 ffff81003ea53a30 Call Trace: [<ffffffff80495ab4>] pcie_isr+0x18e/0x1bc [<ffffffff80260831>] request_irq+0x106/0x12f [<ffffffff80495fb6>] pcie_init+0x15e/0x6cc [<ffffffff804933a3>] pciehp_probe+0x64/0x541 [<ffffffff8048f4e7>] pcie_port_probe_service+0x4c/0x76 [<ffffffff8054af70>] driver_probe_device+0xd4/0x1f0 [<ffffffff8054b108>] __driver_attach+0x7c/0x7e [<ffffffff8054b08c>] ? __driver_attach+0x0/0x7e [<ffffffff8054a4b6>] bus_for_each_dev+0x53/0x7d [<ffffffff8054ad3c>] driver_attach+0x1c/0x1e [<ffffffff8054a9c2>] bus_add_driver+0xdd/0x25b [<ffffffff80c09d3d>] ? pcied_init+0x0/0x8b [<ffffffff8054b288>] driver_register+0x5f/0x13e [<ffffffff80c09d3d>] ? pcied_init+0x0/0x8b [<ffffffff8048f441>] pcie_port_service_register+0x47/0x49 [<ffffffff80c09d52>] pcied_init+0x15/0x8b [<ffffffff80bf3938>] kernel_init+0x75/0x243 [<ffffffff808639d2>] ? _spin_unlock_irq+0x2b/0x3a [<ffffffff80228d1f>] ? finish_task_switch+0x57/0x9a [<ffffffff8020c258>] child_rip+0xa/0x12 [<ffffffff8020bcec>] ? restore_args+0x0/0x30 [<ffffffff80bf38c3>] ? kernel_init+0x0/0x243 [<ffffffff8020c24e>] ? child_rip+0x0/0x12 Code: 83 80 00 00 00 48 39 f0 75 e1 0f b6 c9 48 c7 c2 00 0e 8d 80 48 c7 c6 8a 60 a6 80 48 c7 c7 10 db a8 80 31 c0 e8 3f 8d d9 ff 31 db <48> 8b 43 70 48 8d 75 ef 48 89 df ff 50 30 80 7d ef 00 74 37 48 RIP [<ffffffff80494a8b>] pciehp_handle_presence_change+0x7e/0x113 RSP <ffff81003f83fbb0> CR2: 0000000000000070 Kernel panic - not syncing: Fatal exception The situation under which it occurs is hw and timing related: it appears to happen on a system that has PCI hotplug hardware but with no active hotplug cards, and another interrupt in the same (shared) IRQ line arrives too early, before the hotplug-slot entry has been set up - as triggered by CONFIG_DEBUG_SHIRQ=y: This patch contains the following two fixes. (1) Clear all events bits in Slot Status register to prevent the pciehp driver from detecting the spurious events that would have been occur before pciehp loading. (2) Add check whether slot initialization had been already done. This is short term fix. We need more structural fixes to install interrupt handler after slot initialization is done. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2008-05-27 18:03:16 +08:00
u8 pciehp_handle_power_fault(struct slot *p_slot)
{
u32 event_type;
struct controller *ctrl = p_slot->ctrl;
/* power fault */
ctrl_dbg(ctrl, "Power fault interrupt received\n");
ctrl_err(ctrl, "Power fault on slot %s\n", slot_name(p_slot));
event_type = INT_POWER_FAULT;
ctrl_info(ctrl, "Power fault bit %x set\n", 0);
queue_interrupt_event(p_slot, event_type);
return 1;
}
void pciehp_handle_linkstate_change(struct slot *p_slot)
{
u32 event_type;
struct controller *ctrl = p_slot->ctrl;
/* Link Status Change */
ctrl_dbg(ctrl, "Data Link Layer State change\n");
if (pciehp_check_link_active(ctrl)) {
ctrl_info(ctrl, "slot(%s): Link Up event\n",
slot_name(p_slot));
event_type = INT_LINK_UP;
} else {
ctrl_info(ctrl, "slot(%s): Link Down event\n",
slot_name(p_slot));
event_type = INT_LINK_DOWN;
}
queue_interrupt_event(p_slot, event_type);
}
/* The following routines constitute the bulk of the
hotplug controller logic
*/
static void set_slot_off(struct controller *ctrl, struct slot * pslot)
{
/* turn off slot, turn on Amber LED, turn off Green LED if supported*/
if (POWER_CTRL(ctrl)) {
pciehp_power_off_slot(pslot);
/*
* After turning power off, we must wait for at least 1 second
* before taking any action that relies on power having been
* removed from the slot/adapter.
*/
msleep(1000);
}
pciehp_green_led_off(pslot);
pciehp_set_attention_status(pslot, 1);
}
/**
* board_added - Called after a board has been added to the system.
* @p_slot: &slot where board is added
*
* Turns power on for the board.
* Configures board.
*/
static int board_added(struct slot *p_slot)
{
int retval = 0;
struct controller *ctrl = p_slot->ctrl;
struct pci_bus *parent = ctrl->pcie->port->subordinate;
if (POWER_CTRL(ctrl)) {
/* Power on slot */
retval = pciehp_power_on_slot(p_slot);
if (retval)
return retval;
}
pciehp_green_led_blink(p_slot);
/* Check link training status */
retval = pciehp_check_link_status(ctrl);
if (retval) {
ctrl_err(ctrl, "Failed to check link status\n");
goto err_exit;
}
/* Check for a power fault */
if (ctrl->power_fault_detected || pciehp_query_power_fault(p_slot)) {
ctrl_err(ctrl, "Power fault on slot %s\n", slot_name(p_slot));
retval = -EIO;
goto err_exit;
}
retval = pciehp_configure_device(p_slot);
if (retval) {
ctrl_err(ctrl, "Cannot add device at %04x:%02x:00\n",
pci_domain_nr(parent), parent->number);
if (retval != -EEXIST)
goto err_exit;
}
pciehp_green_led_on(p_slot);
return 0;
err_exit:
set_slot_off(ctrl, p_slot);
return retval;
}
/**
* remove_board - Turns off slot and LEDs
* @p_slot: slot where board is being removed
*/
static int remove_board(struct slot *p_slot)
{
int retval;
struct controller *ctrl = p_slot->ctrl;
retval = pciehp_unconfigure_device(p_slot);
if (retval)
return retval;
if (POWER_CTRL(ctrl)) {
pciehp_power_off_slot(p_slot);
/*
* After turning power off, we must wait for at least 1 second
* before taking any action that relies on power having been
* removed from the slot/adapter.
*/
msleep(1000);
}
/* turn off Green LED */
pciehp_green_led_off(p_slot);
return 0;
}
struct power_work_info {
struct slot *p_slot;
struct work_struct work;
PCI: pciehp: Ensure very fast hotplug events are also processed Today, this is how all the hotplug and unplug events work: Hotplug / Removal needs to be done => Set slot->state (protected by slot->lock) to either POWERON_STATE (for enabling) or POWEROFF_STATE (for disabling). => Submit the work item for pciehp_power_thread() to slot->wq. Problem: There is a problem if the hotplug events can happen fast enough that they do not give SW enough time to add or remove the new devices. => Assume: Event for unplug comes (e.g. surprise removal). But before the pciehp_power_thread() work item was executed, the card was replaced by another card, causing surprise hotplug event. => What goes wrong: => The hot-removal event sets slot->state to POWEROFF_STATE, and schedules the pciehp_power_thread(). => The hot-add event sets slot->state to POWERON_STATE, and schedules the pciehp_power_thread(). => Now the pciehp_power_thread() is scheduled twice, and on both occasions it will find POWERON_STATE and will try to add the devices on the slot, and will fail complaining that the devices already exist. => Why this is a problem: If the device was replaced between the hot removal and hot-add, then we should unload the old driver and reload the new one. This does not happen today. The kernel or the driver is not even aware that the device was replaced. The problem is that the pciehp_power_thread() only looks at the slot->state which would only contain the *latest* state - not the actual event (add / remove) that was the intent of the IRQ handler who submitted the work. What this patch does: => Hotplug events pass on an actual request (for addition or removal) to pciehp_power_thread() which is local to that work item submission. => pciehp_power_thread() does not need to look at slote->state and hence no locks needed in that. => Essentially this results in all the hotplug and unplug events "replayed" by pciehp_power_thread(). Signed-off-by: Rajat Jain <rajatxjain@gmail.com> Signed-off-by: Rajat Jain <rajatjain@juniper.net> Signed-off-by: Guenter Roeck <groeck@juniper.net> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2014-02-05 10:30:56 +08:00
unsigned int req;
#define DISABLE_REQ 0
#define ENABLE_REQ 1
};
/**
* pciehp_power_thread - handle pushbutton events
* @work: &struct work_struct describing work to be done
*
* Scheduled procedure to handle blocking stuff for the pushbuttons.
* Handles all pending events and exits.
*/
static void pciehp_power_thread(struct work_struct *work)
{
struct power_work_info *info =
container_of(work, struct power_work_info, work);
struct slot *p_slot = info->p_slot;
int ret;
PCI: pciehp: Ensure very fast hotplug events are also processed Today, this is how all the hotplug and unplug events work: Hotplug / Removal needs to be done => Set slot->state (protected by slot->lock) to either POWERON_STATE (for enabling) or POWEROFF_STATE (for disabling). => Submit the work item for pciehp_power_thread() to slot->wq. Problem: There is a problem if the hotplug events can happen fast enough that they do not give SW enough time to add or remove the new devices. => Assume: Event for unplug comes (e.g. surprise removal). But before the pciehp_power_thread() work item was executed, the card was replaced by another card, causing surprise hotplug event. => What goes wrong: => The hot-removal event sets slot->state to POWEROFF_STATE, and schedules the pciehp_power_thread(). => The hot-add event sets slot->state to POWERON_STATE, and schedules the pciehp_power_thread(). => Now the pciehp_power_thread() is scheduled twice, and on both occasions it will find POWERON_STATE and will try to add the devices on the slot, and will fail complaining that the devices already exist. => Why this is a problem: If the device was replaced between the hot removal and hot-add, then we should unload the old driver and reload the new one. This does not happen today. The kernel or the driver is not even aware that the device was replaced. The problem is that the pciehp_power_thread() only looks at the slot->state which would only contain the *latest* state - not the actual event (add / remove) that was the intent of the IRQ handler who submitted the work. What this patch does: => Hotplug events pass on an actual request (for addition or removal) to pciehp_power_thread() which is local to that work item submission. => pciehp_power_thread() does not need to look at slote->state and hence no locks needed in that. => Essentially this results in all the hotplug and unplug events "replayed" by pciehp_power_thread(). Signed-off-by: Rajat Jain <rajatxjain@gmail.com> Signed-off-by: Rajat Jain <rajatjain@juniper.net> Signed-off-by: Guenter Roeck <groeck@juniper.net> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2014-02-05 10:30:56 +08:00
switch (info->req) {
case DISABLE_REQ:
ctrl_dbg(p_slot->ctrl,
"Disabling domain:bus:device=%04x:%02x:00\n",
pci_domain_nr(p_slot->ctrl->pcie->port->subordinate),
p_slot->ctrl->pcie->port->subordinate->number);
mutex_lock(&p_slot->hotplug_lock);
pciehp_disable_slot(p_slot);
mutex_unlock(&p_slot->hotplug_lock);
mutex_lock(&p_slot->lock);
p_slot->state = STATIC_STATE;
mutex_unlock(&p_slot->lock);
PCI: pciehp: Ensure very fast hotplug events are also processed Today, this is how all the hotplug and unplug events work: Hotplug / Removal needs to be done => Set slot->state (protected by slot->lock) to either POWERON_STATE (for enabling) or POWEROFF_STATE (for disabling). => Submit the work item for pciehp_power_thread() to slot->wq. Problem: There is a problem if the hotplug events can happen fast enough that they do not give SW enough time to add or remove the new devices. => Assume: Event for unplug comes (e.g. surprise removal). But before the pciehp_power_thread() work item was executed, the card was replaced by another card, causing surprise hotplug event. => What goes wrong: => The hot-removal event sets slot->state to POWEROFF_STATE, and schedules the pciehp_power_thread(). => The hot-add event sets slot->state to POWERON_STATE, and schedules the pciehp_power_thread(). => Now the pciehp_power_thread() is scheduled twice, and on both occasions it will find POWERON_STATE and will try to add the devices on the slot, and will fail complaining that the devices already exist. => Why this is a problem: If the device was replaced between the hot removal and hot-add, then we should unload the old driver and reload the new one. This does not happen today. The kernel or the driver is not even aware that the device was replaced. The problem is that the pciehp_power_thread() only looks at the slot->state which would only contain the *latest* state - not the actual event (add / remove) that was the intent of the IRQ handler who submitted the work. What this patch does: => Hotplug events pass on an actual request (for addition or removal) to pciehp_power_thread() which is local to that work item submission. => pciehp_power_thread() does not need to look at slote->state and hence no locks needed in that. => Essentially this results in all the hotplug and unplug events "replayed" by pciehp_power_thread(). Signed-off-by: Rajat Jain <rajatxjain@gmail.com> Signed-off-by: Rajat Jain <rajatjain@juniper.net> Signed-off-by: Guenter Roeck <groeck@juniper.net> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2014-02-05 10:30:56 +08:00
break;
case ENABLE_REQ:
ctrl_dbg(p_slot->ctrl,
"Enabling domain:bus:device=%04x:%02x:00\n",
pci_domain_nr(p_slot->ctrl->pcie->port->subordinate),
p_slot->ctrl->pcie->port->subordinate->number);
mutex_lock(&p_slot->hotplug_lock);
ret = pciehp_enable_slot(p_slot);
mutex_unlock(&p_slot->hotplug_lock);
if (ret)
pciehp_green_led_off(p_slot);
mutex_lock(&p_slot->lock);
p_slot->state = STATIC_STATE;
PCI: pciehp: Ensure very fast hotplug events are also processed Today, this is how all the hotplug and unplug events work: Hotplug / Removal needs to be done => Set slot->state (protected by slot->lock) to either POWERON_STATE (for enabling) or POWEROFF_STATE (for disabling). => Submit the work item for pciehp_power_thread() to slot->wq. Problem: There is a problem if the hotplug events can happen fast enough that they do not give SW enough time to add or remove the new devices. => Assume: Event for unplug comes (e.g. surprise removal). But before the pciehp_power_thread() work item was executed, the card was replaced by another card, causing surprise hotplug event. => What goes wrong: => The hot-removal event sets slot->state to POWEROFF_STATE, and schedules the pciehp_power_thread(). => The hot-add event sets slot->state to POWERON_STATE, and schedules the pciehp_power_thread(). => Now the pciehp_power_thread() is scheduled twice, and on both occasions it will find POWERON_STATE and will try to add the devices on the slot, and will fail complaining that the devices already exist. => Why this is a problem: If the device was replaced between the hot removal and hot-add, then we should unload the old driver and reload the new one. This does not happen today. The kernel or the driver is not even aware that the device was replaced. The problem is that the pciehp_power_thread() only looks at the slot->state which would only contain the *latest* state - not the actual event (add / remove) that was the intent of the IRQ handler who submitted the work. What this patch does: => Hotplug events pass on an actual request (for addition or removal) to pciehp_power_thread() which is local to that work item submission. => pciehp_power_thread() does not need to look at slote->state and hence no locks needed in that. => Essentially this results in all the hotplug and unplug events "replayed" by pciehp_power_thread(). Signed-off-by: Rajat Jain <rajatxjain@gmail.com> Signed-off-by: Rajat Jain <rajatjain@juniper.net> Signed-off-by: Guenter Roeck <groeck@juniper.net> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2014-02-05 10:30:56 +08:00
mutex_unlock(&p_slot->lock);
break;
default:
break;
}
kfree(info);
}
void pciehp_queue_pushbutton_work(struct work_struct *work)
{
struct slot *p_slot = container_of(work, struct slot, work.work);
struct power_work_info *info;
info = kmalloc(sizeof(*info), GFP_KERNEL);
if (!info) {
ctrl_err(p_slot->ctrl, "%s: Cannot allocate memory\n",
__func__);
return;
}
info->p_slot = p_slot;
INIT_WORK(&info->work, pciehp_power_thread);
mutex_lock(&p_slot->lock);
switch (p_slot->state) {
case BLINKINGOFF_STATE:
p_slot->state = POWEROFF_STATE;
PCI: pciehp: Ensure very fast hotplug events are also processed Today, this is how all the hotplug and unplug events work: Hotplug / Removal needs to be done => Set slot->state (protected by slot->lock) to either POWERON_STATE (for enabling) or POWEROFF_STATE (for disabling). => Submit the work item for pciehp_power_thread() to slot->wq. Problem: There is a problem if the hotplug events can happen fast enough that they do not give SW enough time to add or remove the new devices. => Assume: Event for unplug comes (e.g. surprise removal). But before the pciehp_power_thread() work item was executed, the card was replaced by another card, causing surprise hotplug event. => What goes wrong: => The hot-removal event sets slot->state to POWEROFF_STATE, and schedules the pciehp_power_thread(). => The hot-add event sets slot->state to POWERON_STATE, and schedules the pciehp_power_thread(). => Now the pciehp_power_thread() is scheduled twice, and on both occasions it will find POWERON_STATE and will try to add the devices on the slot, and will fail complaining that the devices already exist. => Why this is a problem: If the device was replaced between the hot removal and hot-add, then we should unload the old driver and reload the new one. This does not happen today. The kernel or the driver is not even aware that the device was replaced. The problem is that the pciehp_power_thread() only looks at the slot->state which would only contain the *latest* state - not the actual event (add / remove) that was the intent of the IRQ handler who submitted the work. What this patch does: => Hotplug events pass on an actual request (for addition or removal) to pciehp_power_thread() which is local to that work item submission. => pciehp_power_thread() does not need to look at slote->state and hence no locks needed in that. => Essentially this results in all the hotplug and unplug events "replayed" by pciehp_power_thread(). Signed-off-by: Rajat Jain <rajatxjain@gmail.com> Signed-off-by: Rajat Jain <rajatjain@juniper.net> Signed-off-by: Guenter Roeck <groeck@juniper.net> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2014-02-05 10:30:56 +08:00
info->req = DISABLE_REQ;
break;
case BLINKINGON_STATE:
p_slot->state = POWERON_STATE;
PCI: pciehp: Ensure very fast hotplug events are also processed Today, this is how all the hotplug and unplug events work: Hotplug / Removal needs to be done => Set slot->state (protected by slot->lock) to either POWERON_STATE (for enabling) or POWEROFF_STATE (for disabling). => Submit the work item for pciehp_power_thread() to slot->wq. Problem: There is a problem if the hotplug events can happen fast enough that they do not give SW enough time to add or remove the new devices. => Assume: Event for unplug comes (e.g. surprise removal). But before the pciehp_power_thread() work item was executed, the card was replaced by another card, causing surprise hotplug event. => What goes wrong: => The hot-removal event sets slot->state to POWEROFF_STATE, and schedules the pciehp_power_thread(). => The hot-add event sets slot->state to POWERON_STATE, and schedules the pciehp_power_thread(). => Now the pciehp_power_thread() is scheduled twice, and on both occasions it will find POWERON_STATE and will try to add the devices on the slot, and will fail complaining that the devices already exist. => Why this is a problem: If the device was replaced between the hot removal and hot-add, then we should unload the old driver and reload the new one. This does not happen today. The kernel or the driver is not even aware that the device was replaced. The problem is that the pciehp_power_thread() only looks at the slot->state which would only contain the *latest* state - not the actual event (add / remove) that was the intent of the IRQ handler who submitted the work. What this patch does: => Hotplug events pass on an actual request (for addition or removal) to pciehp_power_thread() which is local to that work item submission. => pciehp_power_thread() does not need to look at slote->state and hence no locks needed in that. => Essentially this results in all the hotplug and unplug events "replayed" by pciehp_power_thread(). Signed-off-by: Rajat Jain <rajatxjain@gmail.com> Signed-off-by: Rajat Jain <rajatjain@juniper.net> Signed-off-by: Guenter Roeck <groeck@juniper.net> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2014-02-05 10:30:56 +08:00
info->req = ENABLE_REQ;
break;
default:
kfree(info);
goto out;
}
PCI: pciehp: Use per-slot workqueues to avoid deadlock When we have a hotplug-capable PCIe port with a second hotplug-capable PCIe port below it, removing the device below the upstream port causes a deadlock. The deadlock happens because we use the pciehp_wq workqueue to run pciehp_power_thread(), which uses pciehp_disable_slot() to remove devices below the upstream port. When we remove the downstream PCIe port, we call pciehp_remove(), the pciehp driver's .remove() method. That calls flush_workqueue(pciehp_wq), which deadlocks because the pciehp_power_thread() work item is still running. This patch avoids the deadlock by creating a workqueue for every PCIe port and removing the single shared workqueue. Here's the call path that leads to the deadlock: pciehp_queue_pushbutton_work queue_work(pciehp_wq) # queue pciehp_power_thread ... pciehp_power_thread pciehp_disable_slot remove_board pciehp_unconfigure_device pci_stop_and_remove_bus_device ... pciehp_remove # pciehp driver .remove method pciehp_release_ctrl pcie_cleanup_slot flush_workqueue(pciehp_wq) This is fairly urgent because it can be caused by simply unplugging a Thunderbolt adapter, as reported by Daniel below. [bhelgaas: changelog] Reference: http://lkml.kernel.org/r/CAMVG2ssiRgcTD1bej2tkUUfsWmpL5eNtPcNif9va2-Gzb2u8nQ@mail.gmail.com Reported-and-tested-by: Daniel J Blueman <daniel@quora.org> Reviewed-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> Signed-off-by: Yijing Wang <wangyijing@huawei.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> CC: stable@vger.kernel.org
2013-01-11 10:15:54 +08:00
queue_work(p_slot->wq, &info->work);
out:
mutex_unlock(&p_slot->lock);
}
/*
* Note: This function must be called with slot->lock held
*/
static void handle_button_press_event(struct slot *p_slot)
{
struct controller *ctrl = p_slot->ctrl;
u8 getstatus;
switch (p_slot->state) {
case STATIC_STATE:
pciehp_get_power_status(p_slot, &getstatus);
if (getstatus) {
p_slot->state = BLINKINGOFF_STATE;
ctrl_info(ctrl,
"PCI slot #%s - powering off due to button "
"press.\n", slot_name(p_slot));
} else {
p_slot->state = BLINKINGON_STATE;
ctrl_info(ctrl,
"PCI slot #%s - powering on due to button "
"press.\n", slot_name(p_slot));
}
/* blink green LED and turn off amber */
pciehp_green_led_blink(p_slot);
pciehp_set_attention_status(p_slot, 0);
PCI: pciehp: Use per-slot workqueues to avoid deadlock When we have a hotplug-capable PCIe port with a second hotplug-capable PCIe port below it, removing the device below the upstream port causes a deadlock. The deadlock happens because we use the pciehp_wq workqueue to run pciehp_power_thread(), which uses pciehp_disable_slot() to remove devices below the upstream port. When we remove the downstream PCIe port, we call pciehp_remove(), the pciehp driver's .remove() method. That calls flush_workqueue(pciehp_wq), which deadlocks because the pciehp_power_thread() work item is still running. This patch avoids the deadlock by creating a workqueue for every PCIe port and removing the single shared workqueue. Here's the call path that leads to the deadlock: pciehp_queue_pushbutton_work queue_work(pciehp_wq) # queue pciehp_power_thread ... pciehp_power_thread pciehp_disable_slot remove_board pciehp_unconfigure_device pci_stop_and_remove_bus_device ... pciehp_remove # pciehp driver .remove method pciehp_release_ctrl pcie_cleanup_slot flush_workqueue(pciehp_wq) This is fairly urgent because it can be caused by simply unplugging a Thunderbolt adapter, as reported by Daniel below. [bhelgaas: changelog] Reference: http://lkml.kernel.org/r/CAMVG2ssiRgcTD1bej2tkUUfsWmpL5eNtPcNif9va2-Gzb2u8nQ@mail.gmail.com Reported-and-tested-by: Daniel J Blueman <daniel@quora.org> Reviewed-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> Signed-off-by: Yijing Wang <wangyijing@huawei.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> CC: stable@vger.kernel.org
2013-01-11 10:15:54 +08:00
queue_delayed_work(p_slot->wq, &p_slot->work, 5*HZ);
break;
case BLINKINGOFF_STATE:
case BLINKINGON_STATE:
/*
* Cancel if we are still blinking; this means that we
* press the attention again before the 5 sec. limit
* expires to cancel hot-add or hot-remove
*/
ctrl_info(ctrl, "Button cancel on Slot(%s)\n", slot_name(p_slot));
cancel_delayed_work(&p_slot->work);
if (p_slot->state == BLINKINGOFF_STATE)
pciehp_green_led_on(p_slot);
else
pciehp_green_led_off(p_slot);
pciehp_set_attention_status(p_slot, 0);
ctrl_info(ctrl, "PCI slot #%s - action canceled "
"due to button press\n", slot_name(p_slot));
p_slot->state = STATIC_STATE;
break;
case POWEROFF_STATE:
case POWERON_STATE:
/*
* Ignore if the slot is on power-on or power-off state;
* this means that the previous attention button action
* to hot-add or hot-remove is undergoing
*/
ctrl_info(ctrl, "Button ignore on Slot(%s)\n", slot_name(p_slot));
break;
default:
ctrl_warn(ctrl, "Not a valid state\n");
break;
}
}
/*
* Note: This function must be called with slot->lock held
*/
static void handle_surprise_event(struct slot *p_slot)
{
u8 getstatus;
struct power_work_info *info;
info = kmalloc(sizeof(*info), GFP_KERNEL);
if (!info) {
ctrl_err(p_slot->ctrl, "%s: Cannot allocate memory\n",
__func__);
return;
}
info->p_slot = p_slot;
INIT_WORK(&info->work, pciehp_power_thread);
pciehp_get_adapter_status(p_slot, &getstatus);
PCI: pciehp: Ensure very fast hotplug events are also processed Today, this is how all the hotplug and unplug events work: Hotplug / Removal needs to be done => Set slot->state (protected by slot->lock) to either POWERON_STATE (for enabling) or POWEROFF_STATE (for disabling). => Submit the work item for pciehp_power_thread() to slot->wq. Problem: There is a problem if the hotplug events can happen fast enough that they do not give SW enough time to add or remove the new devices. => Assume: Event for unplug comes (e.g. surprise removal). But before the pciehp_power_thread() work item was executed, the card was replaced by another card, causing surprise hotplug event. => What goes wrong: => The hot-removal event sets slot->state to POWEROFF_STATE, and schedules the pciehp_power_thread(). => The hot-add event sets slot->state to POWERON_STATE, and schedules the pciehp_power_thread(). => Now the pciehp_power_thread() is scheduled twice, and on both occasions it will find POWERON_STATE and will try to add the devices on the slot, and will fail complaining that the devices already exist. => Why this is a problem: If the device was replaced between the hot removal and hot-add, then we should unload the old driver and reload the new one. This does not happen today. The kernel or the driver is not even aware that the device was replaced. The problem is that the pciehp_power_thread() only looks at the slot->state which would only contain the *latest* state - not the actual event (add / remove) that was the intent of the IRQ handler who submitted the work. What this patch does: => Hotplug events pass on an actual request (for addition or removal) to pciehp_power_thread() which is local to that work item submission. => pciehp_power_thread() does not need to look at slote->state and hence no locks needed in that. => Essentially this results in all the hotplug and unplug events "replayed" by pciehp_power_thread(). Signed-off-by: Rajat Jain <rajatxjain@gmail.com> Signed-off-by: Rajat Jain <rajatjain@juniper.net> Signed-off-by: Guenter Roeck <groeck@juniper.net> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2014-02-05 10:30:56 +08:00
if (!getstatus) {
p_slot->state = POWEROFF_STATE;
PCI: pciehp: Ensure very fast hotplug events are also processed Today, this is how all the hotplug and unplug events work: Hotplug / Removal needs to be done => Set slot->state (protected by slot->lock) to either POWERON_STATE (for enabling) or POWEROFF_STATE (for disabling). => Submit the work item for pciehp_power_thread() to slot->wq. Problem: There is a problem if the hotplug events can happen fast enough that they do not give SW enough time to add or remove the new devices. => Assume: Event for unplug comes (e.g. surprise removal). But before the pciehp_power_thread() work item was executed, the card was replaced by another card, causing surprise hotplug event. => What goes wrong: => The hot-removal event sets slot->state to POWEROFF_STATE, and schedules the pciehp_power_thread(). => The hot-add event sets slot->state to POWERON_STATE, and schedules the pciehp_power_thread(). => Now the pciehp_power_thread() is scheduled twice, and on both occasions it will find POWERON_STATE and will try to add the devices on the slot, and will fail complaining that the devices already exist. => Why this is a problem: If the device was replaced between the hot removal and hot-add, then we should unload the old driver and reload the new one. This does not happen today. The kernel or the driver is not even aware that the device was replaced. The problem is that the pciehp_power_thread() only looks at the slot->state which would only contain the *latest* state - not the actual event (add / remove) that was the intent of the IRQ handler who submitted the work. What this patch does: => Hotplug events pass on an actual request (for addition or removal) to pciehp_power_thread() which is local to that work item submission. => pciehp_power_thread() does not need to look at slote->state and hence no locks needed in that. => Essentially this results in all the hotplug and unplug events "replayed" by pciehp_power_thread(). Signed-off-by: Rajat Jain <rajatxjain@gmail.com> Signed-off-by: Rajat Jain <rajatjain@juniper.net> Signed-off-by: Guenter Roeck <groeck@juniper.net> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2014-02-05 10:30:56 +08:00
info->req = DISABLE_REQ;
} else {
p_slot->state = POWERON_STATE;
PCI: pciehp: Ensure very fast hotplug events are also processed Today, this is how all the hotplug and unplug events work: Hotplug / Removal needs to be done => Set slot->state (protected by slot->lock) to either POWERON_STATE (for enabling) or POWEROFF_STATE (for disabling). => Submit the work item for pciehp_power_thread() to slot->wq. Problem: There is a problem if the hotplug events can happen fast enough that they do not give SW enough time to add or remove the new devices. => Assume: Event for unplug comes (e.g. surprise removal). But before the pciehp_power_thread() work item was executed, the card was replaced by another card, causing surprise hotplug event. => What goes wrong: => The hot-removal event sets slot->state to POWEROFF_STATE, and schedules the pciehp_power_thread(). => The hot-add event sets slot->state to POWERON_STATE, and schedules the pciehp_power_thread(). => Now the pciehp_power_thread() is scheduled twice, and on both occasions it will find POWERON_STATE and will try to add the devices on the slot, and will fail complaining that the devices already exist. => Why this is a problem: If the device was replaced between the hot removal and hot-add, then we should unload the old driver and reload the new one. This does not happen today. The kernel or the driver is not even aware that the device was replaced. The problem is that the pciehp_power_thread() only looks at the slot->state which would only contain the *latest* state - not the actual event (add / remove) that was the intent of the IRQ handler who submitted the work. What this patch does: => Hotplug events pass on an actual request (for addition or removal) to pciehp_power_thread() which is local to that work item submission. => pciehp_power_thread() does not need to look at slote->state and hence no locks needed in that. => Essentially this results in all the hotplug and unplug events "replayed" by pciehp_power_thread(). Signed-off-by: Rajat Jain <rajatxjain@gmail.com> Signed-off-by: Rajat Jain <rajatjain@juniper.net> Signed-off-by: Guenter Roeck <groeck@juniper.net> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2014-02-05 10:30:56 +08:00
info->req = ENABLE_REQ;
}
PCI: pciehp: Use per-slot workqueues to avoid deadlock When we have a hotplug-capable PCIe port with a second hotplug-capable PCIe port below it, removing the device below the upstream port causes a deadlock. The deadlock happens because we use the pciehp_wq workqueue to run pciehp_power_thread(), which uses pciehp_disable_slot() to remove devices below the upstream port. When we remove the downstream PCIe port, we call pciehp_remove(), the pciehp driver's .remove() method. That calls flush_workqueue(pciehp_wq), which deadlocks because the pciehp_power_thread() work item is still running. This patch avoids the deadlock by creating a workqueue for every PCIe port and removing the single shared workqueue. Here's the call path that leads to the deadlock: pciehp_queue_pushbutton_work queue_work(pciehp_wq) # queue pciehp_power_thread ... pciehp_power_thread pciehp_disable_slot remove_board pciehp_unconfigure_device pci_stop_and_remove_bus_device ... pciehp_remove # pciehp driver .remove method pciehp_release_ctrl pcie_cleanup_slot flush_workqueue(pciehp_wq) This is fairly urgent because it can be caused by simply unplugging a Thunderbolt adapter, as reported by Daniel below. [bhelgaas: changelog] Reference: http://lkml.kernel.org/r/CAMVG2ssiRgcTD1bej2tkUUfsWmpL5eNtPcNif9va2-Gzb2u8nQ@mail.gmail.com Reported-and-tested-by: Daniel J Blueman <daniel@quora.org> Reviewed-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> Signed-off-by: Yijing Wang <wangyijing@huawei.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> CC: stable@vger.kernel.org
2013-01-11 10:15:54 +08:00
queue_work(p_slot->wq, &info->work);
}
/*
* Note: This function must be called with slot->lock held
*/
static void handle_link_event(struct slot *p_slot, u32 event)
{
struct controller *ctrl = p_slot->ctrl;
struct power_work_info *info;
info = kmalloc(sizeof(*info), GFP_KERNEL);
if (!info) {
ctrl_err(p_slot->ctrl, "%s: Cannot allocate memory\n",
__func__);
return;
}
info->p_slot = p_slot;
PCI: pciehp: Ensure very fast hotplug events are also processed Today, this is how all the hotplug and unplug events work: Hotplug / Removal needs to be done => Set slot->state (protected by slot->lock) to either POWERON_STATE (for enabling) or POWEROFF_STATE (for disabling). => Submit the work item for pciehp_power_thread() to slot->wq. Problem: There is a problem if the hotplug events can happen fast enough that they do not give SW enough time to add or remove the new devices. => Assume: Event for unplug comes (e.g. surprise removal). But before the pciehp_power_thread() work item was executed, the card was replaced by another card, causing surprise hotplug event. => What goes wrong: => The hot-removal event sets slot->state to POWEROFF_STATE, and schedules the pciehp_power_thread(). => The hot-add event sets slot->state to POWERON_STATE, and schedules the pciehp_power_thread(). => Now the pciehp_power_thread() is scheduled twice, and on both occasions it will find POWERON_STATE and will try to add the devices on the slot, and will fail complaining that the devices already exist. => Why this is a problem: If the device was replaced between the hot removal and hot-add, then we should unload the old driver and reload the new one. This does not happen today. The kernel or the driver is not even aware that the device was replaced. The problem is that the pciehp_power_thread() only looks at the slot->state which would only contain the *latest* state - not the actual event (add / remove) that was the intent of the IRQ handler who submitted the work. What this patch does: => Hotplug events pass on an actual request (for addition or removal) to pciehp_power_thread() which is local to that work item submission. => pciehp_power_thread() does not need to look at slote->state and hence no locks needed in that. => Essentially this results in all the hotplug and unplug events "replayed" by pciehp_power_thread(). Signed-off-by: Rajat Jain <rajatxjain@gmail.com> Signed-off-by: Rajat Jain <rajatjain@juniper.net> Signed-off-by: Guenter Roeck <groeck@juniper.net> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2014-02-05 10:30:56 +08:00
info->req = event == INT_LINK_UP ? ENABLE_REQ : DISABLE_REQ;
INIT_WORK(&info->work, pciehp_power_thread);
switch (p_slot->state) {
case BLINKINGON_STATE:
case BLINKINGOFF_STATE:
cancel_delayed_work(&p_slot->work);
/* Fall through */
case STATIC_STATE:
p_slot->state = event == INT_LINK_UP ?
POWERON_STATE : POWEROFF_STATE;
queue_work(p_slot->wq, &info->work);
break;
case POWERON_STATE:
if (event == INT_LINK_UP) {
ctrl_info(ctrl,
"Link Up event ignored on slot(%s): already powering on\n",
slot_name(p_slot));
kfree(info);
} else {
ctrl_info(ctrl,
"Link Down event queued on slot(%s): currently getting powered on\n",
slot_name(p_slot));
p_slot->state = POWEROFF_STATE;
queue_work(p_slot->wq, &info->work);
}
break;
case POWEROFF_STATE:
if (event == INT_LINK_UP) {
ctrl_info(ctrl,
"Link Up event queued on slot(%s): currently getting powered off\n",
slot_name(p_slot));
p_slot->state = POWERON_STATE;
queue_work(p_slot->wq, &info->work);
} else {
ctrl_info(ctrl,
"Link Down event ignored on slot(%s): already powering off\n",
slot_name(p_slot));
kfree(info);
}
break;
default:
ctrl_err(ctrl, "Not a valid state on slot(%s)\n",
slot_name(p_slot));
kfree(info);
break;
}
}
static void interrupt_event_handler(struct work_struct *work)
{
struct event_info *info = container_of(work, struct event_info, work);
struct slot *p_slot = info->p_slot;
struct controller *ctrl = p_slot->ctrl;
mutex_lock(&p_slot->lock);
switch (info->event_type) {
case INT_BUTTON_PRESS:
handle_button_press_event(p_slot);
break;
case INT_POWER_FAULT:
if (!POWER_CTRL(ctrl))
break;
pciehp_set_attention_status(p_slot, 1);
pciehp_green_led_off(p_slot);
break;
case INT_PRESENCE_ON:
if (!HP_SUPR_RM(ctrl))
break;
ctrl_dbg(ctrl, "Surprise Insertion\n");
handle_surprise_event(p_slot);
break;
case INT_PRESENCE_OFF:
/*
* Regardless of surprise capability, we need to
* definitely remove a card that has been pulled out!
*/
ctrl_dbg(ctrl, "Surprise Removal\n");
handle_surprise_event(p_slot);
break;
case INT_LINK_UP:
case INT_LINK_DOWN:
handle_link_event(p_slot, info->event_type);
break;
default:
break;
}
mutex_unlock(&p_slot->lock);
kfree(info);
}
/*
* Note: This function must be called with slot->hotplug_lock held
*/
int pciehp_enable_slot(struct slot *p_slot)
{
u8 getstatus = 0;
int rc;
struct controller *ctrl = p_slot->ctrl;
pciehp_get_adapter_status(p_slot, &getstatus);
if (!getstatus) {
ctrl_info(ctrl, "No adapter on slot(%s)\n", slot_name(p_slot));
return -ENODEV;
}
if (MRL_SENS(p_slot->ctrl)) {
pciehp_get_latch_status(p_slot, &getstatus);
if (getstatus) {
ctrl_info(ctrl, "Latch open on slot(%s)\n",
slot_name(p_slot));
return -ENODEV;
}
}
if (POWER_CTRL(p_slot->ctrl)) {
pciehp_get_power_status(p_slot, &getstatus);
if (getstatus) {
ctrl_info(ctrl, "Already enabled on slot(%s)\n",
slot_name(p_slot));
return -EINVAL;
}
}
pciehp_get_latch_status(p_slot, &getstatus);
rc = board_added(p_slot);
if (rc)
pciehp_get_latch_status(p_slot, &getstatus);
return rc;
}
/*
* Note: This function must be called with slot->hotplug_lock held
*/
int pciehp_disable_slot(struct slot *p_slot)
{
u8 getstatus = 0;
struct controller *ctrl = p_slot->ctrl;
if (!p_slot->ctrl)
return 1;
if (POWER_CTRL(p_slot->ctrl)) {
pciehp_get_power_status(p_slot, &getstatus);
if (!getstatus) {
ctrl_info(ctrl, "Already disabled on slot(%s)\n",
slot_name(p_slot));
return -EINVAL;
}
}
return remove_board(p_slot);
}
int pciehp_sysfs_enable_slot(struct slot *p_slot)
{
int retval = -ENODEV;
struct controller *ctrl = p_slot->ctrl;
mutex_lock(&p_slot->lock);
switch (p_slot->state) {
case BLINKINGON_STATE:
cancel_delayed_work(&p_slot->work);
case STATIC_STATE:
p_slot->state = POWERON_STATE;
mutex_unlock(&p_slot->lock);
mutex_lock(&p_slot->hotplug_lock);
retval = pciehp_enable_slot(p_slot);
mutex_unlock(&p_slot->hotplug_lock);
mutex_lock(&p_slot->lock);
p_slot->state = STATIC_STATE;
break;
case POWERON_STATE:
ctrl_info(ctrl, "Slot %s is already in powering on state\n",
slot_name(p_slot));
break;
case BLINKINGOFF_STATE:
case POWEROFF_STATE:
ctrl_info(ctrl, "Already enabled on slot %s\n",
slot_name(p_slot));
break;
default:
ctrl_err(ctrl, "Not a valid state on slot %s\n",
slot_name(p_slot));
break;
}
mutex_unlock(&p_slot->lock);
return retval;
}
int pciehp_sysfs_disable_slot(struct slot *p_slot)
{
int retval = -ENODEV;
struct controller *ctrl = p_slot->ctrl;
mutex_lock(&p_slot->lock);
switch (p_slot->state) {
case BLINKINGOFF_STATE:
cancel_delayed_work(&p_slot->work);
case STATIC_STATE:
p_slot->state = POWEROFF_STATE;
mutex_unlock(&p_slot->lock);
retval = pciehp_disable_slot(p_slot);
mutex_lock(&p_slot->lock);
p_slot->state = STATIC_STATE;
break;
case POWEROFF_STATE:
ctrl_info(ctrl, "Slot %s is already in powering off state\n",
slot_name(p_slot));
break;
case BLINKINGON_STATE:
case POWERON_STATE:
ctrl_info(ctrl, "Already disabled on slot %s\n",
slot_name(p_slot));
break;
default:
ctrl_err(ctrl, "Not a valid state on slot %s\n",
slot_name(p_slot));
break;
}
mutex_unlock(&p_slot->lock);
return retval;
}