The pmsr_lock spinlock used to be necessary to synchronize access to the
PMSR register, because that access could have been triggered from either
config space access in rcar_pcie_config_access() or an exception handler
rcar_pcie_aarch32_abort_handler().
The rcar_pcie_aarch32_abort_handler() case is no longer applicable since
commit 6e36203bc14c ("PCI: rcar: Use PCI_SET_ERROR_RESPONSE after read
which triggered an exception"), which performs more accurate, controlled
invocation of the exception, and a fixup.
This leaves rcar_pcie_config_access() as the only call site from which
rcar_pcie_wakeup() is called. The rcar_pcie_config_access() can only be
called from the controller struct pci_ops .read and .write callbacks,
and those are serialized in drivers/pci/access.c using raw spinlock
'pci_lock' . CONFIG_PCI_LOCKLESS_CONFIG is never set on this platform.
Since the 'pci_lock' is a raw spinlock , and the 'pmsr_lock' is not a
raw spinlock, this constellation triggers 'BUG: Invalid wait context'
with CONFIG_PROVE_RAW_LOCK_NESTING=y .
Remove the pmsr_lock to fix the locking.
Fixes: a115b1bd3af0 ("PCI: rcar: Add L1 link state fix into data abort hook")
Reported-by: Duy Nguyen <duy.nguyen.rh@xxxxxxxxxxx>
Reported-by: Thuan Nguyen <thuan.nguyen-hong@xxxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Marek Vasut <marek.vasut+renesas@xxxxxxxxxxx>
---
=============================
[ BUG: Invalid wait context ]
6.17.0-rc4-next-20250905-00048-ga08e553145e7-dirty #1116 Not tainted
-----------------------------
swapper/0/1 is trying to lock:
ffffffd92cf69c30 (pmsr_lock){....}-{3:3}, at: rcar_pcie_config_access+0x48/0x260
other info that might help us debug this:
context-{5:5}
3 locks held by swapper/0/1:
#0: ffffff84c0f890f8 (&dev->mutex){....}-{4:4}, at: device_lock+0x14/0x1c
#1: ffffffd92cf675b0 (pci_rescan_remove_lock){+.+.}-{4:4}, at: pci_lock_rescan_remove+0x18/0x20
#2: ffffffd92cf674a0 (pci_lock){....}-{2:2}, at: pci_bus_read_config_dword+0x54/0xd8
stack backtrace:
CPU: 3 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.17.0-rc4-next-20250905-00048-ga08e553145e7-dirty #1116 PREEMPT
Hardware name: Renesas Salvator-X 2nd version board based on r8a77951 (DT)
Call trace:
dump_backtrace+0x6c/0x7c (C)
show_stack+0x14/0x1c
dump_stack_lvl+0x68/0x8c
dump_stack+0x14/0x1c
__lock_acquire+0x3e8/0x1064
lock_acquire+0x17c/0x2ac
_raw_spin_lock_irqsave+0x54/0x70
rcar_pcie_config_access+0x48/0x260
rcar_pcie_read_conf+0x44/0xd8
pci_bus_read_config_dword+0x78/0xd8
pci_bus_generic_read_dev_vendor_id+0x30/0x138
pci_bus_read_dev_vendor_id+0x60/0x68
pci_scan_single_device+0x11c/0x1ec
pci_scan_slot+0x7c/0x170
pci_scan_child_bus_extend+0x5c/0x29c
pci_scan_child_bus+0x10/0x18
pci_scan_root_bus_bridge+0x90/0xc8
pci_host_probe+0x24/0xc4
rcar_pcie_probe+0x5e8/0x650
platform_probe+0x58/0x88
really_probe+0x190/0x350
__driver_probe_device+0x120/0x138
driver_probe_device+0x38/0xec
__driver_attach+0x158/0x168
bus_for_each_dev+0x7c/0xd0
driver_attach+0x20/0x28
bus_add_driver+0xe0/0x1d8
driver_register+0xac/0xe8
__platform_driver_register+0x1c/0x24
rcar_pcie_driver_init+0x18/0x20
do_one_initcall+0xd4/0x220
kernel_init_freeable+0x308/0x30c
kernel_init+0x20/0x11c
ret_from_fork+0x10/0x20
---
Cc: "Krzysztof Wilczyński" <kwilczynski@xxxxxxxxxx>
Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Cc: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
Cc: Lorenzo Pieralisi <lpieralisi@xxxxxxxxxx>
Cc: Magnus Damm <magnus.damm@xxxxxxxxx>
Cc: Manivannan Sadhasivam <mani@xxxxxxxxxx>
Cc: Marc Zyngier <maz@xxxxxxxxxx>
Cc: Rob Herring <robh@xxxxxxxxxx>
Cc: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
Cc: linux-pci@xxxxxxxxxxxxxxx
Cc: linux-renesas-soc@xxxxxxxxxxxxxxx
---
drivers/pci/controller/pcie-rcar-host.c | 13 ++-----------
1 file changed, 2 insertions(+), 11 deletions(-)
diff --git a/drivers/pci/controller/pcie-rcar-host.c b/drivers/pci/controller/pcie-rcar-host.c
index 4780e0109e583..625a00f3b2230 100644
--- a/drivers/pci/controller/pcie-rcar-host.c
+++ b/drivers/pci/controller/pcie-rcar-host.c
@@ -52,20 +52,13 @@ struct rcar_pcie_host {
int (*phy_init_fn)(struct rcar_pcie_host *host);
};
-static DEFINE_SPINLOCK(pmsr_lock);
-
static int rcar_pcie_wakeup(struct device *pcie_dev, void __iomem *pcie_base)
{
- unsigned long flags;
u32 pmsr, val;
int ret = 0;
- spin_lock_irqsave(&pmsr_lock, flags);
-
- if (!pcie_base || pm_runtime_suspended(pcie_dev)) {
- ret = -EINVAL;
- goto unlock_exit;
- }
+ if (!pcie_base || pm_runtime_suspended(pcie_dev))
+ return -EINVAL;
pmsr = readl(pcie_base + PMSR);
@@ -87,8 +80,6 @@ static int rcar_pcie_wakeup(struct device *pcie_dev, void __iomem *pcie_base)
writel(L1FAEG | PMEL1RX, pcie_base + PMSR);
}
-unlock_exit:
- spin_unlock_irqrestore(&pmsr_lock, flags);
return ret;
}
--
2.51.0
