FAILED: patch "[PATCH] PCI: rcar-host: Drop PMSR spinlock" failed to apply to 5.15-stable tree
The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x 0a8f173d9dad13930d5888505dc4c4fd6a1d4262 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2025101648-abruptly-poncho-afdd@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 0a8f173d9dad13930d5888505dc4c4fd6a1d4262 Mon Sep 17 00:00:00 2001 From: Marek Vasut marek.vasut+renesas@mailbox.org Date: Tue, 9 Sep 2025 18:26:24 +0200 Subject: [PATCH] PCI: rcar-host: Drop PMSR spinlock
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The rcar_pcie_aarch32_abort_handler() case is no longer applicable since commit 6e36203bc14c ("PCI: rcar: Use PCI_SET_ERROR_RESPONSE after read which triggered an exception"), which performs more accurate, controlled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' . It should be noted that 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@renesas.com Reported-by: Thuan Nguyen thuan.nguyen-hong@banvien.com.vn Signed-off-by: Marek Vasut marek.vasut+renesas@mailbox.org Signed-off-by: Manivannan Sadhasivam mani@kernel.org Reviewed-by: Geert Uytterhoeven geert+renesas@glider.be Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20250909162707.13927-1-marek.vasut+renesas@mailbox....
diff --git a/drivers/pci/controller/pcie-rcar-host.c b/drivers/pci/controller/pcie-rcar-host.c index 4780e0109e58..625a00f3b223 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; }
From: Marek Vasut marek.vasut+renesas@gmail.com
[ Upstream commit 84b576146294c2be702cfcd174eaa74167e276f9 ]
In case the controller is transitioning to L1 in rcar_pcie_config_access(), any read/write access to PCIECDR triggers asynchronous external abort. This is because the transition to L1 link state must be manually finished by the driver. The PCIe IP can transition back from L1 state to L0 on its own.
Avoid triggering the abort in rcar_pcie_config_access() by checking whether the controller is in the transition state, and if so, finish the transition right away. This prevents a lot of unnecessary exceptions, although not all of them.
Link: https://lore.kernel.org/r/20220312212349.781799-1-marek.vasut@gmail.com Tested-by: Geert Uytterhoeven geert+renesas@glider.be Signed-off-by: Marek Vasut marek.vasut+renesas@gmail.com Signed-off-by: Lorenzo Pieralisi lorenzo.pieralisi@arm.com Reviewed-by: Geert Uytterhoeven geert+renesas@glider.be Cc: Arnd Bergmann arnd@arndb.de Cc: Bjorn Helgaas bhelgaas@google.com Cc: Geert Uytterhoeven geert+renesas@glider.be Cc: Krzysztof Wilczyński kw@linux.com Cc: Lorenzo Pieralisi lorenzo.pieralisi@arm.com Cc: Wolfram Sang wsa@the-dreams.de Cc: Yoshihiro Shimoda yoshihiro.shimoda.uh@renesas.com Cc: linux-renesas-soc@vger.kernel.org Stable-dep-of: 0a8f173d9dad ("PCI: rcar-host: Drop PMSR spinlock") Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/pci/controller/pcie-rcar-host.c | 76 +++++++++++++++---------- 1 file changed, 45 insertions(+), 31 deletions(-)
diff --git a/drivers/pci/controller/pcie-rcar-host.c b/drivers/pci/controller/pcie-rcar-host.c index bfb13f358d073..afcfc4218a52c 100644 --- a/drivers/pci/controller/pcie-rcar-host.c +++ b/drivers/pci/controller/pcie-rcar-host.c @@ -67,6 +67,42 @@ 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; + } + + pmsr = readl(pcie_base + PMSR); + + /* + * Test if the PCIe controller received PM_ENTER_L1 DLLP and + * the PCIe controller is not in L1 link state. If true, apply + * fix, which will put the controller into L1 link state, from + * which it can return to L0s/L0 on its own. + */ + if ((pmsr & PMEL1RX) && ((pmsr & PMSTATE) != PMSTATE_L1)) { + writel(L1IATN, pcie_base + PMCTLR); + ret = readl_poll_timeout_atomic(pcie_base + PMSR, val, + val & L1FAEG, 10, 1000); + WARN(ret, "Timeout waiting for L1 link state, ret=%d\n", ret); + writel(L1FAEG | PMEL1RX, pcie_base + PMSR); + } + +unlock_exit: + spin_unlock_irqrestore(&pmsr_lock, flags); + return ret; +} + static struct rcar_pcie_host *msi_to_host(struct rcar_msi *msi) { return container_of(msi, struct rcar_pcie_host, msi); @@ -87,6 +123,14 @@ static int rcar_pcie_config_access(struct rcar_pcie_host *host, { struct rcar_pcie *pcie = &host->pcie; unsigned int dev, func, reg, index; + int ret; + + /* Wake the bus up in case it is in L1 state. */ + ret = rcar_pcie_wakeup(pcie->dev, pcie->base); + if (ret) { + PCI_SET_ERROR_RESPONSE(data); + return PCIBIOS_SET_FAILED; + }
dev = PCI_SLOT(devfn); func = PCI_FUNC(devfn); @@ -1054,40 +1098,10 @@ static struct platform_driver rcar_pcie_driver = { };
#ifdef CONFIG_ARM -static DEFINE_SPINLOCK(pmsr_lock); static int rcar_pcie_aarch32_abort_handler(unsigned long addr, unsigned int fsr, struct pt_regs *regs) { - unsigned long flags; - u32 pmsr, val; - int ret = 0; - - spin_lock_irqsave(&pmsr_lock, flags); - - if (!pcie_base || pm_runtime_suspended(pcie_dev)) { - ret = 1; - goto unlock_exit; - } - - pmsr = readl(pcie_base + PMSR); - - /* - * Test if the PCIe controller received PM_ENTER_L1 DLLP and - * the PCIe controller is not in L1 link state. If true, apply - * fix, which will put the controller into L1 link state, from - * which it can return to L0s/L0 on its own. - */ - if ((pmsr & PMEL1RX) && ((pmsr & PMSTATE) != PMSTATE_L1)) { - writel(L1IATN, pcie_base + PMCTLR); - ret = readl_poll_timeout_atomic(pcie_base + PMSR, val, - val & L1FAEG, 10, 1000); - WARN(ret, "Timeout waiting for L1 link state, ret=%d\n", ret); - writel(L1FAEG | PMEL1RX, pcie_base + PMSR); - } - -unlock_exit: - spin_unlock_irqrestore(&pmsr_lock, flags); - return ret; + return !!rcar_pcie_wakeup(pcie_dev, pcie_base); }
static const struct of_device_id rcar_pcie_abort_handler_of_match[] __initconst = {
From: Marek Vasut marek.vasut+renesas@mailbox.org
[ Upstream commit 0a8f173d9dad13930d5888505dc4c4fd6a1d4262 ]
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' . It should be noted that 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@renesas.com Reported-by: Thuan Nguyen thuan.nguyen-hong@banvien.com.vn Signed-off-by: Marek Vasut marek.vasut+renesas@mailbox.org Signed-off-by: Manivannan Sadhasivam mani@kernel.org Reviewed-by: Geert Uytterhoeven geert+renesas@glider.be Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20250909162707.13927-1-marek.vasut+renesas@mailbox.... Signed-off-by: Sasha Levin sashal@kernel.org --- 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 afcfc4218a52c..a25e76ef7213b 100644 --- a/drivers/pci/controller/pcie-rcar-host.c +++ b/drivers/pci/controller/pcie-rcar-host.c @@ -67,20 +67,13 @@ 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);
@@ -98,8 +91,6 @@ 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; }
linux-stable-mirror@lists.linaro.org
-
gregkh＠linuxfoundation.org -
Sasha Levin