FAILED: patch "[PATCH] PCI: rcar-host: Drop PMSR spinlock" failed to apply to 5.15-stable tree

FAILED: patch "[PATCH] PCI: rcar-host: Drop PMSR spinlock" failed to apply to 5.15-stable tree

[gregkh]

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The rcar_pcie_aarch32_abort_handler() case is no longer applicable since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.org

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;
 }
 

[PATCH 5.15.y 1/2] PCI: rcar: Finish transition to L1 state in rcar_pcie_config_access()

[Sasha Levin]

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 = {
-- 
2.51.0

[PATCH 5.15.y 2/2] PCI: rcar-host: Drop PMSR spinlock

[Sasha Levin]

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.org
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;
 }
 
-- 
2.51.0