* [PATCH] PCI: uniphier: Serialize INTx masking/unmasking
@ 2021-08-23 11:18 Kunihiko Hayashi
2021-08-23 15:09 ` Pali Rohár
0 siblings, 1 reply; 6+ messages in thread
From: Kunihiko Hayashi @ 2021-08-23 11:18 UTC (permalink / raw)
To: Lorenzo Pieralisi, Rob Herring, Krzysztof Wilczyński, Bjorn Helgaas
Cc: Pali Rohár, Masami Hiramatsu, linux-pci, linux-arm-kernel,
linux-kernel, Kunihiko Hayashi
The condition register PCI_RCV_INTX is used in irq_mask(), irq_unmask()
and irq_ack() callbacks. Accesses to register can occur at the same time
without a lock.
Add a lock into each callback to prevent the issue.
Fixes: 7e6d5cd88a6f ("PCI: uniphier: Add UniPhier PCIe host controller support")
Suggested-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
---
drivers/pci/controller/dwc/pcie-uniphier.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)
The previous patch is as follows:
https://lore.kernel.org/linux-pci/1629370566-29984-1-git-send-email-hayashi.kunihiko@socionext.com/
Changes in the previous patch:
- Change the subject and commit message
diff --git a/drivers/pci/controller/dwc/pcie-uniphier.c b/drivers/pci/controller/dwc/pcie-uniphier.c
index ebe43e9..5075714 100644
--- a/drivers/pci/controller/dwc/pcie-uniphier.c
+++ b/drivers/pci/controller/dwc/pcie-uniphier.c
@@ -186,12 +186,17 @@ static void uniphier_pcie_irq_ack(struct irq_data *d)
struct pcie_port *pp = irq_data_get_irq_chip_data(d);
struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
struct uniphier_pcie_priv *priv = to_uniphier_pcie(pci);
+ unsigned long flags;
u32 val;
+ raw_spin_lock_irqsave(&pp->lock, flags);
+
val = readl(priv->base + PCL_RCV_INTX);
val &= ~PCL_RCV_INTX_ALL_STATUS;
val |= BIT(irqd_to_hwirq(d) + PCL_RCV_INTX_STATUS_SHIFT);
writel(val, priv->base + PCL_RCV_INTX);
+
+ raw_spin_unlock_irqrestore(&pp->lock, flags);
}
static void uniphier_pcie_irq_mask(struct irq_data *d)
@@ -199,12 +204,17 @@ static void uniphier_pcie_irq_mask(struct irq_data *d)
struct pcie_port *pp = irq_data_get_irq_chip_data(d);
struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
struct uniphier_pcie_priv *priv = to_uniphier_pcie(pci);
+ unsigned long flags;
u32 val;
+ raw_spin_lock_irqsave(&pp->lock, flags);
+
val = readl(priv->base + PCL_RCV_INTX);
val &= ~PCL_RCV_INTX_ALL_MASK;
val |= BIT(irqd_to_hwirq(d) + PCL_RCV_INTX_MASK_SHIFT);
writel(val, priv->base + PCL_RCV_INTX);
+
+ raw_spin_unlock_irqrestore(&pp->lock, flags);
}
static void uniphier_pcie_irq_unmask(struct irq_data *d)
@@ -212,12 +222,17 @@ static void uniphier_pcie_irq_unmask(struct irq_data *d)
struct pcie_port *pp = irq_data_get_irq_chip_data(d);
struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
struct uniphier_pcie_priv *priv = to_uniphier_pcie(pci);
+ unsigned long flags;
u32 val;
+ raw_spin_lock_irqsave(&pp->lock, flags);
+
val = readl(priv->base + PCL_RCV_INTX);
val &= ~PCL_RCV_INTX_ALL_MASK;
val &= ~BIT(irqd_to_hwirq(d) + PCL_RCV_INTX_MASK_SHIFT);
writel(val, priv->base + PCL_RCV_INTX);
+
+ raw_spin_unlock_irqrestore(&pp->lock, flags);
}
static struct irq_chip uniphier_pcie_irq_chip = {
--
2.7.4
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH] PCI: uniphier: Serialize INTx masking/unmasking 2021-08-23 11:18 [PATCH] PCI: uniphier: Serialize INTx masking/unmasking Kunihiko Hayashi @ 2021-08-23 15:09 ` Pali Rohár 2021-08-23 16:57 ` Marc Zyngier 0 siblings, 1 reply; 6+ messages in thread From: Pali Rohár @ 2021-08-23 15:09 UTC (permalink / raw) To: Kunihiko Hayashi Cc: Marc Zyngier, Lorenzo Pieralisi, Rob Herring, Krzysztof Wilczyński, Bjorn Helgaas, Masami Hiramatsu, linux-pci, linux-arm-kernel, linux-kernel + Marc (who originally reported this issue) On Monday 23 August 2021 20:18:20 Kunihiko Hayashi wrote: > The condition register PCI_RCV_INTX is used in irq_mask(), irq_unmask() > and irq_ack() callbacks. Accesses to register can occur at the same time > without a lock. > Add a lock into each callback to prevent the issue. > > Fixes: 7e6d5cd88a6f ("PCI: uniphier: Add UniPhier PCIe host controller support") > Suggested-by: Pali Rohár <pali@kernel.org> > Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@socionext.com> Acked-by: Pali Rohár <pali@kernel.org> > --- > drivers/pci/controller/dwc/pcie-uniphier.c | 15 +++++++++++++++ > 1 file changed, 15 insertions(+) > > The previous patch is as follows: > https://lore.kernel.org/linux-pci/1629370566-29984-1-git-send-email-hayashi.kunihiko@socionext.com/ > > Changes in the previous patch: > - Change the subject and commit message > > diff --git a/drivers/pci/controller/dwc/pcie-uniphier.c b/drivers/pci/controller/dwc/pcie-uniphier.c > index ebe43e9..5075714 100644 > --- a/drivers/pci/controller/dwc/pcie-uniphier.c > +++ b/drivers/pci/controller/dwc/pcie-uniphier.c > @@ -186,12 +186,17 @@ static void uniphier_pcie_irq_ack(struct irq_data *d) > struct pcie_port *pp = irq_data_get_irq_chip_data(d); > struct dw_pcie *pci = to_dw_pcie_from_pp(pp); > struct uniphier_pcie_priv *priv = to_uniphier_pcie(pci); > + unsigned long flags; > u32 val; > > + raw_spin_lock_irqsave(&pp->lock, flags); > + > val = readl(priv->base + PCL_RCV_INTX); > val &= ~PCL_RCV_INTX_ALL_STATUS; > val |= BIT(irqd_to_hwirq(d) + PCL_RCV_INTX_STATUS_SHIFT); > writel(val, priv->base + PCL_RCV_INTX); > + > + raw_spin_unlock_irqrestore(&pp->lock, flags); > } > > static void uniphier_pcie_irq_mask(struct irq_data *d) > @@ -199,12 +204,17 @@ static void uniphier_pcie_irq_mask(struct irq_data *d) > struct pcie_port *pp = irq_data_get_irq_chip_data(d); > struct dw_pcie *pci = to_dw_pcie_from_pp(pp); > struct uniphier_pcie_priv *priv = to_uniphier_pcie(pci); > + unsigned long flags; > u32 val; > > + raw_spin_lock_irqsave(&pp->lock, flags); > + > val = readl(priv->base + PCL_RCV_INTX); > val &= ~PCL_RCV_INTX_ALL_MASK; > val |= BIT(irqd_to_hwirq(d) + PCL_RCV_INTX_MASK_SHIFT); > writel(val, priv->base + PCL_RCV_INTX); > + > + raw_spin_unlock_irqrestore(&pp->lock, flags); > } > > static void uniphier_pcie_irq_unmask(struct irq_data *d) > @@ -212,12 +222,17 @@ static void uniphier_pcie_irq_unmask(struct irq_data *d) > struct pcie_port *pp = irq_data_get_irq_chip_data(d); > struct dw_pcie *pci = to_dw_pcie_from_pp(pp); > struct uniphier_pcie_priv *priv = to_uniphier_pcie(pci); > + unsigned long flags; > u32 val; > > + raw_spin_lock_irqsave(&pp->lock, flags); > + > val = readl(priv->base + PCL_RCV_INTX); > val &= ~PCL_RCV_INTX_ALL_MASK; > val &= ~BIT(irqd_to_hwirq(d) + PCL_RCV_INTX_MASK_SHIFT); > writel(val, priv->base + PCL_RCV_INTX); > + > + raw_spin_unlock_irqrestore(&pp->lock, flags); > } > > static struct irq_chip uniphier_pcie_irq_chip = { > -- > 2.7.4 > ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] PCI: uniphier: Serialize INTx masking/unmasking 2021-08-23 15:09 ` Pali Rohár @ 2021-08-23 16:57 ` Marc Zyngier 2021-08-25 0:01 ` Kunihiko Hayashi 0 siblings, 1 reply; 6+ messages in thread From: Marc Zyngier @ 2021-08-23 16:57 UTC (permalink / raw) To: Pali Rohár, Kunihiko Hayashi Cc: Lorenzo Pieralisi, Rob Herring, Krzysztof Wilczyński, Bjorn Helgaas, Masami Hiramatsu, linux-pci, linux-arm-kernel, linux-kernel On Mon, 23 Aug 2021 16:09:27 +0100, Pali Rohár <pali@kernel.org> wrote: > > + Marc (who originally reported this issue) > > On Monday 23 August 2021 20:18:20 Kunihiko Hayashi wrote: > > The condition register PCI_RCV_INTX is used in irq_mask(), irq_unmask() > > and irq_ack() callbacks. Accesses to register can occur at the same time > > without a lock. > > Add a lock into each callback to prevent the issue. > > > > Fixes: 7e6d5cd88a6f ("PCI: uniphier: Add UniPhier PCIe host controller support") > > Suggested-by: Pali Rohár <pali@kernel.org> > > Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@socionext.com> > > Acked-by: Pali Rohár <pali@kernel.org> > > > --- > > drivers/pci/controller/dwc/pcie-uniphier.c | 15 +++++++++++++++ > > 1 file changed, 15 insertions(+) > > > > The previous patch is as follows: > > https://lore.kernel.org/linux-pci/1629370566-29984-1-git-send-email-hayashi.kunihiko@socionext.com/ > > > > Changes in the previous patch: > > - Change the subject and commit message > > > > diff --git a/drivers/pci/controller/dwc/pcie-uniphier.c b/drivers/pci/controller/dwc/pcie-uniphier.c > > index ebe43e9..5075714 100644 > > --- a/drivers/pci/controller/dwc/pcie-uniphier.c > > +++ b/drivers/pci/controller/dwc/pcie-uniphier.c > > @@ -186,12 +186,17 @@ static void uniphier_pcie_irq_ack(struct irq_data *d) > > struct pcie_port *pp = irq_data_get_irq_chip_data(d); > > struct dw_pcie *pci = to_dw_pcie_from_pp(pp); > > struct uniphier_pcie_priv *priv = to_uniphier_pcie(pci); > > + unsigned long flags; > > u32 val; > > > > + raw_spin_lock_irqsave(&pp->lock, flags); > > + > > val = readl(priv->base + PCL_RCV_INTX); > > val &= ~PCL_RCV_INTX_ALL_STATUS; > > val |= BIT(irqd_to_hwirq(d) + PCL_RCV_INTX_STATUS_SHIFT); > > writel(val, priv->base + PCL_RCV_INTX); > > + > > + raw_spin_unlock_irqrestore(&pp->lock, flags); > > } > > > > static void uniphier_pcie_irq_mask(struct irq_data *d) > > @@ -199,12 +204,17 @@ static void uniphier_pcie_irq_mask(struct irq_data *d) > > struct pcie_port *pp = irq_data_get_irq_chip_data(d); > > struct dw_pcie *pci = to_dw_pcie_from_pp(pp); > > struct uniphier_pcie_priv *priv = to_uniphier_pcie(pci); > > + unsigned long flags; > > u32 val; > > > > + raw_spin_lock_irqsave(&pp->lock, flags); > > + > > val = readl(priv->base + PCL_RCV_INTX); > > val &= ~PCL_RCV_INTX_ALL_MASK; > > val |= BIT(irqd_to_hwirq(d) + PCL_RCV_INTX_MASK_SHIFT); This looks extremely suspicious. You clear all the INTX mask bits, and only set the one you need. How about the pre-existing bits? > > writel(val, priv->base + PCL_RCV_INTX); > > + > > + raw_spin_unlock_irqrestore(&pp->lock, flags); > > } > > > > static void uniphier_pcie_irq_unmask(struct irq_data *d) > > @@ -212,12 +222,17 @@ static void uniphier_pcie_irq_unmask(struct irq_data *d) > > struct pcie_port *pp = irq_data_get_irq_chip_data(d); > > struct dw_pcie *pci = to_dw_pcie_from_pp(pp); > > struct uniphier_pcie_priv *priv = to_uniphier_pcie(pci); > > + unsigned long flags; > > u32 val; > > > > + raw_spin_lock_irqsave(&pp->lock, flags); > > + > > val = readl(priv->base + PCL_RCV_INTX); > > val &= ~PCL_RCV_INTX_ALL_MASK; > > val &= ~BIT(irqd_to_hwirq(d) + PCL_RCV_INTX_MASK_SHIFT); And by the same token, this second line is totally useless. I think masking/unmasking is broken in this driver, locking or not. M. -- Without deviation from the norm, progress is not possible. ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] PCI: uniphier: Serialize INTx masking/unmasking 2021-08-23 16:57 ` Marc Zyngier @ 2021-08-25 0:01 ` Kunihiko Hayashi 2021-08-25 9:07 ` Marc Zyngier 0 siblings, 1 reply; 6+ messages in thread From: Kunihiko Hayashi @ 2021-08-25 0:01 UTC (permalink / raw) To: Marc Zyngier, Pali Rohár Cc: Lorenzo Pieralisi, Rob Herring, Krzysztof Wilczyński, Bjorn Helgaas, Masami Hiramatsu, linux-pci, linux-arm-kernel, linux-kernel Hi Marc, On 2021/08/24 1:57, Marc Zyngier wrote: > On Mon, 23 Aug 2021 16:09:27 +0100, > Pali Rohár <pali@kernel.org> wrote: >> >> + Marc (who originally reported this issue) >> >> On Monday 23 August 2021 20:18:20 Kunihiko Hayashi wrote: >>> The condition register PCI_RCV_INTX is used in irq_mask(), irq_unmask() >>> and irq_ack() callbacks. Accesses to register can occur at the same time >>> without a lock. >>> Add a lock into each callback to prevent the issue. >>> >>> Fixes: 7e6d5cd88a6f ("PCI: uniphier: Add UniPhier PCIe host controller support") >>> Suggested-by: Pali Rohár <pali@kernel.org> >>> Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@socionext.com> >> >> Acked-by: Pali Rohár <pali@kernel.org> >> >>> --- >>> drivers/pci/controller/dwc/pcie-uniphier.c | 15 +++++++++++++++ >>> 1 file changed, 15 insertions(+) >>> >>> The previous patch is as follows: >>> https://lore.kernel.org/linux-pci/1629370566-29984-1-git-send-email-hayashi.kunihiko@socionext.com/ >>> >>> Changes in the previous patch: >>> - Change the subject and commit message >>> >>> diff --git a/drivers/pci/controller/dwc/pcie-uniphier.c b/drivers/pci/controller/dwc/pcie-uniphier.c >>> index ebe43e9..5075714 100644 >>> --- a/drivers/pci/controller/dwc/pcie-uniphier.c >>> +++ b/drivers/pci/controller/dwc/pcie-uniphier.c >>> @@ -186,12 +186,17 @@ static void uniphier_pcie_irq_ack(struct irq_data *d) >>> struct pcie_port *pp = irq_data_get_irq_chip_data(d); >>> struct dw_pcie *pci = to_dw_pcie_from_pp(pp); >>> struct uniphier_pcie_priv *priv = to_uniphier_pcie(pci); >>> + unsigned long flags; >>> u32 val; >>> >>> + raw_spin_lock_irqsave(&pp->lock, flags); >>> + >>> val = readl(priv->base + PCL_RCV_INTX); >>> val &= ~PCL_RCV_INTX_ALL_STATUS; >>> val |= BIT(irqd_to_hwirq(d) + PCL_RCV_INTX_STATUS_SHIFT); >>> writel(val, priv->base + PCL_RCV_INTX); >>> + >>> + raw_spin_unlock_irqrestore(&pp->lock, flags); >>> } >>> >>> static void uniphier_pcie_irq_mask(struct irq_data *d) >>> @@ -199,12 +204,17 @@ static void uniphier_pcie_irq_mask(struct irq_data *d) >>> struct pcie_port *pp = irq_data_get_irq_chip_data(d); >>> struct dw_pcie *pci = to_dw_pcie_from_pp(pp); >>> struct uniphier_pcie_priv *priv = to_uniphier_pcie(pci); >>> + unsigned long flags; >>> u32 val; >>> >>> + raw_spin_lock_irqsave(&pp->lock, flags); >>> + >>> val = readl(priv->base + PCL_RCV_INTX); >>> val &= ~PCL_RCV_INTX_ALL_MASK; >>> val |= BIT(irqd_to_hwirq(d) + PCL_RCV_INTX_MASK_SHIFT); > > This looks extremely suspicious. You clear all the INTX mask bits, and > only set the one you need. How about the pre-existing bits? Thanks for pointing out. No need to clear all INTX mask bits. The pre-existing bits should be preserved. > >>> writel(val, priv->base + PCL_RCV_INTX); >>> + >>> + raw_spin_unlock_irqrestore(&pp->lock, flags); >>> } >>> >>> static void uniphier_pcie_irq_unmask(struct irq_data *d) >>> @@ -212,12 +222,17 @@ static void uniphier_pcie_irq_unmask(struct irq_data *d) >>> struct pcie_port *pp = irq_data_get_irq_chip_data(d); >>> struct dw_pcie *pci = to_dw_pcie_from_pp(pp); >>> struct uniphier_pcie_priv *priv = to_uniphier_pcie(pci); >>> + unsigned long flags; >>> u32 val; >>> >>> + raw_spin_lock_irqsave(&pp->lock, flags); >>> + >>> val = readl(priv->base + PCL_RCV_INTX); >>> val &= ~PCL_RCV_INTX_ALL_MASK; >>> val &= ~BIT(irqd_to_hwirq(d) + PCL_RCV_INTX_MASK_SHIFT); > > And by the same token, this second line is totally useless. > > I think masking/unmasking is broken in this driver, locking or not. Yes, this second line should be removed, too. I'll fix this bug and add mask locking. Thank you, --- Best Regards Kunihiko Hayashi ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] PCI: uniphier: Serialize INTx masking/unmasking 2021-08-25 0:01 ` Kunihiko Hayashi @ 2021-08-25 9:07 ` Marc Zyngier 2021-08-26 10:02 ` Kunihiko Hayashi 0 siblings, 1 reply; 6+ messages in thread From: Marc Zyngier @ 2021-08-25 9:07 UTC (permalink / raw) To: Kunihiko Hayashi Cc: Pali Rohár, Lorenzo Pieralisi, Rob Herring, Krzysztof Wilczyński, Bjorn Helgaas, Masami Hiramatsu, linux-pci, linux-arm-kernel, linux-kernel On Wed, 25 Aug 2021 01:01:08 +0100, Kunihiko Hayashi <hayashi.kunihiko@socionext.com> wrote: > > Hi Marc, > > On 2021/08/24 1:57, Marc Zyngier wrote: > > On Mon, 23 Aug 2021 16:09:27 +0100, > > Pali Rohár <pali@kernel.org> wrote: > >> > >> + Marc (who originally reported this issue) > >> > >> On Monday 23 August 2021 20:18:20 Kunihiko Hayashi wrote: > >>> The condition register PCI_RCV_INTX is used in irq_mask(), irq_unmask() > >>> and irq_ack() callbacks. Accesses to register can occur at the same time > >>> without a lock. > >>> Add a lock into each callback to prevent the issue. > >>> > >>> Fixes: 7e6d5cd88a6f ("PCI: uniphier: Add UniPhier PCIe host controller support") > >>> Suggested-by: Pali Rohár <pali@kernel.org> > >>> Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@socionext.com> > >> > >> Acked-by: Pali Rohár <pali@kernel.org> > >> > >>> --- > >>> drivers/pci/controller/dwc/pcie-uniphier.c | 15 +++++++++++++++ > >>> 1 file changed, 15 insertions(+) > >>> > >>> The previous patch is as follows: > >>> https://lore.kernel.org/linux-pci/1629370566-29984-1-git-send-email-hayashi.kunihiko@socionext.com/ > >>> > >>> Changes in the previous patch: > >>> - Change the subject and commit message > >>> > >>> diff --git a/drivers/pci/controller/dwc/pcie-uniphier.c b/drivers/pci/controller/dwc/pcie-uniphier.c > >>> index ebe43e9..5075714 100644 > >>> --- a/drivers/pci/controller/dwc/pcie-uniphier.c > >>> +++ b/drivers/pci/controller/dwc/pcie-uniphier.c > >>> @@ -186,12 +186,17 @@ static void uniphier_pcie_irq_ack(struct irq_data *d) > >>> struct pcie_port *pp = irq_data_get_irq_chip_data(d); > >>> struct dw_pcie *pci = to_dw_pcie_from_pp(pp); > >>> struct uniphier_pcie_priv *priv = to_uniphier_pcie(pci); > >>> + unsigned long flags; > >>> u32 val; > >>> + raw_spin_lock_irqsave(&pp->lock, flags); > >>> + > >>> val = readl(priv->base + PCL_RCV_INTX); > >>> val &= ~PCL_RCV_INTX_ALL_STATUS; > >>> val |= BIT(irqd_to_hwirq(d) + PCL_RCV_INTX_STATUS_SHIFT); > >>> writel(val, priv->base + PCL_RCV_INTX); > >>> + > >>> + raw_spin_unlock_irqrestore(&pp->lock, flags); > >>> } > >>> static void uniphier_pcie_irq_mask(struct irq_data *d) > >>> @@ -199,12 +204,17 @@ static void uniphier_pcie_irq_mask(struct irq_data *d) > >>> struct pcie_port *pp = irq_data_get_irq_chip_data(d); > >>> struct dw_pcie *pci = to_dw_pcie_from_pp(pp); > >>> struct uniphier_pcie_priv *priv = to_uniphier_pcie(pci); > >>> + unsigned long flags; > >>> u32 val; > >>> + raw_spin_lock_irqsave(&pp->lock, flags); > >>> + > >>> val = readl(priv->base + PCL_RCV_INTX); > >>> val &= ~PCL_RCV_INTX_ALL_MASK; > >>> val |= BIT(irqd_to_hwirq(d) + PCL_RCV_INTX_MASK_SHIFT); > > > > This looks extremely suspicious. You clear all the INTX mask bits, and > > only set the one you need. How about the pre-existing bits? > > Thanks for pointing out. No need to clear all INTX mask bits. > The pre-existing bits should be preserved. > > > > >>> writel(val, priv->base + PCL_RCV_INTX); > >>> + > >>> + raw_spin_unlock_irqrestore(&pp->lock, flags); > >>> } > >>> static void uniphier_pcie_irq_unmask(struct irq_data *d) > >>> @@ -212,12 +222,17 @@ static void uniphier_pcie_irq_unmask(struct irq_data *d) > >>> struct pcie_port *pp = irq_data_get_irq_chip_data(d); > >>> struct dw_pcie *pci = to_dw_pcie_from_pp(pp); > >>> struct uniphier_pcie_priv *priv = to_uniphier_pcie(pci); > >>> + unsigned long flags; > >>> u32 val; > >>> + raw_spin_lock_irqsave(&pp->lock, flags); > >>> + > >>> val = readl(priv->base + PCL_RCV_INTX); > >>> val &= ~PCL_RCV_INTX_ALL_MASK; > >>> val &= ~BIT(irqd_to_hwirq(d) + PCL_RCV_INTX_MASK_SHIFT); > > > > And by the same token, this second line is totally useless. > > > > I think masking/unmasking is broken in this driver, locking or not. > > Yes, this second line should be removed, too. You mean the *first* line, right? The one clearing all the INTx bits. If you remove the second line, you won't fix anything. Thanks, M. -- Without deviation from the norm, progress is not possible. ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] PCI: uniphier: Serialize INTx masking/unmasking 2021-08-25 9:07 ` Marc Zyngier @ 2021-08-26 10:02 ` Kunihiko Hayashi 0 siblings, 0 replies; 6+ messages in thread From: Kunihiko Hayashi @ 2021-08-26 10:02 UTC (permalink / raw) To: Marc Zyngier Cc: Pali Rohár, Lorenzo Pieralisi, Rob Herring, Krzysztof Wilczyński, Bjorn Helgaas, Masami Hiramatsu, linux-pci, linux-arm-kernel, linux-kernel Hi Marc, On 2021/08/25 18:07, Marc Zyngier wrote: > On Wed, 25 Aug 2021 01:01:08 +0100, > Kunihiko Hayashi <hayashi.kunihiko@socionext.com> wrote: >> >> Hi Marc, >> >> On 2021/08/24 1:57, Marc Zyngier wrote: >>> On Mon, 23 Aug 2021 16:09:27 +0100, >>> Pali Rohár <pali@kernel.org> wrote: >>>> >>>> + Marc (who originally reported this issue) >>>> >>>> On Monday 23 August 2021 20:18:20 Kunihiko Hayashi wrote: >>>>> The condition register PCI_RCV_INTX is used in irq_mask(), irq_unmask() >>>>> and irq_ack() callbacks. Accesses to register can occur at the same time >>>>> without a lock. >>>>> Add a lock into each callback to prevent the issue. >>>>> >>>>> Fixes: 7e6d5cd88a6f ("PCI: uniphier: Add UniPhier PCIe host controller support") >>>>> Suggested-by: Pali Rohár <pali@kernel.org> >>>>> Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@socionext.com> >>>> >>>> Acked-by: Pali Rohár <pali@kernel.org> >>>> >>>>> --- >>>>> drivers/pci/controller/dwc/pcie-uniphier.c | 15 +++++++++++++++ >>>>> 1 file changed, 15 insertions(+) >>>>> >>>>> The previous patch is as follows: >>>>> https://lore.kernel.org/linux-pci/1629370566-29984-1-git-send-email-hayashi.kunihiko@socionext.com/ >>>>> >>>>> Changes in the previous patch: >>>>> - Change the subject and commit message >>>>> >>>>> diff --git a/drivers/pci/controller/dwc/pcie-uniphier.c b/drivers/pci/controller/dwc/pcie-uniphier.c >>>>> index ebe43e9..5075714 100644 >>>>> --- a/drivers/pci/controller/dwc/pcie-uniphier.c >>>>> +++ b/drivers/pci/controller/dwc/pcie-uniphier.c >>>>> @@ -186,12 +186,17 @@ static void uniphier_pcie_irq_ack(struct irq_data *d) >>>>> struct pcie_port *pp = irq_data_get_irq_chip_data(d); >>>>> struct dw_pcie *pci = to_dw_pcie_from_pp(pp); >>>>> struct uniphier_pcie_priv *priv = to_uniphier_pcie(pci); >>>>> + unsigned long flags; >>>>> u32 val; >>>>> + raw_spin_lock_irqsave(&pp->lock, flags); >>>>> + >>>>> val = readl(priv->base + PCL_RCV_INTX); >>>>> val &= ~PCL_RCV_INTX_ALL_STATUS; >>>>> val |= BIT(irqd_to_hwirq(d) + PCL_RCV_INTX_STATUS_SHIFT); >>>>> writel(val, priv->base + PCL_RCV_INTX); >>>>> + >>>>> + raw_spin_unlock_irqrestore(&pp->lock, flags); >>>>> } >>>>> static void uniphier_pcie_irq_mask(struct irq_data *d) >>>>> @@ -199,12 +204,17 @@ static void uniphier_pcie_irq_mask(struct irq_data *d) >>>>> struct pcie_port *pp = irq_data_get_irq_chip_data(d); >>>>> struct dw_pcie *pci = to_dw_pcie_from_pp(pp); >>>>> struct uniphier_pcie_priv *priv = to_uniphier_pcie(pci); >>>>> + unsigned long flags; >>>>> u32 val; >>>>> + raw_spin_lock_irqsave(&pp->lock, flags); >>>>> + >>>>> val = readl(priv->base + PCL_RCV_INTX); >>>>> val &= ~PCL_RCV_INTX_ALL_MASK; >>>>> val |= BIT(irqd_to_hwirq(d) + PCL_RCV_INTX_MASK_SHIFT); >>> >>> This looks extremely suspicious. You clear all the INTX mask bits, and >>> only set the one you need. How about the pre-existing bits? >> >> Thanks for pointing out. No need to clear all INTX mask bits. >> The pre-existing bits should be preserved. >> >>> >>>>> writel(val, priv->base + PCL_RCV_INTX); >>>>> + >>>>> + raw_spin_unlock_irqrestore(&pp->lock, flags); >>>>> } >>>>> static void uniphier_pcie_irq_unmask(struct irq_data *d) >>>>> @@ -212,12 +222,17 @@ static void uniphier_pcie_irq_unmask(struct irq_data *d) >>>>> struct pcie_port *pp = irq_data_get_irq_chip_data(d); >>>>> struct dw_pcie *pci = to_dw_pcie_from_pp(pp); >>>>> struct uniphier_pcie_priv *priv = to_uniphier_pcie(pci); >>>>> + unsigned long flags; >>>>> u32 val; >>>>> + raw_spin_lock_irqsave(&pp->lock, flags); >>>>> + >>>>> val = readl(priv->base + PCL_RCV_INTX); >>>>> val &= ~PCL_RCV_INTX_ALL_MASK; >>>>> val &= ~BIT(irqd_to_hwirq(d) + PCL_RCV_INTX_MASK_SHIFT); >>> >>> And by the same token, this second line is totally useless. >>> >>> I think masking/unmasking is broken in this driver, locking or not. >> >> Yes, this second line should be removed, too. > > You mean the *first* line, right? The one clearing all the INTx > bits. If you remove the second line, you won't fix anything. This is ambiguous. I mean that I will remove the following line: val &= ~PCL_RCV_INTX_ALL_MASK; So the fixed unmasking code is as follows. val = readl(priv->base + PCL_RCV_INTX); val &= ~BIT(irqd_to_hwirq(d) + PCL_RCV_INTX_STATUS_SHIFT); writel(val, priv->base + PCL_RCV_INTX); Thank you, --- Best Regards Kunihiko Hayashi ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2021-08-26 10:02 UTC | newest] Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2021-08-23 11:18 [PATCH] PCI: uniphier: Serialize INTx masking/unmasking Kunihiko Hayashi 2021-08-23 15:09 ` Pali Rohár 2021-08-23 16:57 ` Marc Zyngier 2021-08-25 0:01 ` Kunihiko Hayashi 2021-08-25 9:07 ` Marc Zyngier 2021-08-26 10:02 ` Kunihiko Hayashi
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