* [PATCH] dmaengine: mv_xor: protect MBUS window access with a spinlock
@ 2026-09-16 18:26 Rosen Penev
2026-09-16 19:07 ` Frank Li
0 siblings, 1 reply; 4+ messages in thread
From: Rosen Penev @ 2026-09-16 18:26 UTC (permalink / raw)
To: dmaengine; +Cc: Vinod Koul, Frank Li, Stefan Roese, open list
mv_xor_add_io_win() reads and writes shared MBUS window registers
and updates the shared win_start/win_end arrays in mv_xor_device.
Multiple DMA channels can call this function concurrently via
mv_xor_prep_dma_xor(), leading to races where two threads can
select the same free window slot, corrupt the registers, or produce
inconsistent cached state.
Add a spinlock to struct mv_xor_device and hold it across the
register read-modify-write and cache update in mv_xor_add_io_win().
Fixes: 77ff7a706f01 ("mv_xor: Add support for IO (PCIe) src/dst areas")
Assisted-by: LLM
Signed-off-by: Rosen Penev <rosenp@gmail.com>
---
drivers/dma/mv_xor.c | 15 +++++++++++++--
drivers/dma/mv_xor.h | 1 +
2 files changed, 14 insertions(+), 2 deletions(-)
diff --git a/drivers/dma/mv_xor.c b/drivers/dma/mv_xor.c
index 0de2b1ad5c30..e7c6ec54ce25 100644
--- a/drivers/dma/mv_xor.c
+++ b/drivers/dma/mv_xor.c
@@ -497,11 +497,14 @@ static int mv_xor_add_io_win(struct mv_xor_chan *mv_chan, u32 addr)
u8 target, attr;
int ret;
int i;
+ unsigned long flags;
/* Nothing needs to get done for the Armada 3700 */
if (xordev->xor_type == XOR_ARMADA_37XX)
return 0;
+ spin_lock_irqsave(&xordev->win_lock, flags);
+
/*
* Loop over the cached windows to check, if the requested area
* is already mapped. If this the case, nothing needs to be done
@@ -511,6 +514,7 @@ static int mv_xor_add_io_win(struct mv_xor_chan *mv_chan, u32 addr)
if (addr >= xordev->win_start[i] &&
addr <= xordev->win_end[i]) {
/* Window is already mapped */
+ spin_unlock_irqrestore(&xordev->win_lock, flags);
return 0;
}
}
@@ -521,8 +525,10 @@ static int mv_xor_add_io_win(struct mv_xor_chan *mv_chan, u32 addr)
/* If no IO window is found that addr has to be located in SDRAM */
ret = mvebu_mbus_get_io_win_info(addr, &size, &target, &attr);
- if (ret < 0)
+ if (ret < 0) {
+ spin_unlock_irqrestore(&xordev->win_lock, flags);
return 0;
+ }
/*
* Mask the base addr 'addr' according to 'size' read back from the
@@ -540,8 +546,10 @@ static int mv_xor_add_io_win(struct mv_xor_chan *mv_chan, u32 addr)
/* Set 'i' to the first free window to write the new values to */
i = ffs(~win_enable) - 1;
- if (i >= WINDOW_COUNT)
+ if (i >= WINDOW_COUNT) {
+ spin_unlock_irqrestore(&xordev->win_lock, flags);
return -ENOMEM;
+ }
writel((addr & 0xffff0000) | (attr << 8) | target,
base + WINDOW_BASE(i));
@@ -556,6 +564,8 @@ static int mv_xor_add_io_win(struct mv_xor_chan *mv_chan, u32 addr)
writel(win_enable, base + WINDOW_BAR_ENABLE(0));
writel(win_enable, base + WINDOW_BAR_ENABLE(1));
+ spin_unlock_irqrestore(&xordev->win_lock, flags);
+
return 0;
}
@@ -1353,6 +1363,7 @@ static int mv_xor_probe(struct platform_device *pdev)
platform_set_drvdata(pdev, xordev);
+ spin_lock_init(&xordev->win_lock);
/*
* We need to know which type of XOR device we use before
diff --git a/drivers/dma/mv_xor.h b/drivers/dma/mv_xor.h
index c87cefd38a07..034db4d0bfb1 100644
--- a/drivers/dma/mv_xor.h
+++ b/drivers/dma/mv_xor.h
@@ -80,6 +80,7 @@ struct mv_xor_device {
struct clk *clk;
struct mv_xor_chan *channels[MV_XOR_MAX_CHANNELS];
int xor_type;
+ spinlock_t win_lock;
u32 win_start[WINDOW_COUNT];
u32 win_end[WINDOW_COUNT];
--
2.55.0
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] dmaengine: mv_xor: protect MBUS window access with a spinlock
2026-09-16 18:26 [PATCH] dmaengine: mv_xor: protect MBUS window access with a spinlock Rosen Penev
@ 2026-09-16 19:07 ` Frank Li
2026-09-16 19:34 ` Rosen Penev
0 siblings, 1 reply; 4+ messages in thread
From: Frank Li @ 2026-09-16 19:07 UTC (permalink / raw)
To: Rosen Penev; +Cc: dmaengine, Vinod Koul, Frank Li, Stefan Roese, open list
On Wed, Sep 16, 2026 at 11:26:08AM -0700, Rosen Penev wrote:
> mv_xor_add_io_win() reads and writes shared MBUS window registers
> and updates the shared win_start/win_end arrays in mv_xor_device.
> Multiple DMA channels can call this function concurrently via
> mv_xor_prep_dma_xor(), leading to races where two threads can
> select the same free window slot, corrupt the registers, or produce
> inconsistent cached state.
>
> Add a spinlock to struct mv_xor_device and hold it across the
> register read-modify-write and cache update in mv_xor_add_io_win().
>
> Fixes: 77ff7a706f01 ("mv_xor: Add support for IO (PCIe) src/dst areas")
> Assisted-by: LLM
> Signed-off-by: Rosen Penev <rosenp@gmail.com>
> ---
> drivers/dma/mv_xor.c | 15 +++++++++++++--
> drivers/dma/mv_xor.h | 1 +
> 2 files changed, 14 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/dma/mv_xor.c b/drivers/dma/mv_xor.c
> index 0de2b1ad5c30..e7c6ec54ce25 100644
> --- a/drivers/dma/mv_xor.c
> +++ b/drivers/dma/mv_xor.c
> @@ -497,11 +497,14 @@ static int mv_xor_add_io_win(struct mv_xor_chan *mv_chan, u32 addr)
> u8 target, attr;
> int ret;
> int i;
> + unsigned long flags;
>
> /* Nothing needs to get done for the Armada 3700 */
> if (xordev->xor_type == XOR_ARMADA_37XX)
> return 0;
>
> + spin_lock_irqsave(&xordev->win_lock, flags);
> +
use auto clean up guard()
Frank
> /*
> * Loop over the cached windows to check, if the requested area
> * is already mapped. If this the case, nothing needs to be done
> @@ -511,6 +514,7 @@ static int mv_xor_add_io_win(struct mv_xor_chan *mv_chan, u32 addr)
> if (addr >= xordev->win_start[i] &&
> addr <= xordev->win_end[i]) {
> /* Window is already mapped */
> + spin_unlock_irqrestore(&xordev->win_lock, flags);
> return 0;
> }
> }
> @@ -521,8 +525,10 @@ static int mv_xor_add_io_win(struct mv_xor_chan *mv_chan, u32 addr)
>
> /* If no IO window is found that addr has to be located in SDRAM */
> ret = mvebu_mbus_get_io_win_info(addr, &size, &target, &attr);
> - if (ret < 0)
> + if (ret < 0) {
> + spin_unlock_irqrestore(&xordev->win_lock, flags);
> return 0;
> + }
>
> /*
> * Mask the base addr 'addr' according to 'size' read back from the
> @@ -540,8 +546,10 @@ static int mv_xor_add_io_win(struct mv_xor_chan *mv_chan, u32 addr)
>
> /* Set 'i' to the first free window to write the new values to */
> i = ffs(~win_enable) - 1;
> - if (i >= WINDOW_COUNT)
> + if (i >= WINDOW_COUNT) {
> + spin_unlock_irqrestore(&xordev->win_lock, flags);
> return -ENOMEM;
> + }
>
> writel((addr & 0xffff0000) | (attr << 8) | target,
> base + WINDOW_BASE(i));
> @@ -556,6 +564,8 @@ static int mv_xor_add_io_win(struct mv_xor_chan *mv_chan, u32 addr)
> writel(win_enable, base + WINDOW_BAR_ENABLE(0));
> writel(win_enable, base + WINDOW_BAR_ENABLE(1));
>
> + spin_unlock_irqrestore(&xordev->win_lock, flags);
> +
> return 0;
> }
>
> @@ -1353,6 +1363,7 @@ static int mv_xor_probe(struct platform_device *pdev)
>
> platform_set_drvdata(pdev, xordev);
>
> + spin_lock_init(&xordev->win_lock);
>
> /*
> * We need to know which type of XOR device we use before
> diff --git a/drivers/dma/mv_xor.h b/drivers/dma/mv_xor.h
> index c87cefd38a07..034db4d0bfb1 100644
> --- a/drivers/dma/mv_xor.h
> +++ b/drivers/dma/mv_xor.h
> @@ -80,6 +80,7 @@ struct mv_xor_device {
> struct clk *clk;
> struct mv_xor_chan *channels[MV_XOR_MAX_CHANNELS];
> int xor_type;
> + spinlock_t win_lock;
>
> u32 win_start[WINDOW_COUNT];
> u32 win_end[WINDOW_COUNT];
> --
> 2.55.0
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] dmaengine: mv_xor: protect MBUS window access with a spinlock
2026-09-16 19:07 ` Frank Li
@ 2026-09-16 19:34 ` Rosen Penev
2026-09-16 19:46 ` Frank Li
0 siblings, 1 reply; 4+ messages in thread
From: Rosen Penev @ 2026-09-16 19:34 UTC (permalink / raw)
To: Frank Li; +Cc: dmaengine, Vinod Koul, Frank Li, Stefan Roese, open list
On Wed, Sep 16, 2026 at 12:07 PM Frank Li <Frank.li@oss.nxp.com> wrote:
>
> On Wed, Sep 16, 2026 at 11:26:08AM -0700, Rosen Penev wrote:
> > mv_xor_add_io_win() reads and writes shared MBUS window registers
> > and updates the shared win_start/win_end arrays in mv_xor_device.
> > Multiple DMA channels can call this function concurrently via
> > mv_xor_prep_dma_xor(), leading to races where two threads can
> > select the same free window slot, corrupt the registers, or produce
> > inconsistent cached state.
> >
> > Add a spinlock to struct mv_xor_device and hold it across the
> > register read-modify-write and cache update in mv_xor_add_io_win().
> >
> > Fixes: 77ff7a706f01 ("mv_xor: Add support for IO (PCIe) src/dst areas")
> > Assisted-by: LLM
> > Signed-off-by: Rosen Penev <rosenp@gmail.com>
> > ---
> > drivers/dma/mv_xor.c | 15 +++++++++++++--
> > drivers/dma/mv_xor.h | 1 +
> > 2 files changed, 14 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/dma/mv_xor.c b/drivers/dma/mv_xor.c
> > index 0de2b1ad5c30..e7c6ec54ce25 100644
> > --- a/drivers/dma/mv_xor.c
> > +++ b/drivers/dma/mv_xor.c
> > @@ -497,11 +497,14 @@ static int mv_xor_add_io_win(struct mv_xor_chan *mv_chan, u32 addr)
> > u8 target, attr;
> > int ret;
> > int i;
> > + unsigned long flags;
> >
> > /* Nothing needs to get done for the Armada 3700 */
> > if (xordev->xor_type == XOR_ARMADA_37XX)
> > return 0;
> >
> > + spin_lock_irqsave(&xordev->win_lock, flags);
> > +
>
> use auto clean up guard()
Could that be backported though?
>
> Frank
> > /*
> > * Loop over the cached windows to check, if the requested area
> > * is already mapped. If this the case, nothing needs to be done
> > @@ -511,6 +514,7 @@ static int mv_xor_add_io_win(struct mv_xor_chan *mv_chan, u32 addr)
> > if (addr >= xordev->win_start[i] &&
> > addr <= xordev->win_end[i]) {
> > /* Window is already mapped */
> > + spin_unlock_irqrestore(&xordev->win_lock, flags);
> > return 0;
> > }
> > }
> > @@ -521,8 +525,10 @@ static int mv_xor_add_io_win(struct mv_xor_chan *mv_chan, u32 addr)
> >
> > /* If no IO window is found that addr has to be located in SDRAM */
> > ret = mvebu_mbus_get_io_win_info(addr, &size, &target, &attr);
> > - if (ret < 0)
> > + if (ret < 0) {
> > + spin_unlock_irqrestore(&xordev->win_lock, flags);
> > return 0;
> > + }
> >
> > /*
> > * Mask the base addr 'addr' according to 'size' read back from the
> > @@ -540,8 +546,10 @@ static int mv_xor_add_io_win(struct mv_xor_chan *mv_chan, u32 addr)
> >
> > /* Set 'i' to the first free window to write the new values to */
> > i = ffs(~win_enable) - 1;
> > - if (i >= WINDOW_COUNT)
> > + if (i >= WINDOW_COUNT) {
> > + spin_unlock_irqrestore(&xordev->win_lock, flags);
> > return -ENOMEM;
> > + }
> >
> > writel((addr & 0xffff0000) | (attr << 8) | target,
> > base + WINDOW_BASE(i));
> > @@ -556,6 +564,8 @@ static int mv_xor_add_io_win(struct mv_xor_chan *mv_chan, u32 addr)
> > writel(win_enable, base + WINDOW_BAR_ENABLE(0));
> > writel(win_enable, base + WINDOW_BAR_ENABLE(1));
> >
> > + spin_unlock_irqrestore(&xordev->win_lock, flags);
> > +
> > return 0;
> > }
> >
> > @@ -1353,6 +1363,7 @@ static int mv_xor_probe(struct platform_device *pdev)
> >
> > platform_set_drvdata(pdev, xordev);
> >
> > + spin_lock_init(&xordev->win_lock);
> >
> > /*
> > * We need to know which type of XOR device we use before
> > diff --git a/drivers/dma/mv_xor.h b/drivers/dma/mv_xor.h
> > index c87cefd38a07..034db4d0bfb1 100644
> > --- a/drivers/dma/mv_xor.h
> > +++ b/drivers/dma/mv_xor.h
> > @@ -80,6 +80,7 @@ struct mv_xor_device {
> > struct clk *clk;
> > struct mv_xor_chan *channels[MV_XOR_MAX_CHANNELS];
> > int xor_type;
> > + spinlock_t win_lock;
> >
> > u32 win_start[WINDOW_COUNT];
> > u32 win_end[WINDOW_COUNT];
> > --
> > 2.55.0
> >
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] dmaengine: mv_xor: protect MBUS window access with a spinlock
2026-09-16 19:34 ` Rosen Penev
@ 2026-09-16 19:46 ` Frank Li
0 siblings, 0 replies; 4+ messages in thread
From: Frank Li @ 2026-09-16 19:46 UTC (permalink / raw)
To: Rosen Penev; +Cc: dmaengine, Vinod Koul, Frank Li, Stefan Roese, open list
On Wed, Sep 16, 2026 at 12:34:31PM -0700, Rosen Penev wrote:
> On Wed, Sep 16, 2026 at 12:07 PM Frank Li <Frank.li@oss.nxp.com> wrote:
> >
> > On Wed, Sep 16, 2026 at 11:26:08AM -0700, Rosen Penev wrote:
> > > mv_xor_add_io_win() reads and writes shared MBUS window registers
> > > and updates the shared win_start/win_end arrays in mv_xor_device.
> > > Multiple DMA channels can call this function concurrently via
> > > mv_xor_prep_dma_xor(), leading to races where two threads can
> > > select the same free window slot, corrupt the registers, or produce
> > > inconsistent cached state.
> > >
> > > Add a spinlock to struct mv_xor_device and hold it across the
> > > register read-modify-write and cache update in mv_xor_add_io_win().
> > >
> > > Fixes: 77ff7a706f01 ("mv_xor: Add support for IO (PCIe) src/dst areas")
> > > Assisted-by: LLM
> > > Signed-off-by: Rosen Penev <rosenp@gmail.com>
> > > ---
> > > drivers/dma/mv_xor.c | 15 +++++++++++++--
> > > drivers/dma/mv_xor.h | 1 +
> > > 2 files changed, 14 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/drivers/dma/mv_xor.c b/drivers/dma/mv_xor.c
> > > index 0de2b1ad5c30..e7c6ec54ce25 100644
> > > --- a/drivers/dma/mv_xor.c
> > > +++ b/drivers/dma/mv_xor.c
> > > @@ -497,11 +497,14 @@ static int mv_xor_add_io_win(struct mv_xor_chan *mv_chan, u32 addr)
> > > u8 target, attr;
> > > int ret;
> > > int i;
> > > + unsigned long flags;
> > >
> > > /* Nothing needs to get done for the Armada 3700 */
> > > if (xordev->xor_type == XOR_ARMADA_37XX)
> > > return 0;
> > >
> > > + spin_lock_irqsave(&xordev->win_lock, flags);
> > > +
> >
> > use auto clean up guard()
> Could that be backported though?
I think it should be fine now. guard() already use quick popular.
Frank
> >
> > Frank
> > > /*
> > > * Loop over the cached windows to check, if the requested area
> > > * is already mapped. If this the case, nothing needs to be done
> > > @@ -511,6 +514,7 @@ static int mv_xor_add_io_win(struct mv_xor_chan *mv_chan, u32 addr)
> > > if (addr >= xordev->win_start[i] &&
> > > addr <= xordev->win_end[i]) {
> > > /* Window is already mapped */
> > > + spin_unlock_irqrestore(&xordev->win_lock, flags);
> > > return 0;
> > > }
> > > }
> > > @@ -521,8 +525,10 @@ static int mv_xor_add_io_win(struct mv_xor_chan *mv_chan, u32 addr)
> > >
> > > /* If no IO window is found that addr has to be located in SDRAM */
> > > ret = mvebu_mbus_get_io_win_info(addr, &size, &target, &attr);
> > > - if (ret < 0)
> > > + if (ret < 0) {
> > > + spin_unlock_irqrestore(&xordev->win_lock, flags);
> > > return 0;
> > > + }
> > >
> > > /*
> > > * Mask the base addr 'addr' according to 'size' read back from the
> > > @@ -540,8 +546,10 @@ static int mv_xor_add_io_win(struct mv_xor_chan *mv_chan, u32 addr)
> > >
> > > /* Set 'i' to the first free window to write the new values to */
> > > i = ffs(~win_enable) - 1;
> > > - if (i >= WINDOW_COUNT)
> > > + if (i >= WINDOW_COUNT) {
> > > + spin_unlock_irqrestore(&xordev->win_lock, flags);
> > > return -ENOMEM;
> > > + }
> > >
> > > writel((addr & 0xffff0000) | (attr << 8) | target,
> > > base + WINDOW_BASE(i));
> > > @@ -556,6 +564,8 @@ static int mv_xor_add_io_win(struct mv_xor_chan *mv_chan, u32 addr)
> > > writel(win_enable, base + WINDOW_BAR_ENABLE(0));
> > > writel(win_enable, base + WINDOW_BAR_ENABLE(1));
> > >
> > > + spin_unlock_irqrestore(&xordev->win_lock, flags);
> > > +
> > > return 0;
> > > }
> > >
> > > @@ -1353,6 +1363,7 @@ static int mv_xor_probe(struct platform_device *pdev)
> > >
> > > platform_set_drvdata(pdev, xordev);
> > >
> > > + spin_lock_init(&xordev->win_lock);
> > >
> > > /*
> > > * We need to know which type of XOR device we use before
> > > diff --git a/drivers/dma/mv_xor.h b/drivers/dma/mv_xor.h
> > > index c87cefd38a07..034db4d0bfb1 100644
> > > --- a/drivers/dma/mv_xor.h
> > > +++ b/drivers/dma/mv_xor.h
> > > @@ -80,6 +80,7 @@ struct mv_xor_device {
> > > struct clk *clk;
> > > struct mv_xor_chan *channels[MV_XOR_MAX_CHANNELS];
> > > int xor_type;
> > > + spinlock_t win_lock;
> > >
> > > u32 win_start[WINDOW_COUNT];
> > > u32 win_end[WINDOW_COUNT];
> > > --
> > > 2.55.0
> > >
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2026-09-16 19:46 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2026-09-16 18:26 [PATCH] dmaengine: mv_xor: protect MBUS window access with a spinlock Rosen Penev
2026-09-16 19:07 ` Frank Li
2026-09-16 19:34 ` Rosen Penev
2026-09-16 19:46 ` Frank Li
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