* [PATCH v2 0/2] Fix find_first_zero_bit() usage
@ 2017-11-17 15:00 Niklas Cassel
2017-11-17 15:00 ` [PATCH v2 1/2] PCI: designware-ep: " Niklas Cassel
2017-11-17 15:00 ` [PATCH v2 2/2] PCI: endpoint: " Niklas Cassel
0 siblings, 2 replies; 6+ messages in thread
From: Niklas Cassel @ 2017-11-17 15:00 UTC (permalink / raw)
To: linux-pci; +Cc: Niklas Cassel, linux-kernel
From: Niklas Cassel <niklass@axis.com>
find_first_zero_bit()'s parameter 'size' is defined in bits,
not in bytes.
Calling find_first_zero_bit() with the wrong size unit
will lead to insidious bugs.
Fix all uses of find_first_zero_bit() called with
sizeof() as size argument in drivers/pci.
Niklas Cassel (2):
PCI: designware-ep: Fix find_first_zero_bit() usage
PCI: endpoint: Fix find_first_zero_bit() usage
drivers/pci/dwc/pcie-designware-ep.c | 6 ++----
drivers/pci/endpoint/pci-ep-cfs.c | 3 +--
2 files changed, 3 insertions(+), 6 deletions(-)
--
2.14.2
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH v2 1/2] PCI: designware-ep: Fix find_first_zero_bit() usage
2017-11-17 15:00 [PATCH v2 0/2] Fix find_first_zero_bit() usage Niklas Cassel
@ 2017-11-17 15:00 ` Niklas Cassel
2017-11-17 18:43 ` Lorenzo Pieralisi
2017-11-17 15:00 ` [PATCH v2 2/2] PCI: endpoint: " Niklas Cassel
1 sibling, 1 reply; 6+ messages in thread
From: Niklas Cassel @ 2017-11-17 15:00 UTC (permalink / raw)
To: Jingoo Han, Joao Pinto, Lorenzo Pieralisi, Bjorn Helgaas
Cc: Niklas Cassel, linux-pci, linux-kernel
find_first_zero_bit()'s parameter 'size' is defined in bits,
not in bytes.
find_first_zero_bit() was called with size in bytes rather than bits,
which thus defined a too low upper limit, causing
dw_pcie_ep_inbound_atu() to assign iatu index #4 to both bar 4
and bar 5, which made bar 5 overwrite the settings set by bar 4.
Fix this by using replacing find_first_zero_bit() with ffz(),
since ffz() only works on a single 'unsigned long' and therefore
does not need a size argument.
Fixes: f8aed6ec624f ("PCI: dwc: designware: Add EP mode support")
Signed-off-by: Niklas Cassel <niklas.cassel@axis.com>
---
drivers/pci/dwc/pcie-designware-ep.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/drivers/pci/dwc/pcie-designware-ep.c b/drivers/pci/dwc/pcie-designware-ep.c
index d53d5f168363..ab9a9e160daf 100644
--- a/drivers/pci/dwc/pcie-designware-ep.c
+++ b/drivers/pci/dwc/pcie-designware-ep.c
@@ -70,8 +70,7 @@ static int dw_pcie_ep_inbound_atu(struct dw_pcie_ep *ep, enum pci_barno bar,
u32 free_win;
struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
- free_win = find_first_zero_bit(&ep->ib_window_map,
- sizeof(ep->ib_window_map));
+ free_win = ffz(ep->ib_window_map);
if (free_win >= ep->num_ib_windows) {
dev_err(pci->dev, "no free inbound window\n");
return -EINVAL;
@@ -96,8 +95,7 @@ static int dw_pcie_ep_outbound_atu(struct dw_pcie_ep *ep, phys_addr_t phys_addr,
u32 free_win;
struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
- free_win = find_first_zero_bit(&ep->ob_window_map,
- sizeof(ep->ob_window_map));
+ free_win = ffz(ep->ob_window_map);
if (free_win >= ep->num_ob_windows) {
dev_err(pci->dev, "no free outbound window\n");
return -EINVAL;
--
2.14.2
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH v2 2/2] PCI: endpoint: Fix find_first_zero_bit() usage
2017-11-17 15:00 [PATCH v2 0/2] Fix find_first_zero_bit() usage Niklas Cassel
2017-11-17 15:00 ` [PATCH v2 1/2] PCI: designware-ep: " Niklas Cassel
@ 2017-11-17 15:00 ` Niklas Cassel
1 sibling, 0 replies; 6+ messages in thread
From: Niklas Cassel @ 2017-11-17 15:00 UTC (permalink / raw)
To: Kishon Vijay Abraham I, Lorenzo Pieralisi, Bjorn Helgaas
Cc: Niklas Cassel, linux-pci, linux-kernel
find_first_zero_bit()'s parameter 'size' is defined in bits,
not in bytes.
Calling find_first_zero_bit() with the wrong size unit
will lead to insidious bugs.
Fix this by using replacing find_first_zero_bit() with ffz(),
since ffz() only works on a single 'unsigned long' and therefore
does not need a size argument.
Fixes: d74679911610 ("PCI: endpoint: Introduce configfs entry for configuring EP functions")
Signed-off-by: Niklas Cassel <niklas.cassel@axis.com>
---
drivers/pci/endpoint/pci-ep-cfs.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/drivers/pci/endpoint/pci-ep-cfs.c b/drivers/pci/endpoint/pci-ep-cfs.c
index 4f74386c1ced..96b984685640 100644
--- a/drivers/pci/endpoint/pci-ep-cfs.c
+++ b/drivers/pci/endpoint/pci-ep-cfs.c
@@ -108,8 +108,7 @@ static int pci_epc_epf_link(struct config_item *epc_item,
if (ret)
goto err_add_epf;
- func_no = find_first_zero_bit(&epc_group->function_num_map,
- sizeof(epc_group->function_num_map));
+ func_no = ffz(epc_group->function_num_map);
set_bit(func_no, &epc_group->function_num_map);
epf->func_no = func_no;
--
2.14.2
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH v2 1/2] PCI: designware-ep: Fix find_first_zero_bit() usage
2017-11-17 15:00 ` [PATCH v2 1/2] PCI: designware-ep: " Niklas Cassel
@ 2017-11-17 18:43 ` Lorenzo Pieralisi
2017-11-21 7:54 ` Kishon Vijay Abraham I
0 siblings, 1 reply; 6+ messages in thread
From: Lorenzo Pieralisi @ 2017-11-17 18:43 UTC (permalink / raw)
To: Niklas Cassel
Cc: Jingoo Han, Joao Pinto, Bjorn Helgaas, Niklas Cassel, linux-pci,
linux-kernel, kishon
[+Kishon - please CC him next time]
On Fri, Nov 17, 2017 at 04:00:40PM +0100, Niklas Cassel wrote:
> find_first_zero_bit()'s parameter 'size' is defined in bits,
> not in bytes.
>
> find_first_zero_bit() was called with size in bytes rather than bits,
> which thus defined a too low upper limit, causing
> dw_pcie_ep_inbound_atu() to assign iatu index #4 to both bar 4
> and bar 5, which made bar 5 overwrite the settings set by bar 4.
>
> Fix this by using replacing find_first_zero_bit() with ffz(),
> since ffz() only works on a single 'unsigned long' and therefore
> does not need a size argument.
>
> Fixes: f8aed6ec624f ("PCI: dwc: designware: Add EP mode support")
> Signed-off-by: Niklas Cassel <niklas.cassel@axis.com>
> ---
> drivers/pci/dwc/pcie-designware-ep.c | 6 ++----
> 1 file changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/pci/dwc/pcie-designware-ep.c b/drivers/pci/dwc/pcie-designware-ep.c
> index d53d5f168363..ab9a9e160daf 100644
> --- a/drivers/pci/dwc/pcie-designware-ep.c
> +++ b/drivers/pci/dwc/pcie-designware-ep.c
> @@ -70,8 +70,7 @@ static int dw_pcie_ep_inbound_atu(struct dw_pcie_ep *ep, enum pci_barno bar,
> u32 free_win;
> struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
>
> - free_win = find_first_zero_bit(&ep->ib_window_map,
> - sizeof(ep->ib_window_map));
> + free_win = ffz(ep->ib_window_map);
You fix the bug at hand but code suffers from the same issue since we
should be checking the value against ~0UL first ie if size in bits <
num_ib_windows (that I think it is unlikely anyway but while at it let's
think if we can improve this).
@Kishon: maybe we should add a static upper size and declare a
static bitmap accordingly (and still use find_first_zero_bit()) ?
I think the check against ~0UL should be added anyway, let's get
Kishon's opinion before a v3 (if any).
Thanks,
Lorenzo
> if (free_win >= ep->num_ib_windows) {
> dev_err(pci->dev, "no free inbound window\n");
> return -EINVAL;
> @@ -96,8 +95,7 @@ static int dw_pcie_ep_outbound_atu(struct dw_pcie_ep *ep, phys_addr_t phys_addr,
> u32 free_win;
> struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
>
> - free_win = find_first_zero_bit(&ep->ob_window_map,
> - sizeof(ep->ob_window_map));
> + free_win = ffz(ep->ob_window_map);
> if (free_win >= ep->num_ob_windows) {
> dev_err(pci->dev, "no free outbound window\n");
> return -EINVAL;
> --
> 2.14.2
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v2 1/2] PCI: designware-ep: Fix find_first_zero_bit() usage
2017-11-17 18:43 ` Lorenzo Pieralisi
@ 2017-11-21 7:54 ` Kishon Vijay Abraham I
2017-11-21 16:44 ` Lorenzo Pieralisi
0 siblings, 1 reply; 6+ messages in thread
From: Kishon Vijay Abraham I @ 2017-11-21 7:54 UTC (permalink / raw)
To: Lorenzo Pieralisi, Niklas Cassel
Cc: Jingoo Han, Joao Pinto, Bjorn Helgaas, Niklas Cassel, linux-pci,
linux-kernel
Hi Lorenzo,
On Saturday 18 November 2017 12:13 AM, Lorenzo Pieralisi wrote:
> [+Kishon - please CC him next time]
>
> On Fri, Nov 17, 2017 at 04:00:40PM +0100, Niklas Cassel wrote:
>> find_first_zero_bit()'s parameter 'size' is defined in bits,
>> not in bytes.
>>
>> find_first_zero_bit() was called with size in bytes rather than bits,
>> which thus defined a too low upper limit, causing
>> dw_pcie_ep_inbound_atu() to assign iatu index #4 to both bar 4
>> and bar 5, which made bar 5 overwrite the settings set by bar 4.
>>
>> Fix this by using replacing find_first_zero_bit() with ffz(),
>> since ffz() only works on a single 'unsigned long' and therefore
>> does not need a size argument.
>>
>> Fixes: f8aed6ec624f ("PCI: dwc: designware: Add EP mode support")
>> Signed-off-by: Niklas Cassel <niklas.cassel@axis.com>
>> ---
>> drivers/pci/dwc/pcie-designware-ep.c | 6 ++----
>> 1 file changed, 2 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/pci/dwc/pcie-designware-ep.c b/drivers/pci/dwc/pcie-designware-ep.c
>> index d53d5f168363..ab9a9e160daf 100644
>> --- a/drivers/pci/dwc/pcie-designware-ep.c
>> +++ b/drivers/pci/dwc/pcie-designware-ep.c
>> @@ -70,8 +70,7 @@ static int dw_pcie_ep_inbound_atu(struct dw_pcie_ep *ep, enum pci_barno bar,
>> u32 free_win;
>> struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
>>
>> - free_win = find_first_zero_bit(&ep->ib_window_map,
>> - sizeof(ep->ib_window_map));
>> + free_win = ffz(ep->ib_window_map);
>
> You fix the bug at hand but code suffers from the same issue since we
> should be checking the value against ~0UL first ie if size in bits <
> num_ib_windows (that I think it is unlikely anyway but while at it let's
> think if we can improve this).
>
> @Kishon: maybe we should add a static upper size and declare a
> static bitmap accordingly (and still use find_first_zero_bit()) ?
>
> I think the check against ~0UL should be added anyway, let's get
> Kishon's opinion before a v3 (if any).
Yeah, for both ffz and find_first_zero_bit, the results are undefined if no
zero exists.
I'm thinking if we should just use
find_first_zero_bit(&ep->ib_window_map, ep->num_ib_windows) after checking if
there are some '0' bits left.
Thanks
Kishon
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v2 1/2] PCI: designware-ep: Fix find_first_zero_bit() usage
2017-11-21 7:54 ` Kishon Vijay Abraham I
@ 2017-11-21 16:44 ` Lorenzo Pieralisi
0 siblings, 0 replies; 6+ messages in thread
From: Lorenzo Pieralisi @ 2017-11-21 16:44 UTC (permalink / raw)
To: Kishon Vijay Abraham I
Cc: Niklas Cassel, Jingoo Han, Joao Pinto, Bjorn Helgaas,
Niklas Cassel, linux-pci, linux-kernel
On Tue, Nov 21, 2017 at 01:24:53PM +0530, Kishon Vijay Abraham I wrote:
> Hi Lorenzo,
>
> On Saturday 18 November 2017 12:13 AM, Lorenzo Pieralisi wrote:
> > [+Kishon - please CC him next time]
> >
> > On Fri, Nov 17, 2017 at 04:00:40PM +0100, Niklas Cassel wrote:
> >> find_first_zero_bit()'s parameter 'size' is defined in bits,
> >> not in bytes.
> >>
> >> find_first_zero_bit() was called with size in bytes rather than bits,
> >> which thus defined a too low upper limit, causing
> >> dw_pcie_ep_inbound_atu() to assign iatu index #4 to both bar 4
> >> and bar 5, which made bar 5 overwrite the settings set by bar 4.
> >>
> >> Fix this by using replacing find_first_zero_bit() with ffz(),
> >> since ffz() only works on a single 'unsigned long' and therefore
> >> does not need a size argument.
> >>
> >> Fixes: f8aed6ec624f ("PCI: dwc: designware: Add EP mode support")
> >> Signed-off-by: Niklas Cassel <niklas.cassel@axis.com>
> >> ---
> >> drivers/pci/dwc/pcie-designware-ep.c | 6 ++----
> >> 1 file changed, 2 insertions(+), 4 deletions(-)
> >>
> >> diff --git a/drivers/pci/dwc/pcie-designware-ep.c b/drivers/pci/dwc/pcie-designware-ep.c
> >> index d53d5f168363..ab9a9e160daf 100644
> >> --- a/drivers/pci/dwc/pcie-designware-ep.c
> >> +++ b/drivers/pci/dwc/pcie-designware-ep.c
> >> @@ -70,8 +70,7 @@ static int dw_pcie_ep_inbound_atu(struct dw_pcie_ep *ep, enum pci_barno bar,
> >> u32 free_win;
> >> struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
> >>
> >> - free_win = find_first_zero_bit(&ep->ib_window_map,
> >> - sizeof(ep->ib_window_map));
> >> + free_win = ffz(ep->ib_window_map);
> >
> > You fix the bug at hand but code suffers from the same issue since we
> > should be checking the value against ~0UL first ie if size in bits <
> > num_ib_windows (that I think it is unlikely anyway but while at it let's
> > think if we can improve this).
> >
> > @Kishon: maybe we should add a static upper size and declare a
> > static bitmap accordingly (and still use find_first_zero_bit()) ?
> >
> > I think the check against ~0UL should be added anyway, let's get
> > Kishon's opinion before a v3 (if any).
>
> Yeah, for both ffz and find_first_zero_bit, the results are undefined if no
> zero exists.
>
> I'm thinking if we should just use
> find_first_zero_bit(&ep->ib_window_map, ep->num_ib_windows) after checking if
> there are some '0' bits left.
Well yes but first the &ep->ib_window_map must be sized accordingly.
Lorenzo
^ permalink raw reply [flat|nested] 6+ messages in thread
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2017-11-17 15:00 [PATCH v2 0/2] Fix find_first_zero_bit() usage Niklas Cassel
2017-11-17 15:00 ` [PATCH v2 1/2] PCI: designware-ep: " Niklas Cassel
2017-11-17 18:43 ` Lorenzo Pieralisi
2017-11-21 7:54 ` Kishon Vijay Abraham I
2017-11-21 16:44 ` Lorenzo Pieralisi
2017-11-17 15:00 ` [PATCH v2 2/2] PCI: endpoint: " Niklas Cassel
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