[PATCH] powerpc/fsl_pci: Fix pci stack build bug with FRAME_WARN

Fix this:

  CC      arch/powerpc/sysdev/fsl_pci.o
arch/powerpc/sysdev/fsl_pci.c: In function 'fsl_pcie_check_link':
arch/powerpc/sysdev/fsl_pci.c:91:1: error: the frame size of 1360 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]

when configuring FRAME_WARN, by converting the allocation from the
stack to the heap.  We use GFP_ATOMIC since this function can be
called with interrupts disabled.

Signed-off-by: Kim Phillips <redacted>
---
 arch/powerpc/sysdev/fsl_pci.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/sysdev/fsl_pci.c b/arch/powerpc/sysdev/fsl_pci.c
index 6455c1e..635d743 100644
--- a/arch/powerpc/sysdev/fsl_pci.c
+++ b/arch/powerpc/sysdev/fsl_pci.c

@@ -69,11 +69,13 @@ static int fsl_pcie_check_link(struct pci_controller *hose)
 
 	if (hose->indirect_type & PPC_INDIRECT_TYPE_FSL_CFG_REG_LINK) {
 		if (hose->ops->read == fsl_indirect_read_config) {
-			struct pci_bus bus;
-			bus.number = hose->first_busno;
-			bus.sysdata = hose;
-			bus.ops = hose->ops;
-			indirect_read_config(&bus, 0, PCIE_LTSSM, 4, &val);
+			struct pci_bus *bus;
+			bus = kmalloc(sizeof(*bus), GFP_ATOMIC);
+			bus->number = hose->first_busno;
+			bus->sysdata = hose;
+			bus->ops = hose->ops;
+			indirect_read_config(bus, 0, PCIE_LTSSM, 4, &val);
+			kfree(bus);
 		} else
 			early_read_config_dword(hose, 0, 0, PCIE_LTSSM, &val);
 		if (val < PCIE_LTSSM_L0)

-- 
2.2.2

On Tue, 2015-01-20 at 14:03 -0600, Kim Phillips wrote:

Missing check for allocation failure.

Do we not have a real struct pci_bus we can use here?  Or refactor
indirect_read_config() to take hose and bus number instead?

If putting a pci_bus struct on the stack is no longer OK, then
fake_pci_bus() should be fixed as well.  I wonder if GCC is allocating
separate pci_bus structs on the stack for this one and the one that
early_read_config_dword() uses...

-Scott

On Tue, 20 Jan 2015 18:31:32 -0600
Scott Wood [off-list ref] wrote:

On Tue, 2015-01-20 at 14:03 -0600, Kim Phillips wrote:

quoted

Fix this:

  CC      arch/powerpc/sysdev/fsl_pci.o
arch/powerpc/sysdev/fsl_pci.c: In function 'fsl_pcie_check_link':
arch/powerpc/sysdev/fsl_pci.c:91:1: error: the frame size of 1360 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]

when configuring FRAME_WARN, by converting the allocation from the
stack to the heap.  We use GFP_ATOMIC since this function can be
called with interrupts disabled.

Signed-off-by: Kim Phillips <redacted>
---
 arch/powerpc/sysdev/fsl_pci.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/sysdev/fsl_pci.c b/arch/powerpc/sysdev/fsl_pci.c
index 6455c1e..635d743 100644
--- a/arch/powerpc/sysdev/fsl_pci.c
+++ b/arch/powerpc/sysdev/fsl_pci.c

@@ -69,11 +69,13 @@ static int fsl_pcie_check_link(struct pci_controller *hose)
 
 	if (hose->indirect_type & PPC_INDIRECT_TYPE_FSL_CFG_REG_LINK) {
 		if (hose->ops->read == fsl_indirect_read_config) {
-			struct pci_bus bus;
-			bus.number = hose->first_busno;
-			bus.sysdata = hose;
-			bus.ops = hose->ops;
-			indirect_read_config(&bus, 0, PCIE_LTSSM, 4, &val);
+			struct pci_bus *bus;
+			bus = kmalloc(sizeof(*bus), GFP_ATOMIC);
+			bus->number = hose->first_busno;

Missing check for allocation failure.

thanks.

Do we not have a real struct pci_bus we can use here?  Or refactor
indirect_read_config() to take hose and bus number instead?

indirect_read_config() can't be refactored because it is also used
in the generic struct pci_ops.  Unless you mean making an
__indirect_read_config that the original would call, but that
doesn't look that trivial given it calls pci_exclude_device with a
struct pci_controller hose.

If putting a pci_bus struct on the stack is no longer OK, then
fake_pci_bus() should be fixed as well.  I wonder if GCC is allocating
separate pci_bus structs on the stack for this one and the one that
early_read_config_dword() uses...

fake_pci_bus()' version is static, so it's not on the stack.

given that, maybe fsl_pcie_check_link()'s should be static too?

Kim

On Wed, 2015-01-21 at 20:48 -0600, Kim Phillips wrote:

On Tue, 20 Jan 2015 18:31:32 -0600
Scott Wood [off-list ref] wrote:

quoted

On Tue, 2015-01-20 at 14:03 -0600, Kim Phillips wrote:

quoted

Fix this:

  CC      arch/powerpc/sysdev/fsl_pci.o
arch/powerpc/sysdev/fsl_pci.c: In function 'fsl_pcie_check_link':
arch/powerpc/sysdev/fsl_pci.c:91:1: error: the frame size of 1360 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]

when configuring FRAME_WARN, by converting the allocation from the
stack to the heap.  We use GFP_ATOMIC since this function can be
called with interrupts disabled.

Signed-off-by: Kim Phillips <redacted>
---
 arch/powerpc/sysdev/fsl_pci.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/sysdev/fsl_pci.c b/arch/powerpc/sysdev/fsl_pci.c
index 6455c1e..635d743 100644
--- a/arch/powerpc/sysdev/fsl_pci.c
+++ b/arch/powerpc/sysdev/fsl_pci.c

@@ -69,11 +69,13 @@ static int fsl_pcie_check_link(struct pci_controller *hose)
 
 	if (hose->indirect_type & PPC_INDIRECT_TYPE_FSL_CFG_REG_LINK) {
 		if (hose->ops->read == fsl_indirect_read_config) {
-			struct pci_bus bus;
-			bus.number = hose->first_busno;
-			bus.sysdata = hose;
-			bus.ops = hose->ops;
-			indirect_read_config(&bus, 0, PCIE_LTSSM, 4, &val);
+			struct pci_bus *bus;
+			bus = kmalloc(sizeof(*bus), GFP_ATOMIC);
+			bus->number = hose->first_busno;

Missing check for allocation failure.

thanks.

quoted

Do we not have a real struct pci_bus we can use here?  Or refactor
indirect_read_config() to take hose and bus number instead?

indirect_read_config() can't be refactored because it is also used
in the generic struct pci_ops.  Unless you mean making an
__indirect_read_config that the original would call, 

Yes, that's what I mean.

but that doesn't look that trivial given it calls pci_exclude_device with a
struct pci_controller hose.

Check for excluded devices in indirect_read_config(), not
__indirect_read_config().

quoted

If putting a pci_bus struct on the stack is no longer OK, then
fake_pci_bus() should be fixed as well.  I wonder if GCC is allocating
separate pci_bus structs on the stack for this one and the one that
early_read_config_dword() uses...

fake_pci_bus()' version is static, so it's not on the stack.

given that, maybe fsl_pcie_check_link()'s should be static too?

Oh.  How would you ensure that it's only called once at a time?  It
doesn't look like this is only called during early boot.
fsl_pcie_check_link() is called every time we do any config read through
the normal interface.  This is also a concern for the call to
early_read_config_dword().

-Scott

On Wed, 21 Jan 2015 21:02:27 -0600
Scott Wood [off-list ref] wrote:

On Wed, 2015-01-21 at 20:48 -0600, Kim Phillips wrote:

quoted

On Tue, 20 Jan 2015 18:31:32 -0600
Scott Wood [off-list ref] wrote:

quoted

On Tue, 2015-01-20 at 14:03 -0600, Kim Phillips wrote:

quoted

Fix this:

  CC      arch/powerpc/sysdev/fsl_pci.o
arch/powerpc/sysdev/fsl_pci.c: In function 'fsl_pcie_check_link':
arch/powerpc/sysdev/fsl_pci.c:91:1: error: the frame size of 1360 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]

when configuring FRAME_WARN, by converting the allocation from the
stack to the heap.  We use GFP_ATOMIC since this function can be
called with interrupts disabled.

Signed-off-by: Kim Phillips <redacted>
---
 arch/powerpc/sysdev/fsl_pci.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/sysdev/fsl_pci.c b/arch/powerpc/sysdev/fsl_pci.c
index 6455c1e..635d743 100644
--- a/arch/powerpc/sysdev/fsl_pci.c
+++ b/arch/powerpc/sysdev/fsl_pci.c

@@ -69,11 +69,13 @@ static int fsl_pcie_check_link(struct pci_controller *hose)
 
 	if (hose->indirect_type & PPC_INDIRECT_TYPE_FSL_CFG_REG_LINK) {
 		if (hose->ops->read == fsl_indirect_read_config) {
-			struct pci_bus bus;
-			bus.number = hose->first_busno;
-			bus.sysdata = hose;
-			bus.ops = hose->ops;
-			indirect_read_config(&bus, 0, PCIE_LTSSM, 4, &val);
+			struct pci_bus *bus;
+			bus = kmalloc(sizeof(*bus), GFP_ATOMIC);
+			bus->number = hose->first_busno;

Missing check for allocation failure.

thanks.

quoted

Do we not have a real struct pci_bus we can use here?  Or refactor
indirect_read_config() to take hose and bus number instead?

indirect_read_config() can't be refactored because it is also used
in the generic struct pci_ops.  Unless you mean making an
__indirect_read_config that the original would call, 

Yes, that's what I mean.

quoted

but that doesn't look that trivial given it calls pci_exclude_device with a
struct pci_controller hose.

Check for excluded devices in indirect_read_config(), not
__indirect_read_config().

turns out it wasn't an issue; see below for a v2.

quoted

quoted

If putting a pci_bus struct on the stack is no longer OK, then
fake_pci_bus() should be fixed as well.  I wonder if GCC is allocating
separate pci_bus structs on the stack for this one and the one that
early_read_config_dword() uses...

fake_pci_bus()' version is static, so it's not on the stack.

given that, maybe fsl_pcie_check_link()'s should be static too?

Oh.  How would you ensure that it's only called once at a time?  It
doesn't look like this is only called during early boot.
fsl_pcie_check_link() is called every time we do any config read through
the normal interface.  This is also a concern for the call to
early_read_config_dword().

I really don't know how that works: that code has been there since
before linux was maintained in git.

Below is the v2.

Thanks,

Kim.

From aac5aa245949ea3dadae9ea913d67c456f558a0c Mon Sep 17 00:00:00 2001

From: Kim Phillips <redacted>
Date: Tue, 20 Jan 2015 14:03:49 -0600
Subject: [PATCH v2] powerpc/fsl_pci: Fix pci stack build bug with FRAME_WARN

Fix this:

  CC      arch/powerpc/sysdev/fsl_pci.o
arch/powerpc/sysdev/fsl_pci.c: In function 'fsl_pcie_check_link':
arch/powerpc/sysdev/fsl_pci.c:91:1: error: the frame size of 1360 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]

when configuring FRAME_WARN, by refactoring indirect_read_config()
to take hose and bus number instead of the 1344-byte struct pci_bus.

Signed-off-by: Kim Phillips <redacted>
---
v2: refactor indirect_read_config() instead of kmalloc'ing a struct
pci_bus.

 arch/powerpc/include/asm/pci-bridge.h |  4 ++++
 arch/powerpc/sysdev/fsl_pci.c         | 11 ++++-------
 arch/powerpc/sysdev/indirect_pci.c    | 25 +++++++++++++++++--------
 3 files changed, 25 insertions(+), 15 deletions(-)

diff --git a/arch/powerpc/include/asm/pci-bridge.h b/arch/powerpc/include/asm/pci-bridge.h
index 725247b..546d036 100644
--- a/arch/powerpc/include/asm/pci-bridge.h
+++ b/arch/powerpc/include/asm/pci-bridge.h

@@ -119,6 +119,10 @@ extern void setup_indirect_pci(struct pci_controller* hose,
 extern int indirect_read_config(struct pci_bus *bus, unsigned int devfn,
 				int offset, int len, u32 *val);
 
+extern int __indirect_read_config(struct pci_controller *hose,
+				  unsigned char bus_number, unsigned int devfn,
+				  int offset, int len, u32 *val);
+
 extern int indirect_write_config(struct pci_bus *bus, unsigned int devfn,
 				 int offset, int len, u32 val);
 

diff --git a/arch/powerpc/sysdev/fsl_pci.c b/arch/powerpc/sysdev/fsl_pci.c
index 6455c1e..7cc215e 100644
--- a/arch/powerpc/sysdev/fsl_pci.c
+++ b/arch/powerpc/sysdev/fsl_pci.c

@@ -68,13 +68,10 @@ static int fsl_pcie_check_link(struct pci_controller *hose)
 	u32 val = 0;
 
 	if (hose->indirect_type & PPC_INDIRECT_TYPE_FSL_CFG_REG_LINK) {
-		if (hose->ops->read == fsl_indirect_read_config) {
-			struct pci_bus bus;
-			bus.number = hose->first_busno;
-			bus.sysdata = hose;
-			bus.ops = hose->ops;
-			indirect_read_config(&bus, 0, PCIE_LTSSM, 4, &val);
-		} else
+		if (hose->ops->read == fsl_indirect_read_config)
+			__indirect_read_config(hose, hose->first_busno, 0,
+					       PCIE_LTSSM, 4, &val);
+		else
 			early_read_config_dword(hose, 0, 0, PCIE_LTSSM, &val);
 		if (val < PCIE_LTSSM_L0)
 			return 1;

diff --git a/arch/powerpc/sysdev/indirect_pci.c b/arch/powerpc/sysdev/indirect_pci.c
index 1f6c570..692de9d 100644
--- a/arch/powerpc/sysdev/indirect_pci.c
+++ b/arch/powerpc/sysdev/indirect_pci.c

@@ -20,31 +20,31 @@
 #include <asm/pci-bridge.h>
 #include <asm/machdep.h>
 
-int indirect_read_config(struct pci_bus *bus, unsigned int devfn,
-			 int offset, int len, u32 *val)
+int __indirect_read_config(struct pci_controller *hose,
+			   unsigned char bus_number, unsigned int devfn,
+			   int offset, int len, u32 *val)
 {
-	struct pci_controller *hose = pci_bus_to_host(bus);
 	volatile void __iomem *cfg_data;
 	u8 cfg_type = 0;
 	u32 bus_no, reg;
 
 	if (hose->indirect_type & PPC_INDIRECT_TYPE_NO_PCIE_LINK) {
-		if (bus->number != hose->first_busno)
+		if (bus_number != hose->first_busno)
 			return PCIBIOS_DEVICE_NOT_FOUND;
 		if (devfn != 0)
 			return PCIBIOS_DEVICE_NOT_FOUND;
 	}
 
 	if (ppc_md.pci_exclude_device)
-		if (ppc_md.pci_exclude_device(hose, bus->number, devfn))
+		if (ppc_md.pci_exclude_device(hose, bus_number, devfn))
 			return PCIBIOS_DEVICE_NOT_FOUND;
 
 	if (hose->indirect_type & PPC_INDIRECT_TYPE_SET_CFG_TYPE)
-		if (bus->number != hose->first_busno)
+		if (bus_number != hose->first_busno)
 			cfg_type = 1;
 
-	bus_no = (bus->number == hose->first_busno) ?
-			hose->self_busno : bus->number;
+	bus_no = (bus_number == hose->first_busno) ?
+			hose->self_busno : bus_number;
 
 	if (hose->indirect_type & PPC_INDIRECT_TYPE_EXT_REG)
 		reg = ((offset & 0xf00) << 16) | (offset & 0xfc);

@@ -77,6 +77,15 @@ int indirect_read_config(struct pci_bus *bus, unsigned int devfn,
 	return PCIBIOS_SUCCESSFUL;
 }
 
+int indirect_read_config(struct pci_bus *bus, unsigned int devfn,
+			 int offset, int len, u32 *val)
+{
+	struct pci_controller *hose = pci_bus_to_host(bus);
+
+	return __indirect_read_config(hose, bus->number, devfn, offset, len,
+				      val);
+}
+
 int indirect_write_config(struct pci_bus *bus, unsigned int devfn,
 			  int offset, int len, u32 val)
 {

-- 
2.2.2

On Thu, 2015-01-22 at 18:20 -0600, Kim Phillips wrote:

On Wed, 21 Jan 2015 21:02:27 -0600
Scott Wood [off-list ref] wrote:

quoted

On Wed, 2015-01-21 at 20:48 -0600, Kim Phillips wrote:

quoted

fake_pci_bus()' version is static, so it's not on the stack.

given that, maybe fsl_pcie_check_link()'s should be static too?

Oh.  How would you ensure that it's only called once at a time?  It
doesn't look like this is only called during early boot.
fsl_pcie_check_link() is called every time we do any config read through
the normal interface.  This is also a concern for the call to
early_read_config_dword().

I really don't know how that works: that code has been there since
before linux was maintained in git.

Regardless, now that it's been noticed we should figure it out.
fsl_pcie_check_link() is using the early_*() functions in a context that
is not early and thus appears to be breaking the assumption that
fake_pci_bus() makes.

fsl_pcie_check_link() is fairly recent, FWIW.

Below is the v2.

Please send as a standalone patch so I don't have to edit all the
discussion out of the commit message.

-Scott

Fix this:

  CC      arch/powerpc/sysdev/fsl_pci.o
arch/powerpc/sysdev/fsl_pci.c: In function 'fsl_pcie_check_link':
arch/powerpc/sysdev/fsl_pci.c:91:1: error: the frame size of 1360 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]

when configuring FRAME_WARN, by refactoring indirect_read_config()
to take hose and bus number instead of the 1344-byte struct pci_bus.

Signed-off-by: Kim Phillips <redacted>
---
v2: refactor indirect_read_config() instead of kmalloc'ing a struct
pci_bus.

Scott, I will look deeper into fake_pci_bus() later.

 arch/powerpc/include/asm/pci-bridge.h |  4 ++++
 arch/powerpc/sysdev/fsl_pci.c         | 11 ++++-------
 arch/powerpc/sysdev/indirect_pci.c    | 25 +++++++++++++++++--------
 3 files changed, 25 insertions(+), 15 deletions(-)

diff --git a/arch/powerpc/include/asm/pci-bridge.h b/arch/powerpc/include/asm/pci-bridge.h
index 725247b..546d036 100644
--- a/arch/powerpc/include/asm/pci-bridge.h
+++ b/arch/powerpc/include/asm/pci-bridge.h

@@ -119,6 +119,10 @@ extern void setup_indirect_pci(struct pci_controller* hose,
 extern int indirect_read_config(struct pci_bus *bus, unsigned int devfn,
 				int offset, int len, u32 *val);
 
+extern int __indirect_read_config(struct pci_controller *hose,
+				  unsigned char bus_number, unsigned int devfn,
+				  int offset, int len, u32 *val);
+
 extern int indirect_write_config(struct pci_bus *bus, unsigned int devfn,
 				 int offset, int len, u32 val);
 

diff --git a/arch/powerpc/sysdev/fsl_pci.c b/arch/powerpc/sysdev/fsl_pci.c
index 6455c1e..7cc215e 100644
--- a/arch/powerpc/sysdev/fsl_pci.c
+++ b/arch/powerpc/sysdev/fsl_pci.c

@@ -68,13 +68,10 @@ static int fsl_pcie_check_link(struct pci_controller *hose)
 	u32 val = 0;
 
 	if (hose->indirect_type & PPC_INDIRECT_TYPE_FSL_CFG_REG_LINK) {
-		if (hose->ops->read == fsl_indirect_read_config) {
-			struct pci_bus bus;
-			bus.number = hose->first_busno;
-			bus.sysdata = hose;
-			bus.ops = hose->ops;
-			indirect_read_config(&bus, 0, PCIE_LTSSM, 4, &val);
-		} else
+		if (hose->ops->read == fsl_indirect_read_config)
+			__indirect_read_config(hose, hose->first_busno, 0,
+					       PCIE_LTSSM, 4, &val);
+		else
 			early_read_config_dword(hose, 0, 0, PCIE_LTSSM, &val);
 		if (val < PCIE_LTSSM_L0)
 			return 1;

diff --git a/arch/powerpc/sysdev/indirect_pci.c b/arch/powerpc/sysdev/indirect_pci.c
index 1f6c570..692de9d 100644
--- a/arch/powerpc/sysdev/indirect_pci.c
+++ b/arch/powerpc/sysdev/indirect_pci.c

@@ -20,31 +20,31 @@
 #include <asm/pci-bridge.h>
 #include <asm/machdep.h>
 
-int indirect_read_config(struct pci_bus *bus, unsigned int devfn,
-			 int offset, int len, u32 *val)
+int __indirect_read_config(struct pci_controller *hose,
+			   unsigned char bus_number, unsigned int devfn,
+			   int offset, int len, u32 *val)
 {
-	struct pci_controller *hose = pci_bus_to_host(bus);
 	volatile void __iomem *cfg_data;
 	u8 cfg_type = 0;
 	u32 bus_no, reg;
 
 	if (hose->indirect_type & PPC_INDIRECT_TYPE_NO_PCIE_LINK) {
-		if (bus->number != hose->first_busno)
+		if (bus_number != hose->first_busno)
 			return PCIBIOS_DEVICE_NOT_FOUND;
 		if (devfn != 0)
 			return PCIBIOS_DEVICE_NOT_FOUND;
 	}
 
 	if (ppc_md.pci_exclude_device)
-		if (ppc_md.pci_exclude_device(hose, bus->number, devfn))
+		if (ppc_md.pci_exclude_device(hose, bus_number, devfn))
 			return PCIBIOS_DEVICE_NOT_FOUND;
 
 	if (hose->indirect_type & PPC_INDIRECT_TYPE_SET_CFG_TYPE)
-		if (bus->number != hose->first_busno)
+		if (bus_number != hose->first_busno)
 			cfg_type = 1;
 
-	bus_no = (bus->number == hose->first_busno) ?
-			hose->self_busno : bus->number;
+	bus_no = (bus_number == hose->first_busno) ?
+			hose->self_busno : bus_number;
 
 	if (hose->indirect_type & PPC_INDIRECT_TYPE_EXT_REG)
 		reg = ((offset & 0xf00) << 16) | (offset & 0xfc);

@@ -77,6 +77,15 @@ int indirect_read_config(struct pci_bus *bus, unsigned int devfn,
 	return PCIBIOS_SUCCESSFUL;
 }
 
+int indirect_read_config(struct pci_bus *bus, unsigned int devfn,
+			 int offset, int len, u32 *val)
+{
+	struct pci_controller *hose = pci_bus_to_host(bus);
+
+	return __indirect_read_config(hose, bus->number, devfn, offset, len,
+				      val);
+}
+
 int indirect_write_config(struct pci_bus *bus, unsigned int devfn,
 			  int offset, int len, u32 val)
 {

-- 
2.2.2