Re: [PATCH v2] PCI: keystone: fix msi code that retrieves the pp struct ptr

[Bjorn Helgaas]

[-cc stable, +cc Zhou]

On Mon, Feb 29, 2016 at 10:51:53AM -0500, Murali Karicheri wrote:
> Recent update to pcie-designware core driver, 
> 'commit cbce7900598c ("PCI: designware: Make driver arch-agnostic")'
> broke the keystone PCI driver. After this commit, we see a kernel crash on
> Keystone SoC as shown below in the boot log. This is because, the way pp
> struct ptr is retrieved from  msi desc has changed and require similar
> update in pci-keystone-dw.c as well. This patch fixes this issue. 
> 
> [    1.012999] pci 0000:00:00.0: PCI bridge to [bus 01]
> [    1.018073] pci 0000:00:00.0:   bridge window [io  0x1000-0x1fff]
> [    1.024308] pci 0000:00:00.0:   bridge window [mem 0x60000000-0x600fffff]
> [    1.031216] pci 0000:00:00.0:   bridge window [mem 0x60100000-0x601fffff
> pref]
> [    1.038736] Unable to handle kernel NULL pointer dereference at virtual
> address 00000030
> [    1.046950] pgd = c0003000
> [    1.049750] [00000030] *pgd=80000800004003, *pmd=00000000
> [    1.055265] Internal error: Oops: 206 [#1] PREEMPT SMP ARM
> [    1.060860] Modules linked in:
> [    1.064013] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.4.2-00139-gb74f926 #2
> [    1.071266] Hardware name: Keystone
> [    1.074853] task: eb888000 ti: eb890000 task.ti: eb890000
> [    1.080364] PC is at ks_dw_pcie_msi_irq_unmask+0x24/0x58
> [    1.085785] LR is at ks_dw_pcie_msi_irq_unmask+0x18/0x58
> [    1.091206] pc : [<c02f65c8>]    lr : [<c02f65bc>]    psr: 60000093
> [    1.091206] sp : eb891bc8  ip : 00000000  fp : ebb15010
> [    1.102915] r10: 00000051  r9 : 60000013  r8 : ebafaa20
> [    1.108247] r7 : ebaa9f80  r6 : eb9fd0c0  r5 : ebafa9d0  r4 : ebafa9c0
> [    1.114889] r3 : 00000051  r2 : 00000000  r1 : 00000001  r0 : ebb14c18
> [    1.121533] Flags: nZCv  IRQs off  FIQs on  Mode SVC_32  ISA ARM  Segment
> kernel
> [    1.129049] Control: 30c5387d  Table: 00003000  DAC: fffffffd
> [    1.134905] Process swapper/0 (pid: 1, stack limit = 0xeb890210)
> [    1.141023] Stack: (0xeb891bc8 to 0xeb892000)
> 
> Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> Cc: <stable@xxxxxxxxxxxxxxx> # 4.4.x
> Signed-off-by: Murali Karicheri <m-karicheri2@xxxxxx>

This fixes a regression, so I applied this to for-linus for v4.5, with
changelog as follows:

commit 79e3f4a853ed161cd4c06d84b50beebf961a47c6
Author: Murali Karicheri <m-karicheri2@xxxxxx>
Date:   Mon Feb 29 17:18:22 2016 -0600

    PCI: keystone: Fix MSI code that retrieves struct pcie_port pointer
    
    Commit cbce7900598c ("PCI: designware: Make driver arch-agnostic") changed
    the host bridge sysdata pointer from the ARM pci_sys_data to the DesignWare
    pcie_port structure, and changed pcie-designware.c to reflect that.  But it
    did not change the corresponding code in pci-keystone-dw.c, so it caused
    crashes on Keystone:
    
      Unable to handle kernel NULL pointer dereference at virtual address 00000030
      pgd = c0003000
      [00000030] *pgd=80000800004003, *pmd=00000000
      Internal error: Oops: 206 [#1] PREEMPT SMP ARM
      CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.4.2-00139-gb74f926 #2
      Hardware name: Keystone
      PC is at ks_dw_pcie_msi_irq_unmask+0x24/0x58
    
    Change pci-keystone-dw.c to expect sysdata to be the struct pcie_port
    pointer.
    
    [bhelgaas: changelog]
    Fixes: cbce7900598c ("PCI: designware: Make driver arch-agnostic")
    Signed-off-by: Murali Karicheri <m-karicheri2@xxxxxx>
    Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
    CC: stable@xxxxxxxxxxxxxxx	# v4.4+
    CC: Zhou Wang <wangzhou1@xxxxxxxxxxxxx>

> ---
>  v2 - Looks like I missed the fix version format for stable.
>       Fixed it per best of my knowledge.
>  v1 - Resending as per stable submission procedure
>  drivers/pci/host/pci-keystone-dw.c | 11 +++--------
>  1 file changed, 3 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/pci/host/pci-keystone-dw.c b/drivers/pci/host/pci-keystone-dw.c
> index ed34c95..6153853 100644
> --- a/drivers/pci/host/pci-keystone-dw.c
> +++ b/drivers/pci/host/pci-keystone-dw.c
> @@ -58,11 +58,6 @@
>  
>  #define to_keystone_pcie(x)	container_of(x, struct keystone_pcie, pp)
>  
> -static inline struct pcie_port *sys_to_pcie(struct pci_sys_data *sys)
> -{
> -	return sys->private_data;
> -}
> -
>  static inline void update_reg_offset_bit_pos(u32 offset, u32 *reg_offset,
>  					     u32 *bit_pos)
>  {
> @@ -108,7 +103,7 @@ static void ks_dw_pcie_msi_irq_ack(struct irq_data *d)
>  	struct pcie_port *pp;
>  
>  	msi = irq_data_get_msi_desc(d);
> -	pp = sys_to_pcie(msi_desc_to_pci_sysdata(msi));
> +	pp = (struct pcie_port *) msi_desc_to_pci_sysdata(msi);
>  	ks_pcie = to_keystone_pcie(pp);
>  	offset = d->irq - irq_linear_revmap(pp->irq_domain, 0);
>  	update_reg_offset_bit_pos(offset, &reg_offset, &bit_pos);
> @@ -146,7 +141,7 @@ static void ks_dw_pcie_msi_irq_mask(struct irq_data *d)
>  	u32 offset;
>  
>  	msi = irq_data_get_msi_desc(d);
> -	pp = sys_to_pcie(msi_desc_to_pci_sysdata(msi));
> +	pp = (struct pcie_port *) msi_desc_to_pci_sysdata(msi);
>  	ks_pcie = to_keystone_pcie(pp);
>  	offset = d->irq - irq_linear_revmap(pp->irq_domain, 0);
>  
> @@ -167,7 +162,7 @@ static void ks_dw_pcie_msi_irq_unmask(struct irq_data *d)
>  	u32 offset;
>  
>  	msi = irq_data_get_msi_desc(d);
> -	pp = sys_to_pcie(msi_desc_to_pci_sysdata(msi));
> +	pp = (struct pcie_port *) msi_desc_to_pci_sysdata(msi);
>  	ks_pcie = to_keystone_pcie(pp);
>  	offset = d->irq - irq_linear_revmap(pp->irq_domain, 0);
>  
> -- 
> 1.9.1
> 
> --
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