[PATCH] efi: cper: Fix endianness of PCIe class code

[PATCH] efi: cper: Fix endianness of PCIe class code

[Lukas Wunner]

The CPER parser assumes that the class code is big endian, but at least
on this edk2-derived Intel Purley platform it's little endian:

    efi: EFI v2.50 by EDK II BIOS ID:PLYDCRB1.86B.0119.R05.1701181843
    DMI: Intel Corporation PURLEY/PURLEY, BIOS PLYDCRB1.86B.0119.R05.1701181843 01/18/2017

    {1}[Hardware Error]:   device_id: 0000:5d:00.0
    {1}[Hardware Error]:   slot: 0
    {1}[Hardware Error]:   secondary_bus: 0x5e
    {1}[Hardware Error]:   vendor_id: 0x8086, device_id: 0x2030
    {1}[Hardware Error]:   class_code: 000406
                                       ^^^^^^ (should be 060400)

Signed-off-by: Lukas Wunner <lukas@wunner.de>
---
 drivers/firmware/efi/cper.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/firmware/efi/cper.c b/drivers/firmware/efi/cper.c
index addf0749dd8b..b1af0de2e100 100644
--- a/drivers/firmware/efi/cper.c
+++ b/drivers/firmware/efi/cper.c
@@ -381,7 +381,7 @@ static void cper_print_pcie(const char *pfx, const struct cper_sec_pcie *pcie,
 		printk("%s""vendor_id: 0x%04x, device_id: 0x%04x\n", pfx,
 		       pcie->device_id.vendor_id, pcie->device_id.device_id);
 		p = pcie->device_id.class_code;
-		printk("%s""class_code: %02x%02x%02x\n", pfx, p[0], p[1], p[2]);
+		printk("%s""class_code: %02x%02x%02x\n", pfx, p[2], p[1], p[0]);
 	}
 	if (pcie->validation_bits & CPER_PCIE_VALID_SERIAL_NUMBER)
 		printk("%s""serial number: 0x%04x, 0x%04x\n", pfx,
-- 
2.20.1

Re: [PATCH] efi: cper: Fix endianness of PCIe class code

[Ard Biesheuvel]

On Sun, 25 Aug 2019 at 10:04, Lukas Wunner <lukas@wunner.de> wrote:
>
> The CPER parser assumes that the class code is big endian, but at least
> on this edk2-derived Intel Purley platform it's little endian:
>
>     efi: EFI v2.50 by EDK II BIOS ID:PLYDCRB1.86B.0119.R05.1701181843
>     DMI: Intel Corporation PURLEY/PURLEY, BIOS PLYDCRB1.86B.0119.R05.1701181843 01/18/2017
>
>     {1}[Hardware Error]:   device_id: 0000:5d:00.0
>     {1}[Hardware Error]:   slot: 0
>     {1}[Hardware Error]:   secondary_bus: 0x5e
>     {1}[Hardware Error]:   vendor_id: 0x8086, device_id: 0x2030
>     {1}[Hardware Error]:   class_code: 000406
>                                        ^^^^^^ (should be 060400)
>
> Signed-off-by: Lukas Wunner <lukas@wunner.de>
> ---
>  drivers/firmware/efi/cper.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/firmware/efi/cper.c b/drivers/firmware/efi/cper.c
> index addf0749dd8b..b1af0de2e100 100644
> --- a/drivers/firmware/efi/cper.c
> +++ b/drivers/firmware/efi/cper.c
> @@ -381,7 +381,7 @@ static void cper_print_pcie(const char *pfx, const struct cper_sec_pcie *pcie,
>                 printk("%s""vendor_id: 0x%04x, device_id: 0x%04x\n", pfx,
>                        pcie->device_id.vendor_id, pcie->device_id.device_id);
>                 p = pcie->device_id.class_code;
> -               printk("%s""class_code: %02x%02x%02x\n", pfx, p[0], p[1], p[2]);
> +               printk("%s""class_code: %02x%02x%02x\n", pfx, p[2], p[1], p[0]);
>         }
>         if (pcie->validation_bits & CPER_PCIE_VALID_SERIAL_NUMBER)
>                 printk("%s""serial number: 0x%04x, 0x%04x\n", pfx,

Class codes are always in that order, so the original code is simply wrong.

Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

I'll get this queued shortly.

Thanks,