powerpc/eeh: Fix oops when probing in early boot

If we take an EEH error early enough, we oops:

Call Trace:
[c000000010483770] [c000000000013ee4] .show_stack+0xd8/0x218 (unreliable)
[c000000010483850] [c000000000658940] .dump_stack+0x28/0x3c
[c0000000104838d0] [c000000000057a68] .eeh_dn_check_failure+0x2b8/0x304
[c000000010483990] [c0000000000259c8] .rtas_read_config+0x120/0x168
[c000000010483a40] [c000000000025af4] .rtas_pci_read_config+0xe4/0x124
[c000000010483af0] [c00000000037af18] .pci_bus_read_config_word+0xac/0x104
[c000000010483bc0] [c0000000008fec98] .pcibios_allocate_resources+0x7c/0x220
[c000000010483c90] [c0000000008feed8] .pcibios_resource_survey+0x9c/0x418
[c000000010483d80] [c0000000008fea10] .pcibios_init+0xbc/0xf4
[c000000010483e20] [c000000000009844] .do_one_initcall+0x98/0x1d8
[c000000010483ed0] [c0000000008f0560] .kernel_init+0x228/0x2e8
[c000000010483f90] [c000000000031a08] .kernel_thread+0x54/0x70
EEH: Detected PCI bus error on device <null>
EEH: This PCI device has failed 1 times in the last hour:
EEH: location=U78A5.001.WIH8464-P1 driver= pci addr=0001:00:01.0
EEH: of node=/pci@800000020000209/usb@1
EEH: PCI device/vendor: 00351033
EEH: PCI cmd/status register: 12100146

Unable to handle kernel paging request for data at address 0x00000468
Oops: Kernel access of bad area, sig: 11 [#1]
....
NIP [c000000000057610] .rtas_set_slot_reset+0x38/0x10c
LR [c000000000058724] .eeh_reset_device+0x5c/0x124
Call Trace:
[c00000000bc6bd00] [c00000000005a0e0] .pcibios_remove_pci_devices+0x7c/0xb0 (unreliable)
[c00000000bc6bd90] [c000000000058724] .eeh_reset_device+0x5c/0x124
[c00000000bc6be40] [c0000000000589c0] .handle_eeh_events+0x1d4/0x39c
[c00000000bc6bf00] [c000000000059124] .eeh_event_handler+0xf0/0x188
[c00000000bc6bf90] [c000000000031a08] .kernel_thread+0x54/0x70

We called rtas_set_slot_reset while scanning the bus and before the pci_dn
to pcidev mapping has been created. Since we only need the pcidev to work
out the type of reset and that only gets set after the module for the
device loads, lets just do a hot reset if the pcidev is NULL.

Signed-off-by: Anton Blanchard <anton@samba.org>
Acked-by: Linas Vepstas <linasvepstas@gmail.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

diff --git a/arch/powerpc/platforms/pseries/eeh.c b/arch/powerpc/platforms/pseries/eeh.c
index 7df7fbb7cacb4e96a558c14b77ec6fba490f60dd..34b7dc12e731231e9c0110bbe7caeda20ec5c0c0 100644 (file)
--- a/arch/powerpc/platforms/pseries/eeh.c
+++ b/arch/powerpc/platforms/pseries/eeh.c
@@ -749,7 +749,7 @@ static void __rtas_set_slot_reset(struct pci_dn *pdn)
        /* Determine type of EEH reset required by device,
         * default hot reset or fundamental reset
         */
-       if (dev->needs_freset)
+       if (dev && dev->needs_freset)
                rtas_pci_slot_reset(pdn, 3);
        else
                rtas_pci_slot_reset(pdn, 1);