[PATCH] powerpc/pseries: avoid crash in PCI code if mem system not up.

[PATCH] powerpc/pseries: avoid crash in PCI code if mem system not up.

[Linas Vepstas]

Paul,
Please apply and forward upstream.  And a question: once 
upon a time, the arch PCI subsystem was inited after mem init 
was done; currently, it seems to be happening before mem init. 
Is this intentional? 

--linas


[PATCH] powerpc/pseries: avoid crash in PCI code if mem system not up.

The powerpc code is currently performing PCI setup before
memory initialization. PCI setup touches PCI config space
registers. If the PCI card is bad, this will evoke an error,
which currrently can't be handled, as the PCI error recovery 
code expects kmalloc() to be functional.  This patch will
cause the system to punt instead of crashing with

cpu 0x0: Vector: 300 (Data Access) at [c0000000004434d0]
    pc: c0000000000c06b4: .kmem_cache_alloc+0x8c/0xf4
    lr: c00000000004ad6c: .eeh_send_failure_event+0x48/0xfc

This patch Will also print name of the offending pci device.

Signed-off-by: Linas Vepstas <linas@austin.ibm.com>

----

 arch/powerpc/platforms/pseries/eeh_event.c |    9 +++++++++
 1 files changed, 9 insertions(+)

Index: linux-2.6.17-rc1/arch/powerpc/platforms/pseries/eeh_event.c
===================================================================
--- linux-2.6.17-rc1.orig/arch/powerpc/platforms/pseries/eeh_event.c	2006-04-05 09:56:38.000000000 -0500
+++ linux-2.6.17-rc1/arch/powerpc/platforms/pseries/eeh_event.c	2006-04-20 19:29:48.000000000 -0500
@@ -124,7 +124,16 @@ int eeh_send_failure_event (struct devic
 {
 	unsigned long flags;
 	struct eeh_event *event;
+	char *location;
 
+	if (!mem_init_done)
+	{
+		printk(KERN_ERR "EEH: event during early boot not handled\n");
+		location = (char *) get_property(dn, "ibm,loc-code", NULL);
+		printk(KERN_ERR "EEH: device node = %s\n", dn->full_name);
+		printk(KERN_ERR "EEH: PCI location = %s\n", location);
+		return 1;
+	}
 	event = kmalloc(sizeof(*event), GFP_ATOMIC);
 	if (event == NULL) {
 		printk (KERN_ERR "EEH: out of memory, event not handled\n");

Re: [PATCH] powerpc/pseries: avoid crash in PCI code if mem system not up.

[Paul Mackerras]

Linas Vepstas writes:

> Please apply and forward upstream.  And a question: once 
> upon a time, the arch PCI subsystem was inited after mem init 
> was done; currently, it seems to be happening before mem init. 
> Is this intentional? 

No, and it is bogus if it is.  Do you have the full backtrace from the
crash?

Paul.

Re: [PATCH] powerpc/pseries: avoid crash in PCI code if mem system not up.

[Linas Vepstas]

On Fri, Apr 21, 2006 at 10:02:21PM +1000, Paul Mackerras wrote:
> Linas Vepstas writes:
>
> > Please apply and forward upstream.  And a question: once
> > upon a time, the arch PCI subsystem was inited after mem init
> > was done; currently, it seems to be happening before mem init.
> > Is this intentional?
>
> No, and it is bogus if it is.  Do you have the full backtrace from the
> crash?

Yes, below.
The relevant bits are this:

start_kernel() {
  setup_arch() {
     pSeries_setup_arch () {
         eeh_init () {
           ... if err kmalloc()
               crash.
         }
     }
  }
  mem_init()

  // are there other appropriate arch init points
  // ater mem_init() where we can do arch-dependent
  // i/o bridge initialization ??
}

I also remember there being some nastiness re kmalloc
when initializing dlpar/hot-plug PCI slots before
mem_init was done.  Basically, if the hotplug slots
are present at boot time, we can't use kmalloc/kfree
to manage them.

If the arch dependent I/O bridges/subsystem init could
be moved later, maybe this could be fixed as well.

--linas

Linux zImage starting: loaded at 0x00010000-0x00849cbc
(0x0/0x0/0x00c39a48; sp: 0x0181ffd0)
uncompressing ELF header done. (0x00000100 bytes)
Allocated 0x009f9020 bytes for kernel @ 0x02000000
Allocated 0x005f389c bytes for initrd @ 0x029fa000
uncompressing kernel done. (0x0063d538 bytes)
entering kernel at 0x02010000(29fa000/5f389c/00c39a48)
OF stdout device is: /vdevice/vty@30000000
Hypertas detected, assuming LPAR !
command line:
memory layout at init:
  memory_limit : 0000000000000000 (16 MB aligned)
  alloc_bottom : 0000000002fee000
  alloc_top    : 0000000010000000
 alloc_top_hi : 00000003b0000000
  rmo_top      : 0000000010000000
  ram_top      : 00000003b0000000
Looking for displays
instantiating rtas at 0x000000000f702000 ...RTAS Code version:
bPF060322
rtas_ram_size = 5a1000
fixed_base_addr = f702000
code_base_addr = f99f000
 done
0000000000000000 : boot cpu     0000000000000000
0000000000000002 : starting cpu hw idx 0000000000000002... done
0000000000000004 : starting cpu hw idx 0000000000000004... done
0000000000000006 : starting cpu hw idx 0000000000000006... done
0000000000000008 : starting cpu hw idx 0000000000000008... done
000000000000000a : starting cpu hw idx 000000000000000a... done
000000000000000c : starting cpu hw idx 000000000000000c... done
000000000000000e : starting cpu hw idx 000000000000000e... done
copying OF device tree ...
Building dt strings...
Building dt structure...
Device tree strings 0x0000000002fef000 -> 0x0000000002ff0428
Device tree struct  0x0000000002ff1000 -> 0x000000000300a000
Calling quiesce ...
returning from prom_init
Page orders: linear mapping = 24, others = 12
Found initrd at 0xc0000000029fa000:0xc000000002fed89c
cpu 0x0: Vector: 300 (Data Access) at [c0000000004434d0]
    pc: c0000000000c06b4: .kmem_cache_alloc+0x8c/0xf4
    lr: c00000000004ad6c: .eeh_send_failure_event+0x48/0xfc
    sp: c000000000443750
   msr: 8000000000001032
   dar: 0
 dsisr: 40000000
  current = 0xc00000000048e660
  paca    = 0xc00000000048ee80
    pid   = 0, comm = swapper
enter ? for help
[c0000000004437e0] c00000000004ad6c .eeh_send_failure_event+0x48/0xfc
[c000000000443880] c000000000049dfc .eeh_dn_check_failure+0x250/0x2a8
[c000000000443930] c00000000001da6c .rtas_read_config+0x100/0x13c
[c0000000004439d0] c0000000000497a8 .early_enable_eeh+0x25c/0x2ac
[c000000000443a90] c00000000002ba4c .traverse_pci_devices+0x84/0x100
[c000000000443b30] c00000000041ae7c .eeh_init+0x1a8/0x204
[c000000000443bd0] c00000000041a308 .pSeries_setup_arch+0x1e8/0x2b8
[c000000000443e60] c00000000040a6a0 .setup_arch+0x20c/0x25c
[c000000000443ef0] c00000000040252c .start_kernel+0x40/0x288
[c000000000443f90] c000000000008594 .start_here_common+0x88/0x8c