[PATCH] x86: Allow disabling early pci scans with pci=noearly or disallowing conf1

Some buggy systems can machine check when config space accesses
happen for some non existent devices.  i386/x86-64 do some early
device scans that might trigger this. Allow pci=noearly to disable
this. Also when type 1 is disabling also don't do any early
accesses which are always type1.

This moves the pci= configuration parsing to be a early parameter.
I don't think this can break anything because it only changes
a single global that is only used by PCI.

Cc: gregkh@suse.de
Cc: Trammell Hudson <hudson@osresearch.net>

Signed-off-by: Andi Kleen <ak@suse.de>

1 files changed, 8 insertions, 0 deletions

diff --git a/arch/i386/pci/early.c b/arch/i386/pci/early.c
index b1f7f40d809..713d6c866ca 100644
--- a/arch/i386/pci/early.c
+++ b/arch/i386/pci/early.c
@@ -1,6 +1,8 @@
 #include <linux/kernel.h>
+#include <linux/pci.h>
 #include <asm/pci-direct.h>
 #include <asm/io.h>
+#include "pci.h"
 
 /* Direct PCI access. This is used for PCI accesses in early boot before
    the PCI subsystem works. */
@@ -42,3 +44,9 @@ void write_pci_config(u8 bus, u8 slot, u8 func, u8 offset,
         outl(0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, 0xcf8);
         outl(val, 0xcfc);
 }
+
+int early_pci_allowed(void)
+{
+        return (pci_probe & (PCI_PROBE_CONF1|PCI_PROBE_NOEARLY)) ==
+                        PCI_PROBE_CONF1;
+}