[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>
diff --git a/arch/i386/pci/common.c b/arch/i386/pci/common.c
index 0a362e3..68bce19 100644
--- a/arch/i386/pci/common.c
+++ b/arch/i386/pci/common.c
@@ -242,6 +242,10 @@
acpi_noirq_set();
return NULL;
}
+ else if (!strcmp(str, "noearly")) {
+ pci_probe |= PCI_PROBE_NOEARLY;
+ return NULL;
+ }
#ifndef CONFIG_X86_VISWS
else if (!strcmp(str, "usepirqmask")) {
pci_probe |= PCI_USE_PIRQ_MASK;
diff --git a/arch/i386/pci/early.c b/arch/i386/pci/early.c
index b1f7f40..713d6c8 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 @@
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;
+}
diff --git a/arch/i386/pci/pci.h b/arch/i386/pci/pci.h
index 8a7cf1f..1814f74 100644
--- a/arch/i386/pci/pci.h
+++ b/arch/i386/pci/pci.h
@@ -17,6 +17,7 @@
#define PCI_PROBE_CONF2 0x0004
#define PCI_PROBE_MMCONF 0x0008
#define PCI_PROBE_MASK 0x000f
+#define PCI_PROBE_NOEARLY 0x0010
#define PCI_NO_SORT 0x0100
#define PCI_BIOS_SORT 0x0200