[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/kernel/acpi/earlyquirk.c b/arch/i386/kernel/acpi/earlyquirk.c
index 1649a17..fe799b1 100644
--- a/arch/i386/kernel/acpi/earlyquirk.c
+++ b/arch/i386/kernel/acpi/earlyquirk.c
@@ -48,7 +48,11 @@
int num, slot, func;
/* Assume the machine supports type 1. If not it will
- always read ffffffff and should not have any side effect. */
+ always read ffffffff and should not have any side effect.
+ Actually a few buggy systems can machine check. Allow the user
+ to disable it by command line option at least -AK */
+ if (!early_pci_allowed())
+ return;
/* Poor man's PCI discovery */
for (num = 0; num < 32; num++) {
diff --git a/arch/i386/pci/common.c b/arch/i386/pci/common.c
index 0a362e3..68bce194 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
diff --git a/arch/x86_64/kernel/aperture.c b/arch/x86_64/kernel/aperture.c
index f851e1f..b487396 100644
--- a/arch/x86_64/kernel/aperture.c
+++ b/arch/x86_64/kernel/aperture.c
@@ -212,7 +212,7 @@
u64 aper_base, last_aper_base = 0;
int valid_agp = 0;
- if (iommu_aperture_disabled || !fix_aperture)
+ if (iommu_aperture_disabled || !fix_aperture || !early_pci_allowed())
return;
printk("Checking aperture...\n");
diff --git a/arch/x86_64/kernel/early-quirks.c b/arch/x86_64/kernel/early-quirks.c
index d637cff..208e38a 100644
--- a/arch/x86_64/kernel/early-quirks.c
+++ b/arch/x86_64/kernel/early-quirks.c
@@ -82,6 +82,10 @@
void __init early_quirks(void)
{
int num, slot, func;
+
+ if (!early_pci_allowed())
+ return;
+
/* Poor man's PCI discovery */
for (num = 0; num < 32; num++) {
for (slot = 0; slot < 32; slot++) {
diff --git a/arch/x86_64/kernel/pci-calgary.c b/arch/x86_64/kernel/pci-calgary.c
index 466588f..cfb09b0 100644
--- a/arch/x86_64/kernel/pci-calgary.c
+++ b/arch/x86_64/kernel/pci-calgary.c
@@ -924,6 +924,9 @@
if (swiotlb || no_iommu || iommu_detected)
return;
+ if (!early_pci_allowed())
+ return;
+
specified_table_size = determine_tce_table_size(end_pfn * PAGE_SIZE);
for (bus = 0; bus < MAX_PHB_BUS_NUM; bus++) {
diff --git a/arch/x86_64/kernel/vsmp.c b/arch/x86_64/kernel/vsmp.c
index 92f70c7..044e852 100644
--- a/arch/x86_64/kernel/vsmp.c
+++ b/arch/x86_64/kernel/vsmp.c
@@ -20,6 +20,9 @@
void *address;
unsigned int cap, ctl;
+ if (!early_pci_allowed())
+ return 0;
+
/* Check if we are running on a ScaleMP vSMP box */
if ((read_pci_config_16(0, 0x1f, 0, PCI_VENDOR_ID) != PCI_VENDOR_ID_SCALEMP) ||
(read_pci_config_16(0, 0x1f, 0, PCI_DEVICE_ID) != PCI_DEVICE_ID_SCALEMP_VSMP_CTL))
diff --git a/arch/x86_64/mm/k8topology.c b/arch/x86_64/mm/k8topology.c
index 7c45c2d..5cf594f 100644
--- a/arch/x86_64/mm/k8topology.c
+++ b/arch/x86_64/mm/k8topology.c
@@ -54,6 +54,9 @@
nodes_clear(nodes_parsed);
+ if (!early_pci_allowed())
+ return -1;
+
nb = find_northbridge();
if (nb < 0)
return nb;