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Message-ID: <PSXP216MB0438F3D8C09957C6A45BC43D80580@PSXP216MB0438.KORP216.PROD.OUTLOOK.COM>
Date: Mon, 9 Dec 2019 21:30:23 +0000
From: Nicholas Johnson <nicholas.johnson-opensource@...look.com.au>
To: "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC: Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
"H. Peter Anvin" <hpa@...or.com>,
Nicholas Johnson <nicholas.johnson-opensource@...look.com.au>
Subject: [[RFC PATCH v1] 1/1] PCI: Add pci=nobbn to ignore ACPI _BBN method to
override host bridge bus window
Add pci=nobbn kernel parameter.
Override the host bridge bus resource to [bus 00-ff] when specified.
Update documentation to reflect the above.
Signed-off-by: Nicholas Johnson <nicholas.johnson-opensource@...look.com.au>
---
Documentation/admin-guide/kernel-parameters.txt | 2 ++
arch/x86/include/asm/pci_x86.h | 1 +
arch/x86/pci/acpi.c | 11 +++++++++++
arch/x86/pci/common.c | 3 +++
4 files changed, 17 insertions(+)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index cfe8c2b67..0333d9d63 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -3432,6 +3432,8 @@
please report a bug.
nocrs [X86] Ignore PCI host bridge windows from ACPI.
If you need to use this, please report a bug.
+ nobbn [X86] Ignore PCI BIOS Bus Number from ACPI.
+ If you need to use this, please report a bug.
routeirq Do IRQ routing for all PCI devices.
This is normally done in pci_enable_device(),
so this option is a temporary workaround
diff --git a/arch/x86/include/asm/pci_x86.h b/arch/x86/include/asm/pci_x86.h
index 73bb404f4..179cdd5d1 100644
--- a/arch/x86/include/asm/pci_x86.h
+++ b/arch/x86/include/asm/pci_x86.h
@@ -39,6 +39,7 @@ do { \
#define PCI_ROOT_NO_CRS 0x100000
#define PCI_NOASSIGN_BARS 0x200000
#define PCI_BIG_ROOT_WINDOW 0x400000
+#define PCI_ROOT_NO_BBN 0x800000
extern unsigned int pci_probe;
extern unsigned long pirq_table_addr;
diff --git a/arch/x86/pci/acpi.c b/arch/x86/pci/acpi.c
index 948656069..fc54a1f3c 100644
--- a/arch/x86/pci/acpi.c
+++ b/arch/x86/pci/acpi.c
@@ -20,6 +20,7 @@ struct pci_root_info {
};
static bool pci_use_crs = true;
+static bool pci_use_bbn = true;
static bool pci_ignore_seg = false;
static int __init set_use_crs(const struct dmi_system_id *id)
@@ -156,6 +157,8 @@ void __init pci_acpi_crs_quirks(void)
else if (pci_probe & PCI_USE__CRS)
pci_use_crs = true;
+ pci_use_bbn = !(pci_probe & PCI_ROOT_NO_BBN);
+
printk(KERN_INFO "PCI: %s host bridge windows from ACPI; "
"if necessary, use \"pci=%s\" and report a bug\n",
pci_use_crs ? "Using" : "Ignoring",
@@ -298,6 +301,14 @@ static int pci_acpi_root_prepare_resources(struct acpi_pci_root_info *ci)
struct resource_entry *entry, *tmp;
int status;
+ if (!pci_use_bbn){
+ dev_printk(KERN_DEBUG, &device->dev,
+ "host bridge window %pR (ignored)\n",
+ &ci->root->secondary);
+ ci->root->secondary.start = 0x00;
+ ci->root->secondary.end = 0xff;
+ }
+
status = acpi_pci_probe_root_resources(ci);
if (pci_use_crs) {
resource_list_for_each_entry_safe(entry, tmp, &ci->resources)
diff --git a/arch/x86/pci/common.c b/arch/x86/pci/common.c
index 9acab6ac2..9183a999f 100644
--- a/arch/x86/pci/common.c
+++ b/arch/x86/pci/common.c
@@ -594,6 +594,9 @@ char *__init pcibios_setup(char *str)
} else if (!strcmp(str, "nocrs")) {
pci_probe |= PCI_ROOT_NO_CRS;
return NULL;
+ } else if (!strcmp(str, "nobbn")) {
+ pci_probe |= PCI_ROOT_NO_BBN;
+ return NULL;
#ifdef CONFIG_PHYS_ADDR_T_64BIT
} else if (!strcmp(str, "big_root_window")) {
pci_probe |= PCI_BIG_ROOT_WINDOW;
--
2.24.0
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