From bb71ad880204b79d60331d3384103976e086cb9f Mon Sep 17 00:00:00 2001 From: Gary Hade Date: Mon, 12 May 2008 13:57:46 -0700 Subject: [PATCH] PCI: boot parameter to avoid expansion ROM memory allocation Contention for scarce PCI memory resources has been growing due to an increasing number of PCI slots in large multi-node systems. The kernel currently attempts by default to allocate memory for all PCI expansion ROMs so there has also been an increasing number of PCI memory allocation failures seen on these systems. This occurs because the BIOS either (1) provides insufficient PCI memory resource for all the expansion ROMs or (2) provides adequate PCI memory resource for expansion ROMs but provides the space in kernel unexpected BIOS assigned P2P non-prefetch windows. The resulting PCI memory allocation failures may be benign when related to memory requests for expansion ROMs themselves but in some cases they can occur when attempting to allocate space for more critical BARs. This can happen when a successful expansion ROM allocation request consumes memory resource that was intended for a non-ROM BAR. We have seen this happen during PCI hotplug of an adapter that contains a P2P bridge where successful memory allocation for an expansion ROM BAR on device behind the bridge consumed memory that was intended for a non-ROM BAR on the P2P bridge. In all cases the allocation failure messages can be very confusing for users. This patch provides a new 'pci=norom' kernel boot parameter that can be used to disable the default PCI expansion ROM memory resource allocation. This provides a way to avoid the above described issues on systems that do not contain PCI devices for which drivers or user-level applications depend on the default PCI expansion ROM memory resource allocation behavior. Signed-off-by: Gary Hade Signed-off-by: Jesse Barnes --- Documentation/kernel-parameters.txt | 3 +++ arch/x86/pci/common.c | 22 ++++++++++++++++++++++ arch/x86/pci/pci.h | 1 + 3 files changed, 26 insertions(+) diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index e07c432c731f..9cf7b34f2db0 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -1496,6 +1496,9 @@ and is between 256 and 4096 characters. It is defined in the file Use with caution as certain devices share address decoders between ROMs and other resources. + norom [X86-32,X86_64] Do not assign address space to + expansion ROMs that do not already have + BIOS assigned address ranges. irqmask=0xMMMM [X86-32] Set a bit mask of IRQs allowed to be assigned automatically to PCI devices. You can make the kernel exclude IRQs of your ISA cards diff --git a/arch/x86/pci/common.c b/arch/x86/pci/common.c index 6e64aaf00d1d..3a5261bdff5d 100644 --- a/arch/x86/pci/common.c +++ b/arch/x86/pci/common.c @@ -121,6 +121,21 @@ void __init dmi_check_skip_isa_align(void) dmi_check_system(can_skip_pciprobe_dmi_table); } +static void __devinit pcibios_fixup_device_resources(struct pci_dev *dev) +{ + struct resource *rom_r = &dev->resource[PCI_ROM_RESOURCE]; + + if (pci_probe & PCI_NOASSIGN_ROMS) { + if (rom_r->parent) + return; + if (rom_r->start) { + /* we deal with BIOS assigned ROM later */ + return; + } + rom_r->start = rom_r->end = rom_r->flags = 0; + } +} + /* * Called after each bus is probed, but before its children * are examined. @@ -128,7 +143,11 @@ void __init dmi_check_skip_isa_align(void) void __devinit pcibios_fixup_bus(struct pci_bus *b) { + struct pci_dev *dev; + pci_read_bridge_bases(b); + list_for_each_entry(dev, &b->devices, bus_list) + pcibios_fixup_device_resources(dev); } /* @@ -483,6 +502,9 @@ char * __devinit pcibios_setup(char *str) else if (!strcmp(str, "rom")) { pci_probe |= PCI_ASSIGN_ROMS; return NULL; + } else if (!strcmp(str, "norom")) { + pci_probe |= PCI_NOASSIGN_ROMS; + return NULL; } else if (!strcmp(str, "assign-busses")) { pci_probe |= PCI_ASSIGN_ALL_BUSSES; return NULL; diff --git a/arch/x86/pci/pci.h b/arch/x86/pci/pci.h index 720c4c554534..291dafec07b7 100644 --- a/arch/x86/pci/pci.h +++ b/arch/x86/pci/pci.h @@ -27,6 +27,7 @@ #define PCI_CAN_SKIP_ISA_ALIGN 0x8000 #define PCI_USE__CRS 0x10000 #define PCI_CHECK_ENABLE_AMD_MMCONF 0x20000 +#define PCI_NOASSIGN_ROMS 0x40000 extern unsigned int pci_probe; extern unsigned long pirq_table_addr; -- 2.20.1