From aa0c1d0dc694567a23b3f75821484e5f6150014c Mon Sep 17 00:00:00 2001 From: =?utf8?q?Pali=20Roh=C3=A1r?= Date: Sat, 20 Aug 2022 13:51:13 +0200 Subject: [PATCH] powerpc/pci: Enable PCI domains in /proc when PCI bus numbers are not unique MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit On 32-bit powerpc systems with more PCIe controllers and more PCI domains, where on more PCI domains are same PCI numbers, when kernel is compiled with CONFIG_PROC_FS=y and CONFIG_PPC_PCI_BUS_NUM_DOMAIN_DEPENDENT=y options, kernel prints "proc_dir_entry 'pci/01' already registered" error message. proc_dir_entry 'pci/01' already registered WARNING: CPU: 0 PID: 1 at fs/proc/generic.c:377 proc_register+0x1a8/0x1ac ... NIP proc_register+0x1a8/0x1ac LR proc_register+0x1a8/0x1ac Call Trace: proc_register+0x1a8/0x1ac (unreliable) _proc_mkdir+0x78/0xa4 pci_proc_attach_device+0x11c/0x168 pci_proc_init+0x80/0x98 do_one_initcall+0x80/0x284 kernel_init_freeable+0x1f4/0x2a0 kernel_init+0x24/0x150 ret_from_kernel_thread+0x5c/0x64 This regression started appearing after commit d13e006fcde9 ("powerpc/pci: Add config option for using all 256 PCI buses") in case in each mPCIe slot is connected PCIe card and therefore PCI bus 1 is populated in for every PCIe controller / PCI domain. The reason is that PCI procfs code expects that when PCI bus numbers are not unique across all PCI domains, function pci_proc_domain() returns true for domain dependent buses. Fix this issue by setting PCI_ENABLE_PROC_DOMAINS and PCI_COMPAT_DOMAIN_0 flags for 32-bit powerpc code when CONFIG_PPC_PCI_BUS_NUM_DOMAIN_DEPENDENT is enabled. Same approach is already implemented for 64-bit powerpc code (where PCI bus numbers are always domain dependent). Fixes: d13e006fcde9 ("powerpc/pci: Add config option for using all 256 PCI buses") Signed-off-by: Pali Rohár [mpe: Trim change log oops message] Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20220820115113.30581-1-pali@kernel.org --- arch/powerpc/kernel/pci_32.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/arch/powerpc/kernel/pci_32.c b/arch/powerpc/kernel/pci_32.c index 433965bf37b4b..855b59892c5c9 100644 --- a/arch/powerpc/kernel/pci_32.c +++ b/arch/powerpc/kernel/pci_32.c @@ -245,6 +245,15 @@ static int __init pcibios_init(void) printk(KERN_INFO "PCI: Probing PCI hardware\n"); +#ifdef CONFIG_PPC_PCI_BUS_NUM_DOMAIN_DEPENDENT + /* + * Enable PCI domains in /proc when PCI bus numbers are not unique + * across all PCI domains to prevent conflicts. And keep PCI domain 0 + * backward compatible in /proc for video cards. + */ + pci_add_flags(PCI_ENABLE_PROC_DOMAINS | PCI_COMPAT_DOMAIN_0); +#endif + if (pci_has_flag(PCI_REASSIGN_ALL_BUS)) pci_assign_all_buses = 1; -- 2.39.5