From f4f7eb43c5238fd2636a8e310394ed9920627ab3 Mon Sep 17 00:00:00 2001 From: Naveen Naidu Date: Thu, 18 Nov 2021 19:33:12 +0530 Subject: [PATCH] PCI: Set error response data when config read fails MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When a PCI config read fails, most PCI host bridges fabricate ~0 data to complete the CPU read. But some host bridges do not; their drivers may only return an error from the pci_ops.read() method. In PCI_OP_READ() and PCI_USER_READ_CONFIG(), use PCI_SET_ERROR_RESPONSE() to set the data value to indicate an error when pci_ops.read() fails. This means the host bridge driver no longer needs to fabricate error data when they detect errors. This makes error response fabrication consistent and helps in removal of a lot of repeated code. Suggested-by: Rob Herring Link: https://lore.kernel.org/r/4188fc5465631ce0d472d1423de3d9fb2f09b8ff.1637243717.git.naveennaidu479@gmail.com Signed-off-by: Naveen Naidu Signed-off-by: Bjorn Helgaas Reviewed-by: Rob Herring Reviewed-by: Pali Rohár --- drivers/pci/access.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/drivers/pci/access.c b/drivers/pci/access.c index 46935695cfb9..eac0765d8bed 100644 --- a/drivers/pci/access.c +++ b/drivers/pci/access.c @@ -42,7 +42,10 @@ int noinline pci_bus_read_config_##size \ if (PCI_##size##_BAD) return PCIBIOS_BAD_REGISTER_NUMBER; \ pci_lock_config(flags); \ res = bus->ops->read(bus, devfn, pos, len, &data); \ - *value = (type)data; \ + if (res) \ + PCI_SET_ERROR_RESPONSE(value); \ + else \ + *value = (type)data; \ pci_unlock_config(flags); \ return res; \ } @@ -228,7 +231,10 @@ int pci_user_read_config_##size \ ret = dev->bus->ops->read(dev->bus, dev->devfn, \ pos, sizeof(type), &data); \ raw_spin_unlock_irq(&pci_lock); \ - *val = (type)data; \ + if (ret) \ + PCI_SET_ERROR_RESPONSE(val); \ + else \ + *val = (type)data; \ return pcibios_err_to_errno(ret); \ } \ EXPORT_SYMBOL_GPL(pci_user_read_config_##size);