From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Daney Subject: [PATCH 4/6] PCI: generic: Correct, and avoid overflow, in bus_max calculation. Date: Fri, 11 Sep 2015 16:21:57 -0700 Message-ID: <1442013719-5001-5-git-send-email-ddaney.cavm@gmail.com> References: <1442013719-5001-1-git-send-email-ddaney.cavm@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1442013719-5001-1-git-send-email-ddaney.cavm@gmail.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, Rob Herring , Frank Rowand , Grant Likely , Bjorn Helgaas , linux-pci@vger.kernel.org, Will Deacon , Pawel Moll , Mark Rutland , Ian Campbell , Kumar Gala , linux-arm-kernel@lists.infradead.org Cc: David Daney List-Id: devicetree@vger.kernel.org From: David Daney There are two problems with the bus_max calculation: 1) The u8 data type can overflow for large config space windows. 2) The calculation is incorrect for a bus range that doesn't start at zero. Since the configuration space is relative to bus zero, make bus_max just be the size of the config window scaled by bus_shift. Then clamp it to a maximum of 255, per PCI. Use a data type of int to avoid overflow problems. Signed-off-by: David Daney --- drivers/pci/host/pci-host-generic.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/pci/host/pci-host-generic.c b/drivers/pci/host/pci-host-generic.c index cd6f898..fce5bf7 100644 --- a/drivers/pci/host/pci-host-generic.c +++ b/drivers/pci/host/pci-host-generic.c @@ -164,7 +164,7 @@ out_release_res: static int gen_pci_parse_map_cfg_windows(struct gen_pci *pci) { int err; - u8 bus_max; + int bus_max; resource_size_t busn; struct resource *bus_range; struct device *dev = pci->host.dev.parent; @@ -177,8 +177,9 @@ static int gen_pci_parse_map_cfg_windows(struct gen_pci *pci) } /* Limit the bus-range to fit within reg */ - bus_max = pci->cfg.bus_range->start + - (resource_size(&pci->cfg.res) >> pci->cfg.ops.bus_shift) - 1; + bus_max = (resource_size(&pci->cfg.res) >> pci->cfg.ops.bus_shift) - 1; + if (bus_max > 255) + bus_max = 255; pci->cfg.bus_range->end = min_t(resource_size_t, pci->cfg.bus_range->end, bus_max); -- 1.7.11.7