[PATCH V4 1/2] PCI: rcar: Move the inbound index check

[marek.vasut@gmail.com]

From: Marek Vasut <marek.vasut+renesas@gmail.com>

Since the $idx variable value is stored across multiple calls to
rcar_pcie_inbound_ranges() function, and the $idx value is used to
index registers which are written, subsequent calls might cause
the $idx value to be high enough to trigger writes into nonexistent
registers.

Fix this by moving the $idx value check to the beginning of the loop.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Reviewed-by: Andrew Murray <andrew.murray@arm.com>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Wolfram Sang <wsa@the-dreams.de>
Cc: linux-renesas-soc@vger.kernel.org
To: linux-pci@vger.kernel.org
---
V2: New patch
V3: Adjust the check to idx >= MAX_NR_INBOUND_MAPS - 1
V4: Rebase on next/master
---
 drivers/pci/controller/pcie-rcar.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/drivers/pci/controller/pcie-rcar.c b/drivers/pci/controller/pcie-rcar.c
index e45bb2a7bfa5..b2a5c3e94245 100644
--- a/drivers/pci/controller/pcie-rcar.c
+++ b/drivers/pci/controller/pcie-rcar.c
@@ -1049,6 +1049,10 @@ static int rcar_pcie_inbound_ranges(struct rcar_pcie *pcie,
 	mask &= ~0xf;
 
 	while (cpu_addr < cpu_end) {
+		if (idx >= MAX_NR_INBOUND_MAPS - 1) {
+			dev_err(pcie->dev, "Failed to map inbound regions!\n");
+			return -EINVAL;
+		}
 		/*
 		 * Set up 64-bit inbound regions as the range parser doesn't
 		 * distinguish between 32 and 64-bit types.
@@ -1068,11 +1072,6 @@ static int rcar_pcie_inbound_ranges(struct rcar_pcie *pcie,
 		pci_addr += size;
 		cpu_addr += size;
 		idx += 2;
-
-		if (idx > MAX_NR_INBOUND_MAPS) {
-			dev_err(pcie->dev, "Failed to map inbound regions!\n");
-			return -EINVAL;
-		}
 	}
 	*index = idx;
 
-- 
2.23.0