[PATCH 1/3] arm: a37xx: pci: Extend validation for PCIe resources and oubound windows

Pali Rohár
2021-07-08T18:19:28Z

Remapped address of PCIe outbound window may have set only bits from the
mask. Add additional check that remapped address which is calculated from
PCIe bus address specified in DTS file is valid.

Remove also useless clearing of low 16 bits in win_mask. As win_size is
power of two and is at least 0x10000 it means that it always has zero low
16 bits.

Signed-off-by: Pali Rohár <pali@kernel.org>
---
drivers/pci/pci-aardvark.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/pci-aardvark.c b/drivers/pci/pci-aardvark.c
index 96aa039bdc26..77ce9d0c8d87 100644
--- a/drivers/pci/pci-aardvark.c
+++ b/drivers/pci/pci-aardvark.c
@@ -609,21 +609,22 @@ static void pcie_advk_set_ob_region(struct pcie_advk *pcie, int *wins,
* match with given mask.
* So every PCIe window size must be a power of two and every start
* address must be aligned to window size. Minimal size is 64 KiB
- * because lower 16 bits of mask must be zero.
+ * because lower 16 bits of mask must be zero. Remapped address
+ * may have set only bits from the mask.
*/
while (*wins < OB_WIN_COUNT && size > 0) {
/* Calculate the largest aligned window size */
win_size = (1ULL << (fls64(size) - 1)) |
(phys_start ? (1ULL << __ffs64(phys_start)) : 0);
win_size = 1ULL << __ffs64(win_size);
- if (win_size < 0x10000)
+ win_mask = ~(win_size - 1);
+ if (win_size < 0x10000 || (bus_start & ~win_mask))
break;

dev_dbg(pcie->dev,
"Configuring PCIe window %d: [0x%llx-0x%llx] as 0x%x\n",
*wins, (u64)phys_start, (u64)phys_start + win_size,
actions);
- win_mask = ~(win_size - 1) & ~0xffff;
pcie_advk_set_ob_win(pcie, *wins, phys_start, bus_start,
win_mask, actions);

--
2.20.1