[PATCH v2 05/14] PCI: of_property: Sanitize 32 bit PCI address parsed from DT

[Andrea della Porta <andrea.porta@xxxxxxxx>]

The of_pci_set_address() function parses devicetree PCI range specifier
assuming the address is 'sanitized' at the origin, i.e. without checking
whether the incoming address is 32 or 64 bit has specified in the flags.

In this way an address with no OF_PCI_ADDR_SPACE_MEM64 set in the flags
could leak through and the upper 32 bits of the address will be set too,
and this violates the PCI specs stating that in 32 bit address the upper
bits should be zero.

This could cause mapping translation mismatch on PCI devices (e.g. RP1)
that are expected to be addressed with a 64 bit address while advertising
a 32 bit address in the PCI config region.

Add a check in of_pci_set_address() to set upper 32 bits to zero in case
the address has no 64 bit flag set.

Signed-off-by: Andrea della Porta <andrea.porta@xxxxxxxx>
---
This patch has not been changed from the first version, discussion is
still ongoing here:
https://lore.kernel.org/all/ZwJyk9XouLfd24VG@apocalypse/#t

 drivers/pci/of_property.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/of_property.c b/drivers/pci/of_property.c
index 5a0b98e69795..77865facdb4a 100644
--- a/drivers/pci/of_property.c
+++ b/drivers/pci/of_property.c
@@ -60,7 +60,10 @@ static void of_pci_set_address(struct pci_dev *pdev, u32 *prop, u64 addr,
 	prop[0] |= flags | reg_num;
 	if (!reloc) {
 		prop[0] |= OF_PCI_ADDR_FIELD_NONRELOC;
-		prop[1] = upper_32_bits(addr);
+		if (FIELD_GET(OF_PCI_ADDR_FIELD_SS, flags) == OF_PCI_ADDR_SPACE_MEM64)
+			prop[1] = upper_32_bits(addr);
+		else
+			prop[1] = 0;
 		prop[2] = lower_32_bits(addr);
 	}
 }
-- 
2.35.3