4.18-stable review patch. If anyone has any objections, please let me know.
------------------
From: Andrew Murray <andrew.murray@xxxxxxx>
[ Upstream commit 500dd232449e7c07500e713dc6970aa713f8e4f1 ]
The !CONFIG_GENERIC_IOMAP version of ioport_map uses MMIO_UPPER_LIMIT to
prevent users from making I/O accesses outside the expected I/O range -
however it erroneously treats MMIO_UPPER_LIMIT as a mask which is
contradictory to its other users.
The introduction of CONFIG_INDIRECT_PIO, which subtracts an arbitrary
amount from IO_SPACE_LIMIT to form MMIO_UPPER_LIMIT, results in ioport_map
mangling the given port rather than capping it.
We address this by aligning more closely with the CONFIG_GENERIC_IOMAP
implementation of ioport_map by using the comparison operator and
returning NULL where the port exceeds MMIO_UPPER_LIMIT. Though note that
we preserve the existing behavior of masking with IO_SPACE_LIMIT such that
we don't break existing buggy drivers that somehow rely on this masking.
Fixes: 5745392e0c2b ("PCI: Apply the new generic I/O management on PCI IO hosts")
Reported-by: Will Deacon <will.deacon@xxxxxxx>
Reviewed-by: Arnd Bergmann <arnd@xxxxxxxx>
Signed-off-by: Andrew Murray <andrew.murray@xxxxxxx>
Signed-off-by: Will Deacon <will.deacon@xxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
include/asm-generic/io.h | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/include/asm-generic/io.h
+++ b/include/asm-generic/io.h
@@ -1026,7 +1026,8 @@ static inline void __iomem *ioremap_wt(p
#define ioport_map ioport_map
static inline void __iomem *ioport_map(unsigned long port, unsigned int nr)
{
- return PCI_IOBASE + (port & MMIO_UPPER_LIMIT);
+ port &= IO_SPACE_LIMIT;
+ return (port > MMIO_UPPER_LIMIT) ? NULL : PCI_IOBASE + port;
}
#endif
