4.18-stable review patch. If anyone has any objections, please let me know.
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From: Andrew Murray andrew.murray@arm.com
[ 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@arm.com Reviewed-by: Arnd Bergmann arnd@arndb.de Signed-off-by: Andrew Murray andrew.murray@arm.com Signed-off-by: Will Deacon will.deacon@arm.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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