From: Niklas Schnelle <niklas@xxxxxxxxx> Without MMU support PCI_IOBASE is left undefined because PCI_IO_END is VMEMMAP_START. Nevertheless the in*()/out*() helper macros are left defined with uses of PCI_IOBASE. At the moment this only compiles because asm-generic/io.h defines PCI_IOBASE as 0 if it is undefined and so at macro expansion PCI_IOBASE is defined. This leads to compilation errors when asm-generic/io.h is changed to leave PCI_IOBASE undefined. More importantly it is currently broken at runtime, as accessing a fixed I/O port number of an ISA device on NOMMU RISC-V would turn into a NULL pointer dereference. Instead only define the in*()/out*() helper macros with MMU support and fall back to the asm-generic/io.h helper stubs otherwise. Signed-off-by: Niklas Schnelle <niklas@xxxxxxxxx> --- arch/riscv/include/asm/io.h | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/riscv/include/asm/io.h b/arch/riscv/include/asm/io.h index c025a746a148..31a8b98c0f13 100644 --- a/arch/riscv/include/asm/io.h +++ b/arch/riscv/include/asm/io.h @@ -23,12 +23,12 @@ #include <asm/mmio.h> /* - * I/O port access constants. + * I/O port access constants. Without MMU support leave PCI_IOBASE undefined + * and fall back to generic stubs for I/O access routines. */ #ifdef CONFIG_MMU #define IO_SPACE_LIMIT (PCI_IO_SIZE - 1) #define PCI_IOBASE ((void __iomem *)PCI_IO_START) -#endif /* CONFIG_MMU */ /* * Emulation routines for the port-mapped IO space used by some PCI drivers. @@ -145,6 +145,7 @@ __io_writes_outs(writes, u64, q, __io_bw(), __io_aw()) __io_writes_outs(outs, u64, q, __io_pbr(), __io_paw()) #define outsq(addr, buffer, count) __outsq((void __iomem *)addr, buffer, count) #endif +#endif /* CONFIG_MMU */ #include <asm-generic/io.h> -- 2.25.1
