On Mon, Dec 4, 2023, at 14:39, Philipp Stanner wrote:
On Mon, 2023-12-04 at 13:38 +0100, Philipp Stanner wrote:
- */
+#if defined(ARCH_WANTS_GENERIC_IOMEM_IS_IOPORT) +bool iomem_is_ioport(void __iomem *addr) { - IO_COND(addr, /* nothing */, iounmap(addr)); + unsigned long port = (unsigned long __force)addr;
+ if (port > PIO_OFFSET && port < PIO_RESERVED)
by the way: Reading that again my instinctive feeling would be that it should be port >= PIO_OFFSET.
This is, however, the exactly copied logic from the IO_COND macro in lib/iomap.c. Is it possible that this macro contains a bug here?
Right, I think that would make more sense, but there is no practical difference as long as I/O port 0 is always unused, which is at least true on x86 because of PCIBIOS_MIN_IO. Commit bb356ddb78b2 ("RISC-V: PCI: Avoid handing out address 0 to devices") describes how setting PCIBIOS_MIN_IO to 0 caused other problems.
I would just leave the logic consistent with IO_COND here, or maybe use IO_COND() directly, like
IO_COND(addr, return true, /* nothing */); return false;
Arnd