From: Danilo Krummrich Date: Wed, 5 Aug 2026 21:28:35 +0000 (+0200) Subject: rust: io: gate ioremap/iounmap on CONFIG_HAS_IOMEM X-Git-Tag: v7.2-rc7~10^2~1 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=4f5f23846d6713c05481c8cfc710bb23817bf5e9;p=thirdparty%2Flinux.git rust: io: gate ioremap/iounmap on CONFIG_HAS_IOMEM s390 does not provide ioremap()/iounmap() when CONFIG_HAS_IOMEM is not set (which requires CONFIG_PCI on that architecture). This causes a build failure with Rust enabled on e.g. s390 allnoconfig: In file included from rust/helpers/helpers.c:68: rust/helpers/io.c:8:9: error: call to undeclared function 'ioremap'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration] 8 | return ioremap(offset, size); | ^ rust/helpers/io.c:19:2: error: call to undeclared function 'iounmap'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration] 19 | iounmap(addr); Guard the C helpers behind #ifdef CONFIG_HAS_IOMEM and cfg-gate the Rust io::mem module, such that IoMem, ExclusiveIoMem and IoRequest are not available without CONFIG_HAS_IOMEM. Note that the C API is inconsistent about this. For instance, devm_ioremap() has no stub and produces a link failure without CONFIG_HAS_IOMEM, whereas devm_platform_ioremap_resource() provides an inline stub returning -EINVAL. The approach taken here (compile-time gating) matches the former, which is slightly more appropriate since any driver performing MMIO currently requires CONFIG_HAS_IOMEM. Ideally, s390 should provide ioremap()/iounmap() stubs unconditionally (as UML already does), removing the need for any config gating as discussed in [1]; a follow-up patch for s390 is expected. Cc: Arnd Bergmann Reported-by: Miguel Ojeda Closes: https://lore.kernel.org/all/20260803180931.97202-1-ojeda@kernel.org [1] Fixes: 3f70ebe63858 ("s390: Enable Rust support") Reviewed-by: Arnd Bergmann Link: https://patch.msgid.link/20260805212920.1996937-1-dakr@kernel.org Signed-off-by: Danilo Krummrich --- diff --git a/rust/helpers/io.c b/rust/helpers/io.c index 397810864a24..1edbc274951c 100644 --- a/rust/helpers/io.c +++ b/rust/helpers/io.c @@ -3,6 +3,7 @@ #include #include +#ifdef CONFIG_HAS_IOMEM __rust_helper void __iomem *rust_helper_ioremap(phys_addr_t offset, size_t size) { return ioremap(offset, size); @@ -18,6 +19,7 @@ __rust_helper void rust_helper_iounmap(void __iomem *addr) { iounmap(addr); } +#endif /* CONFIG_HAS_IOMEM */ __rust_helper u8 rust_helper_readb(const void __iomem *addr) { diff --git a/rust/kernel/io.rs b/rust/kernel/io.rs index fcc7678fd9e3..d30bb5c6d4fc 100644 --- a/rust/kernel/io.rs +++ b/rust/kernel/io.rs @@ -9,6 +9,7 @@ use crate::{ prelude::*, // }; +#[cfg(CONFIG_HAS_IOMEM)] pub mod mem; pub mod poll; pub mod register; diff --git a/rust/kernel/platform.rs b/rust/kernel/platform.rs index 9b362e0495d3..d41555a4b31d 100644 --- a/rust/kernel/platform.rs +++ b/rust/kernel/platform.rs @@ -17,10 +17,7 @@ use crate::{ from_result, to_result, // }, - io::{ - mem::IoRequest, - Resource, // - }, + io::Resource, irq::{ self, IrqRequest, // @@ -31,6 +28,9 @@ use crate::{ ThisModule, // }; +#[cfg(CONFIG_HAS_IOMEM)] +use crate::io::mem::IoRequest; + use core::{ marker::PhantomData, mem::offset_of, @@ -307,6 +307,7 @@ impl Device { } } +#[cfg(CONFIG_HAS_IOMEM)] impl Device { /// Returns an `IoRequest` for the resource at `index`, if any. pub fn io_request_by_index(&self, index: u32) -> Option> {