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Message-ID: <20251104140156.4745-3-zhiw@nvidia.com>
Date: Tue, 4 Nov 2025 16:01:54 +0200
From: Zhi Wang <zhiw@...dia.com>
To: <rust-for-linux@...r.kernel.org>, <linux-pci@...r.kernel.org>,
<linux-kernel@...r.kernel.org>
CC: <aliceryhl@...gle.com>, <bhelgaas@...gle.com>, <kwilczynski@...nel.org>,
<ojeda@...nel.org>, <alex.gaynor@...il.com>, <boqun.feng@...il.com>,
<gary@...yguo.net>, <bjorn3_gh@...tonmail.com>, <lossin@...nel.org>,
<a.hindborg@...nel.org>, <tmgross@...ch.edu>, <markus.probst@...teo.de>,
<helgaas@...nel.org>, <cjia@...dia.com>, <smitra@...dia.com>,
<ankita@...dia.com>, <aniketa@...dia.com>, <kwankhede@...dia.com>,
<targupta@...dia.com>, <acourbot@...dia.com>, <joelagnelf@...dia.com>,
<jhubbard@...dia.com>, <zhiwang@...nel.org>, Zhi Wang <zhiw@...dia.com>
Subject: [PATCH v4 2/4] rust: io: factor out MMIO read/write macros
Refactor the existing MMIO accessors to use common call macros
instead of inlining the bindings calls in each `define_{read,write}!`
expansion.
This factoring separates the common offset/bounds checks from the
low-level call pattern, making it easier to add additional I/O accessor
families.
No functional change intended.
Signed-off-by: Zhi Wang <zhiw@...dia.com>
---
rust/kernel/io.rs | 114 +++++++++++++++++++++++++++++-----------------
1 file changed, 73 insertions(+), 41 deletions(-)
diff --git a/rust/kernel/io.rs b/rust/kernel/io.rs
index 0b1e79075c99..2f4206166b86 100644
--- a/rust/kernel/io.rs
+++ b/rust/kernel/io.rs
@@ -113,8 +113,34 @@ pub fn maxsize(&self) -> usize {
#[repr(transparent)]
pub struct Mmio<const SIZE: usize = 0>(MmioRaw<SIZE>);
+macro_rules! call_mmio_read {
+ (infallible, $c_fn:ident, $self:ident, $type:ty, $addr:expr) => {
+ // SAFETY: By the type invariant `addr` is a valid address for MMIO operations.
+ unsafe { bindings::$c_fn($addr as *const c_void) as $type }
+ };
+
+ (fallible, $c_fn:ident, $self:ident, $type:ty, $addr:expr) => {{
+ // SAFETY: By the type invariant `addr` is a valid address for MMIO operations.
+ Ok(unsafe { bindings::$c_fn($addr as *const c_void) as $type })
+ }};
+}
+
+macro_rules! call_mmio_write {
+ (infallible, $c_fn:ident, $self:ident, $ty:ty, $addr:expr, $value:expr) => {
+ // SAFETY: By the type invariant `addr` is a valid address for MMIO operations.
+ unsafe { bindings::$c_fn($value, $addr as *mut c_void) }
+ };
+
+ (fallible, $c_fn:ident, $self:ident, $ty:ty, $addr:expr, $value:expr) => {{
+ // SAFETY: By the type invariant `addr` is a valid address for MMIO operations.
+ unsafe { bindings::$c_fn($value, $addr as *mut c_void) };
+ Ok(())
+ }};
+}
+
macro_rules! define_read {
- (infallible, $(#[$attr:meta])* $vis:vis $name:ident, $c_fn:ident -> $type_name:ty) => {
+ (infallible, $(#[$attr:meta])* $vis:vis $name:ident, $call_macro:ident, $c_fn:ident ->
+ $type_name:ty) => {
/// Read IO data from a given offset known at compile time.
///
/// Bound checks are performed on compile time, hence if the offset is not known at compile
@@ -124,12 +150,13 @@ macro_rules! define_read {
$vis fn $name(&self, offset: usize) -> $type_name {
let addr = self.io_addr_assert::<$type_name>(offset);
- // SAFETY: By the type invariant `addr` is a valid address for MMIO operations.
- unsafe { bindings::$c_fn(addr as *const c_void) }
+ // SAFETY: By the type invariant `addr` is a valid address for IO operations.
+ $call_macro!(infallible, $c_fn, self, $type_name, addr)
}
};
- (fallible, $(#[$attr:meta])* $vis:vis $try_name:ident, $c_fn:ident -> $type_name:ty) => {
+ (fallible, $(#[$attr:meta])* $vis:vis $try_name:ident, $call_macro:ident, $c_fn:ident ->
+ $type_name:ty) => {
/// Read IO data from a given offset.
///
/// Bound checks are performed on runtime, it fails if the offset (plus the type size) is
@@ -138,14 +165,16 @@ macro_rules! define_read {
$vis fn $try_name(&self, offset: usize) -> Result<$type_name> {
let addr = self.io_addr::<$type_name>(offset)?;
- // SAFETY: By the type invariant `addr` is a valid address for MMIO operations.
- Ok(unsafe { bindings::$c_fn(addr as *const c_void) })
+ // SAFETY: By the type invariant `addr` is a valid address for IO operations.
+ $call_macro!(fallible, $c_fn, self, $type_name, addr)
}
};
}
+pub(crate) use define_read;
macro_rules! define_write {
- (infallible, $(#[$attr:meta])* $vis:vis $name:ident, $c_fn:ident <- $type_name:ty) => {
+ (infallible, $(#[$attr:meta])* $vis:vis $name:ident, $call_macro:ident, $c_fn:ident <-
+ $type_name:ty) => {
/// Write IO data from a given offset known at compile time.
///
/// Bound checks are performed on compile time, hence if the offset is not known at compile
@@ -155,12 +184,12 @@ macro_rules! define_write {
$vis fn $name(&self, value: $type_name, offset: usize) {
let addr = self.io_addr_assert::<$type_name>(offset);
- // SAFETY: By the type invariant `addr` is a valid address for MMIO operations.
- unsafe { bindings::$c_fn(value, addr as *mut c_void) }
+ $call_macro!(infallible, $c_fn, self, $type_name, addr, value);
}
};
- (fallible, $(#[$attr:meta])* $vis:vis $try_name:ident, $c_fn:ident <- $type_name:ty) => {
+ (fallible, $(#[$attr:meta])* $vis:vis $try_name:ident, $call_macro:ident, $c_fn:ident <-
+ $type_name:ty) => {
/// Write IO data from a given offset.
///
/// Bound checks are performed on runtime, it fails if the offset (plus the type size) is
@@ -169,12 +198,11 @@ macro_rules! define_write {
$vis fn $try_name(&self, value: $type_name, offset: usize) -> Result {
let addr = self.io_addr::<$type_name>(offset)?;
- // SAFETY: By the type invariant `addr` is a valid address for MMIO operations.
- unsafe { bindings::$c_fn(value, addr as *mut c_void) }
- Ok(())
+ $call_macro!(fallible, $c_fn, self, $type_name, addr, value)
}
};
}
+pub(crate) use define_write;
/// Checks whether an access of type `U` at the given `offset`
/// is valid within this region.
@@ -294,30 +322,30 @@ fn maxsize(&self) -> usize {
self.0.maxsize()
}
- define_read!(infallible, read8, readb -> u8);
- define_read!(infallible, read16, readw -> u16);
- define_read!(infallible, read32, readl -> u32);
+ define_read!(infallible, read8, call_mmio_read, readb -> u8);
+ define_read!(infallible, read16, call_mmio_read, readw -> u16);
+ define_read!(infallible, read32, call_mmio_read, readl -> u32);
- define_read!(fallible, try_read8, readb -> u8);
- define_read!(fallible, try_read16, readw -> u16);
- define_read!(fallible, try_read32, readl -> u32);
+ define_read!(fallible, try_read8, call_mmio_read, readb -> u8);
+ define_read!(fallible, try_read16, call_mmio_read, readw -> u16);
+ define_read!(fallible, try_read32, call_mmio_read, readl -> u32);
- define_write!(infallible, write8, writeb <- u8);
- define_write!(infallible, write16, writew <- u16);
- define_write!(infallible, write32, writel <- u32);
+ define_write!(infallible, write8, call_mmio_write, writeb <- u8);
+ define_write!(infallible, write16, call_mmio_write, writew <- u16);
+ define_write!(infallible, write32, call_mmio_write, writel <- u32);
- define_write!(fallible, try_write8, writeb <- u8);
- define_write!(fallible, try_write16, writew <- u16);
- define_write!(fallible, try_write32, writel <- u32);
+ define_write!(fallible, try_write8, call_mmio_write, writeb <- u8);
+ define_write!(fallible, try_write16, call_mmio_write, writew <- u16);
+ define_write!(fallible, try_write32, call_mmio_write, writel <- u32);
}
#[cfg(CONFIG_64BIT)]
impl<const SIZE: usize> Io64 for Mmio<SIZE> {
- define_read!(infallible, read64, readq -> u64);
- define_read!(fallible, try_read64, readq -> u64);
+ define_read!(infallible, read64, call_mmio_read, readq -> u64);
+ define_read!(fallible, try_read64, call_mmio_read, readq -> u64);
- define_write!(infallible, write64, writeq <- u64);
- define_write!(fallible, try_write64, writeq <- u64);
+ define_write!(infallible, write64, call_mmio_write, writeq <- u64);
+ define_write!(fallible, try_write64, call_mmio_write, writeq <- u64);
}
impl<const SIZE: usize> Mmio<SIZE> {
@@ -332,43 +360,47 @@ pub unsafe fn from_raw(raw: &MmioRaw<SIZE>) -> &Self {
unsafe { &*core::ptr::from_ref(raw).cast() }
}
- define_read!(infallible, pub read8_relaxed, readb_relaxed -> u8);
- define_read!(infallible, pub read16_relaxed, readw_relaxed -> u16);
- define_read!(infallible, pub read32_relaxed, readl_relaxed -> u32);
+ define_read!(infallible, pub read8_relaxed, call_mmio_read, readb_relaxed -> u8);
+ define_read!(infallible, pub read16_relaxed, call_mmio_read, readw_relaxed -> u16);
+ define_read!(infallible, pub read32_relaxed, call_mmio_read, readl_relaxed -> u32);
define_read!(
infallible,
#[cfg(CONFIG_64BIT)]
pub read64_relaxed,
+ call_mmio_read,
readq_relaxed -> u64
);
- define_read!(fallible, pub try_read8_relaxed, readb_relaxed -> u8);
- define_read!(fallible, pub try_read16_relaxed, readw_relaxed -> u16);
- define_read!(fallible, pub try_read32_relaxed, readl_relaxed -> u32);
+ define_read!(fallible, pub try_read8_relaxed, call_mmio_read, readb_relaxed -> u8);
+ define_read!(fallible, pub try_read16_relaxed, call_mmio_read, readw_relaxed -> u16);
+ define_read!(fallible, pub try_read32_relaxed, call_mmio_read, readl_relaxed -> u32);
define_read!(
fallible,
#[cfg(CONFIG_64BIT)]
pub try_read64_relaxed,
+ call_mmio_read,
readq_relaxed -> u64
);
- define_write!(infallible, pub write8_relaxed, writeb_relaxed <- u8);
- define_write!(infallible, pub write16_relaxed, writew_relaxed <- u16);
- define_write!(infallible, pub write32_relaxed, writel_relaxed <- u32);
+ define_write!(infallible, pub write8_relaxed, call_mmio_write, writeb_relaxed <- u8);
+ define_write!(infallible, pub write16_relaxed, call_mmio_write, writew_relaxed <- u16);
+ define_write!(infallible, pub write32_relaxed, call_mmio_write, writel_relaxed <- u32);
define_write!(
infallible,
#[cfg(CONFIG_64BIT)]
pub write64_relaxed,
+ call_mmio_write,
writeq_relaxed <- u64
);
- define_write!(fallible, pub try_write8_relaxed, writeb_relaxed <- u8);
- define_write!(fallible, pub try_write16_relaxed, writew_relaxed <- u16);
- define_write!(fallible, pub try_write32_relaxed, writel_relaxed <- u32);
+ define_write!(fallible, pub try_write8_relaxed, call_mmio_write, writeb_relaxed <- u8);
+ define_write!(fallible, pub try_write16_relaxed, call_mmio_write, writew_relaxed <- u16);
+ define_write!(fallible, pub try_write32_relaxed, call_mmio_write, writel_relaxed <- u32);
define_write!(
fallible,
#[cfg(CONFIG_64BIT)]
pub try_write64_relaxed,
+ call_mmio_write,
writeq_relaxed <- u64
);
}
--
2.51.0
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