samples/rust/Kconfig | 10 +++++ samples/rust/Makefile | 1 + samples/rust/rust_alloc.rs | 88 ++++++++++++++++++++++++++++++++++++++ 3 files changed, 99 insertions(+) create mode 100644 samples/rust/rust_alloc.rs
From: Hui Zhu <zhuhui@kylinos.cn>
Add a sample to the samples memory alloc usage.
It will samples the usage of VBox and KVec.
It also includes a test for allocating alignments larger than PAGE_SIZE
using VBox.
Since this feature is currently unsupported, it will report errors even
when successful.
Changelog:
v2:
According to the comments of Danilo, updated the commit to samples the
usage of VBox and KVec.
Co-developed-by: Geliang Tang <geliang@kernel.org>
Signed-off-by: Geliang Tang <geliang@kernel.org>
Signed-off-by: Hui Zhu <zhuhui@kylinos.cn>
---
samples/rust/Kconfig | 10 +++++
samples/rust/Makefile | 1 +
samples/rust/rust_alloc.rs | 88 ++++++++++++++++++++++++++++++++++++++
3 files changed, 99 insertions(+)
create mode 100644 samples/rust/rust_alloc.rs
diff --git a/samples/rust/Kconfig b/samples/rust/Kconfig
index 7f7371a004ee..03a86f819768 100644
--- a/samples/rust/Kconfig
+++ b/samples/rust/Kconfig
@@ -105,6 +105,16 @@ config SAMPLE_RUST_DRIVER_AUXILIARY
If unsure, say N.
+config SAMPLE_RUST_ALLOC
+ tristate "Alloc Test Driver"
+ help
+ This option builds the Rust alloc Test driver sample.
+
+ To compile this as a module, choose M here:
+ the module will be called rust_alloc.
+
+ If unsure, say N.
+
config SAMPLE_RUST_HOSTPROGS
bool "Host programs"
help
diff --git a/samples/rust/Makefile b/samples/rust/Makefile
index bd2faad63b4f..7c3e68d9ada5 100644
--- a/samples/rust/Makefile
+++ b/samples/rust/Makefile
@@ -10,6 +10,7 @@ obj-$(CONFIG_SAMPLE_RUST_DRIVER_PLATFORM) += rust_driver_platform.o
obj-$(CONFIG_SAMPLE_RUST_DRIVER_FAUX) += rust_driver_faux.o
obj-$(CONFIG_SAMPLE_RUST_DRIVER_AUXILIARY) += rust_driver_auxiliary.o
obj-$(CONFIG_SAMPLE_RUST_CONFIGFS) += rust_configfs.o
+obj-$(CONFIG_SAMPLE_RUST_ALLOC) += rust_alloc.o
rust_print-y := rust_print_main.o rust_print_events.o
diff --git a/samples/rust/rust_alloc.rs b/samples/rust/rust_alloc.rs
new file mode 100644
index 000000000000..61efde37b5f2
--- /dev/null
+++ b/samples/rust/rust_alloc.rs
@@ -0,0 +1,88 @@
+// SPDX-License-Identifier: GPL-2.0
+
+// Copyright (c) 2025, Kylin Software
+
+//! Rust alloc sample.
+
+use kernel::bindings;
+use kernel::prelude::*;
+
+module! {
+ type: RustAlloc,
+ name: "rust_alloc",
+ authors: ["Rust for Linux Contributors"],
+ description: "Rust alloc sample",
+ license: "GPL",
+}
+
+const VBOX_SIZE: usize = 1024;
+const VBOX_LARGE_ALIGN: usize = bindings::PAGE_SIZE * 4;
+const KVEC_VAL: [usize; 3] = [10, 20, 30];
+
+#[repr(align(128))]
+struct VboxBlob([u8; VBOX_SIZE]);
+
+// This structure is used to test the allocation of alignments larger
+// than PAGE_SIZE.
+// Since this is not yet supported, avoid accessing the contents of
+// the structure for now.
+#[allow(dead_code)]
+#[repr(align(8192))]
+struct VboxLargeAlignBlob([u8; VBOX_LARGE_ALIGN]);
+
+struct RustAlloc {
+ vbox_blob: VBox<VboxBlob>,
+ kvec_blob: KVec<usize>,
+}
+
+fn check_align(addr: usize, align: usize) -> bool {
+ debug_assert!(align.is_power_of_two());
+ if addr & (align - 1) != 0 {
+ pr_err!("Address {:#x} is not aligned with {:#x}.\n", addr, align);
+ false
+ } else {
+ true
+ }
+}
+
+impl kernel::Module for RustAlloc {
+ fn init(_module: &'static ThisModule) -> Result<Self> {
+ pr_info!("Rust allocator sample (init)\n");
+
+ let vbox_blob = VBox::<VboxBlob>::new_uninit(GFP_KERNEL)?;
+ if !check_align(vbox_blob.as_ptr() as usize, 128) {
+ return Err(EINVAL);
+ }
+ let vbox_blob = vbox_blob.write(VboxBlob([0xfeu8; VBOX_SIZE]));
+
+ if let Ok(_) = VBox::<VboxLargeAlignBlob>::new_uninit(GFP_KERNEL) {
+ pr_err!("Allocations for VBox with alignments larger than PAGE_SIZE should fail, but here it succeeded.\n");
+ return Err(EINVAL);
+ }
+
+ let mut kvec_blob = KVec::new();
+ kvec_blob.extend_from_slice(&KVEC_VAL, GFP_KERNEL)?;
+
+ Ok(Self {
+ vbox_blob,
+ kvec_blob,
+ })
+ }
+}
+
+impl Drop for RustAlloc {
+ fn drop(&mut self) {
+ pr_info!("Rust allocator sample (exit)\n");
+
+ // check the values
+ for b in self.vbox_blob.0.as_slice().iter() {
+ if *b != 0xfeu8 {
+ pr_err!("vbox_blob contains wrong values\n");
+ }
+ }
+
+ if self.kvec_blob.as_slice() != KVEC_VAL {
+ pr_err!("kvec_blob contains wrong values\n");
+ }
+ }
+}
--
2.43.0(Cc: Lorenzo, Vlastimil, Liam, Uladzislau)
On Thu Jul 17, 2025 at 11:50 AM CEST, Hui Zhu wrote:
> diff --git a/samples/rust/Makefile b/samples/rust/Makefile
> index bd2faad63b4f..7c3e68d9ada5 100644
> --- a/samples/rust/Makefile
> +++ b/samples/rust/Makefile
> @@ -10,6 +10,7 @@ obj-$(CONFIG_SAMPLE_RUST_DRIVER_PLATFORM) += rust_driver_platform.o
> obj-$(CONFIG_SAMPLE_RUST_DRIVER_FAUX) += rust_driver_faux.o
> obj-$(CONFIG_SAMPLE_RUST_DRIVER_AUXILIARY) += rust_driver_auxiliary.o
> obj-$(CONFIG_SAMPLE_RUST_CONFIGFS) += rust_configfs.o
> +obj-$(CONFIG_SAMPLE_RUST_ALLOC) += rust_alloc.o
I think adding an example for large alignment is fine, but let's do this in a
doc-test on VBox in rust/kernel/alloc/kbox.rs. I think adding a separate module
for this is overkill.
Note that doc-tests are executed on boot if CONFIG_RUST_KERNEL_DOCTESTS=y.
> diff --git a/samples/rust/rust_alloc.rs b/samples/rust/rust_alloc.rs
> new file mode 100644
> index 000000000000..61efde37b5f2
> --- /dev/null
> +++ b/samples/rust/rust_alloc.rs
> @@ -0,0 +1,88 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +// Copyright (c) 2025, Kylin Software
> +
> +//! Rust alloc sample.
> +
> +use kernel::bindings;
> +use kernel::prelude::*;
> +
> +module! {
> + type: RustAlloc,
> + name: "rust_alloc",
> + authors: ["Rust for Linux Contributors"],
> + description: "Rust alloc sample",
> + license: "GPL",
> +}
> +
> +const VBOX_SIZE: usize = 1024;
> +const VBOX_LARGE_ALIGN: usize = bindings::PAGE_SIZE * 4;
Please use kernel::page::PAGE_SIZE instead.
> +const KVEC_VAL: [usize; 3] = [10, 20, 30];
> +
> +#[repr(align(128))]
> +struct VboxBlob([u8; VBOX_SIZE]);
> +
> +// This structure is used to test the allocation of alignments larger
> +// than PAGE_SIZE.
> +// Since this is not yet supported, avoid accessing the contents of
> +// the structure for now.
> +#[allow(dead_code)]
> +#[repr(align(8192))]
> +struct VboxLargeAlignBlob([u8; VBOX_LARGE_ALIGN]);
> +
> +struct RustAlloc {
> + vbox_blob: VBox<VboxBlob>,
> + kvec_blob: KVec<usize>,
> +}
> +
> +fn check_align(addr: usize, align: usize) -> bool {
> + debug_assert!(align.is_power_of_two());
> + if addr & (align - 1) != 0 {
> + pr_err!("Address {:#x} is not aligned with {:#x}.\n", addr, align);
> + false
> + } else {
> + true
> + }
> +}
I think check_align() is unnecessary -- we don't need to test this in this
context.
Instead, I suggest to add some doc-tests to the `Allocator` impls for `Kmalloc`,
`Vmalloc` and `KVmalloc` in rust/kernel/alloc/allocator.rs testing that they
return the expected alignment. This would be a valuable test case for those. If
you're interested in adding them, please feel free to do so. :)
> +impl kernel::Module for RustAlloc {
> + fn init(_module: &'static ThisModule) -> Result<Self> {
> + pr_info!("Rust allocator sample (init)\n");
> +
> + let vbox_blob = VBox::<VboxBlob>::new_uninit(GFP_KERNEL)?;
> + if !check_align(vbox_blob.as_ptr() as usize, 128) {
> + return Err(EINVAL);
> + }
> + let vbox_blob = vbox_blob.write(VboxBlob([0xfeu8; VBOX_SIZE]));
Given that you initialize it with a value anyways, you can just do
let blob = VBox::new(Blob([0xfeu8; SIZE]), GFP_KERNEL)?;
instead.
> + if let Ok(_) = VBox::<VboxLargeAlignBlob>::new_uninit(GFP_KERNEL) {
> + pr_err!("Allocations for VBox with alignments larger than PAGE_SIZE should fail, but here it succeeded.\n");
> + return Err(EINVAL);
> + }
This can just be
assert!(VBox::<VboxLargeAlignBlob>::new_uninit(GFP_KERNEL).is_err());
within a doc-test.
> + let mut kvec_blob = KVec::new();
> + kvec_blob.extend_from_slice(&KVEC_VAL, GFP_KERNEL)?;
We already have doc-tests for KVec::new() and KVec::extend_from_slice() in
rust/kernel/alloc/kvec.rs.
> + Ok(Self {
> + vbox_blob,
> + kvec_blob,
> + })
> + }
> +}
> +
> +impl Drop for RustAlloc {
> + fn drop(&mut self) {
> + pr_info!("Rust allocator sample (exit)\n");
> +
> + // check the values
> + for b in self.vbox_blob.0.as_slice().iter() {
> + if *b != 0xfeu8 {
> + pr_err!("vbox_blob contains wrong values\n");
> + }
> + }
> +
> + if self.kvec_blob.as_slice() != KVEC_VAL {
> + pr_err!("kvec_blob contains wrong values\n");
> + }
Here you're basically testing Vec::as_slice(). We don't have doc-tests for
as_slice() and as_slice_mut() in rust/kernel/alloc/kvec.rs. Please feel free to
add them. :)
> + }
> +}
On Thu, Jul 17, 2025 at 01:19:05PM +0200, Danilo Krummrich wrote: > (Cc: Lorenzo, Vlastimil, Liam, Uladzislau) > > On Thu Jul 17, 2025 at 11:50 AM CEST, Hui Zhu wrote: > > diff --git a/samples/rust/Makefile b/samples/rust/Makefile > > index bd2faad63b4f..7c3e68d9ada5 100644 > > --- a/samples/rust/Makefile > > +++ b/samples/rust/Makefile > > @@ -10,6 +10,7 @@ obj-$(CONFIG_SAMPLE_RUST_DRIVER_PLATFORM) += rust_driver_platform.o > > obj-$(CONFIG_SAMPLE_RUST_DRIVER_FAUX) += rust_driver_faux.o > > obj-$(CONFIG_SAMPLE_RUST_DRIVER_AUXILIARY) += rust_driver_auxiliary.o > > obj-$(CONFIG_SAMPLE_RUST_CONFIGFS) += rust_configfs.o > > +obj-$(CONFIG_SAMPLE_RUST_ALLOC) += rust_alloc.o > > I think adding an example for large alignment is fine, but let's do this in a > doc-test on VBox in rust/kernel/alloc/kbox.rs. I think adding a separate module I would suggest using #[kunit_tests(..)], which is similar to how doc-test run, for it if we only use it for test purposes. Regards, Boqun > for this is overkill. > > Note that doc-tests are executed on boot if CONFIG_RUST_KERNEL_DOCTESTS=y. > [...]
Hi Danilo and Boqun, On Thu, Jul 17, 2025 at 09:14:15AM -0700, Boqun Feng wrote: > On Thu, Jul 17, 2025 at 01:19:05PM +0200, Danilo Krummrich wrote: > > (Cc: Lorenzo, Vlastimil, Liam, Uladzislau) > > > > On Thu Jul 17, 2025 at 11:50 AM CEST, Hui Zhu wrote: > > > diff --git a/samples/rust/Makefile b/samples/rust/Makefile > > > index bd2faad63b4f..7c3e68d9ada5 100644 > > > --- a/samples/rust/Makefile > > > +++ b/samples/rust/Makefile > > > @@ -10,6 +10,7 @@ obj-$(CONFIG_SAMPLE_RUST_DRIVER_PLATFORM) += rust_driver_platform.o > > > obj-$(CONFIG_SAMPLE_RUST_DRIVER_FAUX) += rust_driver_faux.o > > > obj-$(CONFIG_SAMPLE_RUST_DRIVER_AUXILIARY) += rust_driver_auxiliary.o > > > obj-$(CONFIG_SAMPLE_RUST_CONFIGFS) += rust_configfs.o > > > +obj-$(CONFIG_SAMPLE_RUST_ALLOC) += rust_alloc.o > > > > I think adding an example for large alignment is fine, but let's do this in a > > doc-test on VBox in rust/kernel/alloc/kbox.rs. I think adding a separate module > > I would suggest using #[kunit_tests(..)], which is similar to how > doc-test run, for it if we only use it for test purposes. > > Regards, > Boqun > > > for this is overkill. > > > > Note that doc-tests are executed on boot if CONFIG_RUST_KERNEL_DOCTESTS=y. > > > [...] I sent version v3 that move vbox code to allocator as unit tests and add move kvec::as_slice to doc example. Best, Hui
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