Re: [PATCH v3 15/16] rust: platform: add basic platform device / driver abstractions

[Dirk Behme <dirk.behme@de.bosch.com>]

On 28.10.2024 11:19, Danilo Krummrich wrote:
> On Thu, Oct 24, 2024 at 11:11:50AM +0200, Dirk Behme wrote:
>>> +/// IdTable type for platform drivers.
>>> +pub type IdTable<T> = &'static dyn kernel::device_id::IdTable<of::DeviceId, T>;
>>> +
>>> +/// The platform driver trait.
>>> +///
>>> +/// # Example
>>> +///
>>> +///```
>>> +/// # use kernel::{bindings, c_str, of, platform};
>>> +///
>>> +/// struct MyDriver;
>>> +///
>>> +/// kernel::of_device_table!(
>>> +///     OF_TABLE,
>>> +///     MODULE_OF_TABLE,
>>
>> It looks to me that OF_TABLE and MODULE_OF_TABLE are quite generic names
>> used here. Shouldn't they be somehow driver specific, e.g. OF_TABLE_MYDRIVER
>> and MODULE_OF_TABLE_MYDRIVER or whatever? Same for the other
>> examples/samples in this patch series. Found that while using the *same*
>> somewhere else ;)
> 
> I think the names by themselves are fine. They're local to the module. However,
> we stringify `OF_TABLE` in `module_device_table` to build the export name, i.e.
> "__mod_of__OF_TABLE_device_table". Hence the potential duplicate symbols.
> 
> I think we somehow need to build the module name into the symbol name as well.

Something like this?


Subject: [PATCH] rust: device: Add the module name to the symbol name

Make the symbol name unique by adding the module name to avoid
duplicate symbol errors like

ld.lld: error: duplicate symbol: __mod_of__OF_TABLE_device_table
 >>> defined at doctests_kernel_generated.ff18649a828ae8c4-cgu.0
 >>> 
rust/doctests_kernel_generated.o:(__mod_of__OF_TABLE_device_table) in 
archive vmlinux.a
 >>> defined at rust_driver_platform.2308c4225c4e08b3-cgu.0
 >>>            samples/rust/rust_driver_platform.o:(.rodata+0x5A8) in 
archive vmlinux.a
make[2]: *** [scripts/Makefile.vmlinux_o:65: vmlinux.o] Error 1
make[1]: *** [Makefile:1154: vmlinux_o] Error 2

__mod_of__OF_TABLE_device_table is too generic. Add the module name.

Proposed-by: Danilo Krummrich <dakr@kernel.org>
Link: https://lore.kernel.org/rust-for-linux/Zx9lFG1XKnC_WaG0@pollux/
Signed-off-by: Dirk Behme <dirk.behme@de.bosch.com>
---
  rust/kernel/device_id.rs             | 4 ++--
  rust/kernel/of.rs                    | 4 ++--
  rust/kernel/pci.rs                   | 5 +++--
  rust/kernel/platform.rs              | 1 +
  samples/rust/rust_driver_pci.rs      | 1 +
  samples/rust/rust_driver_platform.rs | 1 +
  6 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/rust/kernel/device_id.rs b/rust/kernel/device_id.rs
index 5b1329fba528..231f34362da9 100644
--- a/rust/kernel/device_id.rs
+++ b/rust/kernel/device_id.rs
@@ -151,10 +151,10 @@ fn info(&self, index: usize) -> &U {
  /// Create device table alias for modpost.
  #[macro_export]
  macro_rules! module_device_table {
-    ($table_type: literal, $module_table_name:ident, $table_name:ident) 
=> {
+    ($table_type: literal, $device_name: literal, 
$module_table_name:ident, $table_name:ident) => {
          #[rustfmt::skip]
          #[export_name =
-            concat!("__mod_", $table_type, "__", 
stringify!($table_name), "_device_table")
+            concat!("__mod_", $table_type, "__", 
stringify!($table_name), "_", $device_name, "_device_table")
          ]
          static $module_table_name: [core::mem::MaybeUninit<u8>; 
$table_name.raw_ids().size()] =
              unsafe { core::mem::transmute_copy($table_name.raw_ids()) };
diff --git a/rust/kernel/of.rs b/rust/kernel/of.rs
index a37629997974..77679c30638c 100644
--- a/rust/kernel/of.rs
+++ b/rust/kernel/of.rs
@@ -51,13 +51,13 @@ pub fn compatible<'a>(&self) -> &'a CStr {
  /// Create an OF `IdTable` with an "alias" for modpost.
  #[macro_export]
  macro_rules! of_device_table {
-    ($table_name:ident, $module_table_name:ident, $id_info_type: ty, 
$table_data: expr) => {
+    ($device_name: literal, $table_name:ident, 
$module_table_name:ident, $id_info_type: ty, $table_data: expr) => {
          const $table_name: $crate::device_id::IdArray<
              $crate::of::DeviceId,
              $id_info_type,
              { $table_data.len() },
          > = $crate::device_id::IdArray::new($table_data);

-        $crate::module_device_table!("of", $module_table_name, 
$table_name);
+        $crate::module_device_table!("of", $device_name, 
$module_table_name, $table_name);
      };
  }
diff --git a/rust/kernel/pci.rs b/rust/kernel/pci.rs
index 58f7d9c0045b..806d192b9600 100644
--- a/rust/kernel/pci.rs
+++ b/rust/kernel/pci.rs
@@ -176,14 +176,14 @@ fn index(&self) -> usize {
  /// Create a PCI `IdTable` with its alias for modpost.
  #[macro_export]
  macro_rules! pci_device_table {
-    ($table_name:ident, $module_table_name:ident, $id_info_type: ty, 
$table_data: expr) => {
+    ($device_name: literal, $table_name:ident, 
$module_table_name:ident, $id_info_type: ty, $table_data: expr) => {
          const $table_name: $crate::device_id::IdArray<
              $crate::pci::DeviceId,
              $id_info_type,
              { $table_data.len() },
          > = $crate::device_id::IdArray::new($table_data);

-        $crate::module_device_table!("pci", $module_table_name, 
$table_name);
+        $crate::module_device_table!("pci", $device_name, 
$module_table_name, $table_name);
      };
  }

@@ -197,6 +197,7 @@ macro_rules! pci_device_table {
  /// struct MyDriver;
  ///
  /// kernel::pci_device_table!(
+///     "MyDriver",
  ///     PCI_TABLE,
  ///     MODULE_PCI_TABLE,
  ///     <MyDriver as pci::Driver>::IdInfo,
diff --git a/rust/kernel/platform.rs b/rust/kernel/platform.rs
index a926233a789f..fcdd3c5da0e5 100644
--- a/rust/kernel/platform.rs
+++ b/rust/kernel/platform.rs
@@ -118,6 +118,7 @@ macro_rules! module_platform_driver {
  /// struct MyDriver;
  ///
  /// kernel::of_device_table!(
+///     "MyDriver",
  ///     OF_TABLE,
  ///     MODULE_OF_TABLE,
  ///     <MyDriver as platform::Driver>::IdInfo,
diff --git a/samples/rust/rust_driver_pci.rs 
b/samples/rust/rust_driver_pci.rs
index d24dc1fde9e8..6ee570b59233 100644
--- a/samples/rust/rust_driver_pci.rs
+++ b/samples/rust/rust_driver_pci.rs
@@ -31,6 +31,7 @@ struct SampleDriver {
  }

  kernel::pci_device_table!(
+    "SampleDriver",
      PCI_TABLE,
      MODULE_PCI_TABLE,
      <SampleDriver as pci::Driver>::IdInfo,
diff --git a/samples/rust/rust_driver_platform.rs 
b/samples/rust/rust_driver_platform.rs
index fd7a5ad669fe..9dfbe3b9932b 100644
--- a/samples/rust/rust_driver_platform.rs
+++ b/samples/rust/rust_driver_platform.rs
@@ -11,6 +11,7 @@ struct SampleDriver {
  struct Info(u32);

  kernel::of_device_table!(
+    "SampleDriver",
      OF_TABLE,
      MODULE_OF_TABLE,
      <SampleDriver as platform::Driver>::IdInfo,
-- 
2.46.2