linux-kernel - [PATCH v5 09/23] gpu: nova-core: allow register aliases

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20250612-nova-frts-v5-9-14ba7eaf166b@nvidia.com>
Date: Thu, 12 Jun 2025 23:01:37 +0900
From: Alexandre Courbot <acourbot@...dia.com>
To: Miguel Ojeda <ojeda@...nel.org>, Alex Gaynor <alex.gaynor@...il.com>, 
 Boqun Feng <boqun.feng@...il.com>, Gary Guo <gary@...yguo.net>, 
 Björn Roy Baron <bjorn3_gh@...tonmail.com>, 
 Andreas Hindborg <a.hindborg@...nel.org>, Alice Ryhl <aliceryhl@...gle.com>, 
 Trevor Gross <tmgross@...ch.edu>, Danilo Krummrich <dakr@...nel.org>, 
 David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>, 
 Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>, 
 Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>, 
 Benno Lossin <lossin@...nel.org>
Cc: John Hubbard <jhubbard@...dia.com>, Ben Skeggs <bskeggs@...dia.com>, 
 Joel Fernandes <joelagnelf@...dia.com>, Timur Tabi <ttabi@...dia.com>, 
 Alistair Popple <apopple@...dia.com>, linux-kernel@...r.kernel.org, 
 rust-for-linux@...r.kernel.org, nouveau@...ts.freedesktop.org, 
 dri-devel@...ts.freedesktop.org, Alexandre Courbot <acourbot@...dia.com>
Subject: [PATCH v5 09/23] gpu: nova-core: allow register aliases

Some registers (notably scratch registers) don't have a definitive
purpose, but need to be interpreted differently depending on context.

Expand the register!() macro to support a syntax indicating that a
register type should be at the same offset as another one, but under a
different name, and with different fields and documentation.

Signed-off-by: Alexandre Courbot <acourbot@...dia.com>
---
 drivers/gpu/nova-core/regs/macros.rs | 40 ++++++++++++++++++++++++++++++++++--
 1 file changed, 38 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/nova-core/regs/macros.rs b/drivers/gpu/nova-core/regs/macros.rs
index 7cd013f3c90bbd8ca437d4072cae8f11d7946fcd..e0e6fef3796f9dd2ce4e0223444a05bcc53075a6 100644
--- a/drivers/gpu/nova-core/regs/macros.rs
+++ b/drivers/gpu/nova-core/regs/macros.rs
@@ -71,6 +71,20 @@
 /// pr_info!("CPU CTL: {:#x}", cpuctl);
 /// cpuctl.set_start(true).write(&bar, CPU_BASE);
 /// ```
+///
+/// It is also possible to create a alias register by using the `=> ALIAS` syntax. This is useful
+/// for cases where a register's interpretation depends on the context:
+///
+/// ```no_run
+/// register!(SCRATCH_0 @ 0x0000100, "Scratch register 0" {
+///    31:0     value as u32, "Raw value";
+///
+/// register!(SCRATCH_0_BOOT_STATUS => SCRATCH_0, "Boot status of the firmware" {
+///     0:0     completed as bool, "Whether the firmware has completed booting";
+/// ```
+///
+/// In this example, `SCRATCH_0_BOOT_STATUS` uses the same I/O address as `SCRATCH_0`, while also
+/// providing its own `completed` method.
 macro_rules! register {
     // Creates a register at a fixed offset of the MMIO space.
     (
@@ -83,6 +97,17 @@ macro_rules! register {
         register!(@io $name @ $offset);
     };
 
+    // Creates a alias register of fixed offset register `alias` with its own fields.
+    (
+        $name:ident => $alias:ident $(, $comment:literal)? {
+            $($fields:tt)*
+        }
+    ) => {
+        register!(@common $name @ $alias::OFFSET $(, $comment)?);
+        register!(@field_accessors $name { $($fields)* });
+        register!(@io $name @ $alias::OFFSET);
+    };
+
     // Creates a register at a relative offset from a base address.
     (
         $name:ident @ + $offset:literal $(, $comment:literal)? {
@@ -94,11 +119,22 @@ macro_rules! register {
         register!(@io$name @ + $offset);
     };
 
+    // Creates a alias register of relative offset register `alias` with its own fields.
+    (
+        $name:ident => + $alias:ident $(, $comment:literal)? {
+            $($fields:tt)*
+        }
+    ) => {
+        register!(@common $name @ $alias::OFFSET $(, $comment)?);
+        register!(@field_accessors $name { $($fields)* });
+        register!(@io $name @ + $alias::OFFSET);
+    };
+
     // All rules below are helpers.
 
     // Defines the wrapper `$name` type, as well as its relevant implementations (`Debug`, `BitOr`,
     // and conversion to regular `u32`).
-    (@common $name:ident @ $offset:literal $(, $comment:literal)?) => {
+    (@common $name:ident @ $offset:expr $(, $comment:literal)?) => {
         $(
         #[doc=$comment]
         )?
@@ -280,7 +316,7 @@ pub(crate) fn [<set_ $field>](mut self, value: $to_type) -> Self {
     };
 
     // Creates the IO accessors for a fixed offset register.
-    (@io $name:ident @ $offset:literal) => {
+    (@io $name:ident @ $offset:expr) => {
         #[allow(dead_code)]
         impl $name {
             #[inline]

-- 
2.49.0