ARM: 9480/1: entry: expand comment in __switch_tografted

As per discussion between the developers in the mail thread
linked, expand the comment in __switch_to so that readers
of the code understand what is going on.

Suggested-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Linus Walleij <linusw@kernel.org>>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>

1 files changed, 25 insertions, 0 deletions

diff --git a/Documentation/rust/arch-support.rst b/Documentation/rust/arch-support.rst
new file mode 100644
index 000000000..6e6a515d0
--- /dev/null
+++ b/Documentation/rust/arch-support.rst
@@ -0,0 +1,25 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+Arch Support
+============
+
+Currently, the Rust compiler (``rustc``) uses LLVM for code generation,
+which limits the supported architectures that can be targeted. In addition,
+support for building the kernel with LLVM/Clang varies (please see
+Documentation/kbuild/llvm.rst). This support is needed for ``bindgen``
+which uses ``libclang``.
+
+Below is a general summary of architectures that currently work. Level of
+support corresponds to ``S`` values in the ``MAINTAINERS`` file.
+
+=============  ================  ==============================================
+Architecture   Level of support  Constraints
+=============  ================  ==============================================
+``arm``        Maintained        ARMv7 Little Endian only.
+``arm64``      Maintained        Little Endian only.
+``loongarch``  Maintained        \-
+``riscv``      Maintained        ``riscv64`` and LLVM/Clang only.
+``um``         Maintained        \-
+``x86``        Maintained        ``x86_64`` only.
+=============  ================  ==============================================
+