[bazel] Import lowRISC toolchain repo directly

Previously we were accessing the lowRISC toolchain indirectly via CRT,
but this isn't possible with Bzlmod. We need to pull the repo in
directly.

Signed-off-by: James Wainwright <james.wainwright@lowrisc.org>

Author: jwnrt

MODULE.bazel

@@ -114,6 +114,9 @@ use_repo(open_dice, "open-dice")
 hyperdebug = use_extension("//third_party/hyperdebug:extensions.bzl", "hyperdebug")
 use_repo(hyperdebug, "hyperdebug_firmware")
 
+lowrisc_toolchain = use_extension("//third_party/lowrisc:extensions.bzl", "lowrisc_toolchain")
+use_repo(lowrisc_toolchain, "lowrisc_toolchain")
+
 # Extension for linking in externally managed test and provisioning customizations
 # for both secure/non-secure manufacturer domains.
 hooks = use_extension("//rules:extensions.bzl", "hooks")

MODULE.bazel.lock

@@ -13,18 +13,18 @@ if [[ -n ${BAZEL_CACHE} ]]; then
   ${BAZEL_CMD} fetch \
     --distdir="${BAZEL_DISTDIR}" \
     --repository_cache="${BAZEL_CACHE}" \
-    @lowrisc_rv32imcb_files//...
+    @lowrisc_toolchain//...
 else
   BAZEL_CMD="./bazelisk.sh"
-  ${BAZEL_CMD} fetch @lowrisc_rv32imcb_files//...
+  ${BAZEL_CMD} fetch @lowrisc_toolchain//...
 fi
 
 # Set environment variables for the RV32 linker and assembler.
 RV32_TOOL_LD=$(${BAZEL_CMD} query \
-  'deps(@lowrisc_rv32imcb_files//:bin/riscv32-unknown-elf-ld)' \
+  'deps(@lowrisc_toolchain//:bin/riscv32-unknown-elf-ld)' \
   --output location | cut -f1 -d:)
 RV32_TOOL_AS=$(${BAZEL_CMD} query \
-  'deps(@lowrisc_rv32imcb_files//:bin/riscv32-unknown-elf-as)' \
+  'deps(@lowrisc_toolchain//:bin/riscv32-unknown-elf-as)' \
   --output location | cut -f1 -d:)
 export RV32_TOOL_LD
 export RV32_TOOL_AS

hw/ip/otbn/dv/uvm/get-toolchain-paths.sh

@@ -71,7 +71,7 @@ certificate_codegen = rule(
     attrs = {
         "template": attr.label(allow_single_file = True, doc = "path to the hjson template file"),
         "clang_format": attr.label(
-            default = "@lowrisc_rv32imcb_files//:bin/clang-format",
+            default = "@lowrisc_toolchain//:bin/clang-format",
             allow_single_file = True,
             cfg = "host",
             executable = True,

rules/certificates.bzl

@@ -64,7 +64,7 @@ clang_format_attrs = {
         doc = "Command to execute to display diffs",
     ),
     "clang_format": attr.label(
-        default = "@lowrisc_rv32imcb_files//:bin/clang-format",
+        default = "@lowrisc_toolchain//:bin/clang-format",
         allow_single_file = True,
         cfg = "host",
         executable = True,
@@ -192,7 +192,7 @@ def _cc_aspect_impl(target, ctx, action_callback):
 
 # To see which checks clang-tidy knows about, run this command:
 #
-#  ./bazelisk.sh run @lowrisc_rv32imcb_files//:bin/clang-tidy -- --checks='*' --list-checks
+#  ./bazelisk.sh run @lowrisc_toolchain//:bin/clang-tidy -- --checks='*' --list-checks
 _CLANG_TIDY_CHECKS = [
     "clang-analyzer-core.*",
     # Disable advice to replace `memcpy` with `mempcy_s`.
@@ -265,7 +265,7 @@ def _make_clang_tidy_aspect(enable_fix):
                 executable = True,
             ),
             "_clang_tidy": attr.label(
-                default = "@lowrisc_rv32imcb_files//:bin/clang-tidy",
+                default = "@lowrisc_toolchain//:bin/clang-tidy",
                 allow_single_file = True,
                 cfg = "host",
                 executable = True,

rules/quality.bzl

@@ -0,0 +1,3 @@
+# Copyright lowRISC contributors (OpenTitan project).
+# Licensed under the Apache License, Version 2.0, see LICENSE for details.
+# SPDX-License-Identifier: Apache-2.0

third_party/lowrisc/BUILD

@@ -0,0 +1,5 @@
+# Copyright lowRISC contributors (OpenTitan project).
+# Licensed under the Apache License, Version 2.0, see LICENSE for details.
+# SPDX-License-Identifier: Apache-2.0
+
+exports_files(glob(["**"]))

third_party/lowrisc/BUILD.lowrisc_toolchain.bazel

@@ -0,0 +1,19 @@
+# Copyright lowRISC contributors (OpenTitan project).
+# Licensed under the Apache License, Version 2.0, see LICENSE for details.
+# SPDX-License-Identifier: Apache-2.0
+
+load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
+
+def _lowrisc_repos():
+    VERSION = "20240923-1"
+    http_archive(
+        name = "lowrisc_toolchain",
+        url = "https://github.com/lowRISC/lowrisc-toolchains/releases/download/{v}/lowrisc-toolchain-rv32imcb-{v}.tar.xz".format(v = VERSION),
+        sha256 = "aeea1983553f4c81c6409abcf0d6ca33b5ed4716b2b694e7ff030523cf13486a",
+        strip_prefix = "lowrisc-toolchain-rv32imcb-{}".format(VERSION),
+        build_file = ":BUILD.lowrisc_toolchain.bazel",
+    )
+
+lowrisc_toolchain = module_extension(
+    implementation = lambda _: _lowrisc_repos(),
+)

third_party/lowrisc/extensions.bzl

@@ -141,7 +141,7 @@ if [[ ${AIRGAPPED_DIR_CONTENTS} == "ALL" || \
   ${BAZELISK} fetch \
     --repository_cache=${BAZEL_AIRGAPPED_DIR}/${BAZEL_CACHEDIR} \
     //... \
-    @lowrisc_rv32imcb_files//... \
+    @lowrisc_toolchain//... \
     @local_config_platform//... \
     @python3_toolchains//... \
     @riscv-compliance//... \