examples: reorganize crates into TA and CA workspaces

* Split the examples into dedicated TA and CA Cargo workspaces and consolidate
  the protocol definitions into a single proto crate.
* Centralize the workspace build rules, relocate plugin assets, and update
  tests, documentation, license exclusions, and cargo-optee paths for the new
  layout.
* Reuse workspace build artifacts across cargo-optee CI builds, report their
  disk usage, and clean them after the complete build.

Author: ivila

.gitignore

@@ -24,12 +24,9 @@ Cargo.lock
 
 rust/
 
-# Allow tracking Cargo.lock in std examples
-!examples/message_passing_interface-rs/ta/Cargo.lock
-!examples/secure_db_abstraction-rs/ta/Cargo.lock
-!examples/serde-rs/ta/Cargo.lock
-!examples/tls_client-rs/ta/Cargo.lock
-!examples/tls_server-rs/ta/Cargo.lock
+# Allow tracking the consolidated examples workspace lock files
+!examples/ta/Cargo.lock
+!examples/ca/Cargo.lock
 !projects/web3/eth_wallet/ta/Cargo.lock
 
 # Allow tracking Cargo.lock for cargo-optee tool

.licenserc.yaml

@@ -30,7 +30,7 @@ header:
     - 'KEYS'
     - 'DISCLAIMER'
     - '**/*.json'
-    - 'examples/tls_server-rs/ta/test-ca/**'
+    - 'examples/ta/tls_server-rs/test-ca/**'
     - '**/uuid.txt'
     - '**/plugin_uuid.txt'
     - '**/ta_uuid.txt'

LICENSE

@@ -202,11 +202,11 @@
    limitations under the License.
 
 -------------------------------------------------------------------------------
-This product includes the following third-party code: 
-The code in `examples/tls_client-rs/ta/src/main.rs` is modified based on 
+This product includes the following third-party code:
+The code in `examples/ta/tls_client-rs/src/main.rs` is modified based on
 Rustls (Apache License, Version 2.0).
-The code in `examples/mnist-rs/ta/train/src/trainer.rs` and 
-`examples/mnist-rs/ta/common/src/model.rs` is either copied from or inspired by
+The code in `examples/ta/mnist-rs/train/src/trainer.rs` and
+`examples/ta/mnist-rs/common/src/model.rs` is either copied from or inspired by
 the Burn library (Apache License, Version 2.0).
 
 For the full text of the licenses, see the `licenses/` directory.

Makefile

@@ -73,13 +73,13 @@ std-examples no-std-examples:
 install: examples
 	$(echo) '  INSTALL ${out-dir}/lib/optee_armtz'
 	$(q)mkdir -p ${out-dir}/lib/optee_armtz
-	$(q)find examples/*/ta/target/$(TARGET_TA)/ -name *.ta -exec cp {} ${out-dir}/lib/optee_armtz \;
+	$(q)find examples/ta/target/$(TARGET_TA)/ -name *.ta -exec cp {} ${out-dir}/lib/optee_armtz \;
 	$(echo) '  INSTALL ${out-dir}${bindir}'
 	$(q)mkdir -p ${out-dir}${bindir}
-	$(q)cp examples/*/host/target/$(TARGET_HOST)/release/*-rs ${out-dir}${bindir}
+	$(q)cp examples/ca/target/$(TARGET_HOST)/release/*-rs ${out-dir}${bindir}
 	$(echo) '  INSTALL ${out-dir}${libdir}/tee-supplicant/plugins/'
 	$(q)mkdir -p ${out-dir}${libdir}/tee-supplicant/plugins/
-	$(q)find examples/*/plugin/target/$(TARGET_HOST)/ -name *.plugin.so -exec cp {} ${out-dir}${libdir}/tee-supplicant/plugins/ \;
+	$(q)find examples/ca/target/$(TARGET_HOST)/ -name *.plugin.so -exec cp {} ${out-dir}${libdir}/tee-supplicant/plugins/ \;
 
 clean: examples-clean out-clean
 
@@ -96,4 +96,4 @@ help:
 	@echo "  no-std-examples       - Build no-std examples (no-std-only + common)"
 	@echo "  install               - Install built examples to out directory"
 	@echo "  clean                 - Clean all examples and output directory"
-	@echo ""
+	@echo ""

ci/build.sh

@@ -249,14 +249,6 @@ for EXAMPLE_NAME in "${ALL_EXAMPLES[@]}"; do
     fi
 
     CURRENT=$((CURRENT + 1))
-    EXAMPLE_DIR="$EXAMPLES_DIR/$EXAMPLE_NAME"
-    
-    if [ ! -d "$EXAMPLE_DIR" ]; then
-        echo "ERROR: Example directory not found: $EXAMPLE_DIR"
-        FAILED_EXAMPLES="$FAILED_EXAMPLES\n  - $EXAMPLE_NAME"
-        continue
-    fi
-    
     echo ""
     echo "=========================================="
     echo "[$CURRENT] Building: $EXAMPLE_NAME ($CATEGORY)"
@@ -311,8 +303,6 @@ for EXAMPLE_NAME in "${ALL_EXAMPLES[@]}"; do
                 --arch "$ARCH_TA" \
                 $TA_STD_FLAG; then
                 echo "  ✓ TA installed successfully"
-                # Clean up build artifacts
-                $CARGO_OPTEE clean
             else
                 echo "  ✗ ERROR: Failed to install TA: $TA_DIR"
                 FAILED_EXAMPLES="$FAILED_EXAMPLES\n  - $EXAMPLE_NAME ($TA_DIR)"
@@ -358,8 +348,6 @@ for EXAMPLE_NAME in "${ALL_EXAMPLES[@]}"; do
             --optee-client-export "$OPTEE_CLIENT_EXPORT" \
             --arch "$ARCH_HOST"; then
             echo "  ✓ CA installed successfully"
-            # Clean up build artifacts
-            $CARGO_OPTEE clean
         else
             echo "  ✗ ERROR: Failed to install CA: $CA_DIR"
             FAILED_EXAMPLES="$FAILED_EXAMPLES\n  - $EXAMPLE_NAME ($CA_DIR)"
@@ -404,8 +392,6 @@ for EXAMPLE_NAME in "${ALL_EXAMPLES[@]}"; do
             --optee-client-export "$OPTEE_CLIENT_EXPORT" \
             --arch "$ARCH_HOST"; then
             echo "  ✓ Plugin installed successfully"
-            # Clean up build artifacts
-            $CARGO_OPTEE clean
         else
             echo "  ✗ ERROR: Failed to install Plugin: $PLUGIN_DIR"
             FAILED_EXAMPLES="$FAILED_EXAMPLES\n  - $EXAMPLE_NAME ($PLUGIN_DIR)"
@@ -423,6 +409,31 @@ for EXAMPLE_NAME in "${ALL_EXAMPLES[@]}"; do
     echo "✓ Example $EXAMPLE_NAME completed successfully"
 done
 
+echo ""
+echo "==========================================="
+echo "       WORKSPACE TARGET DISK USAGE"
+echo "==========================================="
+
+TARGET_DIRS=()
+if [ -d "$EXAMPLES_DIR/ta/target" ]; then
+    TARGET_DIRS+=("$EXAMPLES_DIR/ta/target")
+fi
+if [ -d "$EXAMPLES_DIR/ca/target" ]; then
+    TARGET_DIRS+=("$EXAMPLES_DIR/ca/target")
+fi
+
+if [ "${#TARGET_DIRS[@]}" -gt 0 ]; then
+    du -sch "${TARGET_DIRS[@]}"
+else
+    echo "No workspace target directories were created."
+fi
+
+echo ""
+echo "Cleaning workspace build artifacts..."
+cargo clean --manifest-path "$EXAMPLES_DIR/ta/Cargo.toml"
+cargo clean --manifest-path "$EXAMPLES_DIR/ca/Cargo.toml"
+echo "Workspace build artifacts cleaned successfully."
+
 # Summary
 echo ""
 echo "==========================================="
@@ -448,4 +459,3 @@ else
     echo "✅ ALL EXAMPLES INSTALLED SUCCESSFULLY!"
     echo ""
 fi
-

docs/building-rust-ca-as-android-elf.md

@@ -63,5 +63,5 @@ clean:
 7. build:
 
 ```
-$ make -C examples/hello_world-rs/host
+$ make -C examples/ca/hello_world-rs
 ```

docs/debugging-optee-ta.md

@@ -46,7 +46,7 @@ D/LD:  ldelf:168 ELF (133af0ca-bdab-11eb-9130-43bf7873bf67) at 0x40014000
 
 Then, you can load symbols from TA file (in debug build) to the address.
 ```sh
-(gdb) add-symbol-file /path/to/examples/hello_world-rs/ta/target/aarch64-unknown-linux-gnu/debug/ta 0x40014000
+(gdb) add-symbol-file /path/to/examples/ta/target/aarch64-unknown-linux-gnu/debug/ta 0x40014000
 ```
 Now, you can add breakpoints according to your own needs in the corresponding
 functions or addresses.

docs/writing-rust-tas-using-optee-utee-build.md

@@ -49,7 +49,7 @@ include!(concat!(env!("OUT_DIR"), "/user_ta_header.rs"));
 
 After that, everything finished, we can start building the TA now.
 
-For full codes, you can check the [`hello_world-rs example`](https://github.com/apache/teaclave-trustzone-sdk/tree/main/examples/hello_world-rs/ta)
+For full codes, you can check the [`hello_world-rs example`](https://github.com/apache/teaclave-trustzone-sdk/tree/main/examples/ta/hello_world-rs)
 
 ## Explaination of Minimal Example
 

examples/Makefile

@@ -25,6 +25,12 @@ TARGET_TA ?= $(TARGET)
 FEATURES ?=
 CARGO_FLAGS ?=
 
+# All CA crates and all TA crates now share their respective workspace target
+# directories. Do not run multiple per-example Cargo commands concurrently,
+# because they may link or clean the same workspace artifacts at the same time.
+# Cargo still parallelizes compilation within each individual invocation.
+.NOTPARALLEL:
+
 # Define example categories based on std/no-std support
 # STD-only examples (require STD=y to build)
 STD_ONLY_EXAMPLES = \
@@ -83,20 +89,23 @@ common-examples: $(COMMON_EXAMPLES)
 
 # Individual example build rules
 $(STD_ONLY_EXAMPLES) $(NO_STD_ONLY_EXAMPLES) $(COMMON_EXAMPLES):
-	$(q)make -C $@ TARGET_HOST=$(TARGET_HOST) \
-		TARGET_TA=$(TARGET_TA) \
-		CROSS_COMPILE_HOST=$(CROSS_COMPILE_HOST) \
-		CROSS_COMPILE_TA=$(CROSS_COMPILE_TA) \
+	$(q)make -C ca/$@ TARGET=$(TARGET_HOST) \
+		CROSS_COMPILE=$(CROSS_COMPILE_HOST) \
+		OPTEE_CLIENT_EXPORT=$(OPTEE_CLIENT_EXPORT)
+	$(q)make -C ta/$@ TARGET=$(TARGET_TA) \
+		CROSS_COMPILE=$(CROSS_COMPILE_TA) \
 		TA_DEV_KIT_DIR=$(TA_DEV_KIT_DIR) \
-		OPTEE_CLIENT_EXPORT=$(OPTEE_CLIENT_EXPORT) \
 		FEATURES="$(FEATURES)" \
 		CARGO_FLAGS="$(CARGO_FLAGS)"
+	$(if $(filter supp_plugin-rs,$@),$(q)make -C ca/supp_plugin-rs-plugin TARGET=$(TARGET_HOST) CROSS_COMPILE=$(CROSS_COMPILE_HOST) OPTEE_CLIENT_EXPORT=$(OPTEE_CLIENT_EXPORT))
 
 # Clean targets
 clean: $(STD_ONLY_EXAMPLES_CLEAN) $(NO_STD_ONLY_EXAMPLES_CLEAN) $(COMMON_EXAMPLES_CLEAN)
 
 $(STD_ONLY_EXAMPLES_CLEAN) $(NO_STD_ONLY_EXAMPLES_CLEAN) $(COMMON_EXAMPLES_CLEAN):
-	$(q)make -C $(@:-clean=) clean
+	$(q)make -C ca/$(@:-clean=) clean
+	$(q)make -C ta/$(@:-clean=) clean
+	$(if $(filter supp_plugin-rs-clean,$@),$(q)make -C ca/supp_plugin-rs-plugin clean)
 
 # Help target
 help: