rust: Add panic handler for the kernel

Adds a Rust panic handler for the Trusty kernel that prints the panic message
and location before calling the kernel panic API.

Bug: 328519718
Test: Manually add panic from Rust in the kernel
Change-Id: I9ed88037f9432d36e8c215994bd8c8f2bc2e9e3e

4 files changed, 88 insertions, 0 deletions

diff --git a/kernel/rules.mk b/kernel/rules.mk
index 433cda8e..e1719a61 100644
--- a/kernel/rules.mk
+++ b/kernel/rules.mk
@@ -5,6 +5,7 @@ MODULE := $(LOCAL_DIR)
 MODULE_DEPS := \
 	lib/debug \
 	lib/heap \
+	lib/rust_support \
 	trusty/kernel/lib/rand
 
 ifeq ($(LK_LIBC_IMPLEMENTATION),lk)
diff --git a/lib/rust_support/bindings.h b/lib/rust_support/bindings.h
new file mode 100644
index 00000000..4fda8c0c
--- /dev/null
+++ b/lib/rust_support/bindings.h
@@ -0,0 +1 @@
+#include <panic.h>
diff --git a/lib/rust_support/lib.rs b/lib/rust_support/lib.rs
new file mode 100644
index 00000000..8f6464a3
--- /dev/null
+++ b/lib/rust_support/lib.rs
@@ -0,0 +1,44 @@
+/*
+ * Copyright (c) 2024 Google Inc. All rights reserved
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files
+ * (the "Software"), to deal in the Software without restriction,
+ * including without limitation the rights to use, copy, modify, merge,
+ * publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+ * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+//! Rust support library for the Trusty kernel
+
+#![no_std]
+#![feature(c_str_literals)]
+
+use alloc::format;
+use core::ffi::CStr;
+use core::panic::PanicInfo;
+
+mod sys {
+    include!(env!("BINDGEN_INC_FILE"));
+}
+
+#[panic_handler]
+fn handle_panic(info: &PanicInfo) -> ! {
+    let panic_message = format!("{info}\0");
+    let panic_message_c = CStr::from_bytes_with_nul(panic_message.as_bytes())
+        .expect("Unexpected null byte in panic message");
+    // SAFETY: Calling C function with string pointers that outlive the call
+    unsafe { sys::_panic(c"Rust in Trusty kernel %s\n".as_ptr(), panic_message_c.as_ptr()) }
+}
diff --git a/lib/rust_support/rules.mk b/lib/rust_support/rules.mk
new file mode 100644
index 00000000..2fd8d422
--- /dev/null
+++ b/lib/rust_support/rules.mk
@@ -0,0 +1,42 @@
+#
+# Copyright (c) 2024, Google, Inc. All rights reserved
+#
+# Permission is hereby granted, free of charge, to any person obtaining
+# a copy of this software and associated documentation files
+# (the "Software"), to deal in the Software without restriction,
+# including without limitation the rights to use, copy, modify, merge,
+# publish, distribute, sublicense, and/or sell copies of the Software,
+# and to permit persons to whom the Software is furnished to do so,
+# subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be
+# included in all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+# IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+# CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+# TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+# SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+#
+
+LOCAL_DIR := $(GET_LOCAL_DIR)
+
+MODULE := $(LOCAL_DIR)
+
+MODULE_CRATE_NAME := rust_support
+
+MODULE_SRCS := \
+	$(LOCAL_DIR)/lib.rs \
+
+MODULE_DEPS := \
+	trusty/user/base/lib/liballoc-rust \
+	trusty/user/base/lib/trusty-std \
+
+MODULE_BINDGEN_ALLOW_FUNCTIONS := \
+	_panic \
+
+MODULE_BINDGEN_SRC_HEADER := $(LOCAL_DIR)/bindings.h
+
+include make/module.mk