Merge #207

207: boards: opentitan: Update the OpenTitan SRAM address r=jrvanwhy a=alistair23

Update the OpenTitan SRAM address to make current master Tock, also
update the submodule to use the latest Tock SHA.

Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

Co-authored-by: Alistair Francis <alistair.francis@wdc.com>
diff --git a/.github/workflows/size-diff.yml b/.github/workflows/size-diff.yml
index 4d14308..6f8c7d0 100644
--- a/.github/workflows/size-diff.yml
+++ b/.github/workflows/size-diff.yml
@@ -44,6 +44,7 @@
           git remote set-branches "${UPSTREAM_REMOTE_NAME}" "${GITHUB_BASE_REF}"
           git fetch --depth=1 "${UPSTREAM_REMOTE_NAME}" "${GITHUB_BASE_REF}"
           git checkout "${UPSTREAM_REMOTE_NAME}/${GITHUB_BASE_REF}"
+          rustup target add riscv32imc-unknown-none-elf thumbv7em-none-eabi
           make -j2 examples
           cargo run --release -p print_sizes >'${{runner.temp}}/base-sizes'
 
diff --git a/Makefile b/Makefile
index 2f48887..fe74caa 100644
--- a/Makefile
+++ b/Makefile
@@ -16,6 +16,7 @@
 	@echo " - opentitan"
 	@echo " - hifive1"
 	@echo " - nrf52"
+	@echo " - imxrt1050"
 	@echo " - apollo3"
 	@echo
 	@echo "Run 'make setup' to setup Rust to build libtock-rs."
@@ -152,6 +153,15 @@
 flash-nrf52:
 	PLATFORM=nrf52 cargo run $(release) --target=thumbv7em-none-eabi --example $(EXAMPLE) $(features)
 
+.PHONY: imxrt1050
+imxrt1050:
+	PLATFORM=imxrt1050 cargo build $(release) --target=thumbv7em-none-eabi --examples $(features)
+
+.PHONY: flash-imxrt1050
+flash-imxrt1050:
+	PLATFORM=imxrt1050 cargo run $(release) --target=thumbv7em-none-eabi --example $(EXAMPLE) $(features)
+
+
 .PHONY: clean
 clean:
 	cargo clean
diff --git a/boards/layout_imxrt1050.ld b/boards/layout_imxrt1050.ld
new file mode 100644
index 0000000..56ecf11
--- /dev/null
+++ b/boards/layout_imxrt1050.ld
@@ -0,0 +1,17 @@
+/* Layout for the iMX.RT1050 board, used by the examples in this repository. */
+
+MEMORY {
+  /* The application region is 64 bytes (0x40) */
+  FLASH (rx) : ORIGIN = 0x63002040, LENGTH = 0xFFFFC0
+  SRAM (rwx) : ORIGIN = 0x20004000, LENGTH = 112K
+}
+
+/*
+ * Any change to STACK_SIZE should be accompanied by a corresponding change to
+ * `elf2tab`'s `--stack` option
+ */
+STACK_SIZE = 2048;
+
+MPU_MIN_ALIGN = 8K;
+
+INCLUDE layout_generic.ld
diff --git a/core/Cargo.toml b/core/Cargo.toml
index 3f1723b..bfa9570 100644
--- a/core/Cargo.toml
+++ b/core/Cargo.toml
@@ -5,7 +5,8 @@
 edition = "2018"
 
 [features]
-alloc = [ "linked_list_allocator" ]
+alloc = ["alloc_init", "linked_list_allocator"]
+alloc_init = []
 custom_panic_handler = []
 custom_alloc_error_handler = []
 
diff --git a/core/src/alloc.rs b/core/src/alloc.rs
index 05e9669..f971849 100644
--- a/core/src/alloc.rs
+++ b/core/src/alloc.rs
@@ -4,7 +4,12 @@
 use core::ptr::NonNull;
 use linked_list_allocator::Heap;
 
-pub static mut HEAP: Heap = Heap::empty();
+static mut HEAP: Heap = Heap::empty();
+
+#[no_mangle]
+unsafe fn libtock_alloc_init(app_heap_start: usize, app_heap_size: usize) {
+    HEAP.init(app_heap_start, app_heap_size);
+}
 
 struct TockAllocator;
 
diff --git a/core/src/debug/platform_arm.rs b/core/src/debug/platform_arm.rs
index 46211b3..a777334 100644
--- a/core/src/debug/platform_arm.rs
+++ b/core/src/debug/platform_arm.rs
@@ -1,5 +1,5 @@
 pub fn get_stack_pointer() -> usize {
     let stack_pointer;
-    unsafe { asm!("mov $0, sp" : "=r"(stack_pointer) : : : "volatile") };
+    unsafe { llvm_asm!("mov $0, sp" : "=r"(stack_pointer) : : : "volatile") };
     stack_pointer
 }
diff --git a/core/src/debug/platform_riscv32.rs b/core/src/debug/platform_riscv32.rs
index 7f4a4e0..c276442 100644
--- a/core/src/debug/platform_riscv32.rs
+++ b/core/src/debug/platform_riscv32.rs
@@ -1,5 +1,5 @@
 pub fn get_stack_pointer() -> usize {
     let stack_pointer;
-    unsafe { asm!("mv $0, sp" : "=r"(stack_pointer) : : : "volatile") };
+    unsafe { llvm_asm!("mv $0, sp" : "=r"(stack_pointer) : : : "volatile") };
     stack_pointer
 }
diff --git a/core/src/entry_point/mod.rs b/core/src/entry_point/mod.rs
index 40bdb62..850c213 100644
--- a/core/src/entry_point/mod.rs
+++ b/core/src/entry_point/mod.rs
@@ -104,10 +104,8 @@
     );
 
     // Zero .bss (specified by the linker script).
-    let bss_end = layout_header.bss_start + layout_header.bss_size; // 1 past the end of .bss
-    for i in layout_header.bss_start..bss_end {
-        core::ptr::write(i as *mut u8, 0);
-    }
+    let bss_start = layout_header.bss_start as *mut u8;
+    core::ptr::write_bytes(bss_start, 0u8, layout_header.bss_size);
 
     // TODO: Wait for rustc to have working ROPI-RWPI relocation support, then
     // implement dynamic relocations here. At the moment, rustc does not have
@@ -127,8 +125,8 @@
     // Tell the kernel the new app heap break.
     memop::set_brk(app_heap_end as *const u8);
 
-    #[cfg(feature = "alloc")]
-    crate::alloc::HEAP.init(app_heap_start, app_heap_size);
+    #[cfg(feature = "alloc_init")]
+    crate::libtock_alloc_init(app_heap_start, app_heap_size);
 
     main(0, ptr::null());
 
diff --git a/core/src/entry_point/start_item_arm.rs b/core/src/entry_point/start_item_arm.rs
index c9390f6..894088e 100644
--- a/core/src/entry_point/start_item_arm.rs
+++ b/core/src/entry_point/start_item_arm.rs
@@ -12,7 +12,7 @@
     _memory_len: usize,
     app_heap_break: usize,
 ) -> ! {
-    asm!("
+    llvm_asm!("
         // Because ROPI-RWPI support in LLVM/rustc is incomplete, Rust
         // applications must be statically linked. An offset between the
         // location the program is linked at and its actual location in flash
@@ -23,7 +23,7 @@
         // the Program Counter) will match the intended location of .start. We
         // don't have an easy way to signal an error, so for now we just yield
         // if the location is wrong.
-        sub r4, pc, #4    // r4 = pc
+        subw r4, pc, #4    // r4 = pc
         ldr r5, =.start   // r5 = address of .start
         cmp r4, r5
         beq .Lstack_init  // Jump to stack initialization if pc was correct
diff --git a/core/src/entry_point/start_item_riscv32.rs b/core/src/entry_point/start_item_riscv32.rs
index 347400c..f8a0e19 100644
--- a/core/src/entry_point/start_item_riscv32.rs
+++ b/core/src/entry_point/start_item_riscv32.rs
@@ -14,7 +14,7 @@
 // Due to Rust issue: https://github.com/rust-lang/rust/issues/42779 we can't have
 // args to the function
 pub unsafe extern "C" fn _start() -> ! {
-    asm!(
+    llvm_asm!(
     // Compute the stack top.
     //
     // struct hdr* myhdr = (struct hdr*) app_start;
@@ -105,7 +105,7 @@
 #[export_name = "abort"]
 pub extern "C" fn abort() {
     unsafe {
-        asm! ("
+        llvm_asm! ("
             // Simply go back to the start as if we had just booted.
             j    _start
         "
diff --git a/core/src/lib.rs b/core/src/lib.rs
index e465f4d..3bdfe5b 100644
--- a/core/src/lib.rs
+++ b/core/src/lib.rs
@@ -1,4 +1,4 @@
-#![feature(asm, lang_items, naked_functions)]
+#![feature(lang_items, llvm_asm, naked_functions)]
 #![cfg_attr(any(target_arch = "arm", target_arch = "riscv32"), no_std)]
 #![cfg_attr(feature = "alloc", feature(alloc_error_handler))]
 
@@ -8,6 +8,11 @@
 #[cfg(any(target_arch = "arm", target_arch = "riscv32"))]
 mod lang_items;
 
+#[cfg(feature = "alloc_init")]
+extern "Rust" {
+    fn libtock_alloc_init(app_heap_start: usize, app_heap_size: usize);
+}
+
 pub mod callback;
 pub mod debug;
 pub mod memop;
diff --git a/core/src/syscalls/platform_arm.rs b/core/src/syscalls/platform_arm.rs
index 4ff146a..066459e 100644
--- a/core/src/syscalls/platform_arm.rs
+++ b/core/src/syscalls/platform_arm.rs
@@ -22,7 +22,7 @@
     // registers r4-r8, r10, r11 and SP (and r9 in PCS variants that designate
     // r9 as v6) As our compilation flags mark r9 as the PIC base register, it
     // does not need to be saved. Thus we must clobber r0-3, r12, and LR
-    asm!(
+    llvm_asm!(
             "svc 0"
             :
             :
@@ -40,7 +40,7 @@
     ud: usize,
 ) -> isize {
     let res;
-    asm!("svc 1" : "={r0}"(res)
+    llvm_asm!("svc 1" : "={r0}"(res)
                  : "{r0}"(major) "{r1}"(minor) "{r2}"(cb) "{r3}"(ud)
                  : "memory"
                  : "volatile");
@@ -52,7 +52,7 @@
 #[allow(clippy::missing_safety_doc)]
 pub unsafe fn command(major: usize, minor: usize, arg1: usize, arg2: usize) -> isize {
     let res;
-    asm!("svc 2" : "={r0}"(res)
+    llvm_asm!("svc 2" : "={r0}"(res)
                      : "{r0}"(major) "{r1}"(minor) "{r2}"(arg1) "{r3}"(arg2)
                      : "memory"
                      : "volatile");
@@ -64,7 +64,7 @@
 #[allow(clippy::missing_safety_doc)]
 pub unsafe fn command1(major: usize, minor: usize, arg: usize) -> isize {
     let res;
-    asm!("svc 2" : "={r0}"(res)
+    llvm_asm!("svc 2" : "={r0}"(res)
                  : "{r0}"(major) "{r1}"(minor) "{r2}"(arg)
                  : "memory"
                  : "volatile");
@@ -76,7 +76,7 @@
 #[allow(clippy::missing_safety_doc)]
 pub unsafe fn allow(major: usize, minor: usize, slice: *mut u8, len: usize) -> isize {
     let res;
-    asm!("svc 3" : "={r0}"(res)
+    llvm_asm!("svc 3" : "={r0}"(res)
                  : "{r0}"(major) "{r1}"(minor) "{r2}"(slice) "{r3}"(len)
                  : "memory"
                  : "volatile");
@@ -88,7 +88,7 @@
 #[allow(clippy::missing_safety_doc)]
 pub unsafe fn memop(major: u32, arg1: usize) -> isize {
     let res;
-    asm!("svc 4" : "={r0}"(res)
+    llvm_asm!("svc 4" : "={r0}"(res)
                  : "{r0}"(major) "{r1}"(arg1)
                  : "memory"
                  : "volatile");
diff --git a/core/src/syscalls/platform_riscv32.rs b/core/src/syscalls/platform_riscv32.rs
index f7d1858..f2c49fe 100644
--- a/core/src/syscalls/platform_riscv32.rs
+++ b/core/src/syscalls/platform_riscv32.rs
@@ -3,7 +3,7 @@
 #[allow(clippy::missing_safety_doc)]
 pub unsafe fn yieldk() {
     /* TODO: Stop yielding */
-    asm! (
+    llvm_asm! (
             "li    a0, 0
             ecall"
             :
@@ -23,7 +23,7 @@
     ud: usize,
 ) -> isize {
     let res;
-    asm!("li    a0, 1
+    llvm_asm!("li    a0, 1
           ecall"
          : "={x10}" (res)
          : "{x11}" (major), "{x12}" (minor), "{x13}" (cb), "{x14}" (ud)
@@ -37,7 +37,7 @@
 #[allow(clippy::missing_safety_doc)]
 pub unsafe fn command(major: usize, minor: usize, arg1: usize, arg2: usize) -> isize {
     let res;
-    asm!("li    a0, 2
+    llvm_asm!("li    a0, 2
           ecall"
          : "={x10}" (res)
          : "{x11}" (major), "{x12}" (minor), "{x13}" (arg1), "{x14}" (arg2)
@@ -51,7 +51,7 @@
 #[allow(clippy::missing_safety_doc)]
 pub unsafe fn command1(major: usize, minor: usize, arg: usize) -> isize {
     let res;
-    asm!("li    a0, 2
+    llvm_asm!("li    a0, 2
           ecall"
          : "={x10}" (res)
          : "{x11}" (major), "{x12}" (minor), "{x13}" (arg)
@@ -65,7 +65,7 @@
 #[allow(clippy::missing_safety_doc)]
 pub unsafe fn allow(major: usize, minor: usize, slice: *mut u8, len: usize) -> isize {
     let res;
-    asm!("li    a0, 3
+    llvm_asm!("li    a0, 3
           ecall"
          : "={x10}" (res)
          : "{x11}" (major), "{x12}" (minor), "{x13}" (slice), "{x14}" (len)
@@ -79,7 +79,7 @@
 #[allow(clippy::missing_safety_doc)]
 pub unsafe fn memop(major: u32, arg1: usize) -> isize {
     let res;
-    asm!("li    a0, 4
+    llvm_asm!("li    a0, 4
           ecall"
          : "={x10}" (res)
          : "{x11}" (major), "{x12}" (arg1)
diff --git a/examples/hello_world.rs b/examples/hello_world.rs
index 4a67404..052cf69 100644
--- a/examples/hello_world.rs
+++ b/examples/hello_world.rs
@@ -1,4 +1,6 @@
 // This example just prints "Hello Tock World" to the terminal.
+// Run `tockloader listen`, or use any serial program of your choice
+//  (e.g. `screen`, `minicom`) to view the message.
 
 #![no_std]
 
diff --git a/layout_generic.ld b/layout_generic.ld
index 35b10f4..dd101ab 100644
--- a/layout_generic.ld
+++ b/layout_generic.ld
@@ -88,6 +88,15 @@
     /* Application stack */
     .stack (NOLOAD) :
     {
+        /* elf2tab requires that the `_sram_origin` symbol be present to
+         * mark the first address in the SRAM memory. Since ELF files do
+         * not really need to specify this address as they only care about
+         * loading into flash, we need to manually mark this address for
+         * elf2tab. elf2tab will use it to add a fixed address header in the
+         * TBF header if needed.
+         */
+        _sram_origin = .;
+
         . = . + STACK_SIZE;
 
 	_stack_top_unaligned = .;
diff --git a/rust-toolchain b/rust-toolchain
index 8bd4ff0..4aec5c6 100644
--- a/rust-toolchain
+++ b/rust-toolchain
@@ -1 +1 @@
-nightly-2020-04-06
+nightly-2020-06-10
diff --git a/src/ble_composer.rs b/src/ble_composer.rs
index 0bb96d8..589dfc3 100644
--- a/src/ble_composer.rs
+++ b/src/ble_composer.rs
@@ -21,7 +21,7 @@
         self.bytes[self.occupied] = (content.len() + 1) as u8;
         self.bytes[self.occupied + 1] = kind;
         let write = &mut self.bytes[self.occupied + 2..(self.occupied + content.len() + 2)];
-        write.clone_from_slice(content);
+        write.copy_from_slice(content);
         self.occupied += 2 + content.len();
         Ok(())
     }
@@ -44,7 +44,7 @@
         self.bytes[self.occupied + 3] = uuid[1];
 
         let write = &mut self.bytes[self.occupied + 4..(self.occupied + content.len() + 4)];
-        write.clone_from_slice(content);
+        write.copy_from_slice(content);
         self.occupied += 4 + content.len();
         Ok(())
     }
diff --git a/src/ble_parser.rs b/src/ble_parser.rs
index 1d12b19..216d974 100644
--- a/src/ble_parser.rs
+++ b/src/ble_parser.rs
@@ -53,7 +53,7 @@
                 0x02, 0x02, 0x01, 0x02, 0x01, 0x03, 0x03, 0x16, 0x01, 0x02, 0x04, 0xFF, 0x01, 0x02,
                 0x03,
             ];
-            slice.clone_from_slice(data);
+            slice.copy_from_slice(data);
         }
         assert_eq!(find(&buf, 0x02), Some(&[0x01][0..1]));
         assert_eq!(find(&buf, 0x01), Some(&[0x03][0..1]));
@@ -67,7 +67,7 @@
         {
             let slice = &mut buf[8..18];
             let data = &[0x02, 0x02, 0x00, 0x00, 0x00, 0x00, 0x0, 0x16, 0x01, 0x02];
-            slice.clone_from_slice(data);
+            slice.copy_from_slice(data);
         }
     }
 
@@ -77,7 +77,7 @@
         {
             let slice = &mut buf[8..10];
             let data = &[0x04, 0x02];
-            slice.clone_from_slice(data);
+            slice.copy_from_slice(data);
         }
         assert_eq!(find(&buf, 0xF2), None);
     }
diff --git a/src/hmac.rs b/src/hmac.rs
index e5475cc..5185128 100644
--- a/src/hmac.rs
+++ b/src/hmac.rs
@@ -99,7 +99,7 @@
         syscalls::allow(DRIVER_NUMBER, allow_nr::DEST, &mut buffer.buffer).map_err(Into::into)
     }
 
-    pub fn subscribe<CB: FnMut(usize, usize) -> () + FnMut(usize, usize)>(
+    pub fn subscribe<CB: FnMut(usize, usize)>(
         &self,
         callback: &'a mut CB,
     ) -> TockResult<CallbackSubscription> {
diff --git a/tools/flash.sh b/tools/flash.sh
index 1a7d74c..cee7571 100755
--- a/tools/flash.sh
+++ b/tools/flash.sh
@@ -40,6 +40,11 @@
         binary_name=rv32imac.elf
         tockload=n
         ;;
+    "imxrt1050")
+        tockloader_flags=""
+        binary_name=cortex-m7.elf
+        tockload=n
+        ;;
     "opentitan")
         tockloader_flags=""
         binary_name=rv32imc.elf