use global allocator in rust user programs

user/Cargo.lock

@@ -1,6 +1,17 @@
+[[package]]
+name = "linked_list_allocator"
+version = "0.6.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "spin 0.4.10 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "rcore-ulib"
 version = "0.1.0"
+dependencies = [
+ "linked_list_allocator 0.6.3 (registry+https://github.com/rust-lang/crates.io-index)",
+]
 
 [[package]]
 name = "rcore-user-programs"
@@ -9,3 +20,11 @@ dependencies = [
  "rcore-ulib 0.1.0",
 ]
 
+[[package]]
+name = "spin"
+version = "0.4.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[metadata]
+"checksum linked_list_allocator 0.6.3 (registry+https://github.com/rust-lang/crates.io-index)" = "655d57c71827fe0891ce72231b6aa5e14033dae3f604609e6a6f807267c1678d"
+"checksum spin 0.4.10 (registry+https://github.com/rust-lang/crates.io-index)" = "ceac490aa12c567115b40b7b7fceca03a6c9d53d5defea066123debc83c5dc1f"

user/rcore-ulib/Cargo.toml

@@ -5,3 +5,4 @@ authors = ["WangRunji <wangrunji0408@163.com>"]
 edition = "2018"
 
 [dependencies]
+linked_list_allocator = "0.6"

user/rcore-ulib/src/lang_items.rs

@@ -1,5 +1,7 @@
 use crate::syscall::{sys_close, sys_dup, sys_exit, sys_open};
 use crate::io::{O_RDONLY, O_WRONLY, STDIN, STDOUT};
+use crate::ALLOCATOR;
+
 use core::alloc::Layout;
 use core::panic::PanicInfo;
 
@@ -31,6 +33,12 @@ fn initfd(fd2: usize, path: &str, open_flags: usize) -> i32 {
     return ret;
 }
 
+fn init_heap() {
+    const HEAP_SIZE: usize = 0x1000;
+    static mut HEAP: [u8; HEAP_SIZE] = [0; HEAP_SIZE];
+    unsafe { ALLOCATOR.lock().init(HEAP.as_ptr() as usize, HEAP_SIZE); }
+}
+
 #[no_mangle]
 pub extern "C" fn _start(_argc: isize, _argv: *const *const u8) -> ! {
     let fd = initfd(STDIN, "stdin:", O_RDONLY);
@@ -42,6 +50,7 @@ pub extern "C" fn _start(_argc: isize, _argv: *const *const u8) -> ! {
         panic!("open <stdout> failed: {}.", fd);
     }
 
+    init_heap();
     main();
     sys_exit(0)
 }
@@ -66,18 +75,3 @@ fn oom(_: Layout) -> ! {
 pub extern "C" fn abort() -> ! {
     sys_exit(2)
 }
-
-#[no_mangle]
-pub extern "C" fn __mulsi3(mut a: u32, mut b: u32) -> u32 {
-    let mut r: u32 = 0;
-
-    while a > 0 {
-        if a & 1 > 0 {
-            r += b;
-        }
-        a >>= 1;
-        b <<= 1;
-    }
-
-    r
-}

user/rcore-ulib/src/lib.rs

@@ -9,3 +9,8 @@
 pub mod io;
 pub mod syscall;
 pub mod lang_items;
+
+use linked_list_allocator::LockedHeap;
+
+#[global_allocator]
+static ALLOCATOR: LockedHeap = LockedHeap::empty();

user/targets/riscv32-rcore.json

@@ -7,7 +7,7 @@
   "os": "none",
   "arch": "riscv32",
   "cpu": "generic-rv32",
-  "features": "",
+  "features": "+m,+a,+c",
   "max-atomic-width": "32",
   "linker": "rust-lld",
   "linker-flavor": "ld.lld",