Replace legacy asm! macro with llvm_asm!

From [RFC 2873](rust-lang/rfcs#2873):

> The existing `asm!` macro will be renamed to `llvm_asm!` to provide an
easy way to maintain backwards-compatibility with existing code using
inline asm.

Author: onehr

kernel/src/arch.rs

@@ -53,42 +53,42 @@ pub fn intr_get() -> bool {
 #[allow(unused_assignments)]
 pub fn hart_id() -> usize {
     let mut hart_id: usize = 0;
-    unsafe { asm!("mv $0, tp" : "=r"(hart_id) ::: "volatile"); }
+    unsafe { llvm_asm!("mv $0, tp" : "=r"(hart_id) ::: "volatile"); }
     hart_id
 }
 
 #[inline]
 #[allow(unused_assignments)]
 pub fn r_sip() -> usize {
     let mut sip: usize = 0;
-    unsafe { asm!("csrr $0, sip" : "=r"(sip) ::: "volatile"); }
+    unsafe { llvm_asm!("csrr $0, sip" : "=r"(sip) ::: "volatile"); }
     sip
 }
 
 #[inline]
 pub fn w_sip(x: usize) {
-    unsafe { asm!("csrw sip, $0" :: "r"(x) :: "volatile"); }
+    unsafe { llvm_asm!("csrw sip, $0" :: "r"(x) :: "volatile"); }
 }
 
 #[inline]
 #[allow(unused_assignments)]
 pub fn r_sstatus() -> usize {
     let mut x: usize = 0;
-    unsafe { asm!("csrr $0, sstatus" : "=r"(x) ::: "volatile"); }
+    unsafe { llvm_asm!("csrr $0, sstatus" : "=r"(x) ::: "volatile"); }
     x
 }
 
 #[inline]
 #[allow(unused_assignments)]
 pub fn r_satp() -> usize {
     let mut x: usize = 0;
-    unsafe { asm!("csrr $0, satp" : "=r"(x) ::: "volatile"); }
+    unsafe { llvm_asm!("csrr $0, satp" : "=r"(x) ::: "volatile"); }
     x
 }
 
 #[inline]
 pub fn w_sstatus(x: usize) {
-    unsafe { asm!("csrw sstatus, $0" :: "r"(x) :: "volatile"); }
+    unsafe { llvm_asm!("csrw sstatus, $0" :: "r"(x) :: "volatile"); }
 }
 
 #[inline(always)]
@@ -99,24 +99,24 @@ pub fn __sync_synchronize() {
 
 #[inline(always)]
 pub fn __sync_lock_test_and_set(a: &u32, mut b: u32) -> u32 {
-    unsafe { asm!("amoswap.w.aq $0, $1, ($2)" :"=r"(b): "r"(b), "r"(a) :: "volatile"); }
+    unsafe { llvm_asm!("amoswap.w.aq $0, $1, ($2)" :"=r"(b): "r"(b), "r"(a) :: "volatile"); }
     b
 }
 
 #[inline(always)]
 pub fn __sync_lock_release(a: &u32) {
-    unsafe { asm!("amoswap.w zero, zero, ($0)" :: "r"(a) :: "volatile"); }
+    unsafe { llvm_asm!("amoswap.w zero, zero, ($0)" :: "r"(a) :: "volatile"); }
 }
 
 #[inline(always)]
 pub unsafe fn w_ra(x: usize) {
-    asm!("mv ra, $0" :: "r"(x) :: "volatile");
+    llvm_asm!("mv ra, $0" :: "r"(x) :: "volatile");
 }
 
 
 pub fn sp() -> usize {
     let mut sp: usize = 0;
-    unsafe { asm!("mv $0, sp" : "=r"(sp) ::: "volatile"); }
+    unsafe { llvm_asm!("mv $0, sp" : "=r"(sp) ::: "volatile"); }
     sp
 }
 

kernel/src/lib.rs

@@ -14,6 +14,7 @@
 #![feature(alloc_error_handler)]
 #![feature(box_syntax)]
 #![feature(alloc_prelude)]
+#![feature(llvm_asm)]
 #![allow(dead_code)]
 #![allow(unused_imports)]
 

kernel/src/mem.rs

@@ -196,7 +196,7 @@ pub fn hartinit() {
     let root_ppn = &KERNEL_PGTABLE as *const Table as usize;
     let satp_val = arch::build_satp(8, 0, root_ppn);
     unsafe {
-        asm!("csrw satp, $0" :: "r"(satp_val));
+        llvm_asm!("csrw satp, $0" :: "r"(satp_val));
         asm::sfence_vma(0, 0);
     }
 }
@@ -261,4 +261,4 @@ pub fn debug() {
 
 pub fn alloc_stack() -> *mut u8 {
     ALLOC().lock().allocate(PAGE_SIZE * 1024)
-}
+}