Modify occlum_entry to be compatible with Linux syscall ABI

src/libos/src/process/do_spawn/mod.rs

@@ -311,8 +311,8 @@ fn init_auxvec(process_vm: &ProcessVM, exec_elf_file: &ElfFile) -> Result<AuxVec
     let ldso_elf_base = process_vm.get_elf_ranges()[1].start() as u64;
     auxvec.set(AuxKey::AT_BASE, ldso_elf_base)?;
 
-    let syscall_addr = __occlum_syscall as *const () as u64;
-    auxvec.set(AuxKey::AT_OCCLUM_ENTRY, syscall_addr)?;
+    let syscall_native_addr = __occlum_syscall_native as *const () as u64;
+    auxvec.set(AuxKey::AT_OCCLUM_ENTRY, syscall_native_addr)?;
     // TODO: init AT_EXECFN
     // auxvec.set_val(AuxKey::AT_EXECFN, "program_name")?;
 
@@ -320,6 +320,6 @@ fn init_auxvec(process_vm: &ProcessVM, exec_elf_file: &ElfFile) -> Result<AuxVec
 }
 
 extern "C" {
-    fn __occlum_syscall(num: i32, arg0: u64, arg1: u64, arg2: u64, arg3: u64, arg4: u64) -> i64;
+    fn __occlum_syscall_native() -> i64;
     fn occlum_gdb_hook_load_elf(elf_base: u64, elf_path: *const u8, elf_path_len: u64);
 }

src/libos/src/syscall/syscall_entry_native_x86-64.S

@@ -0,0 +1,46 @@
+#define __ASSEMBLY__
+#include "task.h"
+
+    .file "syscall_entry_native_x86-64.S"
+    .global __occlum_syscall_native
+    .type __occlum_syscall_native, @function
+__occlum_syscall_native:
+    push %rbp
+    movq %rsp,%rbp
+
+    // Save registers
+    pushq %rdi
+    pushq %rsi
+    pushq %rdx
+    pushq %r10
+    pushq %r8
+    // arg5
+    pushq %r9
+    // arg4--arg0
+    movq %r8, %r9
+    movq %r10, %r8
+    movq %rdx, %rcx
+    movq %rsi, %rdx
+    movq %rdi, %rsi
+    // num
+    movq %rax, %rdi
+
+    // num  - %rdi
+    // arg0 - %rsi
+    // arg1 - %rdx
+    // arg2 - %rcx
+    // arg3 - %r8
+    // arg4 - %r9
+    // arg5 - *0x8(%rsp)
+    call __occlum_syscall
+
+    // Restore registers
+    popq %r9
+    popq %r8
+    popq %r10
+    popq %rdx
+    popq %rsi
+    popq %rdi
+
+    popq %rbp
+    ret