test hardening C inline assembly code (cc crate)

Author: raoulstrackx

src/test/run-make/x86_64-fortanix-unknown-sgx-lvi/cc_plus_one_c_asm.checks

@@ -0,0 +1,15 @@
+CHECK: cc_plus_one_c_asm
+CHECK:      lfence
+CHECK:      lfence
+CHECK:      lfence
+CHECK:      lfence
+CHECK:      lfence
+CHECK-NEXT: incl
+CHECK-NEXT: jmp
+CHECK-NEXT: shlq    $0, (%rsp)
+CHECK-NEXT: lfence
+CHECK-NEXT: retq
+CHECK:      popq
+CHECK-NEXT: popq [[REGISTER:%[a-z]+]]
+CHECK-NEXT: lfence
+CHECK-NEXT: jmpq *[[REGISTER]]

src/test/run-make/x86_64-fortanix-unknown-sgx-lvi/enclave/build.rs

@@ -1,5 +1,5 @@
 fn main() {
     cc::Build::new()
         .file("foo.c")
-        .compile("foo");
+        .compile("foo_c");
 }

src/test/run-make/x86_64-fortanix-unknown-sgx-lvi/enclave/foo.c

@@ -2,3 +2,17 @@
 int cc_plus_one_c(int *arg) {
     return *arg + 1;
 }
+
+int cc_plus_one_c_asm(int *arg) {
+    int value = 0;
+
+    asm volatile ( "    movl (%1), %0\n"
+                   "    inc %0\n"
+                   "    jmp 1f\n"
+                   "    retq\n"  // never executed, but a shortcut to determine how the assembler deals with `ret` instructions
+                   "1:\n"
+                   : "=r"(value)
+                   : "r"(arg) );
+
+    return value;
+}

src/test/run-make/x86_64-fortanix-unknown-sgx-lvi/enclave/src/main.rs

@@ -1,11 +1,13 @@
 extern {
     fn cc_plus_one_c(arg : &u32) -> u32;
+    fn cc_plus_one_c_asm(arg : &u32) -> u32;
 }
 
 fn main() {
     let value : u32 = 41;
 
     unsafe{
         println!("Answer to the Ultimate Question of Life, the Universe, and Everything: {}!", cc_plus_one_c(&value));
+        println!("Answer to the Ultimate Question of Life, the Universe, and Everything: {}!", cc_plus_one_c_asm(&value));
     }
 }

src/test/run-make/x86_64-fortanix-unknown-sgx-lvi/script.sh

@@ -39,3 +39,4 @@ build
 
 check "std::io::stdio::_print::h87f0c238421c45bc" print.checks
 check cc_plus_one_c cc_plus_one_c.checks
+check cc_plus_one_c_asm cc_plus_one_c_asm.checks