From 3eca3b81248aa58cf84ba656d6ec268755519e46 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ciro=20Santilli=20=E5=85=AD=E5=9B=9B=E4=BA=8B=E4=BB=B6=20?=
 =?UTF-8?q?=E6=B3=95=E8=BD=AE=E5=8A=9F?= <ciro.santilli@gmail.com>
Date: Thu, 25 Jun 2020 09:00:08 +0000
Subject: [PATCH] inline_asm: add missing "memory" constraints

---
 userland/arch/aarch64/inline_asm/futex_ldxr_stxr.c | 12 ++++++++++--
 userland/arch/aarch64/inline_asm/wfe_ldxr_str.cpp  | 14 ++++++++++++--
 userland/arch/aarch64/inline_asm/wfe_ldxr_stxr.cpp | 13 +++++++++++--
 3 files changed, 33 insertions(+), 6 deletions(-)

diff --git a/userland/arch/aarch64/inline_asm/futex_ldxr_stxr.c b/userland/arch/aarch64/inline_asm/futex_ldxr_stxr.c
index 3fb4d66..9fa9e14 100644
--- a/userland/arch/aarch64/inline_asm/futex_ldxr_stxr.c
+++ b/userland/arch/aarch64/inline_asm/futex_ldxr_stxr.c
@@ -31,7 +31,11 @@ void __attribute__ ((noinline)) busy_loop(
 
 void* thread_main(void *arg) {
     (void)arg;
-    __asm__ __volatile__ ("ldxr x0, [%0]" : : "r" (&ldxr_var) : "x0");
+    __asm__ __volatile__ (
+        "ldxr x0, [%0]"
+        :
+        : "r" (&ldxr_var) : "x0", "memory"
+    );
     ldxr_done = 1;
     lkmc_futex(&futex1, FUTEX_WAIT, futex1, NULL, NULL, 0);
     lkmc_futex(&futex2, FUTEX_WAIT, futex2, NULL, NULL, 0);
@@ -45,7 +49,11 @@ int main(void) {
     /* Wait for thread1 to sleep on futex1. */
     busy_loop(1000, 1);
     /* Wrongly wake up the thread with a SEV. */
-    __asm__ __volatile__ ("mov x0, 1;ldxr x0, [%0]; stxr w1, x0, [%0]" : : "r" (&ldxr_var) : "x0", "x1");
+    __asm__ __volatile__ (
+        "mov x0, 1;ldxr x0, [%0]; stxr w1, x0, [%0]"
+        :
+        : "r" (&ldxr_var) : "x0", "x1", "memory"
+    );
     /* Wait for thread1 to sleep on futex2. */
     busy_loop(1000, 1);
     /* Wrongly wake thread from futex1 again. */
diff --git a/userland/arch/aarch64/inline_asm/wfe_ldxr_str.cpp b/userland/arch/aarch64/inline_asm/wfe_ldxr_str.cpp
index 54983bd..542c9d3 100644
--- a/userland/arch/aarch64/inline_asm/wfe_ldxr_str.cpp
+++ b/userland/arch/aarch64/inline_asm/wfe_ldxr_str.cpp
@@ -13,7 +13,12 @@ std::atomic_ulong done;
 int futex = 1;
 
 void myfunc() {
-    __asm__ __volatile__ ("sevl;wfe;ldxr x0, [%0];wfe" : : "r" (&futex) : "x0");
+    __asm__ __volatile__ (
+        "sevl;wfe;ldxr x0, [%0];wfe"
+        :
+        : "r" (&futex)
+        : "x0", "memory"
+    );
     done.store(futex);
 }
 
@@ -27,7 +32,12 @@ int main(int argc, char **argv) {
     thread = std::thread(myfunc);
     while (!done.load()) {
         if (do_sev) {
-            __asm__ __volatile__ ("mov x0, 1;str x0, [%0]" : : "r" (&futex) : "x0");
+            __asm__ __volatile__ (
+                "mov x0, 1;str x0, [%0]"
+                :
+                : "r" (&futex)
+                : "x0", "memory"
+            );
         }
     }
     thread.join();
diff --git a/userland/arch/aarch64/inline_asm/wfe_ldxr_stxr.cpp b/userland/arch/aarch64/inline_asm/wfe_ldxr_stxr.cpp
index 9d09390..0a961bc 100644
--- a/userland/arch/aarch64/inline_asm/wfe_ldxr_stxr.cpp
+++ b/userland/arch/aarch64/inline_asm/wfe_ldxr_stxr.cpp
@@ -12,7 +12,11 @@ std::atomic_ulong done;
 int futex = 1;
 
 void myfunc() {
-    __asm__ __volatile__ ("sevl;wfe;ldxr x0, [%0];wfe" : : "r" (&futex) : "x0");
+    __asm__ __volatile__ (
+        "sevl;wfe;ldxr x0, [%0];wfe"
+        :
+        : "r" (&futex) : "x0", "memory"
+    );
     done.store(futex);
 }
 
@@ -26,7 +30,12 @@ int main(int argc, char **argv) {
     thread = std::thread(myfunc);
     while (!done.load()) {
         if (do_sev) {
-            __asm__ __volatile__ ("ldxr x0, [%0];mov x0, 1;stxr w1, x0, [%0]" : : "r" (&futex) : "x0", "x1");
+            __asm__ __volatile__ (
+                "ldxr x0, [%0];mov x0, 1;stxr w1, x0, [%0]"
+                :
+                : "r" (&futex)
+                : "x0", "x1", "memory"
+            );
         }
     }
     thread.join();