From 09cfb248e7b1765865bcc0c174c019acfec6681c Mon Sep 17 00:00:00 2001
From: Amanieu d'Antras <amanieu@gmail.com>
Date: Fri, 30 Apr 2021 18:27:12 +0100
Subject: [PATCH] Avoid using rbx in SGX inline assembly since it is reserved

---
 library/std/src/sys/sgx/ext/arch.rs | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/library/std/src/sys/sgx/ext/arch.rs b/library/std/src/sys/sgx/ext/arch.rs
index 730db34e733..a6718006fe4 100644
--- a/library/std/src/sys/sgx/ext/arch.rs
+++ b/library/std/src/sys/sgx/ext/arch.rs
@@ -32,9 +32,12 @@ pub fn egetkey(request: &Align512<[u8; 512]>) -> Result<Align16<[u8; 16]>, u32>
         let error;
 
         asm!(
+            // rbx is reserved by LLVM
+            "xchg {}, rbx",
             "enclu",
+            "mov rbx, {}",
+            inout(reg) request => _,
             inlateout("eax") ENCLU_EGETKEY => error,
-            in("rbx") request,
             in("rcx") out.as_mut_ptr(),
             options(nostack),
         );
@@ -60,9 +63,12 @@ pub fn ereport(
         let mut report = MaybeUninit::uninit();
 
         asm!(
+            // rbx is reserved by LLVM
+            "xchg {}, rbx",
             "enclu",
+            "mov rbx, {}",
+            inout(reg) targetinfo => _,
             in("eax") ENCLU_EREPORT,
-            in("rbx") targetinfo,
             in("rcx") reportdata,
             in("rdx") report.as_mut_ptr(),
             options(preserves_flags, nostack),