From b0d3e5b154828260db8457534e92dbcdf895a58d Mon Sep 17 00:00:00 2001
From: Jeremy Soller <jackpot51@gmail.com>
Date: Thu, 25 Aug 2022 18:58:12 -0600
Subject: [PATCH] Correct instruction to read aarch64 thread pointer

---
 src/ld_so/mod.rs | 15 ++++-----------
 1 file changed, 4 insertions(+), 11 deletions(-)

diff --git a/src/ld_so/mod.rs b/src/ld_so/mod.rs
index 0d46adaa11..01819030fa 100644
--- a/src/ld_so/mod.rs
+++ b/src/ld_so/mod.rs
@@ -146,17 +146,10 @@ pub unsafe fn init(sp: &'static Stack) {
     }
     #[cfg(all(target_os = "redox", target_arch = "aarch64"))]
     {
-        let mut env = syscall::EnvRegisters::default();
-
-        let file = syscall::open("thisproc:current/regs/env", syscall::O_CLOEXEC | syscall::O_RDONLY)
-            .expect_notls("failed to open handle for process registers");
-
-        let _ = syscall::read(file, &mut env)
-            .expect_notls("failed to read tpidr_el0");
-
-        let _ = syscall::close(file);
-
-        tp = env.tpidr_el0;
+        core::arch::asm!(
+            "mrs {}, tpidr_el0",
+            out(reg) tp,
+        );
     }
     #[cfg(all(target_os = "redox", target_arch = "x86"))]
     {