From 582e3fd8eb6c77b6513bafa195ffa9aadeb2ff71 Mon Sep 17 00:00:00 2001
From: Jeremy Soller <jeremy@system76.com>
Date: Tue, 21 Apr 2020 21:03:17 -0600
Subject: [PATCH] Unlock CONTEXT_SWITCH_LOCK after loading registers but before
switch
---
src/context/arch/x86_64.rs | 6 +++++-
src/context/switch.rs | 3 ---
2 files changed, 5 insertions(+), 4 deletions(-)
diff --git a/src/context/arch/x86_64.rs b/src/context/arch/x86_64.rs
index fa108a0a..2517d268 100644
--- a/src/context/arch/x86_64.rs
+++ b/src/context/arch/x86_64.rs
@@ -1,5 +1,5 @@
use core::mem;
-use core::sync::atomic::AtomicBool;
+use core::sync::atomic::{AtomicBool, Ordering};
use syscall::data::FloatRegisters;
/// This must be used by the kernel to ensure that context switches are done atomically
@@ -127,6 +127,7 @@ impl Context {
}
/// Switch to the next context by restoring its stack and registers
+ /// Check disassembly!
#[cold]
#[inline(never)]
#[naked]
@@ -167,6 +168,9 @@ impl Context {
asm!("mov $0, rbp" : "=r"(self.rbp) : : "memory" : "intel", "volatile");
asm!("mov rbp, $0" : : "r"(next.rbp) : "memory" : "intel", "volatile");
+
+ // Unset global lock after loading registers but before switch
+ CONTEXT_SWITCH_LOCK.store(false, Ordering::SeqCst);
}
}
diff --git a/src/context/switch.rs b/src/context/switch.rs
index 34fdd23a..6e10825f 100644
--- a/src/context/switch.rs
+++ b/src/context/switch.rs
@@ -156,9 +156,6 @@ pub unsafe fn switch() -> bool {
(*from_ptr).arch.switch_to(&mut (*to_ptr).arch);
- // Unset global lock after switch
- arch::CONTEXT_SWITCH_LOCK.store(false, Ordering::SeqCst);
-
true
}
}
--
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