From d4e805e3e3aebb0bd96596985f45df5ebd66b06e Mon Sep 17 00:00:00 2001
From: Avi Kivity <avi@cloudius-systems.com>
Date: Mon, 4 Feb 2013 20:27:57 +0200
Subject: [PATCH] x64: add facility for saving/restoring interrupt flag state
It's somewhat complicated due to the red zone, but there's no way around it.
---
arch/x64/arch.hh | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/arch/x64/arch.hh b/arch/x64/arch.hh
index 5eab78f2f..7185ddabf 100644
--- a/arch/x64/arch.hh
+++ b/arch/x64/arch.hh
@@ -18,6 +18,20 @@ inline void irq_enable()
processor::sti();
}
+class irq_flag {
+public:
+ // need to clear the red zone when playing with the stack. also, can't
+ // use "m" constraint as it might be addressed relative to %rsp
+ void save() {
+ asm volatile("sub $128, %%rsp; pushfq; popq %0; add $128, %%rsp" : "=r"(_rflags));
+ }
+ void restore() {
+ asm volatile("sub $128, %%rsp; pushq %0; popfq; add $128, %%rsp" : : "r"(_rflags));
+ }
+private:
+ unsigned long _rflags;
+};
+
}
--
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