From 4fbe86a9cee6e69936faf2ed1fbc41a29a221e8e Mon Sep 17 00:00:00 2001
From: jD91mZM2 <me@krake.one>
Date: Thu, 16 Jul 2020 16:32:48 +0200
Subject: [PATCH] Fix random userspace page faults
I was an idiot and forgot rbx wasn't always backed up. As a result, we
should never ever write to it
---
src/arch/x86_64/interrupt/handler.rs | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/src/arch/x86_64/interrupt/handler.rs b/src/arch/x86_64/interrupt/handler.rs
index 070454b..274d8d6 100644
--- a/src/arch/x86_64/interrupt/handler.rs
+++ b/src/arch/x86_64/interrupt/handler.rs
@@ -281,11 +281,13 @@ macro_rules! push_fs {
push fs
// Load kernel tls
- // We can't load the value directly into `fs`. We also can't use `rax`
- // as the temporary value, as during errors that's already used for the
- // error code.
- mov rbx, 0x18
- mov fs, bx
+ //
+ // NOTE: We can't load the value directly into `fs`. So we need to use a
+ // scratch register (as preserved registers aren't backed up by the
+ // interrupt! macro) to store it. We also can't use `rax` as the temporary
+ // value, as during errors that's already used for the error code.
+ mov rcx, 0x18
+ mov fs, cx
" };
}
#[macro_export]
--
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