From a5d4ccba57886a4097310397bf4cf533abf7c4c2 Mon Sep 17 00:00:00 2001
From: uuuvn <uuuvn@uuuvn.space>
Date: Tue, 13 Jun 2023 10:15:47 +0000
Subject: [PATCH] More aarch64 stuff
---
src/arch/aarch64/vectors.rs | 2 ++
src/context/arch/aarch64.rs | 29 ++++++++++++++++++-----------
2 files changed, 20 insertions(+), 11 deletions(-)
diff --git a/src/arch/aarch64/vectors.rs b/src/arch/aarch64/vectors.rs
index 340cbdf8..49aede02 100644
--- a/src/arch/aarch64/vectors.rs
+++ b/src/arch/aarch64/vectors.rs
@@ -42,6 +42,8 @@ __vec_03:
// Synchronous
.align 7
__vec_04:
+ mov x18, sp
+ and sp, x18, #0xfffffffffffffff0 // Align sp.
mov x18, #0xb0b4
b synchronous_exception_at_el1_with_spx
b __vec_04
diff --git a/src/context/arch/aarch64.rs b/src/context/arch/aarch64.rs
index beceba52..d5804789 100644
--- a/src/context/arch/aarch64.rs
+++ b/src/context/arch/aarch64.rs
@@ -95,21 +95,29 @@ impl Context {
pub unsafe fn signal_stack(&mut self, handler: extern fn(usize), sig: u8) {
let lr = self.lr.clone();
- self.push_stack(lr);
- self.push_stack(sig as usize);
- self.push_stack(handler as usize);
+ self.push_pair((sig as usize, lr));
+ self.push_pair((0 as usize, handler as usize));
self.set_lr(signal_handler_wrapper as usize);
}
- pub unsafe fn push_stack(&mut self, value: usize) {
+ // It isn't possible to implement "just push one value to stack" on aarch64
+ // https://community.arm.com/arm-community-blogs/b/architectures-and-processors-blog/posts/using-the-stack-in-aarch32-and-aarch64
+ // Looks like QEMU TCG doesn't care about it, so it works in it, but not on bare metal or kvm
+ // Reverese to be compatible with ldp and stp instructions
+ // TODO: optimize?
+ pub unsafe fn push_pair(&mut self, pair: (usize, usize)) {
self.sp -= 1 * mem::size_of::<usize>();
- *(self.sp as *mut usize) = value;
+ *(self.sp as *mut usize) = pair.1;
+ self.sp -= 1 * mem::size_of::<usize>();
+ *(self.sp as *mut usize) = pair.0;
}
- pub unsafe fn pop_stack(&mut self) -> usize {
- let value = *(self.sp as *const usize);
+ pub unsafe fn pop_pair(&mut self) -> (usize, usize) {
+ let a = *(self.sp as *const usize);
+ self.sp += 1 * mem::size_of::<usize>();
+ let b = *(self.sp as *const usize);
self.sp += 1 * mem::size_of::<usize>();
- value
+ (a, b)
}
pub fn dump(&self) {
@@ -365,7 +373,6 @@ unsafe extern fn signal_handler_wrapper() {
// Push scratch registers
core::arch::asm!(
concat!(
- "sub sp, sp, 8",
push_scratch!(),
"
mov x0, sp
@@ -373,8 +380,8 @@ unsafe extern fn signal_handler_wrapper() {
",
pop_scratch!(),
"
- add sp, sp, 24
- ldr x30, [sp], #8
+ add sp, sp, 32
+ ldr x30, [sp, #-8]
ret
"
),
--
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