From 1ee37cb671169e138013029c724e3b0731c1a39e Mon Sep 17 00:00:00 2001
From: Bananymous <oskari.alaranta@bananymous.com>
Date: Mon, 22 Jul 2024 00:10:42 +0300
Subject: [PATCH] Kernel: Make sure stack is aligned on interrupts for i686
 target

I just realized that only x86_64 aligns stack pointer when interrupt is
triggered.
---
 kernel/arch/i686/Syscall.S    | 13 ++++++++++---
 kernel/arch/i686/interrupts.S | 25 ++++++++++++++++++++-----
 2 files changed, 30 insertions(+), 8 deletions(-)

diff --git a/kernel/arch/i686/Syscall.S b/kernel/arch/i686/Syscall.S
index 92753b8173..4edf07cca6 100644
--- a/kernel/arch/i686/Syscall.S
+++ b/kernel/arch/i686/Syscall.S
@@ -15,8 +15,14 @@ asm_syscall_handler:
 	pushl %esi
 	pushl %ebp
 
-	# align stack and push arguments
-	pushl %esp
+	# align stack
+	movl %esp, %ebp
+	subl $15, %esp
+	andl $0xFFFFFFF0, %esp
+
+	# push arguments
+	subl $4, %esp
+	pushl %ebp
 	addl $32, (%esp)
 	pushl %edi
 	pushl %esi
@@ -34,7 +40,8 @@ asm_syscall_handler:
 	movw %ax, %gs
 
 	call cpp_syscall_handler
-	addl $28, %esp
+
+	movl %ebp, %esp
 
 	# restore general purpose registers
 	popl %ebp
diff --git a/kernel/arch/i686/interrupts.S b/kernel/arch/i686/interrupts.S
index 3a7a8e54bb..f93d190595 100644
--- a/kernel/arch/i686/interrupts.S
+++ b/kernel/arch/i686/interrupts.S
@@ -38,13 +38,18 @@ isr_stub:
 	movl 60(%esp), %ecx // error code
 	movl 56(%esp), %edx // isr number
 
-	subl $12, %esp
+	movl %esp, %ebp
+	subl $15, %esp
+	andl $0xFFFFFFF0, %esp
+
 	pushl %eax
 	pushl %ebx
 	pushl %ecx
 	pushl %edx
 	call cpp_isr_handler
-	addl $44, %esp
+
+	movl %ebp, %esp
+	addl $16, %esp
 
 	pop_userspace
 	addl $8, %esp
@@ -56,10 +61,15 @@ irq_stub:
 
 	movl 40(%esp), %eax # interrupt number
 
+	movl %esp, %ebp
+	subl $15, %esp
+	andl $0xFFFFFFF0, %esp
+
 	subl $12, %esp
 	pushl %eax
 	call cpp_irq_handler
-	addl $16, %esp
+
+	movl %ebp, %esp
 
 	pop_userspace
 	addl $8, %esp
@@ -73,11 +83,16 @@ asm_yield_handler:
 	movl %esp,     %eax # interrupt registers ptr
 	leal 32(%esp), %ebx # interrupt stack ptr
 
-	subl $4, %esp
+	movl %esp, %ebp
+	subl $15, %esp
+	andl $0xFFFFFFF0, %esp
+
+	subl $8, %esp
 	pushl %eax
 	pushl %ebx
 	call cpp_yield_handler
-	addl $12, %esp
+
+	movl %ebp, %esp
 
 	popal
 	iret