diff --git a/kernel/arch/i686/Syscall.S b/kernel/arch/i686/Syscall.S
index 6cf888d2..b668722a 100644
--- a/kernel/arch/i686/Syscall.S
+++ b/kernel/arch/i686/Syscall.S
@@ -1,12 +1,6 @@
 // arguments in EAX, EBX, ECX, EDX, ESI, EDI
 .global asm_syscall_handler
 asm_syscall_handler:
-	# save segment registers
-	pushw %ds
-	pushw %es
-	pushw %fs
-	pushw %gs
-
 	# save general purpose registers
 	pushl %ebx
 	pushl %ecx
@@ -18,13 +12,12 @@ asm_syscall_handler:
 
 	# align stack
 	movl %esp, %ebp
-	subl $15, %esp
-	andl $0xFFFFFFF0, %esp
+	andl $-16, %esp
 
 	# push arguments
 	subl $4, %esp
 	pushl %ebp
-	addl $32, (%esp)
+	addl $24, (%esp)
 	pushl %edi
 	pushl %esi
 	pushl %edx
@@ -44,6 +37,15 @@ asm_syscall_handler:
 
 	movl %ebp, %esp
 
+	# restore userspace segments
+	movw $(0x20 | 3), %bx
+	movw %bx, %ds
+	movw %bx, %es
+	movw $(0x30 | 3), %bx
+	movw %bx, %fs
+	movw $(0x38 | 3), %bx
+	movw %bx, %gs
+
 	# restore general purpose registers
 	popl %ebp
 	popl %esi
@@ -52,12 +54,6 @@ asm_syscall_handler:
 	popl %ecx
 	popl %ebx
 
-	# restore segment registers
-	popw %gs
-	popw %fs
-	popw %es
-	popw %ds
-
 	iret
 
 .global sys_fork_trampoline
diff --git a/kernel/arch/i686/Thread.S b/kernel/arch/i686/Thread.S
index 8da4d975..de3b9f98 100644
--- a/kernel/arch/i686/Thread.S
+++ b/kernel/arch/i686/Thread.S
@@ -31,8 +31,6 @@ start_kernel_thread:
 	subl $12, %esp
 	pushl %edi
 	call *%esi
-	addl $16, %esp
-
 
 .global start_userspace_thread
 start_userspace_thread:
@@ -41,14 +39,11 @@ start_userspace_thread:
 	call get_thread_start_sp
 	movl %eax, %esp
 
-	# ds, es = user data
 	movw $(0x20 | 3), %bx
 	movw %bx, %ds
 	movw %bx, %es
-	# fs
 	movw $(0x30 | 3), %bx
 	movw %bx, %fs
-	# gs
 	movw $(0x38 | 3), %bx
 	movw %bx, %gs
 
diff --git a/kernel/arch/i686/interrupts.S b/kernel/arch/i686/interrupts.S
index 4a63dd66..24b82711 100644
--- a/kernel/arch/i686/interrupts.S
+++ b/kernel/arch/i686/interrupts.S
@@ -1,12 +1,7 @@
-.macro push_userspace
-	pushw %gs
-	pushw %fs
-	pushw %es
-	pushw %ds
-	pushal
-.endm
+.macro maybe_load_kernel_segments, n
+	cmpb $0x08, \n(%esp)
+	je 1f
 
-.macro load_kernel_segments
 	movw $0x10, %ax
 	movw %ax, %ds
 	movw %ax, %es
@@ -14,19 +9,26 @@
 
 	movw $0x28, %ax
 	movw %ax, %gs
+1:
 .endm
 
-.macro pop_userspace
-	popal
-	popw %ds
-	popw %es
-	popw %fs
-	popw %gs
+.macro maybe_load_userspace_segments, n
+	cmpb $0x08, \n(%esp)
+	je 1f
+
+	movw $(0x20 | 3), %bx
+	movw %bx, %ds
+	movw %bx, %es
+	movw $(0x30 | 3), %bx
+	movw %bx, %fs
+	movw $(0x38 | 3), %bx
+	movw %bx, %gs
+1:
 .endm
 
 isr_stub:
-	push_userspace
-	load_kernel_segments
+	pushal
+	maybe_load_kernel_segments 44
 	cld
 
 	movl %cr0, %eax; pushl %eax
@@ -34,33 +36,39 @@ isr_stub:
 	movl %cr3, %eax; pushl %eax
 	movl %cr4, %eax; pushl %eax
 
-	movl %esp,     %eax // register ptr
-	leal 64(%esp), %ebx // interrupt stack ptr
-	movl 60(%esp), %ecx // error code
-	movl 56(%esp), %edx // isr number
+	movl 48(%esp), %edi // isr number
+	movl 52(%esp), %esi // error code
+	leal 56(%esp), %edx // interrupt stack ptr
+	movl %esp,     %ecx // register ptr
+
+	# stack frame for stack trace
+	leal 56(%esp), %eax
+	pushl (%eax)
+	pushl %ebp
 
 	movl %esp, %ebp
 	andl $-16, %esp
 
-	pushl %eax
-	pushl %ebx
 	pushl %ecx
 	pushl %edx
+	pushl %esi
+	pushl %edi
 	call cpp_isr_handler
 
 	movl %ebp, %esp
-	addl $16, %esp
+	addl $24, %esp
 
-	pop_userspace
+	maybe_load_userspace_segments 44
+	popal
 	addl $8, %esp
 	iret
 
 irq_stub:
-	push_userspace
-	load_kernel_segments
+	pushal
+	maybe_load_kernel_segments 44
 	cld
 
-	movl 40(%esp), %edi # interrupt number
+	movl 32(%esp), %edi # interrupt number
 
 	movl %esp, %ebp
 	andl $-16, %esp
@@ -71,7 +79,8 @@ irq_stub:
 
 	movl %ebp, %esp
 
-	pop_userspace
+	maybe_load_userspace_segments 44
+	popal
 	addl $8, %esp
 	iret
 
@@ -99,8 +108,8 @@ asm_yield_handler:
 
 .global asm_ipi_handler
 asm_ipi_handler:
-	push_userspace
-	load_kernel_segments
+	pushal
+	maybe_load_kernel_segments 36
 	cld
 
 	movl %esp, %ebp
@@ -110,13 +119,14 @@ asm_ipi_handler:
 
 	movl %ebp, %esp
 
-	pop_userspace
+	maybe_load_userspace_segments 36
+	popal
 	iret
 
 .global asm_timer_handler
 asm_timer_handler:
-	push_userspace
-	load_kernel_segments
+	pushal
+	maybe_load_kernel_segments 36
 	cld
 
 	movl %esp, %ebp
@@ -126,7 +136,8 @@ asm_timer_handler:
 
 	movl %ebp, %esp
 
-	pop_userspace
+	maybe_load_userspace_segments 36
+	popal
 	iret
 
 .macro isr n
diff --git a/kernel/kernel/ACPI/ACPI.cpp b/kernel/kernel/ACPI/ACPI.cpp
index 4a53e361..e36537ef 100644
--- a/kernel/kernel/ACPI/ACPI.cpp
+++ b/kernel/kernel/ACPI/ACPI.cpp
@@ -856,7 +856,7 @@ acpi_release_global_lock:
 			};
 
 		// TODO: EC can also reside in memory space
-		auto crs_buffer = BAN::ConstByteSpan { crs.as.str_buf->bytes, crs.as.str_buf->size };
+		auto crs_buffer = BAN::ConstByteSpan { crs.as.str_buf->bytes, static_cast<size_t>(crs.as.str_buf->size) };
 		const auto data_port = TRY(extract_io_port(crs_buffer));
 		const auto command_port = TRY(extract_io_port(crs_buffer));
 
diff --git a/kernel/kernel/GDT.cpp b/kernel/kernel/GDT.cpp
index d431a7a9..16f5b204 100644
--- a/kernel/kernel/GDT.cpp
+++ b/kernel/kernel/GDT.cpp
@@ -29,8 +29,8 @@ namespace Kernel
 		gdt->write_entry(0x20, 0x00000000, 0xFFFFF, 0xF2, data_flags);	// user data
 #if ARCH(i686)
 		gdt->write_entry(0x28, reinterpret_cast<uint32_t>(processor), sizeof(Processor), 0x92, 0x4); // processor data
-		gdt->write_entry(0x30, 0x00000000, 0x00000, 0x00, 0x0);			// fsbase
-		gdt->write_entry(0x38, 0x00000000, 0x00000, 0x00, 0x0);			// gsbase
+		gdt->write_entry(0x30, 0x00000000, 0x00000, 0xF2, data_flags);	// fsbase
+		gdt->write_entry(0x38, 0x00000000, 0x00000, 0xF2, data_flags);	// gsbase
 #endif
 		gdt->write_tss();
 
diff --git a/kernel/kernel/Input/PS2/Controller.cpp b/kernel/kernel/Input/PS2/Controller.cpp
index 5d52610a..7ce58dc0 100644
--- a/kernel/kernel/Input/PS2/Controller.cpp
+++ b/kernel/kernel/Input/PS2/Controller.cpp
@@ -321,7 +321,7 @@ namespace Kernel::Input
 					result.type = type;
 
 					BAN::Optional<ACPI::ResourceData> data;
-					ACPI::ResourceParser parser({ crs_obj->node.as.str_buf->bytes, crs_obj->node.as.str_buf->size });
+					ACPI::ResourceParser parser({ crs_obj->node.as.str_buf->bytes, static_cast<size_t>(crs_obj->node.as.str_buf->size) });
 					while ((data = parser.get_next()).has_value())
 					{
 						switch (data->type)
diff --git a/kernel/kernel/Thread.cpp b/kernel/kernel/Thread.cpp
index e0e5fc7a..6c396700 100644
--- a/kernel/kernel/Thread.cpp
+++ b/kernel/kernel/Thread.cpp
@@ -386,7 +386,7 @@ namespace Kernel
 
 		vaddr_t vaddr = userspace_stack_top() - needed_size;
 
-		const size_t page_count = BAN::Math::div_round_up(needed_size, PAGE_SIZE);
+		const size_t page_count = BAN::Math::div_round_up<size_t>(needed_size, PAGE_SIZE);
 		for (size_t i = 0; i < page_count; i++)
 			TRY(m_userspace_stack->allocate_page_for_demand_paging(vaddr + i * PAGE_SIZE));