diff --git a/arch/amd64/hw/exc_s.S b/arch/amd64/hw/exc_s.S
index 33e59b5..0e02ae0 100644
--- a/arch/amd64/hw/exc_s.S
+++ b/arch/amd64/hw/exc_s.S
@@ -22,8 +22,8 @@ amd64_exc_generic:
     // 0x10: rip
     // 0x08: error code
     // 0x00: error number
-    cmpq $0x08, 0x18(%rip)
-    jnz 1f
+    cmpq $0x08, 0x18(%rsp)
+    jz 1f
     swapgs
 1:
 
@@ -79,6 +79,7 @@ amd64_exc_generic:
 
     addq $16, %rsp
 
+    iret_swapgs_if_needed
     iretq
 
 amd64_isr_nerr 0
diff --git a/arch/amd64/hw/irq0.S b/arch/amd64/hw/irq0.S
index d2b6f20..a53e942 100644
--- a/arch/amd64/hw/irq0.S
+++ b/arch/amd64/hw/irq0.S
@@ -7,16 +7,16 @@
 
 amd64_irq0_early:
     cli
-    swapgs_if_needed
+    iret_swapgs_if_needed
     pushq %rax
     irq_eoi_lapic 0
     popq %rax
-    swapgs_if_needed
+    iret_swapgs_if_needed
     iretq
 
 amd64_irq0:
     cli
-    swapgs_if_needed
+    iret_swapgs_if_needed
 
     // Push caller-saved registers so it appears as if a thread just called yield()
     pushq %r11
@@ -42,7 +42,7 @@ amd64_irq0:
     popq %r10
     popq %r11
 
-    swapgs_if_needed
+    iret_swapgs_if_needed
     iretq
 
 amd64_irq2_counting:
diff --git a/arch/amd64/hw/irqs_s.S b/arch/amd64/hw/irqs_s.S
index d3e7a33..1387450 100644
--- a/arch/amd64/hw/irqs_s.S
+++ b/arch/amd64/hw/irqs_s.S
@@ -50,7 +50,7 @@ amd64_idt_load:
 .global amd64_irq_msi0
 amd64_irq_msi0:
     cli
-    swapgs_if_needed
+    iret_swapgs_if_needed
 
     pushq %r11
     pushq %r10
@@ -78,5 +78,5 @@ amd64_irq_msi0:
     popq %r10
     popq %r11
 
-    swapgs_if_needed
+    iret_swapgs_if_needed
     iretq
diff --git a/arch/amd64/sched_s.S b/arch/amd64/sched_s.S
index b9c73e7..10e0a75 100644
--- a/arch/amd64/sched_s.S
+++ b/arch/amd64/sched_s.S
@@ -14,7 +14,7 @@ context_enter:
     popq %r10
     popq %r11
 
-    swapgs_if_needed
+    iret_swapgs_if_needed
     iretq
 
 .global context_exec_enter
@@ -53,7 +53,7 @@ context_exec_enter:
     xorq %r14, %r14
     xorq %r15, %r15
 
-    swapgs_if_needed
+    iret_swapgs_if_needed
     iretq
 
 .global context_switch_first
diff --git a/etc/Kernel.makefile b/etc/Kernel.makefile
index 6861d05..9fc9ba5 100644
--- a/etc/Kernel.makefile
+++ b/etc/Kernel.makefile
@@ -170,8 +170,7 @@ KERNEL_CFLAGS=-Iinclude \
 			  -Wall \
 			  -Wextra \
 			  -Wno-unused \
-			  -O2 \
-			  -funroll-loops \
+			  -Og \
 			  -ggdb \
 			  -Werror $(KERNEL_DEF)
 KERNEL_LDFLAGS=-nostdlib \
diff --git a/include/arch/amd64/asm/asm_cpu.h b/include/arch/amd64/asm/asm_cpu.h
index 761cf9e..d29376e 100644
--- a/include/arch/amd64/asm/asm_cpu.h
+++ b/include/arch/amd64/asm/asm_cpu.h
@@ -11,9 +11,9 @@
     (__amd64_cpu + off)(%rip)
 #endif
 
-// To be used in interrupt handlers
+// To be used in interrupt handlers or anything with iret-like stack layout
 // DIRECTLY AFTER ENTRY without prior stack modification
-.macro swapgs_if_needed
+.macro iret_swapgs_if_needed
     cmpq $0x08, 0x08(%rsp)
     je 1f
     swapgs
diff --git a/include/arch/amd64/asm/asm_irq.h b/include/arch/amd64/asm/asm_irq.h
index 7773d64..e88e4e6 100644
--- a/include/arch/amd64/asm/asm_irq.h
+++ b/include/arch/amd64/asm/asm_irq.h
@@ -13,7 +13,7 @@
 .global amd64_irq\n
 amd64_irq\n:
     cli
-    swapgs_if_needed
+    iret_swapgs_if_needed
 
     pushq %r11
     pushq %r10
@@ -39,7 +39,7 @@ amd64_irq\n:
     popq %r10
     popq %r11
 
-    swapgs_if_needed
+    iret_swapgs_if_needed
     iretq
 .endm