From 987ea132656f36adb9f24c0786deee8b72ff5c06 Mon Sep 17 00:00:00 2001
From: Stefan Lankes <slankes@eonerc.rwth-aachen.de>
Date: Fri, 28 Aug 2015 07:55:49 +0200
Subject: [PATCH] create a seperate stack for interrupts

---
 hermit/arch/x86/kernel/gdt.c   |  5 +++--
 hermit/arch/x86/kernel/tasks.c | 16 ++++++++--------
 2 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/hermit/arch/x86/kernel/gdt.c b/hermit/arch/x86/kernel/gdt.c
index 0f98808e1..957dd8170 100644
--- a/hermit/arch/x86/kernel/gdt.c
+++ b/hermit/arch/x86/kernel/gdt.c
@@ -36,9 +36,10 @@
 #include <asm/page.h>
 
 gdt_ptr_t		gp;
-tss_t			task_state_segments[MAX_CORES] __attribute__ ((aligned (PAGE_SIZE)));
 // currently, our kernel has full access to the ioports
 static gdt_entry_t	gdt[GDT_ENTRIES] = {[0 ... GDT_ENTRIES-1] = {0, 0, 0, 0, 0, 0}};
+static uint8_t		irq_stacks[MAX_CORES][KERNEL_STACK_SIZE] __attribute__ ((aligned (PAGE_SIZE)));
+static tss_t		task_state_segments[MAX_CORES] __attribute__ ((aligned (PAGE_SIZE)));
 
 /* 
  * This is defined in entry.asm. We use this to properly reload
@@ -136,7 +137,7 @@ void gdt_install(void)
 	 * Create TSS for each core (we use these segments for task switching)
 	 */
 	for(i=0; i<MAX_CORES; i++) {
-		task_state_segments[i].rsp0 = (size_t) &boot_stack + i * KERNEL_STACK_SIZE - 0x10;
+		task_state_segments[i].rsp0 = (size_t) irq_stacks[i] + KERNEL_STACK_SIZE - 0x10;
 		gdt_set_gate(num+i*2, (unsigned long) (task_state_segments+i), sizeof(tss_t)-1,
 			GDT_FLAG_PRESENT | GDT_FLAG_TSS | GDT_FLAG_RING0, 0);
 	}
diff --git a/hermit/arch/x86/kernel/tasks.c b/hermit/arch/x86/kernel/tasks.c
index 71a272fb2..50f4be836 100644
--- a/hermit/arch/x86/kernel/tasks.c
+++ b/hermit/arch/x86/kernel/tasks.c
@@ -36,11 +36,9 @@
 #include <hermit/vma.h>
 #include <asm/elf.h>
 #include <asm/page.h>
-#include <asm/tss.h>
 
 #define START_ADDRESS	0x40200000
 
-extern tss_t	task_state_segments[MAX_CORES];
 extern uint64_t base;
 
 static inline void enter_user_task(size_t ep, size_t stack)
@@ -108,17 +106,13 @@ static int thread_entry(void* arg, size_t ep)
 
 size_t* get_current_stack(void)
 {
-	uint32_t core_id = CORE_ID;
 	task_t* curr_task = per_core(current_task);
 	size_t stptr = ((size_t) curr_task->stack + KERNEL_STACK_SIZE - 0x10) & ~0xF;
-	size_t cr3;
 
 	set_per_core(kernel_stack, stptr);
-	task_state_segments[core_id].rsp0 = stptr;
 
-	cr3 = read_cr3();
 	// do we change the address space?
-	if (cr3 != curr_task->page_map)
+	if (read_cr3() != curr_task->page_map)
 		write_cr3(curr_task->page_map); // use new page table
 
 	return curr_task->last_stack_pointer;
@@ -488,10 +482,16 @@ static int user_entry(void* arg)
 		return -EINVAL;
 
 	ret = load_task((load_args_t*) arg);
+	if (ret)
+		kprintf("Load task failed: %d\n", ret);
 
 	kfree(arg);
 
-	return ret;
+	sys_exit(ret);
+
+	while(1) {
+		HALT;
+	}
 }
 
 /** @brief Luxus-edition of create_user_task functions. Just call with an exe name