From 0f0df0e66ebaf42d1decb7d401eb5f2e590b4ece Mon Sep 17 00:00:00 2001
From: Stefan Lankes <slankes@eonerc.rwth-aachen.de>
Date: Sat, 5 Nov 2016 23:02:24 +0100
Subject: [PATCH] add debug messages, unmap pages after the failed search for
 the MP tables

---
 hermit/arch/x86/kernel/apic.c | 16 ++++++++++------
 hermit/arch/x86/mm/page.c     | 11 +++++++++--
 2 files changed, 19 insertions(+), 8 deletions(-)

diff --git a/hermit/arch/x86/kernel/apic.c b/hermit/arch/x86/kernel/apic.c
index 2e3be50e6..42975dc4c 100644
--- a/hermit/arch/x86/kernel/apic.c
+++ b/hermit/arch/x86/kernel/apic.c
@@ -327,7 +327,7 @@ int apic_timer_is_running(void)
 int apic_timer_deadline(uint32_t ticks)
 {
 	if (BUILTIN_EXPECT(apic_is_enabled() && icr, 1)) {
-		//kprintf("timer oneshot %ld\n", t);
+		//kprintf("timer oneshot %ld at core %d\n", ticks, CORE_ID);
 
 		lapic_timer_oneshot();
 		lapic_timer_set_counter(ticks * icr);
@@ -343,6 +343,7 @@ int apic_disable_timer(void)
 	if (BUILTIN_EXPECT(!apic_is_enabled(), 0))
 		return -EINVAL;
 
+	//kprintf("Disable local APIC timer at core %d\n", CORE_ID);
 	lapic_timer_disable();
 
 	return 0;
@@ -351,6 +352,7 @@ int apic_disable_timer(void)
 int apic_enable_timer(void)
 {
 	if (BUILTIN_EXPECT(apic_is_enabled() && icr, 1)) {
+		//kprintf("Enable local APIC timer at core %d\n", CORE_ID);
 
 		lapic_timer_periodic();
 		lapic_timer_set_counter(icr);
@@ -378,13 +380,15 @@ static apic_mp_t* search_mptable(size_t base, size_t limit) {
 			vptr = 0;
 		}
 
-		if (BUILTIN_EXPECT(!page_map(ptr & PAGE_MASK, ptr & PAGE_MASK, 1, flags), 1))
+		if (BUILTIN_EXPECT(!page_map(ptr & PAGE_MASK, ptr & PAGE_MASK, 1, flags), 1)) {
 			vptr = ptr & PAGE_MASK;
-		else
+		} else {
+			kprintf("Failed to map 0x%zx, which is required to search for the MP tables\n", ptr);
 			return NULL;
+		}
 
-		for(i=0; (vptr) && (i<PAGE_SIZE); i+=4, vptr+=4) {
-			tmp = (apic_mp_t*) vptr;
+		for(i=0; (vptr) && (i<PAGE_SIZE); i+=4) {
+			tmp = (apic_mp_t*) (vptr+i);
 			if (tmp->signature == MP_FLT_SIGNATURE) {
 				if (!((tmp->version > 4) || (tmp->features[0]))) {
 					vma_add(ptr & PAGE_MASK, (ptr & PAGE_MASK) + PAGE_SIZE, VMA_READ|VMA_WRITE);
@@ -983,7 +987,7 @@ int ipi_tlb_flush(void)
 
 static void apic_tlb_handler(struct state *s)
 {
-	//kputs("Receive IPI to flush the TLB\n");
+	//kprintf("Receive IPI at core %d to flush the TLB\n", CORE_ID);
 	write_cr3(read_cr3());
 }
 #endif
diff --git a/hermit/arch/x86/mm/page.c b/hermit/arch/x86/mm/page.c
index 42ec8fcdb..68612d537 100644
--- a/hermit/arch/x86/mm/page.c
+++ b/hermit/arch/x86/mm/page.c
@@ -122,6 +122,8 @@ int __page_map(size_t viraddr, size_t phyaddr, size_t npages, size_t bits, uint8
 	long first[PAGE_LEVELS], last[PAGE_LEVELS];
 	int8_t send_ipi = 0;
 
+	//kprintf("Map %d pages at 0x%zx\n", npages, viraddr);
+
 	/* Calculate index boundaries for page map traversal */
 	for (lvl=0; lvl<PAGE_LEVELS; lvl++) {
 		first[lvl] = (vpn         ) >> (lvl * PAGE_MAP_BITS);
@@ -157,8 +159,10 @@ int __page_map(size_t viraddr, size_t phyaddr, size_t npages, size_t bits, uint8
 				int8_t flush = 0;
 
 				/* do we have to flush the TLB? */
-				if (self[lvl][vpn] & PG_PRESENT)
+				if (self[lvl][vpn] & PG_PRESENT) {
+					//kprintf("Remap address 0x%zx at core %d\n", viraddr, CORE_ID);
 					send_ipi = flush = 1;
+				}
 
 				self[lvl][vpn] = phyaddr | bits | PG_PRESENT | PG_ACCESSED;
 
@@ -168,6 +172,7 @@ int __page_map(size_t viraddr, size_t phyaddr, size_t npages, size_t bits, uint8
 					tlb_flush_one_page(vpn << PAGE_BITS, 0);
 
 				phyaddr += PAGE_SIZE;
+				//viraddr += PAGE_SIZE;
 			}
 		}
 	}
@@ -187,6 +192,8 @@ int page_unmap(size_t viraddr, size_t npages)
 	if (BUILTIN_EXPECT(!npages, 0))
 		return 0;
 
+	//kprintf("Unmap %d pages at 0x%zx\n", npages, viraddr);
+
 	spinlock_irqsave_lock(&page_lock);
 
 	/* Start iterating through the entries.
@@ -258,7 +265,7 @@ void page_fault_handler(struct state *s)
 		flags = PG_USER|PG_RW;
 		if (has_nx()) // set no execution flag to protect the heap
 			flags |= PG_XD;
-		ret = page_map(viraddr, phyaddr, 1, flags);
+		ret = __page_map(viraddr, phyaddr, 1, flags, 0);
 
 		if (BUILTIN_EXPECT(ret, 0)) {
 			kprintf("map_region: could not map %#lx to %#lx, task = %u\n", phyaddr, viraddr, task->id);