From f46ab8ca2050ee77edf6e6b979875426bdaf29dc Mon Sep 17 00:00:00 2001
From: Jon Santmyer <jon@jonsantmyer.com>
Date: Wed, 13 Mar 2024 09:58:22 -0400
Subject: fix incorrect tss rsp assignment

---
 arch/x86_64/paging.c | 35 +++++++++++++++++++++++++++++++++--
 1 file changed, 33 insertions(+), 2 deletions(-)

(limited to 'arch/x86_64/paging.c')

diff --git a/arch/x86_64/paging.c b/arch/x86_64/paging.c
index 76b5735..29c4863 100644
--- a/arch/x86_64/paging.c
+++ b/arch/x86_64/paging.c
@@ -1,4 +1,5 @@
 #include "paging.h"
+#include "interrupt.h"
 #include <stddef.h>
 #include "lib/jove.h"
 #include "io/log.h"
@@ -128,10 +129,16 @@ mem_pd_ensure_range(struct PageDirectory *pd, uintptr_t from, uintptr_t to, uint
         mem_pd_ensure_4k(pd, from, flg);
 }
 
+void
+mem_ensure_range_for(void *pd, uintptr_t from, uintptr_t to, bool rw, bool user)
+{
+    mem_pd_ensure_range((struct PageDirectory*)pd, from, to, 1 | (rw << 1) | (user << 2));
+}
+
 void
 mem_ensure_range(uintptr_t from, uintptr_t to, bool rw, bool user)
 {
-    mem_pd_ensure_range(mem_current_pd, from, to, 1 | (rw << 1) | (user << 2));
+    mem_ensure_range_for(mem_current_pd, from, to, rw, user);
 }
 
 void mem_pd_new(struct PageDirectory *pd)
@@ -152,10 +159,33 @@ void mem_pd_clone(struct PageDirectory *pd, struct PageDirectory *parent)
 {
     mem_pd_new(pd);
     for(size_t i = 0; i < 256; i++) {
-
+        //TODO: Impl pd cloning
     }
 }
 
+struct Registers*
+s_pagefault_handler(struct Registers *state)
+{
+    extern uint64_t __isr_err;
+    
+    uintptr_t fault_addr = 0;
+    __asm__ volatile("movq %%cr2, %0": "=r"(fault_addr));
+
+    bool present = __isr_err & 1;
+    bool write = __isr_err & 2;
+    bool user = __isr_err & 4;
+    bool fetch = __isr_err & 16;
+
+    klogf("Page fault at %016X\n", fault_addr);
+    klogf("%s %s from a %s address\n", 
+            user ? "user" : "kernel",
+            write ? "wrote" : "read",
+            present ? "present" : "non-present");
+
+    kpanic("Unhandled page fault at %016X\n", state->ip);
+    return state;
+}
+
 void
 mem_paging_setup(void)
 {
@@ -198,5 +228,6 @@ mem_paging_setup(void)
         s_kernel_initial_pml1[0][i] = (i * PAGESIZE) + boot_kernel_physical_address | 3;
     }
     
+    int_set_handler(14, s_pagefault_handler);
     __asm__ volatile("mov %0, %%cr3":: "r"(s_kernel_initial_pd.pml4_paddr));
 }
-- 
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