From ace65b453151845bc361f21f3e5b651c35f9f126 Mon Sep 17 00:00:00 2001
From: Jon Santmyer <jon@jonsantmyer.com>
Date: Wed, 22 May 2024 13:00:41 -0400
Subject: massive refactor for mp and organization

---
 arch/x86_64/pagedirectory.c | 138 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 138 insertions(+)
 create mode 100644 arch/x86_64/pagedirectory.c

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

diff --git a/arch/x86_64/pagedirectory.c b/arch/x86_64/pagedirectory.c
new file mode 100644
index 0000000..cdfffeb
--- /dev/null
+++ b/arch/x86_64/pagedirectory.c
@@ -0,0 +1,138 @@
+#include "arch/page.h"
+#include "arch/processor.h"
+#include "klib/rbtree.h"
+#include "boot.h"
+#include "memory.h"
+#include "string.h"
+#include "print.h"
+
+PAGEALIGN static uint64_t s_kernel_initial_pml4[512];
+PAGEALIGN static uint64_t s_kernel_initial_pml3[2][512];
+PAGEALIGN static uint64_t s_kernel_initial_pml2[2][512];
+PAGEALIGN static uint64_t s_kernel_initial_pml1[2][512];
+static page_directory_t s_kernel_initial_pd;
+
+static rbtree_t s_page_directories;
+static intmax_t s_next_pdid = 0;
+
+page_directory_t*
+pd_new()
+{
+    page_directory_t newpd = {
+        .id = s_next_pdid++,
+        .phys = pm_alloc(1),
+    };
+    newpd.pml = (void*)pm_tovirt(newpd.phys);
+    for(size_t i = 256; i < 512; i++) {
+        pmle_t *kpe = &(s_kernel_initial_pd.pml)[i];
+        pmle_t *ppe = &(newpd.pml)[i];
+        *ppe = *kpe;
+    }
+
+    return rbtree_insert(&s_page_directories, newpd.id, &newpd);
+}
+
+static void
+s_pd_dup_pml(pmle_t *src, pmle_t *dest, size_t l, size_t i)
+{
+    pmle_t srce = src[i];
+    if(!srce.p) return;
+
+    dest[i] = srce;
+    dest[i].paddr = pm_alloc(1);
+    pmle_t dste = dest[i];
+
+    pmle_t *srct = (pmle_t*)pm_tovirt(srce.paddr << PAGE_SHIFT);
+    pmle_t *dstt = (pmle_t*)pm_tovirt(dste.paddr << PAGE_SHIFT);
+
+    if(l == 0) {
+        memcpy(dstt, srct, PAGE_SIZE);
+        return;
+    }
+
+    for(i = 0; i < 512; i++) {
+        dstt[i] = srct[i];
+        if(!srct[i].p) continue;
+        s_pd_dup_pml(srct, dstt, l - 1, i);
+    }
+}
+
+page_directory_t*
+pd_dup(page_directory_t *pd)
+{
+    page_directory_t *newpd = pd_new();
+    for(size_t i = 0; i < 256; i++) {
+        s_pd_dup_pml(pd->pml, newpd->pml, 3, i);
+    }
+    return newpd;
+}
+
+page_directory_t*
+pd_get(pdid_t pdid)
+{
+    return rbtree_find(&s_page_directories, pdid);
+}
+
+void 
+pd_switch(page_directory_t *pd)
+{
+    processor_t *pc = processor_current();
+    if(pc->pd == pd) return;
+    pc->pd = pd;
+    __asm__ volatile("movq %0, %%cr3":: "r"(pd->phys));
+}
+
+void
+vm_setup_early(void)
+{
+    memset(s_kernel_initial_pml4, 0, PAGE_SIZE);
+    memset(s_kernel_initial_pml3, 0, 2 * PAGE_SIZE);
+    memset(s_kernel_initial_pml2, 0, 2 * PAGE_SIZE);
+    memset(s_kernel_initial_pml1, 0, PAGE_SIZE);
+    s_kernel_initial_pd = (page_directory_t){
+        .phys = vm_tophys_koff((uintptr_t)&s_kernel_initial_pml4),
+        .pml = (pmle_t*)&s_kernel_initial_pml4,
+        .id = s_next_pdid++
+    };
+    processor_current()->pd = &s_kernel_initial_pd;
+
+    /* Map first few GiBs */
+    s_kernel_initial_pml4[256] =
+        vm_tophys_koff((uintptr_t)&s_kernel_initial_pml3[0])
+        | 3;
+    s_kernel_initial_pml3[0][0] =
+        vm_tophys_koff((uintptr_t)&s_kernel_initial_pml2[0])
+        | 3;
+    for(int i = 0; i < 512; i++) {
+        s_kernel_initial_pml2[0][i] = (i * (PAGE_SIZE * 512)) | 0x80 | 3;
+    }
+
+    size_t kernel_pml3e = (_kernel_virtual_base >> (30)) % 512;
+    size_t kernel_pml2e = (_kernel_virtual_base >> (21)) % 512;
+    size_t kernel_npages = ((((uintptr_t)&_kernel_end) - _kernel_virtual_base) >> 12) + 1;
+    klogf("Kernel has %i pages\n", kernel_npages);
+
+    /* Map kernel pages */
+    s_kernel_initial_pml4[511] =
+        vm_tophys_koff((uintptr_t)&s_kernel_initial_pml3[1]) | 3;
+    s_kernel_initial_pml3[1][kernel_pml3e] =
+        vm_tophys_koff((uintptr_t)&s_kernel_initial_pml2[1]) | 3;
+    s_kernel_initial_pml2[1][kernel_pml2e] =
+        vm_tophys_koff((uintptr_t)&s_kernel_initial_pml1[0]) | 3;
+    for(size_t i = 0; i < kernel_npages; i++) {
+        s_kernel_initial_pml1[0][i] = (i * PAGE_SIZE) + boot_kernel_physical_address | 3;
+    }
+ 
+    extern int_state_t *_pagefault_handler(int_state_t*);
+    int_handler_set(14, _pagefault_handler);
+    __asm__ volatile("mov %0, %%cr3":: "r"(s_kernel_initial_pd.phys));
+}
+
+void
+vm_setup(void)
+{
+    rbtree_new(&s_page_directories, page_directory_t);
+
+    processor_t *proc = processor_current();
+    pd_switch(pd_new());
+}
-- 
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