cleanup for real hw attempt

1 files changed, 134 insertions, 24 deletions

diff --git a/arch/x86_64/hal/paging.c b/arch/x86_64/hal/paging.c
index 7b45005..47c79f3 100644
--- a/arch/x86_64/hal/paging.c
+++ b/arch/x86_64/hal/paging.c
@@ -1,5 +1,6 @@
 #include "paging.h"
 #include "arch/x86_64/x86_64.h"
+#include "hal/memory.h"
 #include "jove.h"
 #include "init.h"
 #include "config.h"
@@ -73,45 +74,91 @@ s_int_handle_pf_early(struct int_stackframe *frame)
     hcf();
 }
 
-int pagedir_map_frame(
-        jove_owned_obj_t *tgt, jove_owned_obj_t *untyped_obj, 
-        uintptr_t vptr, struct syscall_pagedir_flags flg)
+static page_t*
+s_pagedir_get_pml1(page_t *pml4, uintptr_t vptr)
 {
-    page_t *pml4 = obj_deref(tgt);
-    uintptr_t frame = obj_getvalue(untyped_obj);
-
+    errno = 0;
     size_t pml4i = PML4I(vptr);
-    if(!pml4[pml4i].p) return ENOMAP;
+    if(!pml4[pml4i].p) {
+        errno = ENOMAP;
+        return 0;
+    }
 
     page_t *pml3 = (page_t*)(((uintptr_t)pml4[pml4i].paddr << 12) | IDENT_VIRT_BASE);
     size_t pml3i = PML3I(vptr);
-    if(!pml3[pml3i].p) return ENOMAP;
+    if(!pml3[pml3i].p) {
+        errno = ENOMAP;
+        return 0;
+    }
 
     page_t *pml2 = (page_t*)(((uintptr_t)pml3[pml3i].paddr << 12) | IDENT_VIRT_BASE);
     size_t pml2i = PML2I(vptr);
-    if(!pml2[pml2i].p) return ENOMAP;
+    if(!pml2[pml2i].p) {
+        errno = ENOMAP;
+        return 0;
+    }
+
+    return (page_t*)(((uintptr_t)pml2[pml2i].paddr << 12) | IDENT_VIRT_BASE);
+}
+
+int pagedir_map_frame(page_t *pml4, 
+        uintptr_t pptr, uintptr_t vptr, 
+        uintmax_t flg)
+{
+    page_t *pml1 = s_pagedir_get_pml1(pml4, vptr);
+    if(!pml1)
+        return errno;
 
-    page_t *pml1 = (page_t*)(((uintptr_t)pml2[pml2i].paddr << 12) | IDENT_VIRT_BASE);
     size_t pml1i = PML1I(vptr);
     if(pml1[pml1i].p) return EEXIST;
 
-    pml1[pml1i].value = frame |
-        PAGE_PRESENT |
-        PAGE_USER |
-        (flg.writeable ? PAGE_WRITETHROUGH : 0) |
-        (flg.executable ? 0 : PAGE_XD);
+    pml1[pml1i].value = pptr | PAGE_PRESENT | flg;
+    __asm__ volatile("invlpg (%0)":: "r"(vptr): "memory");
     return 0;
 }
 
-int pagedir_map_table(
+int pagedir_map_untyped_frame(
         jove_owned_obj_t *tgt, jove_owned_obj_t *untyped_obj, 
         uintptr_t vptr, struct syscall_pagedir_flags flg)
 {
-    page_t *target_table = NULL;
     page_t *pml4 = obj_deref(tgt);
     uintptr_t frame = obj_getvalue(untyped_obj);
 
-    void *frame_ident = obj_deref(untyped_obj);
+    return pagedir_map_frame(pml4, frame, vptr, 
+            (flg.writeable ? PAGE_WRITEABLE : 0) |
+            (flg.executable ? PAGE_XD : 0));
+}
+
+int pagedir_unmap_untyped_frame(
+        jove_owned_obj_t *tgt, jove_owned_obj_t *dst, uintptr_t vptr)
+{
+    page_t *pml4 = obj_deref(tgt);
+
+    size_t pml4i = PML4I(vptr);
+    if(!pml4[pml4i].p) return ENOMAP;
+
+    page_t *pml1 = s_pagedir_get_pml1(pml4, vptr);
+    size_t pml1i = PML1I(vptr);
+    if(!pml1[pml1i].p) return ENOMAP;
+
+    uintptr_t untyped_pptr = (pml1[pml1i].paddr << 12);
+    
+    obj_settype(dst, JOVE_OBJ_UNTYPED);
+    obj_setvalue(dst, untyped_pptr);
+
+    jove_untyped_t *untyped_data = obj_deref(dst);
+    untyped_data->limit = 0x1000;
+    __asm__ volatile("invlpg (%0)":: "r"(vptr): "memory");
+
+    return 0;
+}
+
+int pagedir_map_table(page_t *pml4,
+        uintptr_t pptr, uintptr_t vptr)
+{
+    page_t *target_table = NULL;
+
+    void *frame_ident = (void*)(pptr | IDENT_VIRT_BASE);
     memset(frame_ident, 0, 0x1000);
 
     size_t pml4i = PML4I(vptr);
@@ -136,14 +183,77 @@ int pagedir_map_table(
     return EHASMAP;
 
 map_table:
-    target_table->value = frame |
+    target_table->value = pptr |
         PAGE_PRESENT |
-        PAGE_USER |
-        (flg.writeable ? PAGE_WRITETHROUGH : 0) |
-        (flg.executable ? 0 : PAGE_XD);
+        (pptr > IDENT_VIRT_BASE ? 0 : PAGE_USER) |
+        PAGE_WRITEABLE;
+    __asm__ volatile("invlpg (%0)":: "r"(vptr): "memory");
     return 0;
 }
 
+int pagedir_map_untyped_table(
+        jove_owned_obj_t *tgt, jove_owned_obj_t *untyped_obj, 
+        uintptr_t vptr, struct syscall_pagedir_flags flg)
+{
+    page_t *pml4 = obj_deref(tgt);
+    uintptr_t frame = obj_getvalue(untyped_obj);
+
+    return pagedir_map_table(pml4, frame, vptr);
+}
+
+int pagedir_unmap_untyped_table(
+        jove_owned_obj_t *tgt, jove_owned_obj_t *dst, uintptr_t vptr)
+{
+    page_t *target_table = NULL;
+    page_t *pml4 = obj_deref(tgt);
+
+    //If the PML4 entry does not exist at this virtual ptr, the user may be
+    //trying to unmap the entire address space. We don't support this.
+    size_t pml4i = PML4I(vptr);
+    if(!pml4[pml4i].p) {
+        return ENOMAP;
+    }
+    target_table = &pml4[pml4i];
+
+    //Try to unmap the pml4 entry if the pml3 entry does not exist.
+    page_t *pml3 = (page_t*)(((uintptr_t)pml4[pml4i].paddr << 12) | IDENT_VIRT_BASE);
+    size_t pml3i = PML3I(vptr);
+    if(!pml3[pml3i].p) {
+        goto unmap_table;
+    }
+    target_table = &pml3[pml3i];
+
+    //Try to unmap the pml3 entry if the pml2 entry does not exist.
+    page_t *pml2 = (page_t*)(((uintptr_t)pml3[pml3i].paddr << 12) | IDENT_VIRT_BASE);
+    size_t pml2i = PML2I(vptr);
+    if(!pml2[pml2i].p) {
+        goto unmap_table;
+    }
+    //We are unmapping a pml2 entry.
+    target_table = &pml2[pml2i];
+
+unmap_table:
+{
+    uintptr_t frame = target_table->paddr << 12;
+    page_t *target_vals = (page_t*)(frame | IDENT_VIRT_BASE);
+
+    //Check that the page table at our target entry is empty.
+    //If it's not, we return an error saying that the entry contains a map.
+    for(size_t i = 0; i < 512; i++) {
+        if(target_vals[i].p) return EHASMAP;
+    }
+
+    //Populate the none object with an untyped object at the free'd page frame.
+    obj_settype(dst, JOVE_OBJ_UNTYPED);
+    obj_setvalue(dst, frame);
+
+    jove_untyped_t *untyped = obj_deref(dst);
+    untyped->limit = 0x1000;
+
+    __asm__ volatile("invlpg (%0)":: "r"(vptr): "memory");
+    return 0;
+}
+}
 
 void
 paging_pml4_init(void)
@@ -196,7 +306,7 @@ paging_pml4_init(void)
     uintptr_t kernel_rodata_off = kernel_text_off + kernel_text_pages;
     for(size_t i = 0; i < kernel_rodata_pages; i++) {
         size_t off = i + kernel_rodata_off;
-        uintptr_t page_off = kernel_text_start_pptr + (off << 12);
+        uintptr_t page_off = kernel_rodata_start_pptr + (i << 12);
         _kernel_pml1[off].value = page_off | PAGE_PRESENT | PAGE_GLOBAL | PAGE_XD;
     }
 
@@ -210,7 +320,7 @@ paging_pml4_init(void)
     uintptr_t kernel_data_off = kernel_rodata_off + kernel_rodata_pages;
     for(size_t i = 0; i < kernel_data_pages; i++) {
         size_t off = i + kernel_data_off;
-        uintptr_t page_off = kernel_text_start_pptr + (off << 12);
+        uintptr_t page_off = kernel_data_start_pptr + (i << 12);
         _kernel_pml1[off].value = page_off | PAGE_PRESENT | PAGE_WRITEABLE | PAGE_GLOBAL | PAGE_XD;
     }