Nucleus
Barry Kernel threads + threads share address space 6217f0d (3 years, 1 month ago)
diff --git a/memory/fault.c b/memory/fault.c
index 7dfae10..cbff7b2 100644
--- a/memory/fault.c
+++ b/memory/fault.c
@@ -142,14 +142,10 @@ not_present_write(VMRegion *region, uintptr_t addr)
ASSERT(front);
inode = front->inode;
page = find_page(inode->pages, offset);
+ if (page)
+ return install_page(addr, page, region->prot);
newPage = create_page(inode->pages, alloc_frame(), offset);
install_page(addr, newPage, region->prot);
- if (page) {
- copy_page_frame(PAGE_ADDR(page->frame),
- PAGE_ADDR(newPage->frame));
- remove(inode->pages, page);
- return;
- }
/* Anonymous region, zero-fill */
if (region->flags & MAP_ANONYMOUS) {
@@ -179,14 +175,20 @@ page_fault_handler(struct InterruptFrame *frame)
uint8_t present = frame->err & (1 << 0);
uint8_t write = frame->err & (1 << 1);
uint8_t user = frame->err & (1 << 2);
+ page_t pg = get_page(addr);
ASSERT(current && current->vm);
+ /* Handle lazy invalidation */
+ if (!present && (pg & PTE_PRESENT))
+ return flush_tlb(addr);
+ if (write && (pg & PTE_WRITE))
+ return flush_tlb(addr);
+
/* Iterate VM Regions */
VMRegion *region = find_region(addr);
if (__builtin_expect(!region, 0)) {
/* Not in a region */
- page_t pg = get_page(addr);
panic("Page Fault [%d:%d] (%#.8x -> %#.8x [tbl:%d, pg:%d][%#.8x], %s, %s, %s)",
current->tgid, current->tid, frame->eip,
addr, (addr >> 12) / 1024, (addr >> 12) % 1024, pg,
@@ -195,9 +197,12 @@ page_fault_handler(struct InterruptFrame *frame)
user ? "user" : "kernel");
}
+ /* Protection violation, kill process */
if (user && write && !(region->prot & PROT_WRITE))
- panic("Segmentation violation");
+ panic("Segmentation violation : %#.8x[%#.8x] (%#.8x -> %#.8x)",
+ region, region->prot, frame->eip, addr);
+ /* Update paging structures correctly */
if (present && write)
return copy_on_write(region, addr);
if (!present && write)
diff --git a/memory/frame.c b/memory/frame.c
index 428aae9..0e0f8fd 100644
--- a/memory/frame.c
+++ b/memory/frame.c
@@ -174,6 +174,7 @@ init_frames(uint32_t size, void *addr)
struct {uint32_t start, end;} remaps[] = {
{.start = 0x0000, .end = bumpAlloc}, /* PMM bitmaps */
{.start = 0x100000, .end = 0x180000 }, /* Kernel */
+ {.start = 0x200000, .end = 0x800000 }, /* Kernel heap */
};
/* Check bitmaps */
@@ -183,10 +184,11 @@ init_frames(uint32_t size, void *addr)
numFrames += region->numFrames;
uintptr_t end = region->base + (region->numFrames * PAGE_SIZE);
/* Iterate the remaps[] to find overlapping regions */
- for (i = 0; i < sizeof(remaps)/sizeof(remaps[0]); i++)
+ for (i = 0; i < sizeof(remaps)/sizeof(remaps[0]); i++) {
for (j = remaps[i].start;
j < remaps[i].end && j >= region->base && j < end;
j += PAGE_SIZE)
set_frame(region, (j - region->base) >> 12);
+ }
}
}
diff --git a/memory/mmap.c b/memory/mmap.c
index 2093bf3..f6e94c7 100644
--- a/memory/mmap.c
+++ b/memory/mmap.c
@@ -26,7 +26,7 @@ mmap(void *addr, size_t len, int prot, int flags, int fildes, off_t off)
break;
region = head;
}
- if (!head && region->end + len >= 0xDFC00000)
+ if (region && region->end + len >= 0xDFC00000)
return (void *) -ENOMEM;
addr = (void *) region->end;
}
diff --git a/memory/namespace.h b/memory/namespace.h
index bd5b0a1..b0f3528 100644
--- a/memory/namespace.h
+++ b/memory/namespace.h
@@ -1,7 +1,9 @@
#ifndef MEMORY_NAMESPACE_H
#define MEMORY_NAMESPACE_H
+#include <nucleus/memory.h>
#include <nucleus/object.h>
+#include <nucleus/types.h>
#include <nucleus/vfs.h>
/* Structure for a Page in a Cache */
@@ -15,6 +17,8 @@ struct Page {
struct VirtualMemory {
Object obj;
ObjectList *regions;
+ VMRegion *stack;
+ page_dir_t pageDir;
};
/* Structure for a Virtual Memory Region object */
@@ -27,6 +31,7 @@ struct VMRegion {
File *front, *back;
};
+void switch_dir(page_dir_t dir);
VMRegion *vm_create_region(void *addr, size_t len, int prot, int flags,
off_t offset, File *back);
diff --git a/memory/paging.c b/memory/paging.c
index e9a8a83..aa5fa17 100644
--- a/memory/paging.c
+++ b/memory/paging.c
@@ -16,7 +16,7 @@ page_t zeroFrame;
static page_dir_t kernelDir;
/* Switch page directory */
-static void
+void
switch_dir(page_dir_t dir)
{
asm volatile("mov %0, %%cr3" :: "r" (dir));
@@ -43,6 +43,8 @@ set_page(uintptr_t vaddr, page_t page)
page_table_t *tables = (void *) 0xFFFFF000;
uintptr_t address = vaddr >> 12;
uint32_t tbl = address / 1024;
+ if (!(tables[tbl] & PDE_PRESENT) && !page)
+ return;
/* Create table if not present */
if (!(tables[tbl] & PDE_PRESENT)) {
tables[tbl] = alloc_frame() | PDE_PRESENT | PDE_WRITE;
@@ -91,18 +93,9 @@ clone_dir(void)
}
/* Link the pages for Copy-On-Write */
- if (tbl < 960) { /* 0xF0000000 */
- oldTable[pg] &= ~PTE_WRITE;
- flush_tlb(((tbl * 1024) + pg) << 12);
- newTable[pg] = oldTable[pg];
- } else {
- /* Copy the kernel stack area immediately */
- newTable[pg] = alloc_frame()
- | PAGE_ATTR(oldTable[pg]);
- flush_tlb(((tbl * 1024) + pg) << 12);
- copy_page_frame(PAGE_ADDR(oldTable[pg]),
- PAGE_ADDR(newTable[pg]));
- }
+ oldTable[pg] &= ~PTE_WRITE;
+ flush_tlb(((tbl * 1024) + pg) << 12);
+ newTable[pg] = oldTable[pg];
}
}
newTables[1023] = oldTables[1022];
@@ -142,23 +135,17 @@ init_paging(void)
/*
* By mapping the page directory as the last page table, the page
* directory entries are read as page table entries, and the page
- * table entries become the pages. This means that each page contains
- * the contents of a page table, and the region in memory represented by
- * the last page table contains a contiguous list of all pages in
- * memory. The very last page contains the contents of the page
- * directory itself. This means that each virtual address space
- * contains it's own paging structures.
+ * tables become the pages. This means that each page contains the
+ * contents of a page table, and the region in memory represented by the
+ * last page table contains a contiguous list of all pages in memory.
+ * The very last page contains the contents of the page directory
+ * itself. This means that each virtual address space contains it's own
+ * paging structures.
*/
/* Use kernel directory */
register_exception(14, page_fault_handler);
cpu_load_paging();
-
- /* Allocate a kernel stack */
- uintptr_t stk;
- for (stk = 0xF0400000; stk < 0xF0800000; stk += PAGE_SIZE)
- set_page(stk, alloc_frame() | PTE_PRESENT | PTE_WRITE);
-
zeroFrame = alloc_frame();
}
diff --git a/memory/region.c b/memory/region.c
index 26cbc37..469f6b4 100644
--- a/memory/region.c
+++ b/memory/region.c
@@ -17,6 +17,7 @@ static void vm_copy(Object *, Object *);
static void region_new(Object *);
static void region_delete(Object *);
static void region_copy(Object *, Object *);
+static int region_compare(void *, void *);
/* Virtual Memory Namespace object type */
ObjectType virtualMemoryType = {
@@ -40,7 +41,17 @@ static void
vm_new(Object *obj)
{
VirtualMemory *vm = (void *) obj;
- vm->regions = create_list(&vmRegionType, LIST_NORMAL);
+ vm->regions = create_list(&vmRegionType, LIST_ORDERED, region_compare);
+
+ /* Create stack region */
+ VMRegion *stack = new(&vmRegionType);
+ stack->start = 0xDFC00000;
+ stack->end = 0xE0000000;
+ stack->prot = PROT_READ | PROT_WRITE;
+ stack->flags = MAP_PRIVATE | MAP_ANONYMOUS;
+ vm->stack = stack;
+
+ asm volatile("mov %%cr3, %0" : "=r" (vm->pageDir));
}
/* Destroy a Virtual Memory object */
@@ -49,6 +60,8 @@ vm_delete(Object *obj)
{
VirtualMemory *vm = (void *) obj;
destroy_list(vm->regions);
+ if (vm->stack)
+ put(vm->stack);
}
/* Copy a Virtual Memory object */
@@ -62,6 +75,9 @@ vm_copy(Object *a, Object *b)
add(child->regions, insert);
put(insert);
}
+ if (parent->stack)
+ child->stack = copy(parent->stack);
+ child->pageDir = clone_dir();
}
/* Delete a Virtual Memory Region */
@@ -105,6 +121,14 @@ region_copy(Object *a, Object *b)
child->back = get(parent->back);
}
+/* Compare two regions of memory */
+static int
+region_compare(void *a, void *b)
+{
+ VMRegion *ra = a, *rb = b;
+ return rb->start - ra->start;
+}
+
/* Remove a range of pages from a region's page cache */
static void
remove_cache_range(VMRegion *region, uintptr_t start, uintptr_t end)
@@ -130,6 +154,18 @@ remove_cache_range(VMRegion *region, uintptr_t start, uintptr_t end)
}
}
+/* Switch to another virtual memory namespace */
+void
+switch_to_mm(VirtualMemory *vm)
+{
+ if (!current || !current->vm)
+ return;
+ if (!vm->pageDir)
+ return;
+ if (current->vm->pageDir != vm->pageDir)
+ switch_dir(vm->pageDir);
+}
+
/* Find a Virtual Memory Region by address */
VMRegion *
find_region(uintptr_t addr)
@@ -140,7 +176,7 @@ find_region(uintptr_t addr)
return region;
}
- region = current->stack;
+ region = current->vm->stack;
if (region->start <= addr && region->end > addr)
return region;
@@ -203,14 +239,3 @@ vm_create_region(void *addr, size_t len, int prot, int flags, off_t offset,
add(current->vm->regions, region);
return region;
}
-
-/* Create a Virtual Memory Region for the stack */
-VMRegion *
-vm_create_stack(void)
-{
- VMRegion *stack = vm_create_region((void *) 0xDFC00000, 0x400000,
- PROT_READ | PROT_WRITE,
- MAP_PRIVATE | MAP_ANONYMOUS, 0, NULL);
- remove(current->vm->regions, stack);
- return stack;
-}