more fixes

core/mem/meson.build

@@ -3,6 +3,7 @@ kernel_sources += files(
     'init.c',
     'pmm.c',
     'slab.c',
+    'stack.c',
     'usercopy.c',
     'virt.c',
     'vma.c',

core/mem/pmap.c

@@ -116,3 +116,21 @@ fail:
     spin_unlock(&pt->lock);
     return status;
 }
+
+errno_t pmap_unmap(struct pmap* pt, uintptr_t vaddr) {
+    spin_lock(&pt->lock);
+
+    errno_t status = 0;
+    pte_t* pte = get_pte(pt, vaddr, false, true);
+    if (pte == nullptr || !pte_is_present(pte)) {
+        status = ENOENT;
+        goto fail;
+    }
+
+    pte_clear(pte);
+    pte_flush(vaddr);
+
+fail:
+    spin_unlock(&pt->lock);
+    return status;
+}

core/mem/stack.c

@@ -0,0 +1,60 @@
+#include <zinnia/alloc.h>
+#include <zinnia/errno.h>
+#include <zinnia/pmap.h>
+#include <zinnia/stack.h>
+#include <zinnia/utils.h>
+#include <zinnia/virt.h>
+#include <zinnia/vma.h>
+#include <arch/mem.h>
+
+errno_t stack_init(struct stack* ks, size_t size) {
+    if (!ks || size == 0)
+        return EINVAL;
+
+    const size_t page_size = arch_mem_page_size();
+    size = ALIGN_UP(size, page_size);
+
+    uintptr_t va = vm_alloc(size + page_size);
+    if (!va)
+        return ENOMEM;
+
+    phys_t phys;
+    errno_t status = mem_phys_alloc(size / page_size, 0, &phys);
+    if (status)
+        goto err_vm;
+
+    const uintptr_t base = va + page_size;
+    size_t mapped = 0;
+    for (; mapped < size; mapped += page_size) {
+        status = pmap_map(&kernel_vma.pmap, base + mapped, phys + mapped, PTE_READ | PTE_WRITE, CACHE_WRITE_BACK);
+        if (status)
+            goto err_map;
+    }
+
+    ks->base = base;
+    ks->phys = phys;
+    ks->size = size;
+    return 0;
+
+err_map:
+    for (size_t i = 0; i < mapped; i += page_size)
+        pmap_unmap(&kernel_vma.pmap, base + i);
+    mem_phys_free(phys, size / page_size);
+err_vm:
+    vm_free(va, size + page_size);
+    return status;
+}
+
+void stack_destroy(struct stack* ks) {
+    if (!ks || !ks->base)
+        return;
+
+    const size_t page_size = arch_mem_page_size();
+    for (size_t i = 0; i < ks->size; i += page_size)
+        pmap_unmap(&kernel_vma.pmap, ks->base + i);
+
+    mem_phys_free(ks->phys, ks->size / page_size);
+    vm_free(ks->base - page_size, ks->size + page_size);
+
+    *ks = (struct stack){0};
+}