1 files changed, 137 insertions, 0 deletions
diff --git a/kern/syscall_memory.c b/kern/syscall_memory.c
new file mode 100644
index 0000000..288d6df
--- /dev/null
+++ b/kern/syscall_memory.c
@@ -0,0 +1,137 @@
+/** @file syscall_memory.c
+ *
+ *  @brief memory syscalls.
+ *
+ *  @author Hanjie Wu (hanjiew)
+ *  @bug No functional bugs
+ */
+
+#include <string.h>
+#include <common_kern.h>
+#include <elf/elf_410.h>
+#include <ureg.h>
+
+#include <x86/asm.h>
+#include <x86/cr.h>
+#include <x86/eflags.h>
+#include <x86/seg.h>
+
+#include <asm_instr.h>
+#include <malloc.h>
+#include <mm.h>
+#include <paging.h>
+#include <sched.h>
+#include <usermem.h>
+
+/**
+ * @brief new_pages() syscall handler
+ * @param f saved regs
+ */
+void sys_new_pages_real(stack_frame_t* f) {
+    reg_t esi = f->esi;
+    va_t base;
+    if (copy_from_user((va_t)esi, sizeof(va_t), &base) != 0) {
+        goto read_fail;
+    }
+    if ((base & PAGE_OFFSET_MASK) != 0) {
+        goto read_fail;
+    }
+    int len;
+    if (copy_from_user((va_t)esi + sizeof(va_t), sizeof(int), &len) != 0) {
+        goto read_fail;
+    }
+    if ((len & PAGE_OFFSET_MASK) != 0) {
+        goto read_fail;
+    }
+
+    process_t* p = get_current()->process;
+    mutex_lock(&p->mm_lock);
+    int n_pages = len / PAGE_SIZE;
+    pa_t paddr = alloc_user_pages(n_pages);
+    if (paddr == 0) {
+        goto alloc_segment_fail;
+    }
+    if (add_region(p, base, n_pages, paddr, 1) != 0) {
+        goto add_region_fail;
+    }
+
+    int i = 0;
+    int offset = 0;
+    /* file page table one entry per loop */
+    pa_t pt_pa = find_or_create_pt(p, base);
+    if (pt_pa == BAD_PA) {
+        goto add_pt_fail;
+    }
+    do {
+        offset = i * PAGE_SIZE;
+        /* step to next page table */
+        int pt_index = get_pt_index(base + offset);
+        if (pt_index == 0) {
+            pt_pa = find_or_create_pt(p, base + offset);
+            if (pt_pa == BAD_PA) {
+                goto add_pt_fail;
+            }
+        }
+
+        int old_if = save_clear_if();
+        page_table_t* pt = (page_table_t*)map_phys_page(pt_pa, NULL);
+        (*pt)[pt_index] = make_pte(paddr + offset, 0, PTE_USER, PTE_RW, 0);
+        restore_if(old_if);
+        invlpg(base + offset);
+    } while (++i < n_pages);
+    mutex_unlock(&p->mm_lock);
+    f->eax = 0;
+    return;
+
+add_pt_fail:
+    /* page tables are reachable from page directory so no need to free them */
+    vector_pop(&p->regions);
+add_region_fail:
+    free_user_pages(paddr, n_pages);
+alloc_segment_fail:
+    mutex_unlock(&p->mm_lock);
+read_fail:
+    f->eax = (reg_t)-1;
+}
+
+/**
+ * @brief remove_pages() syscall handler
+ * @param f saved regs
+ */
+void sys_remove_pages_real(stack_frame_t* f) {
+    process_t* p = get_current()->process;
+    mutex_lock(&p->mm_lock);
+    va_t base = (va_t)f->esi;
+    int i, j, n = vector_size(&p->regions);
+    for (i = 0; i < n; i++) {
+        region_t* r = (region_t*)vector_at(&p->regions, i);
+        if (base == r->addr) {
+            int n_pages = r->size / PAGE_SIZE;
+            j = 0;
+            int offset = 0;
+            pa_t pt_pa = find_or_create_pt(p, base);
+            do {
+                offset = j * PAGE_SIZE;
+                int pt_index = get_pt_index(base + offset);
+                if (pt_index == 0) {
+                    pt_pa = find_or_create_pt(p, base + offset);
+                }
+
+                int old_if = save_clear_if();
+                page_table_t* pt = (page_table_t*)map_phys_page(pt_pa, NULL);
+                (*pt)[pt_index] = BAD_PDE;
+                restore_if(old_if);
+                invlpg(base + offset);
+            } while (++j < n_pages);
+
+            free_user_pages(r->paddr, r->size / PAGE_SIZE);
+            vector_remove(&p->regions, i);
+            mutex_unlock(&p->mm_lock);
+            f->eax = 0;
+            return;
+        }
+    }
+    /* no such region */
+    mutex_unlock(&p->mm_lock);
+    f->eax = (reg_t)-1;
+}