Redesign userspace memory management

kernel/amd64/proc.c

@@ -20,7 +20,6 @@ static atomic_int pids = 1;
 
 struct proc* proc_from_elf (uint8_t* elf_contents) {
   struct limine_hhdm_response* hhdm = limine_hhdm_request.response;
-  int rid;
 
   struct proc* proc = malloc (sizeof (*proc));
   if (proc == NULL)
@@ -39,32 +38,11 @@ struct proc* proc_from_elf (uint8_t* elf_contents) {
   }
   procgroup_attach (proc->procgroup, proc);
 
-  rid = procgroup_get_sys_rid (proc->procgroup);
-  struct proc_resource* kstk_r =
-      proc_create_resource_mem (proc->procgroup, rid, KSTACK_SIZE / PAGE_SIZE, 0, false);
-  if (kstk_r == NULL) {
-    procgroup_detach (proc->procgroup, proc);
-    free (proc);
-    return NULL;
-  }
+  uintptr_t kstack_paddr = pmm_alloc (KSTACK_SIZE / PAGE_SIZE);
+  proc->pdata.kernel_stack = kstack_paddr + (uintptr_t)hhdm->offset + KSTACK_SIZE;
 
-  proc->pdata.kernel_stack = kstk_r->u.mem.paddr + (uintptr_t)hhdm->offset + KSTACK_SIZE;
-
-  rid = procgroup_get_sys_rid (proc->procgroup);
-  struct proc_resource* ustk_r =
-      proc_create_resource_mem (proc->procgroup, rid, USTACK_SIZE / PAGE_SIZE, 0, false);
-  if (ustk_r == NULL) {
-    kstk_r->ops.cleanup (kstk_r);
-    free (kstk_r);
-    procgroup_detach (proc->procgroup, proc);
-    free (proc);
-    return NULL;
-  }
-
-  proc->pdata.user_stack = ustk_r->u.mem.paddr;
-
-  proc_map (proc, proc->pdata.user_stack, PROC_USTACK_TOP - USTACK_SIZE, USTACK_SIZE / PAGE_SIZE,
-            MM_PG_USER | MM_PG_PRESENT | MM_PG_RW);
+  procgroup_map (proc->procgroup, PROC_USTACK_TOP - USTACK_SIZE, USTACK_SIZE / PAGE_SIZE,
+                 MM_PG_USER | MM_PG_PRESENT | MM_PG_RW, NULL);
 
   proc->flags |= PROC_USTK_PREALLOC;
 
@@ -83,7 +61,6 @@ struct proc* proc_clone (struct proc* proto, uintptr_t vstack_top, size_t stack_
                          uintptr_t entry) {
   struct limine_hhdm_response* hhdm = limine_hhdm_request.response;
   spin_lock_ctx_t ctxprt;
-  int rid;
 
   struct proc* proc = malloc (sizeof (*proc));
   if (proc == NULL)
@@ -102,27 +79,8 @@ struct proc* proc_clone (struct proc* proto, uintptr_t vstack_top, size_t stack_
 
   spin_unlock (&proto->lock, &ctxprt);
 
-  uintptr_t vstack_bottom = vstack_top - stack_size;
-
-  uintptr_t pstack_bottom = mm_v2p (&proc->procgroup->pd, vstack_bottom, MM_PD_LOCK);
-  if (pstack_bottom == 0) {
-    procgroup_detach (proc->procgroup, proc);
-    free (proc);
-    return NULL;
-  }
-
-  rid = procgroup_get_sys_rid (proc->procgroup);
-  struct proc_resource* kstk_r =
-      proc_create_resource_mem (proc->procgroup, rid, KSTACK_SIZE / PAGE_SIZE, 0, false);
-  if (kstk_r == NULL) {
-    procgroup_detach (proc->procgroup, proc);
-    free (proc);
-    return NULL;
-  }
-
-  proc->pdata.kernel_stack = kstk_r->u.mem.paddr + (uintptr_t)hhdm->offset + KSTACK_SIZE;
-
-  proc->pdata.user_stack = pstack_bottom + stack_size;
+  uintptr_t kstack_paddr = pmm_alloc (KSTACK_SIZE / PAGE_SIZE);
+  proc->pdata.kernel_stack = kstack_paddr + (uintptr_t)hhdm->offset + KSTACK_SIZE;
 
   proc->pdata.regs.ss = GDT_UDATA | 0x03;
   proc->pdata.regs.rsp = (uint64_t)vstack_top;
@@ -161,24 +119,7 @@ void proc_cleanup (struct proc* proc) {
 
   procgroup_detach (proc->procgroup, proc);
 
-  /* clean virtual address space */
-  /* if (atomic_fetch_sub (&proc->pd->refs, 1) == 1) { */
-  /*   DEBUG ("PID %d Free virtual address space\n", proc->pid); */
-  /*   struct list_node_link *mapping_link, *mapping_link_tmp; */
-  /*   spin_lock (&proc->pd->lock, &ctxprpd); */
-
-  /*   list_foreach (proc->mappings, mapping_link, mapping_link_tmp) { */
-  /*     struct proc_mapping* mapping = */
-  /*         list_entry (mapping_link, struct proc_mapping, proc_mappings_link); */
-
-  /*     list_remove (proc->mappings, mapping_link); */
-  /*     free (mapping); */
-  /*   } */
-
-  /*   pmm_free (proc->pd->cr3_paddr, 1); */
-  /*   spin_unlock (&proc->pd->lock, &ctxprpd); */
-  /*   free (proc->pd); */
-  /* } */
+  pmm_free (proc->pdata.kernel_stack, KSTACK_SIZE / PAGE_SIZE);
 
   /* clean the process */
   free (proc);

kernel/amd64/proc.h

@@ -4,15 +4,16 @@
 #include <amd64/intr.h>
 #include <libk/std.h>
 
-/// Top of userspace process' stack
+/* Top of userspace process' stack */
 #define PROC_USTACK_TOP 0x00007FFFFFFFF000ULL
-/// Size of userspace process' stack
+/* Size of userspace process' stack */
 #define USTACK_SIZE (256 * PAGE_SIZE)
+/* proc_map () base address */
+#define PROC_MAP_BASE 0x0000700000000000
 
-/// Platform-dependent process data
+/* Platform-dependent process data */
 struct proc_platformdata {
   struct saved_regs regs;
-  uintptr_t user_stack;
   uintptr_t kernel_stack;
   uint64_t gs_base;
 };

kernel/amd64/syscall.c

@@ -13,7 +13,7 @@
 
 extern void amd64_syscall_entry (void);
 
-int amd64_syscall_dispatch (void* stack_ptr) {
+uintptr_t amd64_syscall_dispatch (void* stack_ptr) {
   spin_lock_ctx_t ctxcpu, ctxpr;
 
   amd64_load_kernel_cr3 ();
@@ -35,8 +35,7 @@ int amd64_syscall_dispatch (void* stack_ptr) {
     return -ST_SYSCALL_NOT_FOUND;
   }
 
-  int result = func (caller, regs, regs->rdi, regs->rsi, regs->rdx, regs->r10, regs->r8, regs->r9);
-  return result;
+  return func (caller, regs, regs->rdi, regs->rsi, regs->rdx, regs->r10, regs->r8, regs->r9);
 }
 
 void syscall_init (void) {