pretty massive virtual memory rewrite

+ The system is now a bit simpler and hopefully easier to understand, while also
  extending the shared memory to be 1:N, where there is one owner who
  may become a zombie while waiting for the N to die.

3 files changed, 21 insertions, 8 deletions

diff --git a/arch/riscv64/kernel/entry.S b/arch/riscv64/kernel/entry.S
index 1680a35..e37d5cc 100644
--- a/arch/riscv64/kernel/entry.S
+++ b/arch/riscv64/kernel/entry.S
@@ -104,6 +104,13 @@ handle_exception:
 	save_regs
 	save_args
 
+	csrr a0, CSR_SEPC
+	csrr a1, CSR_STVAL
+	/* not really a kernel panic but used for now to signify that something
+	 * happened in userspace that we can't deal with */
+	csrr a2, CSR_SCAUSE
+	call kernel_panic
+
 	j	_load_context
 
 handle_dispatch:
diff --git a/arch/riscv64/kernel/proc.c b/arch/riscv64/kernel/proc.c
index 0c43b3d..f1a62c4 100644
--- a/arch/riscv64/kernel/proc.c
+++ b/arch/riscv64/kernel/proc.c
@@ -83,7 +83,7 @@ vm_t get_stack(struct tcb *t)
 	return r->sp;
 }
 
-void clone_regs(struct tcb *d, struct tcb *s)
+void copy_regs(struct tcb *d, struct tcb *s)
 {
 	struct riscv_regs *rd = (struct riscv_regs *)(d->regs) - 1;
 	struct riscv_regs *rs = (struct riscv_regs *)(s->regs) - 1;
diff --git a/arch/riscv64/kernel/vmem.c b/arch/riscv64/kernel/vmem.c
index 3f29446..f717771 100644
--- a/arch/riscv64/kernel/vmem.c
+++ b/arch/riscv64/kernel/vmem.c
@@ -236,6 +236,9 @@ stat_t stat_vpage(struct vmem *branch, vm_t vaddr, pm_t *paddr,
 static struct vmem *__create_leaf()
 {
 	pm_t new_leaf = alloc_page(MM_KPAGE);
+	if (!new_leaf)
+		return NULL;
+
 	memset((void *)new_leaf, 0, sizeof(struct vmem));
 	return (struct vmem *)to_pte((pm_t)__pa(new_leaf), VM_V);
 }
@@ -293,8 +296,13 @@ stat_t map_vpage(struct vmem *branch, pm_t paddr, vm_t vaddr, vmflags_t flags,
 	while (top != order) {
 		size_t idx = vm_to_index(vaddr, top);
 
-		if (__unused((pm_t)branch->leaf[idx]))
-			branch->leaf[idx] = __create_leaf();
+		if (__unused((pm_t)branch->leaf[idx])) {
+			struct vmem *leaf = __create_leaf();
+			if (!leaf)
+				return ERR_OOMEM;
+
+			branch->leaf[idx] = leaf;
+		}
 
 		branch = (struct vmem *)pte_addr(branch->leaf[idx]);
 		top--;
@@ -438,16 +446,14 @@ struct vmem *create_vmem()
 	return b;
 }
 
-stat_t use_vmem(struct vmem *b)
+void use_vmem(struct vmem *b)
 {
 	__use_vmem(__pa(b), DEFAULT_Sv_MODE);
-	return OK;
 }
 
-stat_t destroy_vmem(struct vmem *b)
+void destroy_vmem(struct vmem *b)
 {
 	__destroy_branch(b);
-	return OK;
 }
 
 stat_t populate_kvmem(struct vmem *b)
@@ -541,7 +547,7 @@ void destroy_rpc_stack(struct tcb *t)
 		pm_t page = 0; enum mm_order order = BASE_PAGE;
 		stat_vpage(t->rpc.vmem, RPC_STACK_BASE + BASE_PAGE_SIZE * i,
 		           &page, &order, NULL);
-		free_page(page, order);
+		free_page(order, page);
 	}
 }