1 files changed, 79 insertions, 0 deletions
diff --git a/arch/um/kernel/skas/mmu.c b/arch/um/kernel/skas/mmu.c
new file mode 100644
index 000000000..125df465e
--- /dev/null
+++ b/arch/um/kernel/skas/mmu.c
@@ -0,0 +1,79 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2015 Thomas Meyer (thomas@m3y3r.de)
+ * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
+ */
+
+#include <linux/mm.h>
+#include <linux/sched/signal.h>
+#include <linux/slab.h>
+
+#include <asm/pgalloc.h>
+#include <asm/sections.h>
+#include <as-layout.h>
+#include <os.h>
+#include <skas.h>
+
+int init_new_context(struct task_struct *task, struct mm_struct *mm)
+{
+ 	struct mm_context *from_mm = NULL;
+	struct mm_context *to_mm = &mm->context;
+	unsigned long stack = 0;
+	int ret = -ENOMEM;
+
+	stack = get_zeroed_page(GFP_KERNEL);
+	if (stack == 0)
+		goto out;
+
+	to_mm->id.stack = stack;
+	if (current->mm != NULL && current->mm != &init_mm)
+		from_mm = &current->mm->context;
+
+	block_signals_trace();
+	if (from_mm)
+		to_mm->id.u.pid = copy_context_skas0(stack,
+						     from_mm->id.u.pid);
+	else to_mm->id.u.pid = start_userspace(stack);
+	unblock_signals_trace();
+
+	if (to_mm->id.u.pid < 0) {
+		ret = to_mm->id.u.pid;
+		goto out_free;
+	}
+
+	ret = init_new_ldt(to_mm, from_mm);
+	if (ret < 0) {
+		printk(KERN_ERR "init_new_context_skas - init_ldt"
+		       " failed, errno = %d\n", ret);
+		goto out_free;
+	}
+
+	return 0;
+
+ out_free:
+	if (to_mm->id.stack != 0)
+		free_page(to_mm->id.stack);
+ out:
+	return ret;
+}
+
+void destroy_context(struct mm_struct *mm)
+{
+	struct mm_context *mmu = &mm->context;
+
+	/*
+	 * If init_new_context wasn't called, this will be
+	 * zero, resulting in a kill(0), which will result in the
+	 * whole UML suddenly dying.  Also, cover negative and
+	 * 1 cases, since they shouldn't happen either.
+	 */
+	if (mmu->id.u.pid < 2) {
+		printk(KERN_ERR "corrupt mm_context - pid = %d\n",
+		       mmu->id.u.pid);
+		return;
+	}
+	os_kill_ptraced_process(mmu->id.u.pid, 1);
+
+	free_page(mmu->id.stack);
+	free_ldt(mmu);
+}