1 files changed, 132 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/ima_kexec.c b/arch/powerpc/kernel/ima_kexec.c
new file mode 100644
index 000000000000..36e5a5df3804
--- /dev/null
+++ b/arch/powerpc/kernel/ima_kexec.c
@@ -0,0 +1,132 @@
+/*
+ * Copyright (C) 2016 IBM Corporation
+ *
+ * Authors:
+ * Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/slab.h>
+#include <linux/kexec.h>
+#include <linux/of.h>
+#include <linux/memblock.h>
+#include <linux/libfdt.h>
+
+static int get_addr_size_cells(int *addr_cells, int *size_cells)
+{
+        struct device_node *root;
+
+        root = of_find_node_by_path("/");
+        if (!root)
+                return -EINVAL;
+
+        *addr_cells = of_n_addr_cells(root);
+        *size_cells = of_n_size_cells(root);
+
+        of_node_put(root);
+
+        return 0;
+}
+
+static int do_get_kexec_buffer(const void *prop, int len, unsigned long *addr,
+                               size_t *size)
+{
+        int ret, addr_cells, size_cells;
+
+        ret = get_addr_size_cells(&addr_cells, &size_cells);
+        if (ret)
+                return ret;
+
+        if (len < 4 * (addr_cells + size_cells))
+                return -ENOENT;
+
+        *addr = of_read_number(prop, addr_cells);
+        *size = of_read_number(prop + 4 * addr_cells, size_cells);
+
+        return 0;
+}
+
+/**
+ * ima_get_kexec_buffer - get IMA buffer from the previous kernel
+ * @addr:       On successful return, set to point to the buffer contents.
+ * @size:       On successful return, set to the buffer size.
+ *
+ * Return: 0 on success, negative errno on error.
+ */
+int ima_get_kexec_buffer(void **addr, size_t *size)
+{
+        int ret, len;
+        unsigned long tmp_addr;
+        size_t tmp_size;
+        const void *prop;
+
+        prop = of_get_property(of_chosen, "linux,ima-kexec-buffer", &len);
+        if (!prop)
+                return -ENOENT;
+
+        ret = do_get_kexec_buffer(prop, len, &tmp_addr, &tmp_size);
+        if (ret)
+                return ret;
+
+        *addr = __va(tmp_addr);
+        *size = tmp_size;
+
+        return 0;
+}
+
+/**
+ * ima_free_kexec_buffer - free memory used by the IMA buffer
+ */
+int ima_free_kexec_buffer(void)
+{
+        int ret;
+        unsigned long addr;
+        size_t size;
+        struct property *prop;
+
+        prop = of_find_property(of_chosen, "linux,ima-kexec-buffer", NULL);
+        if (!prop)
+                return -ENOENT;
+
+        ret = do_get_kexec_buffer(prop->value, prop->length, &addr, &size);
+        if (ret)
+                return ret;
+
+        ret = of_remove_property(of_chosen, prop);
+        if (ret)
+                return ret;
+
+        return memblock_free(addr, size);
+
+}
+
+/**
+ * remove_ima_buffer - remove the IMA buffer property and reservation from @fdt
+ *
+ * The IMA measurement buffer is of no use to a subsequent kernel, so we always
+ * remove it from the device tree.
+ */
+void remove_ima_buffer(void *fdt, int chosen_node)
+{
+        int ret, len;
+        unsigned long addr;
+        size_t size;
+        const void *prop;
+
+        prop = fdt_getprop(fdt, chosen_node, "linux,ima-kexec-buffer", &len);
+        if (!prop)
+                return;
+
+        ret = do_get_kexec_buffer(prop, len, &addr, &size);
+        fdt_delprop(fdt, chosen_node, "linux,ima-kexec-buffer");
+        if (ret)
+                return;
+
+        ret = delete_fdt_mem_rsv(fdt, addr, size);
+        if (!ret)
+                pr_debug("Removed old IMA buffer reservation.\n");
+}