#include <asm/cacheflush.h>
#include "core.h"
#include "patch.h"
+#include "state.h"
#include "transition.h"
/*
mutex_lock(&klp_mutex);
+ if (!klp_is_patch_compatible(patch)) {
+ pr_err("Livepatch patch (%s) is not compatible with the already installed livepatches.\n",
+ patch->mod->name);
+ mutex_unlock(&klp_mutex);
+ return -EINVAL;
+ }
+
ret = klp_init_patch_early(patch);
if (ret) {
mutex_unlock(&klp_mutex);
#include <linux/livepatch.h>
#include "core.h"
+#include "state.h"
#include "transition.h"
#define klp_for_each_state(patch, state) \
return last_state;
}
EXPORT_SYMBOL_GPL(klp_get_prev_state);
+
+/* Check if the patch is able to deal with the existing system state. */
+static bool klp_is_state_compatible(struct klp_patch *patch,
+ struct klp_state *old_state)
+{
+ struct klp_state *state;
+
+ state = klp_get_state(patch, old_state->id);
+
+ /* A cumulative livepatch must handle all already modified states. */
+ if (!state)
+ return !patch->replace;
+
+ return state->version >= old_state->version;
+}
+
+/*
+ * Check that the new livepatch will not break the existing system states.
+ * Cumulative patches must handle all already modified states.
+ * Non-cumulative patches can touch already modified states.
+ */
+bool klp_is_patch_compatible(struct klp_patch *patch)
+{
+ struct klp_patch *old_patch;
+ struct klp_state *old_state;
+
+ klp_for_each_patch(old_patch) {
+ klp_for_each_state(old_patch, old_state) {
+ if (!klp_is_state_compatible(patch, old_state))
+ return false;
+ }
+ }
+
+ return true;
+}
--- /dev/null
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LIVEPATCH_STATE_H
+#define _LIVEPATCH_STATE_H
+
+#include <linux/livepatch.h>
+
+bool klp_is_patch_compatible(struct klp_patch *patch);
+
+#endif /* _LIVEPATCH_STATE_H */