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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120// SPDX-License-Identifier: GPL-2.0-or-later/* * system_state.c - State of the system modified by livepatches * * Copyright (C) 2019 SUSE */
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/livepatch.h>#include "core.h"#include "state.h"#include "transition.h"
#define klp_for_each_state(patch, state) \ for (state = patch->states; state && state->id; state++)
/** * klp_get_state() - get information about system state modified by * the given patch * @patch: livepatch that modifies the given system state * @id: custom identifier of the modified system state * * Checks whether the given patch modifies the given system state. * * The function can be called either from pre/post (un)patch * callbacks or from the kernel code added by the livepatch. * * Return: pointer to struct klp_state when found, otherwise NULL. */struct klp_state *klp_get_state(struct klp_patch *patch, unsigned long id){ struct klp_state *state;
klp_for_each_state(patch, state) { if (state->id == id) return state; }
return NULL;}EXPORT_SYMBOL_GPL(klp_get_state);
/** * klp_get_prev_state() - get information about system state modified by * the already installed livepatches * @id: custom identifier of the modified system state * * Checks whether already installed livepatches modify the given * system state. * * The same system state can be modified by more non-cumulative * livepatches. It is expected that the latest livepatch has * the most up-to-date information. * * The function can be called only during transition when a new * livepatch is being enabled or when such a transition is reverted. * It is typically called only from pre/post (un)patch * callbacks. * * Return: pointer to the latest struct klp_state from already * installed livepatches, NULL when not found. */struct klp_state *klp_get_prev_state(unsigned long id){ struct klp_patch *patch; struct klp_state *state, *last_state = NULL;
if (WARN_ON_ONCE(!klp_transition_patch)) return NULL;
klp_for_each_patch(patch) { if (patch == klp_transition_patch) goto out;
state = klp_get_state(patch, id); if (state) last_state = state; }
out: 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;}