^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1) // SPDX-License-Identifier: GPL-2.0-or-later
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3) * system_state.c - State of the system modified by livepatches
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 4) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 5) * Copyright (C) 2019 SUSE
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 6) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 7)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 8) #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 9)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) #include <linux/livepatch.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) #include "core.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) #include "state.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) #include "transition.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) #define klp_for_each_state(patch, state) \
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) for (state = patch->states; state && state->id; state++)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) * klp_get_state() - get information about system state modified by
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) * the given patch
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) * @patch: livepatch that modifies the given system state
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) * @id: custom identifier of the modified system state
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) * Checks whether the given patch modifies the given system state.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) * The function can be called either from pre/post (un)patch
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) * callbacks or from the kernel code added by the livepatch.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) * Return: pointer to struct klp_state when found, otherwise NULL.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) struct klp_state *klp_get_state(struct klp_patch *patch, unsigned long id)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) struct klp_state *state;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) klp_for_each_state(patch, state) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) if (state->id == id)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) return state;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) return NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) EXPORT_SYMBOL_GPL(klp_get_state);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) * klp_get_prev_state() - get information about system state modified by
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) * the already installed livepatches
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) * @id: custom identifier of the modified system state
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) * Checks whether already installed livepatches modify the given
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) * system state.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) * The same system state can be modified by more non-cumulative
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) * livepatches. It is expected that the latest livepatch has
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) * the most up-to-date information.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) * The function can be called only during transition when a new
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) * livepatch is being enabled or when such a transition is reverted.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) * It is typically called only from pre/post (un)patch
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) * callbacks.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) * Return: pointer to the latest struct klp_state from already
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62) * installed livepatches, NULL when not found.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64) struct klp_state *klp_get_prev_state(unsigned long id)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) struct klp_patch *patch;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) struct klp_state *state, *last_state = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69) if (WARN_ON_ONCE(!klp_transition_patch))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) return NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72) klp_for_each_patch(patch) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73) if (patch == klp_transition_patch)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74) goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76) state = klp_get_state(patch, id);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77) if (state)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78) last_state = state;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81) out:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82) return last_state;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 84) EXPORT_SYMBOL_GPL(klp_get_prev_state);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 85)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 86) /* Check if the patch is able to deal with the existing system state. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 87) static bool klp_is_state_compatible(struct klp_patch *patch,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 88) struct klp_state *old_state)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 89) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 90) struct klp_state *state;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 91)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 92) state = klp_get_state(patch, old_state->id);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 93)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 94) /* A cumulative livepatch must handle all already modified states. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 95) if (!state)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 96) return !patch->replace;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 97)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 98) return state->version >= old_state->version;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 99) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) * Check that the new livepatch will not break the existing system states.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) * Cumulative patches must handle all already modified states.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) * Non-cumulative patches can touch already modified states.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) bool klp_is_patch_compatible(struct klp_patch *patch)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) struct klp_patch *old_patch;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) struct klp_state *old_state;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) klp_for_each_patch(old_patch) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) klp_for_each_state(old_patch, old_state) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) if (!klp_is_state_compatible(patch, old_state))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) return false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) return true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) }
Orange Pi5 kernel
Deprecated Linux kernel 5.10.110 for OrangePi 5/5B/5+ boards
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