mirror of
https://github.com/torvalds/linux.git
synced 2025-10-31 16:48:26 +02:00
7b7b8a2c95
Fix multiple occurrences of duplicated words in kernel/. Fix one typo/spello on the same line as a duplicate word. Change one instance of "the the" to "that the". Otherwise just drop one of the repeated words. Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Link: https://lkml.kernel.org/r/98202fa6-8919-ef63-9efe-c0fad5ca7af1@infradead.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
119 lines
3.1 KiB
C
119 lines
3.1 KiB
C
// 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;
|
|
}
|