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authorPeter Zijlstra <peterz@infradead.org>2022-03-08 16:30:30 +0100
committerPeter Zijlstra <peterz@infradead.org>2022-03-15 10:32:37 +0100
commitd15cb3dab1e4f00e29599a4f5e1f6678a530d270 (patch)
tree0a1cdf9129615771da2f0f2cabc00274b60e2ce4 /kernel/livepatch
parentaebfd12521d9c7d0b502cf6d06314cfbcdccfe3b (diff)
x86/livepatch: Validate __fentry__ location
Currently livepatch assumes __fentry__ lives at func+0, which is most likely untrue with IBT on. Instead make it use ftrace_location() by default which both validates and finds the actual ip if there is any in the same symbol. Suggested-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lore.kernel.org/r/20220308154318.285971256@infradead.org
Diffstat (limited to 'kernel/livepatch')
-rw-r--r--kernel/livepatch/patch.c19
1 files changed, 2 insertions, 17 deletions
diff --git a/kernel/livepatch/patch.c b/kernel/livepatch/patch.c
index fe316c021d73..c172bf92b576 100644
--- a/kernel/livepatch/patch.c
+++ b/kernel/livepatch/patch.c
@@ -124,19 +124,6 @@ unlock:
ftrace_test_recursion_unlock(bit);
}
-/*
- * Convert a function address into the appropriate ftrace location.
- *
- * Usually this is just the address of the function, but on some architectures
- * it's more complicated so allow them to provide a custom behaviour.
- */
-#ifndef klp_get_ftrace_location
-static unsigned long klp_get_ftrace_location(unsigned long faddr)
-{
- return faddr;
-}
-#endif
-
static void klp_unpatch_func(struct klp_func *func)
{
struct klp_ops *ops;
@@ -153,8 +140,7 @@ static void klp_unpatch_func(struct klp_func *func)
if (list_is_singular(&ops->func_stack)) {
unsigned long ftrace_loc;
- ftrace_loc =
- klp_get_ftrace_location((unsigned long)func->old_func);
+ ftrace_loc = ftrace_location((unsigned long)func->old_func);
if (WARN_ON(!ftrace_loc))
return;
@@ -186,8 +172,7 @@ static int klp_patch_func(struct klp_func *func)
if (!ops) {
unsigned long ftrace_loc;
- ftrace_loc =
- klp_get_ftrace_location((unsigned long)func->old_func);
+ ftrace_loc = ftrace_location((unsigned long)func->old_func);
if (!ftrace_loc) {
pr_err("failed to find location for function '%s'\n",
func->old_name);