diff options
| author | Peter Zijlstra | 2022-03-08 16:30:29 +0100 |
|---|---|---|
| committer | Peter Zijlstra | 2022-03-15 10:32:37 +0100 |
| commit | aebfd12521d9c7d0b502cf6d06314cfbcdccfe3b (patch) | |
| tree | 32b122cd707b1a26aef2d1ac5612f013ee2821e4 /kernel/bpf | |
| parent | 6649fa876da4c505548b8e8945a6fc48e62e427c (diff) | |
x86/ibt,ftrace: Search for __fentry__ location
Currently a lot of ftrace code assumes __fentry__ is at sym+0. However
with Intel IBT enabled the first instruction of a function will most
likely be ENDBR.
Change ftrace_location() to not only return the __fentry__ location
when called for the __fentry__ location, but also when called for the
sym+0 location.
Then audit/update all callsites of this function to consistently use
these new semantics.
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20220308154318.227581603@infradead.org
Diffstat (limited to 'kernel/bpf')
| -rw-r--r-- | kernel/bpf/trampoline.c | 20 |
1 files changed, 4 insertions, 16 deletions
diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c index 5e7edf913060..455f1b4f312e 100644 --- a/kernel/bpf/trampoline.c +++ b/kernel/bpf/trampoline.c @@ -117,18 +117,6 @@ static void bpf_trampoline_module_put(struct bpf_trampoline *tr) tr->mod = NULL; } -static int is_ftrace_location(void *ip) -{ - long addr; - - addr = ftrace_location((long)ip); - if (!addr) - return 0; - if (WARN_ON_ONCE(addr != (long)ip)) - return -EFAULT; - return 1; -} - static int unregister_fentry(struct bpf_trampoline *tr, void *old_addr) { void *ip = tr->func.addr; @@ -160,12 +148,12 @@ static int modify_fentry(struct bpf_trampoline *tr, void *old_addr, void *new_ad static int register_fentry(struct bpf_trampoline *tr, void *new_addr) { void *ip = tr->func.addr; + unsigned long faddr; int ret; - ret = is_ftrace_location(ip); - if (ret < 0) - return ret; - tr->func.ftrace_managed = ret; + faddr = ftrace_location((unsigned long)ip); + if (faddr) + tr->func.ftrace_managed = true; if (bpf_trampoline_module_get(tr)) return -ENOENT; |