x86/ibt,ftrace: Search for __fentry__ location

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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

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This commit is contained in:

Peter Zijlstra 2022-03-08 16:30:29 +01:00

parent 6649fa876d

commit aebfd12521

4 changed files with 48 additions and 39 deletions

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11

arch/x86/kernel/kprobes/core.c

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20

kernel/bpf/trampoline.c

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8

kernel/kprobes.c

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48

kernel/trace/ftrace.c

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