From ca45c84afb8c91a8d688b0012657099c24f59266 Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Wed, 3 Dec 2025 19:32:15 -0800 Subject: bpf: Add bpf_has_frame_pointer() Introduce a bpf_has_frame_pointer() helper that unwinders can call to determine whether a given instruction pointer is within the valid frame pointer region of a BPF JIT program or trampoline (i.e., after the prologue, before the epilogue). This will enable livepatch (with the ORC unwinder) to reliably unwind through BPF JIT frames. Acked-by: Song Liu Acked-and-tested-by: Andrey Grodzovsky Signed-off-by: Josh Poimboeuf Link: https://lore.kernel.org/r/fd2bc5b4e261a680774b28f6100509fd5ebad2f0.1764818927.git.jpoimboe@kernel.org Signed-off-by: Alexei Starovoitov Reviewed-by: Jiri Olsa --- kernel/bpf/core.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'kernel/bpf/core.c') diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index c8ae6ab31651..1b9b18e5b03c 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -760,6 +760,22 @@ struct bpf_prog *bpf_prog_ksym_find(unsigned long addr) NULL; } +bool bpf_has_frame_pointer(unsigned long ip) +{ + struct bpf_ksym *ksym; + unsigned long offset; + + guard(rcu)(); + + ksym = bpf_ksym_find(ip); + if (!ksym || !ksym->fp_start || !ksym->fp_end) + return false; + + offset = ip - ksym->start; + + return offset >= ksym->fp_start && offset < ksym->fp_end; +} + const struct exception_table_entry *search_bpf_extables(unsigned long addr) { const struct exception_table_entry *e = NULL; -- cgit