[PATCH v3 4/6] powerpc64/bpf: Add arch_bpf_stack_walk() for BPF JIT
From: <hidden>
Date: 2026-01-22 16:59:18
Also in:
linux-kselftest, linuxppc-dev, lkml
Subsystem:
bpf jit for powerpc (32-bit and 64-bit), bpf [general] (safe dynamic programs and tools), linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Hari Bathini, Christophe Leroy, Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Madhavan Srinivasan, Michael Ellerman, Linus Torvalds
From: Abhishek Dubey <redacted> This function is used by bpf_throw() to unwind the stack until frame of exception-boundary during BPF exception handling. This function is necessary to support BPF exceptions on PowerPC. Signed-off-by: Abhishek Dubey <redacted> --- arch/powerpc/net/bpf_jit_comp64.c | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+)
diff --git a/arch/powerpc/net/bpf_jit_comp64.c b/arch/powerpc/net/bpf_jit_comp64.c
index 18da5a866447..c25ba1ad587a 100644
--- a/arch/powerpc/net/bpf_jit_comp64.c
+++ b/arch/powerpc/net/bpf_jit_comp64.c@@ -247,6 +247,34 @@ void bpf_jit_build_epilogue(u32 *image, struct codegen_context *ctx) bpf_jit_build_fentry_stubs(image, ctx); } +void arch_bpf_stack_walk(bool (*consume_fn)(void *, u64, u64, u64), void *cookie) +{ + // callback processing always in current context + unsigned long fp = current_stack_frame(); + + for (;;) { + unsigned long *frame = (unsigned long *) fp; + unsigned long ip; + + if (!validate_sp(fp, current)) + return; + + ip = frame[STACK_FRAME_LR_SAVE]; + if (!ip) + break; + + /* + * consume_fn common code expects stack pointer(sp) in third + * argument. There is no sp in ppc64, rather pass frame + * pointer. + */ + if (ip && !consume_fn(cookie, ip, fp, fp)) + break; + + fp = frame[0]; + } +} + int bpf_jit_emit_func_call_rel(u32 *image, u32 *fimage, struct codegen_context *ctx, u64 func) { unsigned long func_addr = func ? ppc_function_entry((void *)func) : 0;
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2.48.1