On Fri, Nov 14, 2025 at 1:25 AM Menglong Dong <[email protected]> wrote: > > In the origin call case, if BPF_TRAMP_F_SKIP_FRAME is not set, it means > that the trampoline is not called, but "jmp". > > Introduce the function bpf_trampoline_need_jmp() to check if the > trampoline is in "jmp" mode. > > Do some adjustment on the "jmp" mode for the x86_64. The main adjustment > that we make is for the stack parameter passing case, as the stack > alignment logic changes in the "jmp" mode without the "rip". What's more, > the location of the parameters on the stack also changes. > > Signed-off-by: Menglong Dong <[email protected]> > --- > arch/x86/net/bpf_jit_comp.c | 15 ++++++++++----- > include/linux/bpf.h | 12 ++++++++++++ > 2 files changed, 22 insertions(+), 5 deletions(-) > > diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c > index 2d300ab37cdd..21ce2b8457ec 100644 > --- a/arch/x86/net/bpf_jit_comp.c > +++ b/arch/x86/net/bpf_jit_comp.c > @@ -2830,7 +2830,7 @@ static int get_nr_used_regs(const struct btf_func_model > *m) > } > > static void save_args(const struct btf_func_model *m, u8 **prog, > - int stack_size, bool for_call_origin) > + int stack_size, bool for_call_origin, bool jmp)
I have an allergy to bool args. Please pass flags and do boll jmp_based_tramp = bpf_trampoline_uses_jmp(flags); I think bpf_trampoline_uses_jmp() is more descriptive than bpf_trampoline_need_jmp(). The actual math lgtm.
