Messages in this thread | | | Date | Fri, 13 Nov 2015 18:39:33 -0800 | Subject | Re: [PATCH V3 2/2] arm64: bpf: make BPF prologue and epilogue align with ARM64 AAPCS | From | Z Lim <> |
| |
Yang, I noticed another thing...
On Fri, Nov 13, 2015 at 10:09 AM, Yang Shi <yang.shi@linaro.org> wrote: > Save and restore FP/LR in BPF prog prologue and epilogue, save SP to FP > in prologue in order to get the correct stack backtrace. > > However, ARM64 JIT used FP (x29) as eBPF fp register, FP is subjected to > change during function call so it may cause the BPF prog stack base address > change too. > > Use x25 to replace FP as BPF stack base register (fp). Since x25 is callee > saved register, so it will keep intact during function call.
Can you please add save/restore for x25 also? :)
> It is initialized in BPF prog prologue when BPF prog is started to run > everytime. When BPF prog exits, it could be just tossed. >
| |