[PATCH bpf-next v6 0/7] Mixing bpf2bpf and tailcalls for RV64
patchwork-bot+netdevbpf at kernel.org
patchwork-bot+netdevbpf at kernel.org
Tue Jul 21 11:30:18 PDT 2026
Hello:
This series was applied to bpf/bpf-next.git (master)
by Kumar Kartikeya Dwivedi <memxor at gmail.com>:
On Wed, 8 Jul 2026 06:44:29 +0000 you wrote:
> In the current RV64 JIT, if we just don't initialize the TCC in subprog,
> the TCC can be propagated from the parent process to the subprocess, but
> the updated TCC of the parent process cannot be restored when the
> subprocess exits. Since the RV64 TCC is initialized before saving the
> callee saved registers into the stack, we cannot use the callee saved
> register to pass the TCC, otherwise the original value of the callee
> saved register will be destroyed. So we implemented mixing bpf2bpf and
> tailcalls similar to x86_64, i.e. using a non-callee saved register to
> transfer the TCC between functions, and saving that register to the
> stack to protect the TCC value. As for the tailcall hierarchy issue,
> inspired by the s390's low-overhead approach, we store TCC from
> RV_REG_TCC back to stack after calling bpf2bpf call or calling orig bpf
> func in bpf trampoline.
>
> [...]
Here is the summary with links:
- [bpf-next,v6,1/7] bpf: Extract the is_struct_ops_tramp helper
https://git.kernel.org/bpf/bpf-next/c/6bcecae4b65d
- [bpf-next,v6,2/7] riscv, bpf: Fix memory leak in bpf_jit_free
https://git.kernel.org/bpf/bpf-next/c/369e4635d048
- [bpf-next,v6,3/7] riscv, bpf: Using kvzalloc_objs to allocate cache buffer
https://git.kernel.org/bpf/bpf-next/c/f3ab878594b5
- [bpf-next,v6,4/7] riscv, bpf: Fix kernel stack corruption in tailcall with CFI
https://git.kernel.org/bpf/bpf-next/c/52fb1756ea1d
- [bpf-next,v6,5/7] riscv, bpf: Add RV_TAILCALL_OFFSET macro to format tailcall offset
https://git.kernel.org/bpf/bpf-next/c/a21731f54cfe
- [bpf-next,v6,6/7] riscv, bpf: Mixing bpf2bpf and tailcalls
https://git.kernel.org/bpf/bpf-next/c/ec72848ca0ad
- [bpf-next,v6,7/7] selftests/bpf: Remove tailcalls tests from DENYLIST.riscv64
https://git.kernel.org/bpf/bpf-next/c/683ed8b78c1d
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