From: Peter Zijlstra <peterz@infradead.org>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Jiri Olsa <olsajiri@gmail.com>, Song Liu <song@kernel.org>,
Song Liu <songliubraving@meta.com>,
Paul Walmsley <paul.walmsley@sifive.com>,
Palmer Dabbelt <palmer@dabbelt.com>,
Albert Ou <aou@eecs.berkeley.edu>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
X86 ML <x86@kernel.org>, "H. Peter Anvin" <hpa@zytor.com>,
"David S. Miller" <davem@davemloft.net>,
David Ahern <dsahern@kernel.org>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>,
Martin KaFai Lau <martin.lau@linux.dev>,
Yonghong Song <yonghong.song@linux.dev>,
John Fastabend <john.fastabend@gmail.com>,
KP Singh <kpsingh@kernel.org>,
Stanislav Fomichev <sdf@google.com>, Hao Luo <haoluo@google.com>,
Arnd Bergmann <arnd@arndb.de>,
Sami Tolvanen <samitolvanen@google.com>,
Kees Cook <keescook@chromium.org>,
Nathan Chancellor <nathan@kernel.org>,
Nick Desaulniers <ndesaulniers@google.com>,
linux-riscv <linux-riscv@lists.infradead.org>,
LKML <linux-kernel@vger.kernel.org>,
Network Development <netdev@vger.kernel.org>,
bpf <bpf@vger.kernel.org>,
linux-arch <linux-arch@vger.kernel.org>,
clang-built-linux <llvm@lists.linux.dev>,
Josh Poimboeuf <jpoimboe@kernel.org>,
Joao Moreira <joao@overdrivepizza.com>,
Mark Rutland <mark.rutland@arm.com>
Subject: Re: [PATCH v2 2/2] x86/cfi,bpf: Fix BPF JIT call
Date: Fri, 8 Dec 2023 21:52:41 +0100 [thread overview]
Message-ID: <20231208205241.GK28727@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <CAADnVQJzCw=qcG+jHBYG0q0SxLPkwghni0wpgV4A4PkpgVbGPw@mail.gmail.com>
On Fri, Dec 08, 2023 at 12:41:03PM -0800, Alexei Starovoitov wrote:
> On Fri, Dec 8, 2023 at 12:35 PM Peter Zijlstra <peterz@infradead.org> wrote:
> > -__bpf_kfunc void bpf_task_release(struct task_struct *p)
> > +__bpf_kfunc void bpf_task_release(void *p)
>
> Yeah. That won't work. We need a wrapper.
> Since bpf prog is also calling it directly.
> In progs/task_kfunc_common.h
> void bpf_task_release(struct task_struct *p) __ksym;
>
> than later both libbpf and the verifier check that
> what bpf prog is calling actually matches the proto
> of what is in the kernel.
> Effectively we're doing strong prototype check at load time.
I'm still somewhat confused on how this works, where does BPF get the
address of the function from? and what should I call the wrapper?
> btw instead of EXPORT_SYMBOL_GPL(bpf_task_release)
> can __ADDRESSABLE be used ?
> Since it's not an export symbol.
No __ADDRESSABLE() is expressly ignored, but we have IBT_NOSEAL() that
should do it. I'll rename the thing and lift it out of x86 to avoid
breaking all other arch builds.
next prev parent reply other threads:[~2023-12-08 20:53 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-30 13:36 [PATCH v2 0/2] x86/bpf: Fix FineIBT vs eBPF Peter Zijlstra
2023-11-30 13:36 ` [PATCH v2 1/2] cfi: Flip headers Peter Zijlstra
2023-12-04 19:18 ` Sami Tolvanen
2023-11-30 13:36 ` [PATCH v2 2/2] x86/cfi,bpf: Fix BPF JIT call Peter Zijlstra
2023-12-03 22:56 ` Alexei Starovoitov
2023-12-04 9:13 ` Peter Zijlstra
2023-12-04 11:11 ` Peter Zijlstra
2023-12-04 12:52 ` Peter Zijlstra
2023-12-04 17:25 ` Jiri Olsa
2023-12-04 18:16 ` Peter Zijlstra
2023-12-04 18:33 ` Peter Zijlstra
2023-12-04 18:58 ` Sami Tolvanen
2023-12-05 1:18 ` Alexei Starovoitov
2023-12-06 15:35 ` Peter Zijlstra
2023-12-06 16:38 ` Peter Zijlstra
2023-12-06 18:37 ` Peter Zijlstra
2023-12-06 21:39 ` Alexei Starovoitov
2023-12-07 9:31 ` Peter Zijlstra
2023-12-07 22:32 ` Alexei Starovoitov
2023-12-08 10:29 ` Peter Zijlstra
2023-12-08 13:40 ` Peter Zijlstra
2023-12-08 17:21 ` Peter Zijlstra
2023-12-08 19:40 ` Alexei Starovoitov
2023-12-08 20:27 ` Peter Zijlstra
2023-12-08 20:35 ` Peter Zijlstra
2023-12-08 20:41 ` Alexei Starovoitov
2023-12-08 20:52 ` Peter Zijlstra [this message]
2023-12-08 20:58 ` Alexei Starovoitov
2023-12-08 22:45 ` Peter Zijlstra
2023-12-09 4:51 ` Alexei Starovoitov
2023-12-08 19:32 ` Alexei Starovoitov
2023-12-08 20:18 ` Peter Zijlstra
2023-12-08 20:45 ` Alexei Starovoitov
2023-12-08 20:56 ` Peter Zijlstra
2023-12-08 21:04 ` Alexei Starovoitov
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