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[176.36.0.241]) by smtp.gmail.com with ESMTPSA id g18-20020a2eb5d2000000b002ca013cb05csm922433ljn.79.2023.12.05.15.21.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 05 Dec 2023 15:21:35 -0800 (PST) Message-ID: Subject: Re: [PATCH bpf-next 05/13] bpf: abstract away global subprog arg preparation logic from reg state setup From: Eduard Zingerman To: Andrii Nakryiko , bpf@vger.kernel.org, ast@kernel.org, daniel@iogearbox.net, martin.lau@kernel.org Cc: kernel-team@meta.com Date: Wed, 06 Dec 2023 01:21:34 +0200 In-Reply-To: <20231204233931.49758-6-andrii@kernel.org> References: <20231204233931.49758-1-andrii@kernel.org> <20231204233931.49758-6-andrii@kernel.org> Autocrypt: addr=eddyz87@gmail.com; prefer-encrypt=mutual; keydata=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 nYzhLWGcczc6J71q1Dje0l5vIPaSFOgwmWD4DA+WvuxM/shH4rtWeodbv iCTce6yYIygHgUAtJcHozAlgRrL0jz44cggBTcoeXp/atckXK546OugZPnl00J3qmm5uWAznU6T5YDv2vCvAMEbz69ib+kHtnOSBvR0Jb86UZZqSb4ATfwMOWe9htGTjKMb0QQOLK0mTcrk/TtymaG+T4Fsos0kgrxqjgfrxxEhYcVNW8v8HISmFGFbqsJmFbVtgk68BcU0wgF8oFxo7u+XYQDdKbI1uQGNBGKNNQEBDADbQIdo8L3sdSWGQtu+LnFqCZoAbYurZCmUjLV3df1b+sg+GJZvVTmMZnzDP/ADufcbjopBBjGTRAY4L76T2niu2EpjclMMM3mtrOc738Kr3+RvPjUupdkZ1ZEZaWpf4cZm+4wH5GUfyu5pmD5WXX2i1r9XaUjeVtebvbuXWmWI1ZDTfOkiz/6Z0GDSeQeEqx2PXYBcepU7S9UNWttDtiZ0+IH4DZcvyKPUcK3tOj4u8GvO3RnOrglERzNCM/WhVdG1+vgU9fXO83TB/PcfAsvxYSie7u792s/I+yA4XKKh82PSTvTzg2/4vEDGpI9yubkfXRkQN28w+HKF5qoRB8/L1ZW/brlXkNzA6SveJhCnH7aOF0Yezl6TfX27w1CW5Xmvfi7X33V/SPvo0tY1THrO1c+bOjt5F+2/K3tvejmXMS/I6URwa8n1e767y5ErFKyXAYRweE9zarEgpNZTuSIGNNAqK+SiLLXt51G7P30TVavIeB6s2lCt1QKt62ccLqUAEQEAAYkBvAQYAQoAJhYhBMfui64wKUMqp1wmBC4MZXpJYEQJBQJijTUBAhsMBQkDwmcAAAoJEC4MZXpJYEQJkRAMAKNvWVwtXm/WxWoiLnXyF2WGXKoDe5+itTLvBmKcV/b1OKZF1s90V7WfSBz712eFAynEzyeezPbwU8QBiTpZcHXwQni3IYKvsh7s t1iq+gsfnXbPz5AnS598ScZI1oP7OrPSFJkt/z4acEbOQDQs8aUqrd46PV jsdqGvKnXZxzylux29UTNby4jTlz9pNJM+wPrDRmGfchLDUmf6CffaUYCbu4FiId+9+dcTCDvxbABRy1C3OJ8QY7cxfJ+pEZW18fRJ0XCl/fiV/ecAOfB3HsqgTzAn555h0rkFgay0hAvMU/mAW/CFNSIxV397zm749ZNLA0L2dMy1AKuOqH+/B+/ImBfJMDjmdyJQ8WU/OFRuGLdqOd2oZrA1iuPIa+yUYyZkaZfz/emQwpIL1+Q4p1R/OplA4yc301AqruXXUcVDbEB+joHW3hy5FwK5t5OwTKatrSJBkydSF9zdXy98fYzGniRyRA65P0Ix/8J3BYB4edY2/w0Ip/mdYsYQljBY0A== Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.50.1 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Mon, 2023-12-04 at 15:39 -0800, Andrii Nakryiko wrote: Acked-by: Eduard Zingerman [...] > diff --git a/include/linux/bpf.h b/include/linux/bpf.h > index 379ac0a28405..c3a5d0fe3cdf 100644 > --- a/include/linux/bpf.h > +++ b/include/linux/bpf.h > @@ -704,6 +704,7 @@ enum bpf_arg_type { > =20 > ARG_PTR_TO_CTX, /* pointer to context */ > ARG_ANYTHING, /* any (initialized) argument is ok */ > + ARG_SCALAR =3D ARG_ANYTHING, /* scalar value */ Nit: I agree that use of ARG_ANYTHING to denote scalars is confusing, but having two names for the same thing seems even more confusing. [...] > diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c > index d56433bf8aba..33a62df9c5a8 100644 > --- a/kernel/bpf/btf.c > +++ b/kernel/bpf/btf.c > @@ -6955,9 +6955,9 @@ int btf_check_subprog_call(struct bpf_verifier_env = *env, int subprog, > * 0 - Successfully converted BTF into bpf_reg_state > * (either PTR_TO_CTX or SCALAR_VALUE). > */ > -int btf_prepare_func_args(struct bpf_verifier_env *env, int subprog, > - struct bpf_reg_state *regs, u32 *arg_cnt) > +int btf_prepare_func_args(struct bpf_verifier_env *env, int subprog) Could you please also update the comment above this function? It currently says: "Convert BTF of a function into bpf_reg_state if possibl= e". [...] > diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c > index ee707736ce6b..16d5550eda4d 100644 > --- a/kernel/bpf/verifier.c > +++ b/kernel/bpf/verifier.c [...] > @@ -19860,33 +19855,44 @@ static int do_check_common(struct bpf_verifier_= env *env, int subprog) [...] > for (i =3D BPF_REG_1; i <=3D BPF_REG_5; i++) { > - if (regs[i].type =3D=3D PTR_TO_CTX) > + arg =3D &sub->args[i - BPF_REG_1]; > + reg =3D ®s[i]; > + > + if (arg->arg_type =3D=3D ARG_PTR_TO_CTX) { > + reg->type =3D PTR_TO_CTX; > mark_reg_known_zero(env, regs, i); > - else if (regs[i].type =3D=3D SCALAR_VALUE) > + } else if (arg->arg_type =3D=3D ARG_SCALAR) { > + reg->type =3D SCALAR_VALUE; > mark_reg_unknown(env, regs, i); > - else if (base_type(regs[i].type) =3D=3D PTR_TO_MEM) { > - const u32 mem_size =3D regs[i].mem_size; > - > + } else if (base_type(arg->arg_type) =3D=3D ARG_PTR_TO_MEM) { > + reg->type =3D PTR_TO_MEM; > + if (arg->arg_type & PTR_MAYBE_NULL) > + reg->type |=3D PTR_MAYBE_NULL; > mark_reg_known_zero(env, regs, i); > - regs[i].mem_size =3D mem_size; > - regs[i].id =3D ++env->id_gen; > + reg->mem_size =3D arg->mem_size; > + reg->id =3D ++env->id_gen; > } Nit: maybe add an else branch here and report an error if unexpected argument type is returned by btf_prepare_func_args()?