From 82347179f6d58b4cc2dce3737525ead7f4d7e6d8 Mon Sep 17 00:00:00 2001 From: Tamir Duberstein Date: Thu, 27 Jul 2023 18:33:55 -0400 Subject: [PATCH] bpf: Remove builtin global functions This commit removes memset and memcpy, relying instead on implementations provided by std/compiler-builtins. This commit adds `#![no_builtins]` to all the BPF programs written in Rust, and the same should be propagated to aya-template and all examples in the book and elsewhere before this commit is merged. It turns out that without the `#![no_builtins]` annotation rustc generates LLVM IR that calls LLVM intrinsics rather than libcalls. These may end up as libcalls after lowering, but not before emitting errors in BPF lowering[0]. This works thanks to https://github.com/rust-lang/rust/pull/113716 which causes `#![no_builtins]` to behave similarly to `-fno-builtin` in clang, which was added in https://reviews.llvm.org/D68028 with similar motivation. This commit implies that we now require rustc nightly >= 2023-07-20. [0] https://github.com/llvm/llvm-project/blob/7b2745b/llvm/lib/Target/BPF/BPFISelLowering.cpp#L472-L474 --- bpf/aya-bpf/src/lib.rs | 18 +----------------- test/integration-ebpf/src/bpf_probe_read.rs | 3 ++- test/integration-ebpf/src/log.rs | 3 ++- test/integration-ebpf/src/map_test.rs | 3 ++- test/integration-ebpf/src/name_test.rs | 3 ++- test/integration-ebpf/src/pass.rs | 3 ++- test/integration-ebpf/src/relocations.rs | 3 ++- test/integration-ebpf/src/test.rs | 3 ++- 8 files changed, 15 insertions(+), 24 deletions(-) diff --git a/bpf/aya-bpf/src/lib.rs b/bpf/aya-bpf/src/lib.rs index 517e23fa9..b7f83d8ab 100644 --- a/bpf/aya-bpf/src/lib.rs +++ b/bpf/aya-bpf/src/lib.rs @@ -25,7 +25,7 @@ pub mod programs; pub use aya_bpf_cty as cty; use core::ffi::c_void; -use cty::{c_int, c_long}; +use cty::c_long; use helpers::{bpf_get_current_comm, bpf_get_current_pid_tgid, bpf_get_current_uid_gid}; pub use aya_bpf_macros as macros; @@ -57,22 +57,6 @@ pub trait BpfContext { } } -#[no_mangle] -pub unsafe extern "C" fn memset(s: *mut u8, c: c_int, n: usize) { - #[allow(clippy::cast_sign_loss)] - let b = c as u8; - for i in 0..n { - *s.add(i) = b; - } -} - -#[no_mangle] -pub unsafe extern "C" fn memcpy(dest: *mut u8, src: *mut u8, n: usize) { - for i in 0..n { - *dest.add(i) = *src.add(i); - } -} - /// Check if a value is within a range, using conditional forms compatible with /// the verifier. #[inline(always)] diff --git a/test/integration-ebpf/src/bpf_probe_read.rs b/test/integration-ebpf/src/bpf_probe_read.rs index 027287672..0cfa739e7 100644 --- a/test/integration-ebpf/src/bpf_probe_read.rs +++ b/test/integration-ebpf/src/bpf_probe_read.rs @@ -1,5 +1,6 @@ -#![no_std] +#![no_builtins] #![no_main] +#![no_std] use aya_bpf::{ helpers::{bpf_probe_read_kernel_str_bytes, bpf_probe_read_user_str_bytes}, diff --git a/test/integration-ebpf/src/log.rs b/test/integration-ebpf/src/log.rs index 03cdde765..03a31241e 100644 --- a/test/integration-ebpf/src/log.rs +++ b/test/integration-ebpf/src/log.rs @@ -1,5 +1,6 @@ -#![no_std] +#![no_builtins] #![no_main] +#![no_std] use aya_bpf::{macros::uprobe, programs::ProbeContext}; use aya_log_ebpf::{debug, error, info, trace, warn}; diff --git a/test/integration-ebpf/src/map_test.rs b/test/integration-ebpf/src/map_test.rs index d63d6fc62..725fae853 100644 --- a/test/integration-ebpf/src/map_test.rs +++ b/test/integration-ebpf/src/map_test.rs @@ -1,5 +1,6 @@ -#![no_std] +#![no_builtins] #![no_main] +#![no_std] use aya_bpf::{ bindings::xdp_action, diff --git a/test/integration-ebpf/src/name_test.rs b/test/integration-ebpf/src/name_test.rs index 1a5f870c5..c319778a4 100644 --- a/test/integration-ebpf/src/name_test.rs +++ b/test/integration-ebpf/src/name_test.rs @@ -1,5 +1,6 @@ -#![no_std] +#![no_builtins] #![no_main] +#![no_std] use aya_bpf::{bindings::xdp_action, macros::xdp, programs::XdpContext}; diff --git a/test/integration-ebpf/src/pass.rs b/test/integration-ebpf/src/pass.rs index 120ef7cc6..824e4e062 100644 --- a/test/integration-ebpf/src/pass.rs +++ b/test/integration-ebpf/src/pass.rs @@ -1,5 +1,6 @@ -#![no_std] +#![no_builtins] #![no_main] +#![no_std] use aya_bpf::{bindings::xdp_action, macros::xdp, programs::XdpContext}; diff --git a/test/integration-ebpf/src/relocations.rs b/test/integration-ebpf/src/relocations.rs index bfbcd1cdf..557fda77a 100644 --- a/test/integration-ebpf/src/relocations.rs +++ b/test/integration-ebpf/src/relocations.rs @@ -1,5 +1,6 @@ -#![no_std] +#![no_builtins] #![no_main] +#![no_std] use core::hint; diff --git a/test/integration-ebpf/src/test.rs b/test/integration-ebpf/src/test.rs index 187a39262..747085d26 100644 --- a/test/integration-ebpf/src/test.rs +++ b/test/integration-ebpf/src/test.rs @@ -1,5 +1,6 @@ -#![no_std] +#![no_builtins] #![no_main] +#![no_std] use aya_bpf::{ bindings::xdp_action,