From 52dbd67dff5d050e99301100e2cac578eef9b2e9 Mon Sep 17 00:00:00 2001 From: "Jose E. Marchesi" Date: Thu, 8 Feb 2024 21:36:12 +0100 Subject: bpf: Abstract loop unrolling pragmas in BPF selftests [Changes from V1: - Avoid conflict by rebasing with latest master.] Some BPF tests use loop unrolling compiler pragmas that are clang specific and not supported by GCC. These pragmas, along with their GCC equivalences are: #pragma clang loop unroll_count(N) #pragma GCC unroll N #pragma clang loop unroll(full) #pragma GCC unroll 65534 #pragma clang loop unroll(disable) #pragma GCC unroll 1 #pragma unroll [aka #pragma clang loop unroll(enable)] There is no GCC equivalence to this pragma. It enables unrolling on loops that the compiler would not ordinarily unroll even with -O2|-funroll-loops, but it is not equivalent to full unrolling either. This patch adds a new header progs/bpf_compiler.h that defines the following macros, which correspond to each pair of compiler-specific pragmas above: __pragma_loop_unroll_count(N) __pragma_loop_unroll_full __pragma_loop_no_unroll __pragma_loop_unroll The selftests using loop unrolling pragmas are then changed to include the header and use these macros in place of the explicit pragmas. Tested in bpf-next master. No regressions. Signed-off-by: Jose E. Marchesi Signed-off-by: Andrii Nakryiko Acked-by: Yonghong Song Link: https://lore.kernel.org/bpf/20240208203612.29611-1-jose.marchesi@oracle.com --- tools/testing/selftests/bpf/progs/loop4.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'tools/testing/selftests/bpf/progs/loop4.c') diff --git a/tools/testing/selftests/bpf/progs/loop4.c b/tools/testing/selftests/bpf/progs/loop4.c index b35337926d66..0de0357f57cc 100644 --- a/tools/testing/selftests/bpf/progs/loop4.c +++ b/tools/testing/selftests/bpf/progs/loop4.c @@ -3,6 +3,8 @@ #include #include +#include "bpf_compiler.h" + char _license[] SEC("license") = "GPL"; SEC("socket") @@ -10,7 +12,7 @@ int combinations(volatile struct __sk_buff* skb) { int ret = 0, i; -#pragma nounroll + __pragma_loop_no_unroll for (i = 0; i < 20; i++) if (skb->len) ret |= 1 << i; -- cgit v1.2.3