Files
ack-tegra/scripts/Makefile.btf
T
Giuliano Procida 1766170417 ANDROID: pahole -J -j1 for reproducible BTF, again
Versions of pahole from 1.22 support multi-threaded operation with
separate CUs being processed independently. This results in
non-deterministic and effectively non-reproducible output for kernel
objects. Later versions of pahole aim to support determinism by
retiring CUs in order.

We regain determinism by restricting parallelism to 1 at the cost of
some performance.

This is a repeat of commit a1e6a310ad which got obliterated during
merge conflict resolution of commit 01c5dfcaad. It has also been
extended to cover later versions of pahole.

Bug: 453481228
Change-Id: Iccf949a27ccad7faf49adb7878e2e7c6f6537c60
Signed-off-by: Giuliano Procida <gprocida@google.com>
2025-10-22 23:58:07 -07:00

38 lines
1.2 KiB
Makefile

# SPDX-License-Identifier: GPL-2.0
pahole-ver := $(CONFIG_PAHOLE_VERSION)
pahole-flags-y :=
JOBS := $(patsubst -j%,%,$(filter -j%,$(MAKEFLAGS)))
ifeq ($(call test-le, $(pahole-ver), 125),y)
# pahole 1.18 through 1.21 can't handle zero-sized per-CPU vars
ifeq ($(call test-le, $(pahole-ver), 121),y)
pahole-flags-$(call test-ge, $(pahole-ver), 118) += --skip_encoding_btf_vars
endif
pahole-flags-$(call test-ge, $(pahole-ver), 121) += --btf_gen_floats
pahole-flags-$(call test-ge, $(pahole-ver), 122) += -j1
pahole-flags-$(call test-ge, $(pahole-ver), 125) += --skip_encoding_btf_inconsistent_proto --btf_gen_optimized
else
# Switch to using --btf_features for v1.26 and later.
pahole-flags-$(call test-ge, $(pahole-ver), 126) = -j1 --btf_features=encode_force,var,float,enum64,decl_tag,type_tag,optimized_func,consistent_func,decl_tag_kfuncs
pahole-flags-$(call test-ge, $(pahole-ver), 130) += --btf_features=attributes
ifneq ($(KBUILD_EXTMOD),)
module-pahole-flags-$(call test-ge, $(pahole-ver), 128) += --btf_features=distilled_base
endif
endif
pahole-flags-$(CONFIG_PAHOLE_HAS_LANG_EXCLUDE) += --lang_exclude=rust
export PAHOLE_FLAGS := $(pahole-flags-y)
export MODULE_PAHOLE_FLAGS := $(module-pahole-flags-y)