From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 42B9B4D596C for ; Wed, 16 Sep 2026 18:44:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789584270; cv=none; b=fxvo5BQPIrzyTpP1oV96rmyzMVb2vJTooeAUOlCsmSWVA4HmRe42aedD4Z/ryAwyIoOUrt8/Mbx/54JS6qZafJ5K04SM0fLxlr38BgglECZw4qfm4O/yJnEROyH8PeFA2tURXvdnOyX/XydF2ZnFlifQs0BmSEU5FgNkiXCIN8c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789584270; c=relaxed/simple; bh=WJGAEZCd2eA64HLDIzo7aEFFIxuXp4f/4+ZS975+Kwc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=tbeotNl1XxUWkh5F//Pkaoef6wicBPqc6zgAQUBRn5g4MtUiB1My8xw1/6UHbBB1Z8A57EpZBy0qFGI99wKwbUXH12Szh8ILuBojC4C4yCm3U6cdoIReRvU9AyWftV1vMTCPb92gZ7hkNQKTpsKZH8UUIB3C5ehVLuO+JCEObaQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=dVPwCbvS; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="dVPwCbvS" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B41E01F00893; Wed, 16 Sep 2026 18:44:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789584247; bh=6Ggd6XWbTt6dZBrPSSD4vGkBNiFRmruv7nYpTP4xQy8=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=dVPwCbvSy12IDo0auveZit4SUY0UsFcTroq0YJgL2DpPuW9WlWVF/vsH0XM5G8J3M np1EQZFPdkmWdmAfJsUNBir24OuUHot4q4/1jW9fyigqo9AbnebCV6wyaCWnBU2plf xaH+EXG4qEOF+treC+RDEoBMD4iT8voStK3CK6yNu4mgkShXKWe/AqJIqvXIo2RWXk wav8QtDirpjWVkp21cHvFbr2DNVWblvKEOHjqQNkC7HwKaSvsBbcxLh5ZhIxtq6oJP KwolL5PTMDLTdvP0UhGqSZyKHM5TmKJZQYJYU68WkijFbGQw4rTQBwfWmkmMfBupfF rqeEXOSw7y1cQ== From: Song Liu To: live-patching@vger.kernel.org Cc: jpoimboe@kernel.org, peterz@infradead.org, jikos@kernel.org, mbenes@suse.cz, pmladek@suse.com, joe.lawrence@redhat.com, puranjay@kernel.org, kernel-team@meta.com, Song Liu Subject: [PATCH v5 02/58] objtool/klp: Check the klp test environment once, before any test Date: Wed, 16 Sep 2026 11:42:55 -0700 Message-ID: <20260916184351.2720310-3-song@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260916184351.2720310-1-song@kernel.org> References: <20260916184351.2720310-1-song@kernel.org> Precedence: bulk X-Mailing-List: live-patching@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Every test checked for itself that objtool exists, was built with klp support, and that $CC runs. Three problems with that: it is the same work done 40 times, a missing objtool reads as a per-test skip rather than as a suite which cannot run, and a run in which everything skipped still exits 0. Do it once, before any test, in klp_preflight() in lib.sh, and export the answers where the tests can read them. If the suite cannot run the whole run fails and says why; a test which gets as far as running can assume its environment. Nothing is written down, so nothing can go stale. Sourcing lib.sh runs the checks, which means a test run by hand establishes its own answers rather than inheriting those of some earlier run with a different CC, and a test is never handed an empty value for where objtool is or which architecture it is on: either the exports are set or the run has already failed. preflight answers only whether the suite can run at all -- not what the compiler is capable of. A test needing a particular compiler feature probes for it and skips; that costs one compile and keeps the reason next to the test that has to justify it. Assisted-by: Claude:claude-opus-5 Signed-off-by: Song Liu --- tools/objtool/Makefile | 3 +- tools/objtool/tests/lib.sh | 124 +++++++++++++++++++++++++------ tools/objtool/tests/run-tests.sh | 7 ++ 3 files changed, 112 insertions(+), 22 deletions(-) diff --git a/tools/objtool/Makefile b/tools/objtool/Makefile index f4ec9f813a20..2c200d05c276 100644 --- a/tools/objtool/Makefile +++ b/tools/objtool/Makefile @@ -152,7 +152,8 @@ mrproper: clean $(call QUIET_CLEAN, objtool) $(RM) $(OBJTOOL) tests: $(OBJTOOL) - $(Q)OBJTOOL=$(abspath $(OBJTOOL)) $(srctree)/tools/objtool/tests/run-tests.sh + $(Q)OBJTOOL=$(abspath $(OBJTOOL)) ARCH=$(ARCH) CROSS_COMPILE=$(CROSS_COMPILE) \ + $(srctree)/tools/objtool/tests/run-tests.sh FORCE: diff --git a/tools/objtool/tests/lib.sh b/tools/objtool/tests/lib.sh index 7b29db76aa5e..46bdb985765e 100644 --- a/tools/objtool/tests/lib.sh +++ b/tools/objtool/tests/lib.sh @@ -11,8 +11,104 @@ TESTS_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)" FIXTURES_DIR="$TESTS_DIR/fixtures" +# The kernel's convention: CROSS_COMPILE is the one knob, with per-tool +# overrides for what it does not cover. objtool itself is always a host binary +# -- it is built with HOSTCC and only reads ELF -- so an arm64 machine can run +# the x86 tests against x86 objects given a compiler that emits them. +# +# readelf reads any target, so it rarely needs overriding, and either GNU +# readelf or llvm-readelf will do: the assertions match on fields rather than +# on columns, and where the two spell something differently -- "OS [0xff20]" +# against "OS[0xff20]" for SHN_LIVEPATCH -- they accept both. BFD's objcopy is +# usually built for the host's target alone, and llvm-objcopy is the +# target-agnostic replacement. +CROSS_COMPILE="${CROSS_COMPILE:-}" +CC="${CC:-${CROSS_COMPILE}gcc}" +LD="${LD:-${CROSS_COMPILE}ld}" +READELF="${READELF:-${CROSS_COMPILE}readelf}" +OBJCOPY="${OBJCOPY:-${CROSS_COMPILE}objcopy}" + OBJTOOL="${OBJTOOL:-$TESTS_DIR/../objtool}" -CC="${CC:-gcc}" + +# klp_preflight +# +# Check the environment once, before any test runs, and report what was found. +# +klp_preflight() +{ + local tmp tool cc_version host cc_arch + + bail() { echo "Bail out! $*" >&2; exit 1; } + + # A relative $OBJTOOL is relative to the objtool directory, not tests/. + [ -x "$OBJTOOL" ] || [ ! -x "$TESTS_DIR/../$OBJTOOL" ] || + OBJTOOL="$TESTS_DIR/../$OBJTOOL" + + [ -x "$OBJTOOL" ] || + bail "objtool not found at '$OBJTOOL' -- build it first" + + # run_diff() runs objtool from inside the test's working directory, so + # a relative path would resolve against that instead. + OBJTOOL="$(realpath "$OBJTOOL")" + + "$OBJTOOL" klp 2>&1 | grep -q checksum || + bail "objtool was built without klp support; install libxxhash (>= 0.8) and rebuild" + + command -v "${CC%% *}" >/dev/null || bail "compiler not found: $CC" + + for tool in "$READELF" "$OBJCOPY" "$LD"; do + command -v "${tool%% *}" >/dev/null || bail "$tool not found" + done + + tmp="$(mktemp -d)" || bail "mktemp failed" + echo 'int probe(void) { return 0; }' > "$tmp/probe.c" + $CC -c -o "$tmp/probe.o" "$tmp/probe.c" 2>/dev/null || + { rm -rf "$tmp"; bail "$CC cannot compile a trivial object"; } + + # $CC, $ARCH and objtool have to agree about the target, and cross runs + # are where they stop agreeing: plain "CC=clang ARCH=x86_64" on an arm64 + # box selects the x86 tests and then builds arm64 objects, because clang + # needs --target= to emit anything but the host's. + # + # Ask objtool rather than comparing machine names. It rejects an object + # it was not built for -- "unexpected ELF machine type" -- so one check + # covers every way the three can disagree, and says so once instead of + # failing every test for the same reason. + "$OBJTOOL" klp checksum "$tmp/probe.o" >/dev/null 2>&1 || + { rm -rf "$tmp" + bail "objtool rejects an object built by '$CC'; they target" \ + "different architectures (set CROSS_COMPILE, or" \ + "--target= for clang)"; } + + # BFD objcopy is usually built for the host's target alone, and + # checksum_of() needs it to read the object under test. + $OBJCOPY -O binary --only-section=.text "$tmp/probe.o" "$tmp/probe.bin" 2>/dev/null || + { rm -rf "$tmp" + bail "$OBJCOPY cannot read objects built by '$CC'; install" \ + "binutils-multiarch or set OBJCOPY=llvm-objcopy"; } + # $ARCH only chooses which directory of tests runs, so it can disagree + # with what $CC builds without objtool noticing -- and the result is the + # wrong set of tests, quietly. + case "$($READELF -hW "$tmp/probe.o" | sed -n 's/.*Machine: *//p')" in + *X86-64*|*Intel*80386*) cc_arch=x86 ;; + *AArch64*) cc_arch=arm64 ;; + *) cc_arch= ;; + esac + rm -rf "$tmp" + + KLP_TEST_PREFLIGHT=done + export OBJTOOL CC KLP_TEST_PREFLIGHT + + cc_version="$($CC --version 2>/dev/null | head -1)" + cat <&1 | grep -q checksum || - skip "objtool built without klp support (needs libxxhash)" - command -v "${CC%% *}" >/dev/null || skip "no compiler ($CC)" - + # The environment was checked once when this file was sourced, so there + # is nothing to verify here: objtool exists at the resolved path, has + # klp support, and $CC works. workdir="$(mktemp -d)" || fail "mktemp failed" trap cleanup EXIT @@ -155,9 +237,9 @@ find_thinlto_toolchain() return 1 } -out_sections() { readelf -S -W "$workdir/out.o" 2>/dev/null; } -out_relocs() { readelf -r -W "$workdir/out.o" 2>/dev/null; } -out_symbols() { readelf -s -W "$workdir/out.o" 2>/dev/null; } +out_sections() { $READELF -S -W "$workdir/out.o" 2>/dev/null; } +out_relocs() { $READELF -r -W "$workdir/out.o" 2>/dev/null; } +out_symbols() { $READELF -s -W "$workdir/out.o" 2>/dev/null; } diff_log() { cat "$workdir/diff.log"; } assert_section() diff --git a/tools/objtool/tests/run-tests.sh b/tools/objtool/tests/run-tests.sh index ab1dea58811e..f6a3e1b7677e 100755 --- a/tools/objtool/tests/run-tests.sh +++ b/tools/objtool/tests/run-tests.sh @@ -2,6 +2,9 @@ # SPDX-License-Identifier: GPL-2.0 # # Run the objtool klp tests. Each test-*.sh prints one TAP result line. +# +# The harness checks the environment once up front and fails the run if the +# suite cannot execute, rather than letting every test skip and exit 0. set -u @@ -10,6 +13,10 @@ cd "$(dirname "$0")" || exit 1 tests=( test-*.sh ) [ "${tests[0]}" = "test-*.sh" ] && { echo "1..0 # SKIP no tests found"; exit 0; } +# Sourcing the harness runs its preflight, and exports what it found so the +# tests inherit it rather than working it out again. +. ./lib.sh + echo "1..${#tests[@]}" rc=0 -- 2.53.0-Meta