From a9e3760b0838299649c0d57cca44daaf40ba3c33 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Mon, 14 Sep 2026 22:12:34 -1000 Subject: sched_ext: Maintain an online cid mask in the scheduler arena Schedulers on the default cid mapping treat [0, nr_online_cids) as the online set and restart on hotplug. Schedulers that install their own mapping with scx_bpf_cid_override() have no way to learn which cids are online: the count no longer identifies members and the CPU-form cpumask is unusable from cid programs. This is an obvious hole in the cid API. Add scx_bpf_online_cmask(), a kernel-maintained cmask in the scheduler's arena, allocated alongside the per-CPU scratch masks and populated after the cid mapping is finalized and before ops.init(), for child schedulers too. The pointer stays valid through ops.exit() with no reference to take. It is the arena offset as a void pointer, the same form struct_ops arena arguments arrive in. The verifier types the void return as a scalar for the program's arena cast. The mask follows the SCX hotplug notifications: seeded from cpu_active_mask and updated before ops.cid_online/offline() runs, so it lags cpu_online_mask only inside a hotplug transition. Updates walk the scheduler list under the lock that also serializes unlinking. Reads are live, not atomic snapshots. Root initialization excludes hotplug. v2: Reworded the getter kerneldoc (Andrea Righi). Signed-off-by: Tejun Heo Reviewed-by: Andrea Righi --- scripts/dtc/dtx_diff | 361 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 361 insertions(+) create mode 100755 scripts/dtc/dtx_diff (limited to 'scripts/dtc/dtx_diff') diff --git a/scripts/dtc/dtx_diff b/scripts/dtc/dtx_diff new file mode 100755 index 000000000..f2bbde4bb --- /dev/null +++ b/scripts/dtc/dtx_diff @@ -0,0 +1,361 @@ +#! /bin/bash +# SPDX-License-Identifier: GPL-2.0-only + +# Copyright (C) 2015 Frank Rowand +# + + +usage() { + + # use spaces instead of tabs in the usage message + cat >&2 <tmp_dtx_1.dts + `basename $0` ARCH=arch_of_dtx_2 DTx_2 >tmp_dtx_2.dts + `basename $0` tmp_dtx_1.dts tmp_dtx_2.dts + rm tmp_dtx_1.dts tmp_dtx_2.dts + + If DTx_1 and DTx_2 are in different directories, then this script will + add the path of DTx_1 and DTx_2 to the include paths. If DTx_2 includes + a local file that exists in both the path of DTx_1 and DTx_2 then the + file in the path of DTx_1 will incorrectly be included. Possible + workaround: + + `basename $0` DTx_1 >tmp_dtx_1.dts + `basename $0` DTx_2 >tmp_dtx_2.dts + `basename $0` tmp_dtx_1.dts tmp_dtx_2.dts + rm tmp_dtx_1.dts tmp_dtx_2.dts + +eod +} + + +compile_to_dts() { + + dtx="$1" + dtc_include="$2" + + if [ -d "${dtx}" ] ; then + + # ----- input is file tree + + if ( ! ${DTC} -I fs ${dtx} ) ; then + exit 3 + fi + + elif [ -f "${dtx}" ] && [ -r "${dtx}" ] ; then + + magic=`hexdump -n 4 -e '/1 "%02x"' ${dtx}` + if [ "${magic}" = "d00dfeed" ] ; then + + # ----- input is FDT (binary blob) + + if ( ! ${DTC} -I dtb ${dtx} ) ; then + exit 3 + fi + + return + + fi + + # ----- input is DTS (source) + + if ( cpp ${cpp_flags} -x assembler-with-cpp ${dtx} \ + | ${DTC} ${dtc_include} -I dts ) ; then + return + fi + + echo "" >&2 + echo "Possible hints to resolve the above error:" >&2 + echo " (hints might not fix the problem)" >&2 + + hint_given=0 + + if [ "${ARCH}" = "" ] ; then + hint_given=1 + echo "" >&2 + echo " shell variable \$ARCH not set" >&2 + fi + + dtx_arch=`echo "/${dtx}" | sed -e 's|.*/arch/||' -e 's|/.*||'` + + if [ "${dtx_arch}" != "" -a "${dtx_arch}" != "${ARCH}" ] ; then + hint_given=1 + echo "" >&2 + echo " architecture ${dtx_arch} is in file path," >&2 + echo " but does not match shell variable \$ARCH" >&2 + echo " >>\$ARCH<< is: >>${ARCH}<<" >&2 + fi + + if [ ! -d ${srctree}/arch/${ARCH} ] ; then + hint_given=1 + echo "" >&2 + echo " ${srctree}/arch/${ARCH}/ does not exist" >&2 + echo " Is \$ARCH='${ARCH}' correct?" >&2 + echo " Possible fix: use '-s' option" >&2 + + git_root=`git rev-parse --show-toplevel 2>/dev/null` + if [ -d ${git_root}/arch/ ] ; then + echo " Possible fix: use '-S' option" >&2 + fi + fi + + if [ $hint_given = 0 ] ; then + echo "" >&2 + echo " No hints available." >&2 + fi + + echo "" >&2 + + exit 3 + + else + echo "" >&2 + echo "ERROR: ${dtx} does not exist or is not readable" >&2 + echo "" >&2 + exit 2 + fi + +} + + +# ----- start of script + +annotate="" +cmd_diff=0 +diff_flags="-u" +diff_color="" +dtx_file_1="" +dtx_file_2="" +dtc_sort="-s" +help=0 +srctree="" + + +while [ $# -gt 0 ] ; do + + case $1 in + + -c | --color ) + if diff --color /dev/null /dev/null 2>/dev/null ; then + diff_color="--color=always" + fi + shift + ;; + + -f ) + diff_flags="--unified=999999" + shift + ;; + + -h | -help | --help ) + help=1 + shift + ;; + + -s ) + srctree="$2" + shift 2 + ;; + + -S ) + git_root=`git rev-parse --show-toplevel 2>/dev/null` + srctree="${git_root}" + shift + ;; + + -T | --annotate ) + if [ "${annotate}" = "" ] ; then + annotate="-T" + elif [ "${annotate}" = "-T" ] ; then + annotate="-T -T" + fi + shift + ;; + -u ) + dtc_sort="" + shift + ;; + + *) + if [ "${dtx_file_1}" = "" ] ; then + dtx_file_1="$1" + elif [ "${dtx_file_2}" = "" ] ; then + dtx_file_2="$1" + else + echo "" >&2 + echo "ERROR: Unexpected parameter: $1" >&2 + echo "" >&2 + exit 2 + fi + shift + ;; + + esac + +done + +if [ "${srctree}" = "" ] ; then + srctree="." +fi + +if [ "${dtx_file_2}" != "" ]; then + cmd_diff=1 +fi + +if (( ${help} )) ; then + usage + exit 1 +fi + +# this must follow check for ${help} +if [ "${dtx_file_1}" = "" ]; then + echo "" >&2 + echo "ERROR: parameter DTx required" >&2 + echo "" >&2 + exit 2 +fi + + +# ----- prefer dtc from linux kernel, allow fallback to dtc in $PATH + +if [ "${KBUILD_OUTPUT:0:2}" = ".." ] ; then + __KBUILD_OUTPUT="${srctree}/${KBUILD_OUTPUT}" +elif [ "${KBUILD_OUTPUT}" = "" ] ; then + __KBUILD_OUTPUT="." +else + __KBUILD_OUTPUT="${KBUILD_OUTPUT}" +fi + +DTC="${__KBUILD_OUTPUT}/scripts/dtc/dtc" + +if [ ! -x ${DTC} ] ; then + __DTC="dtc" + if grep -q "^CONFIG_DTC=y" ${__KBUILD_OUTPUT}/.config 2>/dev/null; then + make_command=' + make scripts' + else + make_command=' + Enable CONFIG_DTC in the kernel configuration + make scripts' + fi + if ( ! which ${__DTC} >/dev/null ) ; then + + # use spaces instead of tabs in the error message + cat >&2 <