1*76e7630dSPuranjay Mohan#!/bin/bash 2*76e7630dSPuranjay Mohan# SPDX-License-Identifier: GPL-2.0 3*76e7630dSPuranjay Mohan# 4*76e7630dSPuranjay Mohan# Both halves of a split function belong to the patch; carrying only the hot 5*76e7630dSPuranjay Mohan# part leaves the cold path branching into unpatched code. 6*76e7630dSPuranjay Mohan 7*76e7630dSPuranjay Mohan. "$(dirname "$0")/../lib.sh" 8*76e7630dSPuranjay Mohan 9*76e7630dSPuranjay Mohan# Clang does not split functions into a cold part at all, so there is nothing 10*76e7630dSPuranjay Mohan# for this test to look at there. A given gcc may or may not split, which is a 11*76e7630dSPuranjay Mohan# version property rather than a compiler choice -- that stays a probe below. 12*76e7630dSPuranjay Mohangcc_only "clang does not split functions into a cold part" 13*76e7630dSPuranjay Mohan 14*76e7630dSPuranjay Mohansetup 15*76e7630dSPuranjay Mohan 16*76e7630dSPuranjay Mohansplit_flag=-freorder-blocks-and-partition 17*76e7630dSPuranjay Mohancc_supports "$split_flag" || split_flag= 18*76e7630dSPuranjay Mohan 19*76e7630dSPuranjay Mohanbuild_pair cold_function.c $split_flag 20*76e7630dSPuranjay Mohan 21*76e7630dSPuranjay Mohan# Find what the compiler called the cold half -- target.cold, target.cold.0, 22*76e7630dSPuranjay Mohan# depending on version -- and name it exactly from here on. 23*76e7630dSPuranjay Mohancold_sym="$(in_symbols orig.o | awk '$NF ~ /^target\.cold/ { print $NF; exit }')" 24*76e7630dSPuranjay Mohan[ -n "$cold_sym" ] || 25*76e7630dSPuranjay Mohan probe_skip "compiler did not split the function into a cold part" 26*76e7630dSPuranjay Mohan 27*76e7630dSPuranjay Mohanrun_diff 28*76e7630dSPuranjay Mohan 29*76e7630dSPuranjay Mohanassert_patched target 30*76e7630dSPuranjay Mohan# Match the name field exactly, and require it to be defined. Had the cold 31*76e7630dSPuranjay Mohan# half been left behind, the branch to it would appear as an undefined 32*76e7630dSPuranjay Mohan# .klp.sym.vmlinux.target.cold,0 -- a different name, which happens to contain 33*76e7630dSPuranjay Mohan# this one. Asking about a column instead of the name would not tell them 34*76e7630dSPuranjay Mohan# apart: readelf prints SHN_LIVEPATCH as "OS [0xff20]" and llvm-readelf as 35*76e7630dSPuranjay Mohan# "OS[0xff20]", so the fields either side of the name shift between the two. 36*76e7630dSPuranjay Mohanout_symbols | awk -v n="$cold_sym" '$NF == n && $(NF - 1) != "UND"' | grep -q . || 37*76e7630dSPuranjay Mohan fail "cold half ($cold_sym) was not carried into the patch" 38*76e7630dSPuranjay Mohan 39*76e7630dSPuranjay Mohanpass "cold half carried into the patch with its parent" 40