1*1a50e18bSSong Liu#!/bin/bash 2*1a50e18bSSong Liu# SPDX-License-Identifier: GPL-2.0 3*1a50e18bSSong Liu# 4*1a50e18bSSong Liu# sympos for vmlinux, which is resolved differently from sympos for a module. 5*1a50e18bSSong Liu# 6*1a50e18bSSong Liu# A module's .ko preserves symbol table order, so klp diff can count -- that is 7*1a50e18bSSong Liu# what test-sympos covers. vmlinux cannot be counted: the final link reorders 8*1a50e18bSSong Liu# sub-sections, so the order in vmlinux.o is not the order the running kernel 9*1a50e18bSSong Liu# has. klp diff bridges that with .klp.symid, a table of { id, address } 10*1a50e18bSSong Liu# emitted into vmlinux.o whose addresses the linker resolves, read back out of 11*1a50e18bSSong Liu# the linked vmlinux. 12*1a50e18bSSong Liu# 13*1a50e18bSSong Liu# Getting it wrong points the relocation at a different symbol of the same 14*1a50e18bSSong Liu# name. Nothing fails to build or load; the patched code uses the wrong 15*1a50e18bSSong Liu# object. 16*1a50e18bSSong Liu# 17*1a50e18bSSong Liu# The fixture is arranged so the two answers differ: the static that comes 18*1a50e18bSSong Liu# first in the symbol table is placed at the *higher* address, so counting 19*1a50e18bSSong Liu# gives 1 and reading the linked image gives 2. Without that, both paths agree 20*1a50e18bSSong Liu# and the test cannot tell them apart. 21*1a50e18bSSong Liu 22*1a50e18bSSong Liu. "$(dirname "$0")/../lib.sh" 23*1a50e18bSSong Liu 24*1a50e18bSSong Liusetup 25*1a50e18bSSong Liu 26*1a50e18bSSong Liu# use_a's static sorts last by section name, use_b's first. Only use_a is 27*1a50e18bSSong Liu# patched, so exactly one sympos comes out. 28*1a50e18bSSong Liubuild_one sympos_vmlinux.c orig_a.o -DFUNC_NAME=use_a -DVARSEC='".data.zzz"' 29*1a50e18bSSong Liubuild_one sympos_vmlinux.c patched_a.o -DFUNC_NAME=use_a -DVARSEC='".data.zzz"' -DPATCHED 30*1a50e18bSSong Liubuild_one sympos_vmlinux.c b.o -DFUNC_NAME=use_b -DVARSEC='".data.aaa"' -DNO_MODINFO 31*1a50e18bSSong Liu 32*1a50e18bSSong Liumake_vmlinux_pair "$workdir/orig_a.o" "$workdir/b.o" \ 33*1a50e18bSSong Liu -- "$workdir/patched_a.o" "$workdir/b.o" 34*1a50e18bSSong Liu 35*1a50e18bSSong Liu[ "$(count_input_symbols vmlinux.o dup_counter)" = 2 ] || 36*1a50e18bSSong Liu fail "fixture did not produce two dup_counter symbols" 37*1a50e18bSSong Liuhas_input_section vmlinux.o .klp.symid || 38*1a50e18bSSong Liu fail "objtool --klp-symids emitted no .klp.symid table" 39*1a50e18bSSong Liuhas_input_section vmlinux .klp.symid || 40*1a50e18bSSong Liu fail ".klp.symid did not survive the link" 41*1a50e18bSSong Liu 42*1a50e18bSSong Liu# The premise: symbol table order and address order must disagree, or the test 43*1a50e18bSSong Liu# proves nothing. 44*1a50e18bSSong Liufirst_addr="$(in_symbols vmlinux | awk '$8 == "dup_counter" { print $2; exit }')" 45*1a50e18bSSong Liulow_addr="$(in_symbols vmlinux | awk '$8 == "dup_counter" { print $2 }' | sort | head -1)" 46*1a50e18bSSong Liu[ "$first_addr" != "$low_addr" ] || 47*1a50e18bSSong Liu probe_skip "linker did not reorder the two statics" 48*1a50e18bSSong Liu 49*1a50e18bSSong Liuassert_input_symbol dup_counter 50*1a50e18bSSong Liurun_diff 51*1a50e18bSSong Liu 52*1a50e18bSSong Liu# Address order says 2. Counting symbol table order would say 1. 53*1a50e18bSSong Liuassert_klp_sympos dup_counter 2 54*1a50e18bSSong Liuout_symbols | grep -q 'dup_counter,1' && 55*1a50e18bSSong Liu fail "sympos 1 emitted: counted symbol table order instead of reading the linked vmlinux" 56*1a50e18bSSong Liu 57*1a50e18bSSong Liupass "vmlinux sympos taken from the linked image, not from symbol table order" 58