LXR linux/arch/powerpc/kernel/prom_init

   1#!/bin/sh
   2# SPDX-License-Identifier: GPL-2.0-or-later
   3#
   4# Copyright © 2008 IBM Corporation
   5#
   6
   7# This script checks prom_init.o to see what external symbols it
   8# is using, if it finds symbols not in the whitelist it returns
   9# an error. The point of this is to discourage people from
  10# intentionally or accidentally adding new code to prom_init.c
  11# which has side effects on other parts of the kernel.
  12
  13# If you really need to reference something from prom_init.o add
  14# it to the list below:
  15
  16grep "^CONFIG_KASAN=y$" .config >/dev/null
  17if [ $? -eq 0 ]
  18then
  19        MEM_FUNCS="__memcpy __memset"
  20else
  21        MEM_FUNCS="memcpy memset"
  22fi
  23
  24WHITELIST="add_reloc_offset __bss_start __bss_stop copy_and_flush
  25_end enter_prom $MEM_FUNCS reloc_offset __secondary_hold
  26__secondary_hold_acknowledge __secondary_hold_spinloop __start
  27logo_linux_clut224 btext_prepare_BAT
  28reloc_got2 kernstart_addr memstart_addr linux_banner _stext
  29__prom_init_toc_start __prom_init_toc_end btext_setup_display TOC."
  30
  31NM="$1"
  32OBJ="$2"
  33
  34ERROR=0
  35
  36function check_section()
  37{
  38    file=$1
  39    section=$2
  40    size=$(objdump -h -j $section $file 2>/dev/null | awk "\$2 == \"$section\" {print \$3}")
  41    size=${size:-0}
  42    if [ $size -ne 0 ]; then
  43        ERROR=1
  44        echo "Error: Section $section not empty in prom_init.c" >&2
  45    fi
  46}
  47
  48for UNDEF in $($NM -u $OBJ | awk '{print $2}')
  49do
  50        # On 64-bit nm gives us the function descriptors, which have
  51        # a leading . on the name, so strip it off here.
  52        UNDEF="${UNDEF#.}"
  53
  54        if [ $KBUILD_VERBOSE ]; then
  55                if [ $KBUILD_VERBOSE -ne 0 ]; then
  56                        echo "Checking prom_init.o symbol '$UNDEF'"
  57                fi
  58        fi
  59
  60        OK=0
  61        for WHITE in $WHITELIST
  62        do
  63                if [ "$UNDEF" = "$WHITE" ]; then
  64                        OK=1
  65                        break
  66                fi
  67        done
  68
  69        # ignore register save/restore funcitons
  70        case $UNDEF in
  71        _restgpr_*|_restgpr0_*|_rest32gpr_*)
  72                OK=1
  73                ;;
  74        _savegpr_*|_savegpr0_*|_save32gpr_*)
  75                OK=1
  76                ;;
  77        esac
  78
  79        if [ $OK -eq 0 ]; then
  80                ERROR=1
  81                echo "Error: External symbol '$UNDEF' referenced" \
  82                     "from prom_init.c" >&2
  83        fi
  84done
  85
  86check_section $OBJ .data
  87check_section $OBJ .bss
  88check_section $OBJ .init.data
  89
  90exit $ERROR
  91