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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-29 20:30:35 +00:00
6b1992bcde
Currently, using llvm-objtool, this script just silently succeeds without actually do the intended checking. So this updates it to work properly. Firstly, llvm-objdump does not add target symbol names to the end of branches in its asm output, so we have to drop the branch to __start_initialization_multiplatform using its address. Secondly, v9 and 10 specify branch targets as .+<offset>, so we convert those to actual addresses. Thirdly, v10 and 11 error out on a vmlinux if given the -R option complaining that it is "not a dynamic object". The -R does not make any difference to the asm output, so remove it. Lastly, v11 produces asm that is very similar to Gnu objtool (at least as far as branches are concerned), so no further changes are necessary to make it work. Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200812081036.7969-3-sfr@canb.auug.org.au
79 lines
1.8 KiB
Bash
Executable file
79 lines
1.8 KiB
Bash
Executable file
#!/bin/bash
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# SPDX-License-Identifier: GPL-2.0+
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# Copyright © 2016,2020 IBM Corporation
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#
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# This script checks the unrelocated code of a vmlinux for "suspicious"
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# branches to relocated code (head_64.S code).
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# Have Kbuild supply the path to objdump and nm so we handle cross compilation.
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objdump="$1"
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nm="$2"
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vmlinux="$3"
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kstart=0xc000000000000000
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end_intr=0x$($nm -p "$vmlinux" |
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sed -E -n '/\s+[[:alpha:]]\s+__end_interrupts\s*$/{s///p;q}')
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if [ "$end_intr" = "0x" ]; then
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exit 0
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fi
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# we know that there is a correct branch to
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# __start_initialization_multiplatform, so find its address
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# so we can exclude it.
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sim=0x$($nm -p "$vmlinux" |
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sed -E -n '/\s+[[:alpha:]]\s+__start_initialization_multiplatform\s*$/{s///p;q}')
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$objdump -D --no-show-raw-insn --start-address="$kstart" --stop-address="$end_intr" "$vmlinux" |
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sed -E -n '
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# match lines that start with a kernel address
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/^c[0-9a-f]*:\s*b/ {
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# drop branches via ctr or lr
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/\<b.?.?(ct|l)r/d
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# cope with some differences between Clang and GNU objdumps
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s/\<bt.?\s*[[:digit:]]+,/beq/
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s/\<bf.?\s*[[:digit:]]+,/bne/
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# tidy up
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s/\s0x/ /
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s/://
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# format for the loop below
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s/^(\S+)\s+(\S+)\s+(\S+)\s*(\S*).*$/\1:\2:\3:\4/
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# strip out condition registers
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s/:cr[0-7],/:/
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p
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}' | {
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all_good=true
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while IFS=: read -r from branch to sym; do
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case "$to" in
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c*) to="0x$to"
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;;
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.+*)
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to=${to#.+}
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if [ "$branch" = 'b' ]; then
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if (( to >= 0x2000000 )); then
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to=$(( to - 0x4000000 ))
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fi
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elif (( to >= 0x8000 )); then
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to=$(( to - 0x10000 ))
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fi
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printf -v to '0x%x' $(( "0x$from" + to ))
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;;
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*) printf 'Unkown branch format\n'
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;;
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esac
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if [ "$to" = "$sim" ]; then
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continue
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fi
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if (( to > end_intr )); then
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if $all_good; then
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printf '%s\n' 'WARNING: Unrelocated relative branches'
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all_good=false
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fi
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printf '%s %s-> %s %s\n' "$from" "$branch" "$to" "$sym"
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fi
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done
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$all_good
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}
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