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When ld detects unaligned relocations, it emits R_PPC64_UADDR64
relocations instead of R_PPC64_RELATIVE. Currently R_PPC64_UADDR64 are
detected by arch/powerpc/tools/relocs_check.sh and expected not to work.
Below is a simple chunk to trigger this behaviour (this disables
optimization for the demonstration purposes only, this also happens with
-O1/-O2 when CONFIG_PRINTK_INDEX=y, for example):
\#pragma GCC push_options
\#pragma GCC optimize ("O0")
struct entry {
const char *file;
int line;
} __attribute__((packed));
static const struct entry e1 = { .file = __FILE__, .line = __LINE__ };
static const struct entry e2 = { .file = __FILE__, .line = __LINE__ };
...
prom_printf("e1=%s %lx %lx\n", e1.file, (unsigned long) e1.file, mfmsr());
prom_printf("e2=%s %lx\n", e2.file, (unsigned long) e2.file);
\#pragma GCC pop_options
This adds support for UADDR64 for 64bit. This reuses __dynamic_symtab
from the 32bit code which supports more relocation types already.
Because RELACOUNT includes only R_PPC64_RELATIVE, this replaces it with
RELASZ which is the size of all relocation records.
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220309061822.168173-1-aik@ozlabs.ru
58 lines
1.3 KiB
Bash
Executable File
58 lines
1.3 KiB
Bash
Executable File
#!/bin/sh
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# SPDX-License-Identifier: GPL-2.0-or-later
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# Copyright © 2015 IBM Corporation
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# This script checks the relocations of a vmlinux for "suspicious"
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# relocations.
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# based on relocs_check.pl
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# Copyright © 2009 IBM Corporation
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if [ $# -lt 3 ]; then
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echo "$0 [path to objdump] [path to nm] [path to vmlinux]" 1>&2
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exit 1
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fi
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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="$3"
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# Remove from the bad relocations those that match an undefined weak symbol
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# which will result in an absolute relocation to 0.
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# Weak unresolved symbols are of that form in nm output:
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# " w _binary__btf_vmlinux_bin_end"
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undef_weak_symbols=$($nm "$vmlinux" | awk '$1 ~ /w/ { print $2 }')
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bad_relocs=$(
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$objdump -R "$vmlinux" |
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# Only look at relocation lines.
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grep -E '\<R_' |
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# These relocations are okay
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# On PPC64:
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# R_PPC64_RELATIVE, R_PPC64_NONE
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# On PPC:
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# R_PPC_RELATIVE, R_PPC_ADDR16_HI,
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# R_PPC_ADDR16_HA,R_PPC_ADDR16_LO,
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# R_PPC_NONE
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grep -F -w -v 'R_PPC64_RELATIVE
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R_PPC64_NONE
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R_PPC64_UADDR64
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R_PPC_ADDR16_LO
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R_PPC_ADDR16_HI
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R_PPC_ADDR16_HA
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R_PPC_RELATIVE
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R_PPC_NONE' |
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([ "$undef_weak_symbols" ] && grep -F -w -v "$undef_weak_symbols" || cat)
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)
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if [ -z "$bad_relocs" ]; then
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exit 0
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fi
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num_bad=$(echo "$bad_relocs" | wc -l)
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echo "WARNING: $num_bad bad relocations"
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echo "$bad_relocs"
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