82 lines
2.9 KiB
Diff
82 lines
2.9 KiB
Diff
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commit cb19cef087eaa551568739aa5b59cf97b8d5da1e
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Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>
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Date: Tue Jul 16 07:57:45 2024 -0300
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elf: Fix localplt.awk for DT_RELR-enabled builds (BZ 31978)
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For each input readelf output, localplt.awk parses each 'Relocation
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section' entry, checks its offset against the dynamic section entry, and
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saves each DT_JMPREL, DT_RELA, and DT_REL offset value it finds. After
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all lines are read, the script checks if any segment offset differed
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from 0, meaning at least one 'Relocation section' was matched.
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However, if the shared object was built with RELR support and the static
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linker could place all the relocation on DT_RELR, there would be no
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DT_JMPREL, DT_RELA, and DT_REL entries; only a DT_RELR.
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For the current three ABIs that support (aarch64, x86, and powerpc64),
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the powerpc64 ld.so shows the behavior above. Both x86_64 and aarch64
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show extra relocations on '.rela.dyn', which makes the script check to
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succeed.
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This patch fixes by handling DT_RELR, where the offset is checked
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against the dynamic section entries and if the shared object contains an
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entry it means that there are no extra PLT entries (since all
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relocations are relative).
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It fixes the elf/check-localplt failure on powerpc.
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Checked with a build/check for aarch64-linux-gnu, x86_64-linux-gnu,
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i686-linux-gnu, arm-linux-gnueabihf, s390x-linux-gnu, powerpc-linux-gnu,
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powerpc64-linux-gnu, and powerpc64le-linux-gnu.
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Reviewed-by: Carlos O'Donell <carlos@redhat.com>
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(cherry picked from commit 4f047d9edecb1a9b796a9a904dcd42bd3cc3d3b6)
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diff --git a/scripts/localplt.awk b/scripts/localplt.awk
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index fe79ca01abcb1a75..621ae7d8e815a4e5 100644
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--- a/scripts/localplt.awk
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+++ b/scripts/localplt.awk
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@@ -10,7 +10,8 @@ BEGIN {
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}
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FILENAME != lastfile {
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- if (lastfile && jmprel_offset == 0 && rela_offset == 0 && rel_offset == 0) {
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+ if (lastfile && jmprel_offset == 0 && rela_offset == 0 && rel_offset == 0 \
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+ && relr_offset == 0) {
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print FILENAME ": *** failed to find expected output (readelf -WSdr)";
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result = 2;
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}
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@@ -22,6 +23,7 @@ FILENAME != lastfile {
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jmprel_offset = 0;
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rela_offset = 0;
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rel_offset = 0;
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+ relr_offset = 0;
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pltrelsz = -1;
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delete section_offset_by_address;
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}
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@@ -77,6 +79,8 @@ in_relocs && relocs_offset == rel_offset && NF >= 5 {
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}
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}
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+# No need to handle DT_RELR (all packed relocations are relative).
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+
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in_relocs { next }
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$1 == "Relocation" && $2 == "section" && $5 == "offset" {
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@@ -121,4 +125,14 @@ $2 == "(REL)" {
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}
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next
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}
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+
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+$2 == "(RELR)" {
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+ relr_addr = strtonum($3);
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+ if (relr_addr in section_offset_by_address) {
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+ relr_offset = section_offset_by_address[relr_addr];
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+ } else {
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+ print FILENAME ": *** DT_RELR does not match any section's address";
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+ result = 2;
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+ }
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+}
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END { exit(result) }
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