From 51def3dc6a168d03d28e0d4e2935d9ddb2929192 Mon Sep 17 00:00:00 2001
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From: Stafford Horne <shorne@gmail.com>
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Date: Sun, 2 Jan 2022 09:03:28 +0900
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Subject: [PATCH] or1k: Avoid R_OR1K_GOT16 signed overflow by using special
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howto
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Previously when fixing PR 21464 we masked out upper bits of the
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relocation value in order to avoid overflow complaints when acceptable.
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It turns out this does not work when the relocation value ends up being
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signed.
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To fix this this patch introduces a special howto with
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complain_on_overflow set to complain_overflow_dont. This is used in
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place of the normal R_OR1K_GOT16 howto when we detect R_OR1K_GOT_AHI16
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relocations.
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bfd/ChangeLog:
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PR 28735
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* elf32-or1k.c (or1k_elf_got16_no_overflow_howto): Define.
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(or1k_elf_relocate_section): Use new howto instead of trying to
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mask out relocation bits.
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Signed-off-by: Giulio Benetti <giulio.benetti@benettiengineering.com>
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---
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bfd/elf32-or1k.c | 24 ++++++++++++++++++++----
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1 file changed, 20 insertions(+), 4 deletions(-)
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diff --git a/bfd/elf32-or1k.c b/bfd/elf32-or1k.c
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index cfa292f0032..ecb70753b6a 100644
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--- a/bfd/elf32-or1k.c
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+++ b/bfd/elf32-or1k.c
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@@ -828,6 +828,23 @@ static reloc_howto_type or1k_elf_howto_table[] =
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FALSE), /* pcrel_offset */
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};
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+/* A copy of the R_OR1K_GOT16 used in the presense of R_OR1K_GOT_AHI16
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+ relocations when we know we can ignore overflows. */
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+static reloc_howto_type or1k_elf_got16_no_overflow_howto =
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+ HOWTO (R_OR1K_GOT16, /* type */
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+ 0, /* rightshift */
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+ 2, /* size (0 = byte, 1 = short, 2 = long) */
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+ 16, /* bitsize */
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+ FALSE, /* pc_relative */
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+ 0, /* bitpos */
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+ complain_overflow_dont, /* complain_on_overflow */
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+ bfd_elf_generic_reloc, /* special_function */
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+ "R_OR1K_GOT16", /* name */
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+ FALSE, /* partial_inplace */
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+ 0, /* src_mask */
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+ 0xffff, /* dst_mask */
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+ FALSE); /* pcrel_offset */
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+
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/* Map BFD reloc types to Or1k ELF reloc types. */
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struct or1k_reloc_map
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@@ -1477,12 +1494,11 @@ or1k_elf_relocate_section (bfd *output_bfd,
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if (r_type == R_OR1K_GOT_AHI16)
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saw_gotha = TRUE;
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- /* If we have a R_OR1K_GOT16 followed by a R_OR1K_GOT_AHI16
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+ /* If we have a R_OR1K_GOT16 following a R_OR1K_GOT_AHI16
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relocation we assume the code is doing the right thing to avoid
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- overflows. Here we mask the lower 16-bit of the relocation to
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- avoid overflow validation failures. */
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+ overflows. */
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if (r_type == R_OR1K_GOT16 && saw_gotha)
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- relocation &= 0xffff;
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+ howto = &or1k_elf_got16_no_overflow_howto;
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/* Addend should be zero. */
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if (rel->r_addend != 0)
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--
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2.25.1
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