From 51fec5f1ff46d9c56ab6486f4e8d710748ef4df0 Mon Sep 17 00:00:00 2001 From: Rui Ueyama Date: Wed, 23 Aug 2023 14:02:03 +0900 Subject: [PATCH] Avoid reading data from .plt --- elf/arch-ppc64v1.cc | 12 ++++++------ elf/elf.h | 2 +- 2 files changed, 7 insertions(+), 7 deletions(-) diff --git a/elf/arch-ppc64v1.cc b/elf/arch-ppc64v1.cc index 32670078..dc7a37a7 100644 --- a/elf/arch-ppc64v1.cc +++ b/elf/arch-ppc64v1.cc @@ -72,22 +72,22 @@ void write_plt_header(Context &ctx, u8 *buf) { 0x7d88'02a6, // mflr r12 0x429f'0005, // bcl 20, 31, 4 // obtain PC 0x7d68'02a6, // mflr r11 - 0xe84b'0024, // ld r2,36(r11) 0x7d88'03a6, // mtlr r12 - 0x7d62'5a14, // add r11,r2,r11 + 0x3d6b'0000, // addis r11, r11, GOTPLT_OFFSET@ha + 0x396b'0000, // addi r11, r11, GOTPLT_OFFSET@lo 0xe98b'0000, // ld r12,0(r11) 0xe84b'0008, // ld r2,8(r11) 0x7d89'03a6, // mtctr r12 0xe96b'0010, // ld r11,16(r11) 0x4e80'0420, // bctr - // .quad .got.plt - .plt - 8 - 0x0000'0000, - 0x0000'0000, }; static_assert(sizeof(insn) == E::plt_hdr_size); memcpy(buf, insn, sizeof(insn)); - *(ub64 *)(buf + 44) = ctx.gotplt->shdr.sh_addr - ctx.plt->shdr.sh_addr - 8; + + i64 val = ctx.gotplt->shdr.sh_addr - ctx.plt->shdr.sh_addr - 8; + *(ub32 *)(buf + 16) |= higha(val); + *(ub32 *)(buf + 20) |= lo(val); } template <> diff --git a/elf/elf.h b/elf/elf.h index 5f303f81..37e1e4e4 100644 --- a/elf/elf.h +++ b/elf/elf.h @@ -2149,7 +2149,7 @@ struct PPC64 { struct PPC64V1 : PPC64 { static constexpr std::string_view target_name = "ppc64v1"; static constexpr bool is_le = false; - static constexpr u32 plt_hdr_size = 52; + static constexpr u32 plt_hdr_size = 44; static constexpr u32 pltgot_size = 0; static constexpr u32 thunk_hdr_size = 0; static constexpr u32 thunk_size = 28;