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Play the code-golf with our s390x PLT header

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This commit is contained in:
Rui Ueyama 2023-08-23 22:37:30 +09:00
parent 03b5ce7c6f
commit 8f5c49c655
2 changed files with 5 additions and 9 deletions
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12
elf/arch-s390x.cc
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@ -51,24 +51,20 @@ void write_plt_header(Context<E> &ctx, u8 *buf) {
// Compute PLT_INDEX
0xa7, 0x15, 0x00, 0x02, // bras %r1, 1f
0xb9, 0x09, 0x00, 0x01, // 1: sgr %r0, %r1
0xa7, 0x0b, 0xff, 0xb6, // aghi %r0, -74
0xeb, 0x00, 0x00, 0x04, 0x00, 0x0c, // srlg %r0, %r0, 4
// Multiply PLT_INDEX by 24 (i.e. sizeof(ElfRel<E>))
0xeb, 0x10, 0x00, 0x01, 0x00, 0x0d, // sllg %r1, %r0, 1
0xa7, 0x0b, 0xff, 0xc6, // aghi %r0, -58
0xeb, 0x10, 0x00, 0x01, 0x00, 0x0c, // srlg %r1, %r0, 1
0xb9, 0x08, 0x00, 0x01, // agr %r0, %r1
0xeb, 0x00, 0x00, 0x03, 0x00, 0x0d, // sllg %r0, %r0, 3
0xe3, 0x00, 0xf0, 0x38, 0x00, 0x24, // stg %r0, 56(%r15)
// Branch to _dl_runtime_resolve
0xc0, 0x10, 0, 0, 0, 0, // larl %r1, GOTPLT_OFFSET
0xd2, 0x07, 0xf0, 0x30, 0x10, 0x08, // mvc 48(8, %r15), 8(%r1)
0xe3, 0x10, 0x10, 0x10, 0x00, 0x04, // lg %r1, 16(%r1)
0x07, 0xf1, // br %r1
0x07, 0x00, 0x07, 0x00, // nopr; nopr
};
memcpy(buf, insn, sizeof(insn));
*(ub32 *)(buf + 42) =
(ctx.gotplt->shdr.sh_addr - ctx.plt->shdr.sh_addr - 40) >> 1;
*(ub32 *)(buf + 30) =
(ctx.gotplt->shdr.sh_addr - ctx.plt->shdr.sh_addr - 28) >> 1;
}
template <>

2
elf/elf.h
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@ -2172,7 +2172,7 @@ struct S390X {
static constexpr bool is_rela = true;
static constexpr u32 page_size = 4096;
static constexpr u32 e_machine = EM_S390X;
static constexpr u32 plt_hdr_size = 64;
static constexpr u32 plt_hdr_size = 48;
static constexpr u32 plt_size = 16;
static constexpr u32 pltgot_size = 16;