From 4cb77761d68791aa3fd9e7c0ec37fce86a4661f3 Mon Sep 17 00:00:00 2001 From: Lulu Cai Date: Mon, 30 Sep 2024 16:08:59 +0800 Subject: [PATCH] LoongArch: Check PC-relative relocations for shared libraries Building shared libraries should not be allowed for PC-relative relocations against external symbols. Currently LoongArch has no corresponding checks and silently generates wrong shared libraries. However, In the first version of the medium cmodel, pcalau12i+jirl was used for function calls, in which case PC-relative relocations were allowed. --- bfd/elfnn-loongarch.c | 21 +++++++++++++++++++ .../ld-loongarch-elf/bad_pcala_hi20_global.d | 5 +++++ .../ld-loongarch-elf/bad_pcala_hi20_global.s | 8 +++++++ .../ld-loongarch-elf/bad_pcala_hi20_weak.d | 5 +++++ .../ld-loongarch-elf/bad_pcala_hi20_weak.s | 9 ++++++++ .../ld-loongarch-elf/bad_pcrel20_s2_global.d | 5 +++++ .../ld-loongarch-elf/bad_pcrel20_s2_global.s | 8 +++++++ .../ld-loongarch-elf/bad_pcrel20_s2_weak.d | 5 +++++ .../ld-loongarch-elf/bad_pcrel20_s2_weak.s | 9 ++++++++ ld/testsuite/ld-loongarch-elf/data-plt.s | 1 + .../ld-loongarch-elf/ld-loongarch-elf.exp | 4 ++++ 11 files changed, 80 insertions(+) create mode 100644 ld/testsuite/ld-loongarch-elf/bad_pcala_hi20_global.d create mode 100644 ld/testsuite/ld-loongarch-elf/bad_pcala_hi20_global.s create mode 100644 ld/testsuite/ld-loongarch-elf/bad_pcala_hi20_weak.d create mode 100644 ld/testsuite/ld-loongarch-elf/bad_pcala_hi20_weak.s create mode 100644 ld/testsuite/ld-loongarch-elf/bad_pcrel20_s2_global.d create mode 100644 ld/testsuite/ld-loongarch-elf/bad_pcrel20_s2_global.s create mode 100644 ld/testsuite/ld-loongarch-elf/bad_pcrel20_s2_weak.d create mode 100644 ld/testsuite/ld-loongarch-elf/bad_pcrel20_s2_weak.s diff --git a/bfd/elfnn-loongarch.c b/bfd/elfnn-loongarch.c index 9c3cd6745d6..3b1a6a4f95a 100644 --- a/bfd/elfnn-loongarch.c +++ b/bfd/elfnn-loongarch.c @@ -1079,6 +1079,18 @@ loongarch_elf_check_relocs (bfd *abfd, struct bfd_link_info *info, h->non_got_ref = 1; break; + /* Since shared library global symbols interpose, any + PC-relative relocations against external symbols + should not be used to build shared libraries. */ + case R_LARCH_PCREL20_S2: + if (bfd_link_pic (info) + && (sec->flags & SEC_ALLOC) != 0 + && (sec->flags & SEC_READONLY) != 0 + && ! LARCH_REF_LOCAL (info, h)) + return bad_static_reloc (abfd, rel, sec, r_type, h, NULL); + + break; + /* For normal cmodel, pcalau12i + addi.d/w used to data. For first version medium cmodel, pcalau12i + jirl are used to function call, it need to creat PLT entry for STT_FUNC and @@ -1096,6 +1108,15 @@ loongarch_elf_check_relocs (bfd *abfd, struct bfd_link_info *info, h->pointer_equality_needed = 1; } + /* PC-relative relocations are allowed For first version + medium cmodel function call. */ + if (h != NULL && !h->needs_plt + && bfd_link_pic (info) + && (sec->flags & SEC_ALLOC) != 0 + && (sec->flags & SEC_READONLY) != 0 + && ! LARCH_REF_LOCAL (info, h)) + return bad_static_reloc (abfd, rel, sec, r_type, h, NULL); + break; case R_LARCH_B16: diff --git a/ld/testsuite/ld-loongarch-elf/bad_pcala_hi20_global.d b/ld/testsuite/ld-loongarch-elf/bad_pcala_hi20_global.d new file mode 100644 index 00000000000..6ecefd1d48a --- /dev/null +++ b/ld/testsuite/ld-loongarch-elf/bad_pcala_hi20_global.d @@ -0,0 +1,5 @@ +#name: PC-relative relocation making shared +#source: bad_pcala_hi20_global.s +#target: [check_shared_lib_support] +#ld: -shared --defsym global_a=0x10 --defsym global_b=0x20 +#error: .*: relocation R_LARCH_PCALA_HI20 against `global_b` can not be used when making a shared object; recompile with -fPIC diff --git a/ld/testsuite/ld-loongarch-elf/bad_pcala_hi20_global.s b/ld/testsuite/ld-loongarch-elf/bad_pcala_hi20_global.s new file mode 100644 index 00000000000..d8189e45370 --- /dev/null +++ b/ld/testsuite/ld-loongarch-elf/bad_pcala_hi20_global.s @@ -0,0 +1,8 @@ + .hidden global_a + .text + .align 2 +main: + # Symbols defined .hidden are bound local and + # the linker should differenciate them. + la.pcrel $a0, global_a + la.pcrel $a0, global_b diff --git a/ld/testsuite/ld-loongarch-elf/bad_pcala_hi20_weak.d b/ld/testsuite/ld-loongarch-elf/bad_pcala_hi20_weak.d new file mode 100644 index 00000000000..cefc42cf89f --- /dev/null +++ b/ld/testsuite/ld-loongarch-elf/bad_pcala_hi20_weak.d @@ -0,0 +1,5 @@ +#name: PC-relative relocation making shared +#source: bad_pcala_hi20_weak.s +#target: [check_shared_lib_support] +#ld: -shared --defsym global_a=0x10 --defsym global_b=0x20 +#error: .*: relocation R_LARCH_PCALA_HI20 against `global_b` can not be used when making a shared object; recompile with -fPIC diff --git a/ld/testsuite/ld-loongarch-elf/bad_pcala_hi20_weak.s b/ld/testsuite/ld-loongarch-elf/bad_pcala_hi20_weak.s new file mode 100644 index 00000000000..73c6ec5f9c3 --- /dev/null +++ b/ld/testsuite/ld-loongarch-elf/bad_pcala_hi20_weak.s @@ -0,0 +1,9 @@ + .hidden global_a + .weak global_b + .text + .align 2 +main: + # Symbols defined .hidden are bound local and + # the linker should differenciate them. + la.pcrel $a0, global_a + la.pcrel $a0, global_b diff --git a/ld/testsuite/ld-loongarch-elf/bad_pcrel20_s2_global.d b/ld/testsuite/ld-loongarch-elf/bad_pcrel20_s2_global.d new file mode 100644 index 00000000000..8e063dfb0ec --- /dev/null +++ b/ld/testsuite/ld-loongarch-elf/bad_pcrel20_s2_global.d @@ -0,0 +1,5 @@ +#name: PC-relative relocation making shared +#source: bad_pcrel20_s2_global.s +#target: [check_shared_lib_support] +#ld: -shared --defsym global_a=0x10 --defsym global_b=0x20 +#error: .*: relocation R_LARCH_PCREL20_S2 against `global_b` can not be used when making a shared object; recompile with -fPIC diff --git a/ld/testsuite/ld-loongarch-elf/bad_pcrel20_s2_global.s b/ld/testsuite/ld-loongarch-elf/bad_pcrel20_s2_global.s new file mode 100644 index 00000000000..39cedbd2743 --- /dev/null +++ b/ld/testsuite/ld-loongarch-elf/bad_pcrel20_s2_global.s @@ -0,0 +1,8 @@ + .hidden global_a + .text + .align 2 +main: + # Symbols defined .hidden are bound local and + # the linker should differenciate them. + pcaddi $a0, %pcrel_20(global_a) + pcaddi $a0, %pcrel_20(global_b) diff --git a/ld/testsuite/ld-loongarch-elf/bad_pcrel20_s2_weak.d b/ld/testsuite/ld-loongarch-elf/bad_pcrel20_s2_weak.d new file mode 100644 index 00000000000..605df24988a --- /dev/null +++ b/ld/testsuite/ld-loongarch-elf/bad_pcrel20_s2_weak.d @@ -0,0 +1,5 @@ +#name: PC-relative relocation making shared +#source: bad_pcrel20_s2_weak.s +#target: [check_shared_lib_support] +#ld: -shared --defsym global_a=0x10 --defsym global_b=0x20 +#error: .*: relocation R_LARCH_PCREL20_S2 against `global_b` can not be used when making a shared object; recompile with -fPIC diff --git a/ld/testsuite/ld-loongarch-elf/bad_pcrel20_s2_weak.s b/ld/testsuite/ld-loongarch-elf/bad_pcrel20_s2_weak.s new file mode 100644 index 00000000000..82faa5bbf86 --- /dev/null +++ b/ld/testsuite/ld-loongarch-elf/bad_pcrel20_s2_weak.s @@ -0,0 +1,9 @@ + .hidden global_a + .weak global_b + .text + .align 2 +main: + # Symbols defined .hidden are bound local and + # the linker should differenciate them. + pcaddi $a0, %pcrel_20(global_a) + pcaddi $a0, %pcrel_20(global_b) diff --git a/ld/testsuite/ld-loongarch-elf/data-plt.s b/ld/testsuite/ld-loongarch-elf/data-plt.s index faff052c628..6c1a8eac35c 100644 --- a/ld/testsuite/ld-loongarch-elf/data-plt.s +++ b/ld/testsuite/ld-loongarch-elf/data-plt.s @@ -2,6 +2,7 @@ # R_LARCH_PCALA_HI20 only need to generate PLT entry for function symbols. .text .globl a + .hidden a .data .align 2 diff --git a/ld/testsuite/ld-loongarch-elf/ld-loongarch-elf.exp b/ld/testsuite/ld-loongarch-elf/ld-loongarch-elf.exp index 6bef97c260f..4e0068d9f89 100644 --- a/ld/testsuite/ld-loongarch-elf/ld-loongarch-elf.exp +++ b/ld/testsuite/ld-loongarch-elf/ld-loongarch-elf.exp @@ -166,6 +166,10 @@ if [istarget "loongarch64-*-*"] { run_dump_test "relr-got-shared" run_dump_test "relr-text-shared" run_dump_test "abssym_shared" + run_dump_test "bad_pcala_hi20_global" + run_dump_test "bad_pcala_hi20_weak" + run_dump_test "bad_pcrel20_s2_global" + run_dump_test "bad_pcrel20_s2_weak" } if [check_pie_support] { -- 2.39.5