[binutils-gdb] LoongArch: Check PC-relative relocations for shared libraries
liu & zhensong
liuzhensong@sourceware.org
Thu Oct 17 13:02:58 GMT 2024
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=4cb77761d68791aa3fd9e7c0ec37fce86a4661f3
commit 4cb77761d68791aa3fd9e7c0ec37fce86a4661f3
Author: Lulu Cai <cailulu@loongson.cn>
Date: Mon Sep 30 16:08:59 2024 +0800
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.
Diff:
---
bfd/elfnn-loongarch.c | 21 +++++++++++++++++++++
.../ld-loongarch-elf/bad_pcala_hi20_global.d | 5 +++++
.../ld-loongarch-elf/bad_pcala_hi20_global.s | 8 ++++++++
ld/testsuite/ld-loongarch-elf/bad_pcala_hi20_weak.d | 5 +++++
ld/testsuite/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/testsuite/ld-loongarch-elf/bad_pcrel20_s2_weak.d | 5 +++++
ld/testsuite/ld-loongarch-elf/bad_pcrel20_s2_weak.s | 9 +++++++++
ld/testsuite/ld-loongarch-elf/data-plt.s | 1 +
ld/testsuite/ld-loongarch-elf/ld-loongarch-elf.exp | 4 ++++
11 files changed, 80 insertions(+)
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] {
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