* [PATCH] aarch64: Allow PC-relative relocations against protected STT_FUNC
@ 2022-06-02 6:50 Fangrui Song
2022-06-22 18:02 ` Fangrui Song
2022-06-23 8:00 ` Szabolcs Nagy
0 siblings, 2 replies; 3+ messages in thread
From: Fangrui Song @ 2022-06-02 6:50 UTC (permalink / raw)
To: binutils, Szabolcs Nagy; +Cc: Fangrui Song
__attribute__((visibility("protected"))) void *foo() {
return (void *)foo;
}
gcc -fpic -shared incorrectly fails with:
relocation R_AARCH64_ADR_PREL_PG_HI21 against symbol `foo' which may bind externally can not be used when making a shared object; recompile with -fPIC
Call _bfd_elf_symbol_refs_local_p with local_protected==true to suppress
the error. The new behavior matches gold and ld.lld.
Note: if some code tries to use direct access relocations to take the
address of foo (likely due to -fno-pic), the pointer equality will
break, but the error should be reported on that link.
---
bfd/elfnn-aarch64.c | 2 +-
ld/testsuite/ld-aarch64/aarch64-elf.exp | 1 +
ld/testsuite/ld-aarch64/pcrel-protected.s | 13 +++++++++++++
ld/testsuite/ld-aarch64/pcrel_pic_protected.d | 7 +++++++
4 files changed, 22 insertions(+), 1 deletion(-)
create mode 100644 ld/testsuite/ld-aarch64/pcrel-protected.s
create mode 100644 ld/testsuite/ld-aarch64/pcrel_pic_protected.d
diff --git a/bfd/elfnn-aarch64.c b/bfd/elfnn-aarch64.c
index cb316a928ef..2c8e3439d43 100644
--- a/bfd/elfnn-aarch64.c
+++ b/bfd/elfnn-aarch64.c
@@ -5878,7 +5878,7 @@ elfNN_aarch64_final_link_relocate (reloc_howto_type *howto,
if (bfd_link_pic (info)
&& (input_section->flags & SEC_ALLOC) != 0
&& (input_section->flags & SEC_READONLY) != 0
- && !SYMBOL_REFERENCES_LOCAL (info, h))
+ && !_bfd_elf_symbol_refs_local_p (h, info, 1))
{
int howto_index = bfd_r_type - BFD_RELOC_AARCH64_RELOC_START;
diff --git a/ld/testsuite/ld-aarch64/aarch64-elf.exp b/ld/testsuite/ld-aarch64/aarch64-elf.exp
index 64476f111e0..565a67aa9aa 100644
--- a/ld/testsuite/ld-aarch64/aarch64-elf.exp
+++ b/ld/testsuite/ld-aarch64/aarch64-elf.exp
@@ -248,6 +248,7 @@ run_dump_test_lp64 "local-addend-r"
# test error handling on pcrel relocation for shared libraries.
run_dump_test_lp64 "pcrel_pic_undefined"
run_dump_test_lp64 "pcrel_pic_defined"
+run_dump_test_lp64 "pcrel_pic_protected"
run_dump_test "limit-b"
run_dump_test "limit-bl"
diff --git a/ld/testsuite/ld-aarch64/pcrel-protected.s b/ld/testsuite/ld-aarch64/pcrel-protected.s
new file mode 100644
index 00000000000..ce2a92851ad
--- /dev/null
+++ b/ld/testsuite/ld-aarch64/pcrel-protected.s
@@ -0,0 +1,13 @@
+.protected protected_a
+.protected protected_b
+.type protected_b, %object
+.protected protected_c
+.type protected_c, %function
+
+.text
+ adrp x0, protected_a
+ add x0, x0, :lo12:protected_a
+ adrp x0, protected_b
+ add x0, x0, :lo12:protected_b
+ adrp x0, protected_c
+ add x0, x0, :lo12:protected_c
diff --git a/ld/testsuite/ld-aarch64/pcrel_pic_protected.d b/ld/testsuite/ld-aarch64/pcrel_pic_protected.d
new file mode 100644
index 00000000000..1b6f24cf2fb
--- /dev/null
+++ b/ld/testsuite/ld-aarch64/pcrel_pic_protected.d
@@ -0,0 +1,7 @@
+#name: PC-Rel relocation against protected
+#source: pcrel-protected.s
+#target: [check_shared_lib_support]
+#ld: -shared -e0 --defsym protected_a=0x1000 --defsym protected_b=0x1010 --defsym protected_c=0x1020
+#readelf: -r -W
+#...
+There are no relocations in this file.
--
2.36.1.255.ge46751e96f-goog
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] aarch64: Allow PC-relative relocations against protected STT_FUNC
2022-06-02 6:50 [PATCH] aarch64: Allow PC-relative relocations against protected STT_FUNC Fangrui Song
@ 2022-06-22 18:02 ` Fangrui Song
2022-06-23 8:00 ` Szabolcs Nagy
1 sibling, 0 replies; 3+ messages in thread
From: Fangrui Song @ 2022-06-22 18:02 UTC (permalink / raw)
To: binutils, Szabolcs Nagy, Nick Clifton
On Wed, Jun 1, 2022 at 11:50 PM Fangrui Song <maskray@google.com> wrote:
>
> __attribute__((visibility("protected"))) void *foo() {
> return (void *)foo;
> }
>
> gcc -fpic -shared incorrectly fails with:
>
> relocation R_AARCH64_ADR_PREL_PG_HI21 against symbol `foo' which may bind externally can not be used when making a shared object; recompile with -fPIC
>
> Call _bfd_elf_symbol_refs_local_p with local_protected==true to suppress
> the error. The new behavior matches gold and ld.lld.
>
> Note: if some code tries to use direct access relocations to take the
> address of foo (likely due to -fno-pic), the pointer equality will
> break, but the error should be reported on that link.
> ---
> bfd/elfnn-aarch64.c | 2 +-
> ld/testsuite/ld-aarch64/aarch64-elf.exp | 1 +
> ld/testsuite/ld-aarch64/pcrel-protected.s | 13 +++++++++++++
> ld/testsuite/ld-aarch64/pcrel_pic_protected.d | 7 +++++++
> 4 files changed, 22 insertions(+), 1 deletion(-)
> create mode 100644 ld/testsuite/ld-aarch64/pcrel-protected.s
> create mode 100644 ld/testsuite/ld-aarch64/pcrel_pic_protected.d
>
> diff --git a/bfd/elfnn-aarch64.c b/bfd/elfnn-aarch64.c
> index cb316a928ef..2c8e3439d43 100644
> --- a/bfd/elfnn-aarch64.c
> +++ b/bfd/elfnn-aarch64.c
> @@ -5878,7 +5878,7 @@ elfNN_aarch64_final_link_relocate (reloc_howto_type *howto,
> if (bfd_link_pic (info)
> && (input_section->flags & SEC_ALLOC) != 0
> && (input_section->flags & SEC_READONLY) != 0
> - && !SYMBOL_REFERENCES_LOCAL (info, h))
> + && !_bfd_elf_symbol_refs_local_p (h, info, 1))
> {
> int howto_index = bfd_r_type - BFD_RELOC_AARCH64_RELOC_START;
>
> diff --git a/ld/testsuite/ld-aarch64/aarch64-elf.exp b/ld/testsuite/ld-aarch64/aarch64-elf.exp
> index 64476f111e0..565a67aa9aa 100644
> --- a/ld/testsuite/ld-aarch64/aarch64-elf.exp
> +++ b/ld/testsuite/ld-aarch64/aarch64-elf.exp
> @@ -248,6 +248,7 @@ run_dump_test_lp64 "local-addend-r"
> # test error handling on pcrel relocation for shared libraries.
> run_dump_test_lp64 "pcrel_pic_undefined"
> run_dump_test_lp64 "pcrel_pic_defined"
> +run_dump_test_lp64 "pcrel_pic_protected"
>
> run_dump_test "limit-b"
> run_dump_test "limit-bl"
> diff --git a/ld/testsuite/ld-aarch64/pcrel-protected.s b/ld/testsuite/ld-aarch64/pcrel-protected.s
> new file mode 100644
> index 00000000000..ce2a92851ad
> --- /dev/null
> +++ b/ld/testsuite/ld-aarch64/pcrel-protected.s
> @@ -0,0 +1,13 @@
> +.protected protected_a
> +.protected protected_b
> +.type protected_b, %object
> +.protected protected_c
> +.type protected_c, %function
> +
> +.text
> + adrp x0, protected_a
> + add x0, x0, :lo12:protected_a
> + adrp x0, protected_b
> + add x0, x0, :lo12:protected_b
> + adrp x0, protected_c
> + add x0, x0, :lo12:protected_c
> diff --git a/ld/testsuite/ld-aarch64/pcrel_pic_protected.d b/ld/testsuite/ld-aarch64/pcrel_pic_protected.d
> new file mode 100644
> index 00000000000..1b6f24cf2fb
> --- /dev/null
> +++ b/ld/testsuite/ld-aarch64/pcrel_pic_protected.d
> @@ -0,0 +1,7 @@
> +#name: PC-Rel relocation against protected
> +#source: pcrel-protected.s
> +#target: [check_shared_lib_support]
> +#ld: -shared -e0 --defsym protected_a=0x1000 --defsym protected_b=0x1010 --defsym protected_c=0x1020
> +#readelf: -r -W
> +#...
> +There are no relocations in this file.
> --
> 2.36.1.255.ge46751e96f-goog
>
:)
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] aarch64: Allow PC-relative relocations against protected STT_FUNC
2022-06-02 6:50 [PATCH] aarch64: Allow PC-relative relocations against protected STT_FUNC Fangrui Song
2022-06-22 18:02 ` Fangrui Song
@ 2022-06-23 8:00 ` Szabolcs Nagy
1 sibling, 0 replies; 3+ messages in thread
From: Szabolcs Nagy @ 2022-06-23 8:00 UTC (permalink / raw)
To: Fangrui Song; +Cc: binutils
The 06/01/2022 23:50, Fangrui Song wrote:
> __attribute__((visibility("protected"))) void *foo() {
> return (void *)foo;
> }
>
> gcc -fpic -shared incorrectly fails with:
>
> relocation R_AARCH64_ADR_PREL_PG_HI21 against symbol `foo' which may bind externally can not be used when making a shared object; recompile with -fPIC
>
> Call _bfd_elf_symbol_refs_local_p with local_protected==true to suppress
> the error. The new behavior matches gold and ld.lld.
>
> Note: if some code tries to use direct access relocations to take the
> address of foo (likely due to -fno-pic), the pointer equality will
> break, but the error should be reported on that link.
This patch looks good to me.
Thanks.
> ---
> bfd/elfnn-aarch64.c | 2 +-
> ld/testsuite/ld-aarch64/aarch64-elf.exp | 1 +
> ld/testsuite/ld-aarch64/pcrel-protected.s | 13 +++++++++++++
> ld/testsuite/ld-aarch64/pcrel_pic_protected.d | 7 +++++++
> 4 files changed, 22 insertions(+), 1 deletion(-)
> create mode 100644 ld/testsuite/ld-aarch64/pcrel-protected.s
> create mode 100644 ld/testsuite/ld-aarch64/pcrel_pic_protected.d
>
> diff --git a/bfd/elfnn-aarch64.c b/bfd/elfnn-aarch64.c
> index cb316a928ef..2c8e3439d43 100644
> --- a/bfd/elfnn-aarch64.c
> +++ b/bfd/elfnn-aarch64.c
> @@ -5878,7 +5878,7 @@ elfNN_aarch64_final_link_relocate (reloc_howto_type *howto,
> if (bfd_link_pic (info)
> && (input_section->flags & SEC_ALLOC) != 0
> && (input_section->flags & SEC_READONLY) != 0
> - && !SYMBOL_REFERENCES_LOCAL (info, h))
> + && !_bfd_elf_symbol_refs_local_p (h, info, 1))
> {
> int howto_index = bfd_r_type - BFD_RELOC_AARCH64_RELOC_START;
>
> diff --git a/ld/testsuite/ld-aarch64/aarch64-elf.exp b/ld/testsuite/ld-aarch64/aarch64-elf.exp
> index 64476f111e0..565a67aa9aa 100644
> --- a/ld/testsuite/ld-aarch64/aarch64-elf.exp
> +++ b/ld/testsuite/ld-aarch64/aarch64-elf.exp
> @@ -248,6 +248,7 @@ run_dump_test_lp64 "local-addend-r"
> # test error handling on pcrel relocation for shared libraries.
> run_dump_test_lp64 "pcrel_pic_undefined"
> run_dump_test_lp64 "pcrel_pic_defined"
> +run_dump_test_lp64 "pcrel_pic_protected"
>
> run_dump_test "limit-b"
> run_dump_test "limit-bl"
> diff --git a/ld/testsuite/ld-aarch64/pcrel-protected.s b/ld/testsuite/ld-aarch64/pcrel-protected.s
> new file mode 100644
> index 00000000000..ce2a92851ad
> --- /dev/null
> +++ b/ld/testsuite/ld-aarch64/pcrel-protected.s
> @@ -0,0 +1,13 @@
> +.protected protected_a
> +.protected protected_b
> +.type protected_b, %object
> +.protected protected_c
> +.type protected_c, %function
> +
> +.text
> + adrp x0, protected_a
> + add x0, x0, :lo12:protected_a
> + adrp x0, protected_b
> + add x0, x0, :lo12:protected_b
> + adrp x0, protected_c
> + add x0, x0, :lo12:protected_c
> diff --git a/ld/testsuite/ld-aarch64/pcrel_pic_protected.d b/ld/testsuite/ld-aarch64/pcrel_pic_protected.d
> new file mode 100644
> index 00000000000..1b6f24cf2fb
> --- /dev/null
> +++ b/ld/testsuite/ld-aarch64/pcrel_pic_protected.d
> @@ -0,0 +1,7 @@
> +#name: PC-Rel relocation against protected
> +#source: pcrel-protected.s
> +#target: [check_shared_lib_support]
> +#ld: -shared -e0 --defsym protected_a=0x1000 --defsym protected_b=0x1010 --defsym protected_c=0x1020
> +#readelf: -r -W
> +#...
> +There are no relocations in this file.
> --
> 2.36.1.255.ge46751e96f-goog
>
^ permalink raw reply [flat|nested] 3+ messages in thread
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2022-06-02 6:50 [PATCH] aarch64: Allow PC-relative relocations against protected STT_FUNC Fangrui Song
2022-06-22 18:02 ` Fangrui Song
2022-06-23 8:00 ` Szabolcs Nagy
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