Hi Richard
On 02/04/2019 10:25, Sudakshina Das wrote:
> Hi
>
> On 02/04/2019 03:27, H.J. Lu wrote:
>> On Tue, Apr 2, 2019 at 10:05 AM Richard Henderson <[email protected]>
>> wrote:
>>>
>>> On 4/1/19 8:53 PM, Sudakshina Das wrote:
>>>>> This could stand to use a comment, a moment's thinking about the
>>>>> sizes, and to
>>>>> use the existing asm output functions.
>>>>>
>>>>> /* PT_NOTE header: namesz, descsz, type.
>>>>> namesz = 4 ("GNU\0")
>>>>> descsz = 12 (see below)
>>>> I was trying out these changes but the descsz of 12 gets rejected by
>>>> readelf. It hits the following
>>>>
>>>> unsigned int size = is_32bit_elf ? 4 : 8;
>>>>
>>>> printf (_(" Properties: "));
>>>>
>>>> if (pnote->descsz < 8 || (pnote->descsz % size) != 0)
>>>> {
>>>> printf (_("<corrupt GNU_PROPERTY_TYPE, size = %#lx>\n"),
>>>> pnote->descsz);
>>>> return;
>>>> }
>>>
>>> Hmm, interesting. The docs say that padding is not to be included in
>>> descsz
>>> (gabi4.1, page 82). To my eye this is a bug in binutils, but perhaps
>>> we will
>>> have to live with it.
>>>
>>> Nick, thoughts?
>>
>> descsz is wrong. From:
>>
>> https://github.com/hjl-tools/linux-abi/wiki/Linux-Extensions-to-gABI
>>
>> n_desc The note descriptor. The first n_descsz bytes in n_desc is the
>> pro-
>> gram property array.
>>
>> The program property array
>> Each array element represents one program property with type, data
>> size and data.
>> In 64-bit objects, each element is an array of 8-byte integers in the
>> format of the
>> target processor. In 32-bit objects, each element is an array of
>> 4-byte integers in
>> the format of the target processor.
>
> Thanks @HJ for clarifying that. I should have been more careful in
> spotting the difference.
>
> @Richard I will update my patch according to your suggestions but
> keeping in mind decssz should be the size of the entire program property
> array so 16 in this case.
>
I have updated the patch as per your suggestions. The Changelog is still
valid from my original patch.
Thanks
Sudi
> Thanks
> Sudi
>>
>>
>
diff --git a/gcc/config/aarch64/aarch64-linux.h b/gcc/config/aarch64/aarch64-linux.h
index 9d0292d64f20939ccedd7ab56027aa1282826b23..5e8b34ded03c78493f868e38647bf57c2da5187c 100644
--- a/gcc/config/aarch64/aarch64-linux.h
+++ b/gcc/config/aarch64/aarch64-linux.h
@@ -83,7 +83,7 @@
#define GNU_USER_TARGET_D_CRITSEC_SIZE 48
-#define TARGET_ASM_FILE_END file_end_indicate_exec_stack
+#define TARGET_ASM_FILE_END aarch64_file_end_indicate_exec_stack
/* Uninitialized common symbols in non-PIE executables, even with
strong definitions in dependent shared libraries, will resolve
diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
index b38505b0872688634b2d3f625ab8d313e89cfca0..f25f7da8f0224167db68e61a2ba88f0943316360 100644
--- a/gcc/config/aarch64/aarch64.c
+++ b/gcc/config/aarch64/aarch64.c
@@ -18744,6 +18744,56 @@ aarch64_stack_protect_guard (void)
return NULL_TREE;
}
+/* Implement TARGET_ASM_FILE_END for AArch64. This adds the AArch64 GNU NOTE
+ section at the end if needed. */
+#define GNU_PROPERTY_AARCH64_FEATURE_1_AND 0xc0000000
+#define GNU_PROPERTY_AARCH64_FEATURE_1_BTI (1U << 0)
+#define GNU_PROPERTY_AARCH64_FEATURE_1_PAC (1U << 1)
+void
+aarch64_file_end_indicate_exec_stack ()
+{
+ file_end_indicate_exec_stack ();
+
+ unsigned feature_1_and = 0;
+ if (aarch64_bti_enabled ())
+ feature_1_and |= GNU_PROPERTY_AARCH64_FEATURE_1_BTI;
+
+ if (aarch64_ra_sign_scope != AARCH64_FUNCTION_NONE)
+ feature_1_and |= GNU_PROPERTY_AARCH64_FEATURE_1_PAC;
+
+ if (feature_1_and)
+ {
+ /* Generate .note.gnu.property section. */
+ switch_to_section (get_section (".note.gnu.property",
+ SECTION_NOTYPE, NULL));
+
+ /* PT_NOTE header: namesz, descsz, type.
+ namesz = 4 ("GNU\0")
+ descsz = 16 (Size of the program property array)
+ type = 5 (NT_GNU_PROPERTY_TYPE_0). */
+ assemble_align (POINTER_SIZE);
+ assemble_integer (GEN_INT (4), 4, 32, 1);
+ assemble_integer (GEN_INT (16), 4, 32, 1);
+ assemble_integer (GEN_INT (5), 4, 32, 1);
+
+ /* PT_NOTE name. */
+ assemble_string ("GNU", 4);
+
+ /* PT_NOTE contents for NT_GNU_PROPERTY_TYPE_0:
+ type = GNU_PROPERTY_AARCH64_FEATURE_1_AND
+ datasz = 4
+ data = feature_1_and. */
+ assemble_integer (GEN_INT (GNU_PROPERTY_AARCH64_FEATURE_1_AND), 4, 32, 1);
+ assemble_integer (GEN_INT (4), 4, 32, 1);
+ assemble_integer (GEN_INT (feature_1_and), 4, 32, 1);
+
+ /* Pad the size of the note to the required alignment. */
+ assemble_align (POINTER_SIZE);
+ }
+}
+#undef GNU_PROPERTY_AARCH64_FEATURE_1_PAC
+#undef GNU_PROPERTY_AARCH64_FEATURE_1_BTI
+#undef GNU_PROPERTY_AARCH64_FEATURE_1_AND
/* Target-specific selftests. */
diff --git a/gcc/testsuite/gcc.target/aarch64/bti-1.c b/gcc/testsuite/gcc.target/aarch64/bti-1.c
index a8c60412e310a4f322372f334ae5314f426d310e..5a556b08ed15679b25676a11fe9c7a64641ee671 100644
--- a/gcc/testsuite/gcc.target/aarch64/bti-1.c
+++ b/gcc/testsuite/gcc.target/aarch64/bti-1.c
@@ -61,3 +61,4 @@ lab2:
}
/* { dg-final { scan-assembler-times "hint\t34" 1 } } */
/* { dg-final { scan-assembler-times "hint\t36" 12 } } */
+/* { dg-final { scan-assembler ".note.gnu.property" { target *-*-linux* } } } */
diff --git a/gcc/testsuite/gcc.target/aarch64/va_arg_1.c b/gcc/testsuite/gcc.target/aarch64/va_arg_1.c
index e8e3cdac51350b545e5c2a644a3e1f4d1c37f88d..1fe92ff08935d4c6f08affcbd77ea91537030640 100644
--- a/gcc/testsuite/gcc.target/aarch64/va_arg_1.c
+++ b/gcc/testsuite/gcc.target/aarch64/va_arg_1.c
@@ -4,7 +4,9 @@
int
f (int a, ...)
{
- /* { dg-final { scan-assembler-not "str" } } */
+ /* Fails on aarch64*-*-linux* if configured with
+ --enable-standard-branch-protection because of the GNU NOTE section. */
+ /* { dg-final { scan-assembler-not "str" { target { ! aarch64*-*-linux* } || { ! default_branch_protection } } } } */
return a;
}
