Hi
This patch adds the GNU NOTE section to the BTI and/or PAC
enabled objects for linux targets.
The ABI document that we published mentioning GNU NOTE section is below:
https://developer.arm.com/docs/ihi0056/latest/elf-for-the-arm-64-bit-architecture-aarch64-abi-2018q4
The patches needed for these in binutils are already approved and committed.
https://sourceware.org/ml/binutils/2019-03/msg00072.html
Bootstrapped and regression tested with aarch64-none-linux-gnu.
Is this ok for trunk?
Thanks
Sudi
*** gcc/ChangeLog ***
2018-xx-xx Sudakshina Das <[email protected]>
* config/aarch64/aarch64-linux.h (TARGET_ASM_FILE_END): Define for
AArch64.
(aarch64_file_end_indicate_exec_stack): Add gnu note section.
gcc/testsuite/ChangeLog:
2018-xx-xx Sudakshina Das <[email protected]>
* gcc.target/aarch64/bti-1.c: Add scan directive for gnu note section
for linux targets.
* gcc.target/aarch64/va_arg_1.c: Don't run for aarch64 linux
targets
with --enable-standard-branch-protection.
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..d616c8360b396ebe3ab2ac0fb799b30830df2b3e 100644
--- a/gcc/config/aarch64/aarch64.c
+++ b/gcc/config/aarch64/aarch64.c
@@ -18744,6 +18744,67 @@ 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 ASM_LONG "\t.long\t"
+#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 ();
+
+ if (!aarch64_bti_enabled ()
+ && aarch64_ra_sign_scope == AARCH64_FUNCTION_NONE)
+ {
+ return;
+ }
+
+ 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)
+ {
+ int p2align = ptr_mode == SImode ? 2 : 3;
+
+ /* Generate GNU_PROPERTY_AARCH64_FEATURE_1_XXX. */
+ switch_to_section (get_section (".note.gnu.property",
+ SECTION_NOTYPE, NULL));
+
+ ASM_OUTPUT_ALIGN (asm_out_file, p2align);
+ /* name length. */
+ fprintf (asm_out_file, ASM_LONG " 1f - 0f\n");
+ /* data length. */
+ fprintf (asm_out_file, ASM_LONG " 4f - 1f\n");
+ /* note type: NT_GNU_PROPERTY_TYPE_0. */
+ fprintf (asm_out_file, ASM_LONG " 5\n");
+ fprintf (asm_out_file, "0:\n");
+ /* vendor name: "GNU". */
+ fprintf (asm_out_file, STRING_ASM_OP " \"GNU\"\n");
+ fprintf (asm_out_file, "1:\n");
+ ASM_OUTPUT_ALIGN (asm_out_file, p2align);
+ /* pr_type: GNU_PROPERTY_AARCH64_FEATURE_1_AND. */
+ fprintf (asm_out_file, ASM_LONG " 0x%x\n",
+ GNU_PROPERTY_AARCH64_FEATURE_1_AND);
+ /* pr_datasz. */\
+ fprintf (asm_out_file, ASM_LONG " 3f - 2f\n");
+ fprintf (asm_out_file, "2:\n");
+ /* GNU_PROPERTY_AARCH64_FEATURE_1_XXX. */
+ fprintf (asm_out_file, ASM_LONG " 0x%x\n", feature_1_and);
+ fprintf (asm_out_file, "3:\n");
+ ASM_OUTPUT_ALIGN (asm_out_file, p2align);
+ fprintf (asm_out_file, "4:\n");
+ }
+}
+#undef GNU_PROPERTY_AARCH64_FEATURE_1_PAC
+#undef GNU_PROPERTY_AARCH64_FEATURE_1_BTI
+#undef GNU_PROPERTY_AARCH64_FEATURE_1_AND
+#undef ASM_LONG
/* 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;
}
