https://gcc.gnu.org/ml/gcc-patches/2016-03/msg00614.html added this
workaround to get kernel building with when TARGET_FIX_ERR_A53_843419
is enabled.
This was added to support building kernel loadable modules. In kernel,
when CONFIG_ARM64_ERRATUM_843419 is selected, the relocation needed
for ADRP/LDR (R_AARCH64_ADR_PREL_PG_HI21 and
R_AARCH64_ADR_PREL_PG_HI21_NC are removed from the kernel to avoid
loading objects with possibly offending sequence). Thus, it could only
support pc relative literal loads.
However, the following patch was posted to kernel to add
-mpc-relative-literal-loads
http://www.spinics.net/lists/arm-kernel/msg476149.html
-mpc-relative-literal-loads is unconditionally added to the kernel
build as can be seen from:
https://github.com/torvalds/linux/blob/master/arch/arm64/Makefile
Therefore this patch removes the hunk so that applications like
SPECcpu2017's 521/621.wrf can be built (with LTO in this case) without
-mno-pc-relative-literal-loads
Bootstrapped and regression tested on aarch64-linux-gnu with no new regressions.
Is this OK for trunk?
Thanks,
Kugan
gcc/testsuite/ChangeLog:
2017-06-27 Kugan Vivekanandarajah <kug...@linaro.org>
* gcc.target/aarch64/pr63304_1.c: Remove-mno-fix-cortex-a53-843419.
gcc/ChangeLog:
2017-06-27 Kugan Vivekanandarajah <kug...@linaro.org>
* config/aarch64/aarch64.c (aarch64_override_options_after_change_1):
Disable pc relative literal load irrespective of TARGET_FIX_ERR_A53_84341
for default.
From bf5d8151ad6a83903f51529655e83181bdb67200 Mon Sep 17 00:00:00 2001
From: Kugan Vivekanandarajah <kugan.vivekanandara...@linaro.org>
Date: Thu, 8 Jun 2017 15:51:29 +1000
Subject: [PATCH] Disable pc relative literal load irrespective of
TARGET_FIX_ERR_A53_84341
---
gcc/config/aarch64/aarch64.c | 11 -----------
gcc/testsuite/gcc.target/aarch64/pr63304_1.c | 2 +-
2 files changed, 1 insertion(+), 12 deletions(-)
diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
index 71f9819..99cfd20 100644
--- a/gcc/config/aarch64/aarch64.c
+++ b/gcc/config/aarch64/aarch64.c
@@ -8632,17 +8632,6 @@ aarch64_override_options_after_change_1 (struct gcc_options *opts)
if (opts->x_pcrelative_literal_loads == 1)
aarch64_pcrelative_literal_loads = true;
- /* This is PR70113. When building the Linux kernel with
- CONFIG_ARM64_ERRATUM_843419, support for relocations
- R_AARCH64_ADR_PREL_PG_HI21 and R_AARCH64_ADR_PREL_PG_HI21_NC is
- removed from the kernel to avoid loading objects with possibly
- offending sequences. Without -mpc-relative-literal-loads we would
- generate such relocations, preventing the kernel build from
- succeeding. */
- if (opts->x_pcrelative_literal_loads == 2
- && TARGET_FIX_ERR_A53_843419)
- aarch64_pcrelative_literal_loads = true;
-
/* In the tiny memory model it makes no sense to disallow PC relative
literal pool loads. */
if (aarch64_cmodel == AARCH64_CMODEL_TINY
diff --git a/gcc/testsuite/gcc.target/aarch64/pr63304_1.c b/gcc/testsuite/gcc.target/aarch64/pr63304_1.c
index c917f81c..fa0fb56 100644
--- a/gcc/testsuite/gcc.target/aarch64/pr63304_1.c
+++ b/gcc/testsuite/gcc.target/aarch64/pr63304_1.c
@@ -1,5 +1,5 @@
/* { dg-do assemble } */
-/* { dg-options "-O1 --save-temps -mno-fix-cortex-a53-843419" } */
+/* { dg-options "-O1 --save-temps" } */
#pragma GCC push_options
#pragma GCC target ("+nothing+simd, cmodel=small")
--
2.7.4
