machine/arch-arm64: add -mbranch-protection=standard

Enable branch protection (PAC/BTI) for all aarch64 builds.  This was
previously enabled at a global level in the GCC build, but that breaks
the gcc test suite.

(From OE-Core rev: a1119750e9b3b9fae4fa9698d2ea3710a5a73768)

Signed-off-by: Ross Burton <ross.burton@arm.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit 8905639d1cdc5ce809cc5ecd9672f5e86bf8a579)
Signed-off-by: Steve Sakoman <steve@sakoman.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/meta/conf/machine/include/arm/arch-arm64.inc b/meta/conf/machine/include/arm/arch-arm64.inc
index 0e2efb5a40..832d0000ac 100644
--- a/meta/conf/machine/include/arm/arch-arm64.inc
+++ b/meta/conf/machine/include/arm/arch-arm64.inc
@@ -37,3 +37,8 @@ TUNE_ARCH = "${@bb.utils.contains('TUNE_FEATURES', 'aarch64', '${TUNE_ARCH_64}',
 TUNE_PKGARCH = "${@bb.utils.contains('TUNE_FEATURES', 'aarch64', '${TUNE_PKGARCH_64}', '${TUNE_PKGARCH_32}', d)}"
 ABIEXTENSION = "${@bb.utils.contains('TUNE_FEATURES', 'aarch64', '${ABIEXTENSION_64}', '${ABIEXTENSION_32}', d)}"
 TARGET_FPU = "${@bb.utils.contains('TUNE_FEATURES', 'aarch64', '${TARGET_FPU_64}', '${TARGET_FPU_32}', d)}"
+
+# Emit branch protection (PAC/BTI) instructions.  On hardware that doesn't
+# support these they're meaningless NOP instructions, so there's very little
+# reason not to.
+TUNE_CCARGS .= "${@bb.utils.contains('TUNE_FEATURES', 'aarch64', ' -mbranch-protection=standard', '', d)}"