Keep the previous option as a way to signal generic retpoline support
regardless of the underlying compiler, while introducing a new
CC_INDIRECT_THUNK that signals whether the underlying compiler
supports retpoline.
No functional change intended.
Signed-off-by: Roger Pau Monné <roger....@citrix.com>
---
Changes since v2:
- Make the compiler option check generic instead of GCC only.
Changes since v1:
- Put def_bool before depend on.
---
xen/arch/x86/Kconfig | 6 +++++-
xen/arch/x86/arch.mk | 10 ++++++----
2 files changed, 11 insertions(+), 5 deletions(-)
diff --git a/xen/arch/x86/Kconfig b/xen/arch/x86/Kconfig
index b4abfca46f..a1a90da4fc 100644
--- a/xen/arch/x86/Kconfig
+++ b/xen/arch/x86/Kconfig
@@ -32,9 +32,13 @@ config ARCH_DEFCONFIG
string
default "arch/x86/configs/x86_64_defconfig"
-config INDIRECT_THUNK
+config CC_INDIRECT_THUNK
def_bool $(cc-option,-mindirect-branch-register)
+config INDIRECT_THUNK
+ def_bool y
+ depends on CC_INDIRECT_THUNK
+
config HAS_AS_CET_SS
# binutils >= 2.29 or LLVM >= 6
def_bool $(as-instr,wrssq %rax$(comma)0;setssbsy)
diff --git a/xen/arch/x86/arch.mk b/xen/arch/x86/arch.mk
index fa7cf38443..6388b1d93f 100644
--- a/xen/arch/x86/arch.mk
+++ b/xen/arch/x86/arch.mk
@@ -42,10 +42,12 @@ CFLAGS += -mno-red-zone -fpic
# SSE setup for variadic function calls.
CFLAGS += -mno-sse $(call cc-option,$(CC),-mskip-rax-setup)
-# Compile with thunk-extern, indirect-branch-register if avaiable.
-CFLAGS-$(CONFIG_INDIRECT_THUNK) += -mindirect-branch=thunk-extern
-CFLAGS-$(CONFIG_INDIRECT_THUNK) += -mindirect-branch-register
-CFLAGS-$(CONFIG_INDIRECT_THUNK) += -fno-jump-tables
+ifeq ($(CONFIG_INDIRECT_THUNK),y)
+# Compile with gcc thunk-extern, indirect-branch-register if available.
+CFLAGS-$(CONFIG_CC_IS_GCC) += -mindirect-branch=thunk-extern
+CFLAGS-$(CONFIG_CC_IS_GCC) += -mindirect-branch-register
+CFLAGS-$(CONFIG_CC_IS_GCC) += -fno-jump-tables
+endif
# If supported by the compiler, reduce stack alignment to 8 bytes. But allow
# this to be overridden elsewhere.
--
2.34.1
