[PATCH v2 2/2] MIPS: Error out if unsupported compact branch policy is set

[Paul Burton]

If an explicit compact branch policy is requested by the user via the
debug options in Kconfig, and the toolchain does not support specifying
an explicit compact branch policy, then error out with an understandable
error message to make it clearer what's happened.

Signed-off-by: Paul Burton <paul.burton@xxxxxxxxxx>
Fixes: c1a0e9bc885d ("MIPS: Allow compact branch policy to be changed")
Cc: stable <stable@xxxxxxxxxxxxxxx> # v4.4+

---

Changes in v2:
- New patch.

 arch/mips/Makefile | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/arch/mips/Makefile b/arch/mips/Makefile
index e78d60d..1ac4612 100644
--- a/arch/mips/Makefile
+++ b/arch/mips/Makefile
@@ -194,9 +194,13 @@ toolchain-msa				:= $(call cc-option-yn,$(mips-cflags) -mhard-float -mfp64 -Wa$(
 cflags-$(toolchain-msa)			+= -DTOOLCHAIN_SUPPORTS_MSA
 endif
 
-cflags-$(CONFIG_MIPS_COMPACT_BRANCHES_NEVER)	+= -mcompact-branches=never
-cflags-$(CONFIG_MIPS_COMPACT_BRANCHES_OPTIMAL)	+= -mcompact-branches=optimal
-cflags-$(CONFIG_MIPS_COMPACT_BRANCHES_ALWAYS)	+= -mcompact-branches=always
+ifeq ($(call cc-option-yn,-mcompact-branches=optimal), y)
+  cflags-$(CONFIG_MIPS_COMPACT_BRANCHES_NEVER)		+= -mcompact-branches=never
+  cflags-$(CONFIG_MIPS_COMPACT_BRANCHES_OPTIMAL)	+= -mcompact-branches=optimal
+  cflags-$(CONFIG_MIPS_COMPACT_BRANCHES_ALWAYS)		+= -mcompact-branches=always
+else ifneq ($(CONFIG_MIPS_COMPACT_BRANCHES_DEFAULT),y)
+  $(error Compact branch policy specified, but lacking toolchain support)
+endif
 
 #
 # Firmware support
-- 
2.8.2