@@ -36,6 +36,18 @@ label##2: \
.align 2; \
label##3:
+/*
+ * If the .org directive fails, it means that the feature instructions
+ * are smaller than the alternate instructions. This used to be written
+ * as
+ *
+ * .ifgt (label##4b-label##3b) - (label##2b-label##1b)
+ * .error "Feature section else case larger than body"
+ * .endif
+ *
+ * but clang's assembler complains about the expression being non-absolute
+ * when the code appears in an inline assembly statement.
+ */
#define MAKE_FTR_SECTION_ENTRY(msk, val, label, sect) \
label##4: \
.popsection; \
@@ -48,11 +60,8 @@ label##5: \
FTR_ENTRY_OFFSET label##2b-label##5b; \
FTR_ENTRY_OFFSET label##3b-label##5b; \
FTR_ENTRY_OFFSET label##4b-label##5b; \
- .ifgt (label##4b- label##3b)-(label##2b- label##1b); \
- .error "Feature section else case larger than body"; \
- .endif; \
- .popsection;
-
+ .popsection; \
+ .org . - ((label##4b-label##3b) > (label##2b-label##1b));
/* CPU feature dependent sections */
#define BEGIN_FTR_SECTION_NESTED(label) START_FTR_SECTION(label)
The clang toolchain treats inline assembly a bit differently than straight assembly code. In particular, inline assembly doesn't have the complete context available to resolve expressions. This is intentional to avoid divergence in the resulting assembly code. We can work around this issue by borrowing a workaround done for ARM, i.e. not directly testing the labels themselves, but by moving the current output pointer by a value that should always be zero. If this value is not null, then we will trigger a backward move, which is explicitly forbidden. Signed-off-by: Bill Wendling <morbo@google.com> --- arch/powerpc/include/asm/feature-fixups.h | 19 ++++++++++++++----- 1 file changed, 14 insertions(+), 5 deletions(-)