1 files changed, 51 insertions, 0 deletions
diff --git a/arch/s390/include/asm/asm.h b/arch/s390/include/asm/asm.h
new file mode 100644
index 000000000000..ec011b94af2a
--- /dev/null
+++ b/arch/s390/include/asm/asm.h
@@ -0,0 +1,51 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_S390_ASM_H
+#define _ASM_S390_ASM_H
+
+#include <linux/stringify.h>
+
+/*
+ * Helper macros to be used for flag output operand handling.
+ * Inline assemblies must use four of the five supplied macros:
+ *
+ * Use CC_IPM(sym) at the end of the inline assembly; this extracts the
+ * condition code and program mask with the ipm instruction and writes it to
+ * the variable with symbolic name [sym] if the compiler has no support for
+ * flag output operands. If the compiler has support for flag output operands
+ * this generates no code.
+ *
+ * Use CC_OUT(sym, var) at the output operand list of an inline assembly. This
+ * defines an output operand with symbolic name [sym] for the variable
+ * [var]. [var] must be an int variable and [sym] must be identical with [sym]
+ * used with CC_IPM().
+ *
+ * Use either CC_CLOBBER or CC_CLOBBER_LIST() for the clobber list. Use
+ * CC_CLOBBER if the clobber list contains only "cc", otherwise use
+ * CC_CLOBBER_LIST() and add all clobbers as argument to the macro.
+ *
+ * Use CC_TRANSFORM() to convert the variable [var] which contains the
+ * extracted condition code. If the condition code is extracted with ipm, the
+ * [var] also contains the program mask. CC_TRANSFORM() moves the condition
+ * code to the two least significant bits and sets all other bits to zero.
+ */
+#if defined(__GCC_ASM_FLAG_OUTPUTS__) && !(IS_ENABLED(CONFIG_GCC_ASM_FLAG_OUTPUT_BROKEN))
+
+#define __HAVE_ASM_FLAG_OUTPUTS__
+
+#define CC_IPM(sym)
+#define CC_OUT(sym, var)	"=@cc" (var)
+#define CC_TRANSFORM(cc)	({ cc; })
+#define CC_CLOBBER
+#define CC_CLOBBER_LIST(...)	__VA_ARGS__
+
+#else
+
+#define CC_IPM(sym)		"	ipm	%[" __stringify(sym) "]\n"
+#define CC_OUT(sym, var)	[sym] "=d" (var)
+#define CC_TRANSFORM(cc)	({ (cc) >> 28; })
+#define CC_CLOBBER		"cc"
+#define CC_CLOBBER_LIST(...)	"cc", __VA_ARGS__
+
+#endif
+
+#endif /* _ASM_S390_ASM_H */