[PATCH v9 15/24] KVM: s390: Use arm64 code

[Steffen Eiden <seiden@linux.ibm.com>]

Add the infrastructure to extract KVM/arm64 code into s390 at build
time similar to the arm64 header sharing. Add copy-arm64c.awk that
detects ARM64_S390_COMMON markers and extracts marked section into an
.inc file that can be consumed by arm on s390 host code. If no marker is
found make will fail.

To ensure that no code is consumed twice by accident a guard is added
during file generation. A s390 C file wanting to consume such an inc
file must first define __INCL_GEN_ARM_FILE otherwise the inc file will
emit a compile error.

Example:
	#define __INCL_GEN_ARM_FILE
	#include <generated/arm.inc>
	#undef __INCL_GEN_ARM_FILE

Signed-off-by: Steffen Eiden <seiden@linux.ibm.com>
---
 arch/s390/kvm/arm64/.gitignore      |  2 +
 arch/s390/kvm/arm64/Makefile.gen    | 28 ++++++++++
 arch/s390/kvm/arm64/copy-arm64c.awk | 82 +++++++++++++++++++++++++++++
 3 files changed, 112 insertions(+)
 create mode 100644 arch/s390/kvm/arm64/.gitignore
 create mode 100644 arch/s390/kvm/arm64/Makefile.gen
 create mode 100644 arch/s390/kvm/arm64/copy-arm64c.awk

diff --git a/arch/s390/kvm/arm64/.gitignore b/arch/s390/kvm/arm64/.gitignore
new file mode 100644
index 000000000000..bd9d90694676
--- /dev/null
+++ b/arch/s390/kvm/arm64/.gitignore
@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0-only
+generated/*
diff --git a/arch/s390/kvm/arm64/Makefile.gen b/arch/s390/kvm/arm64/Makefile.gen
new file mode 100644
index 000000000000..9c33b068fab5
--- /dev/null
+++ b/arch/s390/kvm/arm64/Makefile.gen
@@ -0,0 +1,28 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Extracts ARM64 marked sections to .inc files that are included by main source
+# files
+
+# List of ARM64 C files to extract
+ARM64_CFILES := \
+	arm.c \
+	guest.c \
+	mmio.c
+
+quiet_cmd_extract_inc = GEN     $@
+      cmd_extract_inc = mkdir -p $(dir $@); \
+                        $(AWK) -f $(src)/copy-arm64c.awk $< > $@ || \
+                        { echo "Error: No or unbalanced ARM64_S390_COMMON markers in $<" >&2; rm -f $@; exit 1; }
+
+ARM64_INC_FILES := $(foreach cfile,$(ARM64_CFILES),generated/$(basename $(cfile)).inc)
+
+$(addprefix $(obj)/,$(ARM64_INC_FILES)): $(obj)/generated/%.inc: $(srctree)/arch/arm64/kvm/%.c $(src)/copy-arm64c.awk FORCE
+	$(call if_changed,extract_inc)
+
+targets += $(ARM64_INC_FILES)
+clean-files += generated/*.inc
+
+$(foreach cfile,$(basename $(ARM64_CFILES)),\
+	$(eval $(obj)/$(cfile).o $(obj)/$(cfile).i $(obj)/$(cfile).s \
+		$(obj)/$(cfile).ll $(obj)/$(cfile).lst: \
+		$(obj)/generated/$(cfile).inc))
diff --git a/arch/s390/kvm/arm64/copy-arm64c.awk b/arch/s390/kvm/arm64/copy-arm64c.awk
new file mode 100644
index 000000000000..640a7bcb7e23
--- /dev/null
+++ b/arch/s390/kvm/arm64/copy-arm64c.awk
@@ -0,0 +1,82 @@
+#!/usr/bin/awk -f
+# SPDX-License-Identifier: GPL-2.0
+#
+# Extract marked sections from ARM64 C files for sharing with s390 KVM
+#
+# Usage: copy-arm64c.awk <input_file>
+#
+# Extracts all sections between start/end markers. If no markers found, signals failure.
+
+BEGIN {
+	# Constants
+	start_pattern = "^#if ARM64_S390_COMMON == 1$"
+	end_pattern = "^#endif /\\* ARM64_S390_COMMON == 1 \\*/$"
+
+	# State variables
+	copying = found_marker = 0
+	file_header_done = 0
+	depth = 0
+}
+
+!file_header_done {
+	if (/^\/\*/ || /^\/\/ SPDX-License-Identifier:/) {
+		print
+		next
+	}
+	if (/[[:space:]]\*([[:space:]]|$)/) {
+		print
+		next
+	}
+	if (/\*\//) {
+		print " *"
+	} else {
+		print "/*"
+	}
+
+	print " * This file was automatically generated from " FILENAME
+	print " * Do not modify this file directly."
+	print " */"
+	print ""
+	print "#ifndef __INCL_GEN_ARM_FILE"
+	print "#error do not include this file directly."
+	print "#endif /* __INCL_GEN_ARM_FILE */"
+	print "#undef __INCL_GEN_ARM_FILE"
+	print ""
+
+	file_header_done = 1
+}
+
+$0 ~ start_pattern {
+	if (copying) { error = 1; exit }
+	depth = copying = found_marker = 1
+	# Map subsequent lines back to the original ARM64 source file so that
+	# compiler diagnostics point there rather than at the generated copy.
+	print "#line " (NR + 1) " \"" FILENAME "\""
+	next
+}
+
+copying && /^[ \t]*#[ \t]*if(def|ndef)?([ \t]|$)/ { depth++ }
+
+$0 ~ /^[ \t]*#[ \t]*endif/ {
+	depth--
+	if (depth == 0) {
+		if ($0 ~ end_pattern) {
+			copying = 0
+			next
+		}
+		error = 1; exit
+	}
+}
+
+/ARM64_S390_COMMON/ { error = 1; exit }
+
+copying {
+	gsub(/#include <asm\//, "#include <arm64/")
+	gsub(/#include <uapi\/asm\//, "#include <uapi/arm64/")
+	print
+	next
+}
+
+END {
+	exit error || !found_marker || copying
+}
-- 
2.53.0