gen_syscalls: Refactor the scripts

Make the extractor configurable to extract {amd64,i386,x32}
from amd64 and other companion architecture syscalls if needed.

Also introduce "GDB" environment variable allowing invocation
of custom GDB, i.e:

GDB=gdb-multiarch ./gen_syscalls.sh /tmp/vmlinux-armmp

Signed-off-by: Vasyl Gello <vasek.gello@gmail.com>

Author: basilgello

tools/gen_syscalls/extract.py

@@ -17,9 +17,11 @@
    limitations under the License.
 """
 
+import os
 import re
+import sys
 
-out_file = open('output_syscalls.c', 'w')
+# Functions
 
 def output(str):
 	out_file.write(str)
@@ -45,21 +47,57 @@ def output_syscall(nr, name):
 		real_name = m.group(1)
 	else:
 		real_name = name
-	output('\t{"'+real_name+'", '+str(nr)+', {')
+	output('\t{"'+real_name+'", '+str(nr | sys_call_bit)+', {')
 	for j in range(0, nb_args):
 		arg_name = get_string_val("print __syscall_meta__"+name+"->args["+str(j)+"]")
 		arg_type = get_string_val("print __syscall_meta__"+name+"->types["+str(j)+"]")
 		arg_size = get_int_val("print sizeof("+arg_type+")")
 		output('[ARG_'+str(j)+'] = {"'+arg_name+'", '+str(arg_size)+'}, ')
 	output('}},\n')
 
-num_syscalls=get_int_val("print sizeof(sys_call_table)/sizeof(sys_call_table[0])")
-table_cmd = "print sys_call_table"
+# Start of script
+
+# "xrange" was renamed to "range" in Python 3
+
+try:
+    # Python 2
+    xrange
+except NameError:
+    # Python 3, xrange is now named range
+    xrange = range
+
+# Define syscall table name
+
+sys_call_table_name = os.getenv("SYSCALLTABLENAME")
+if (sys_call_table_name is None) or (sys_call_table_name == ""):
+	print("WARNING: Environment variable 'SYSCALLTABLENAME' not set!")
+	out_file.close()
+	sys.exit(1)
+
+# Define syscall bit
+
+sys_call_bit = os.getenv("SYSCALLBIT")
+if (sys_call_bit is None) or (sys_call_bit == ""):
+	print("WARNING: Environment variable 'SYSCALLBIT' not set!")
+	out_file.close()
+	sys.exit(1)
+else:
+	try:
+		sys_call_bit = int(sys_call_bit)
+	except:
+		print("WARNING: Wring value of environment varibable 'SYSCALLBIT'!")
+		out_file.close()
+		sys.exit(1)
+
+out_file = open('output_syscalls.c', 'a')
+
+num_syscalls=get_int_val(str("print sizeof(" + sys_call_table_name + ")/sizeof(" + sys_call_table_name + "[0])"))
+table_cmd = "print " + sys_call_table_name
 syscall_regex = "<([Ss]y[Ss]|stub)_([^>]*)>"
 
 if num_syscalls <= 0:
 	num_syscalls = 1000
-	table_cmd = "info symbol ((void**)sys_call_table)"
+	table_cmd = "info symbol ((void**)" + sys_call_table_name + ")"
 	syscall_regex = "([Ss]y[Ss]|stub)_([^ ]*)"
 
 for i in range(0, num_syscalls):

tools/gen_syscalls/gen_syscalls.sh

@@ -19,24 +19,28 @@
 #   limitations under the License.
 #
 
-if [ $# -ne 1 ] || [ ! -e "$1" -o -d "$1" ]; then
-	echo "USAGE: $0 [linux_with_debugging_symbols]"
-	exit 1
-fi
+# Start of functions
 
-export LANG=C
+generate_syscall_file()
+{
+	# $1 - linux file ($linux)
+	# $2 - architecture ($arch)
+	# $3 - (optional) syscall table symbol name (sys_call_table)
+	# $4 - (optional) syscall bit (0 or _X32_SYSCALL_BIT)
 
-linux="$1"
-arch="$(readelf -h "$linux" | sed -ne '/Machine:/{s/^[[:space:]]*Machine:[[:space:]]*//;P}')"
-if [ "$arch" = "Advanced Micro Devices X86-64" ]; then
-	arch="AMD64"
-fi
-outname="${arch,,}_syscalls.c"
+	linux="$1"
+	arch="$2"
+	SYSCALLTABLENAME="$3"
+	SYSCALLBIT="$4"
+
+	[ -z "$SYSCALLTABLENAME" ] && SYSCALLTABLENAME="sys_call_table"
+	[ -z "$SYSCALLBIT" ] && SYSCALLBIT=0
 
-echo -n "Generating syscalls for $arch... "
+	echo -n "Generating syscalls for $arch ... "
+	outname="${arch,,}_syscalls.c"
 
-year=$(date +%Y)
-cat > "$outname" <<HEADER
+	year=$(date +%Y)
+	cat > "$outname" <<HEADER
 /*
    Kafel - syscalls ($arch)
    -----------------------------------------
@@ -71,26 +75,75 @@ cat > "$outname" <<HEADER
 const struct syscall_descriptor ${arch,,}_syscall_list[] = {
 HEADER
 
-case "$arch" in
-ARM)
-	gdb --batch -ex 'set gnutarget elf32-littlearm' -ex "file $linux" -x extract.py
-	;;
-*)
-	gdb --batch -ex "file $linux" -x extract.py
-	;;
-esac
-
-if [ -f "missing/${arch,,}.c" ]; then
-	cat "missing/${arch,,}.c" >> output_syscalls.c
-fi
+	echo -n "" > output_syscalls.c
+
+
+	case "$arch" in
+	ARM)
+		SYSCALLTABLENAME="$SYSCALLTABLENAME" \
+		SYSCALLBIT=$SYSCALLBIT \
+			"$GDB" --batch \
+			-ex 'set gnutarget elf32-littlearm' \
+			-ex "file $linux" \
+			-x extract.py
+		;;
+	*)
+		SYSCALLTABLENAME="$SYSCALLTABLENAME" \
+		SYSCALLBIT=$SYSCALLBIT \
+			"$GDB" --batch \
+			-ex "file $linux" \
+			-x extract.py
+		;;
+	esac
 
-cat output_syscalls.c | sort -k1,1 --unique --stable -t',' >> "$outname"
-rm output_syscalls.c
+	if [ -f "missing/${arch,,}.c" ]; then
+		cat "missing/${arch,,}.c" >> output_syscalls.c
+	fi
 
-cat >> "$outname" <<FOOTER
+	cat output_syscalls.c | sort -k1,1 --unique --stable -t',' >> "$outname"
+
+	rm output_syscalls.c
+
+	cat >> "$outname" <<FOOTER
 };
 
 const size_t ${arch,,}_syscall_list_size = sizeof(${arch,,}_syscall_list)/sizeof(${arch,,}_syscall_list[0]);
 FOOTER
 
-echo "DONE"
+	echo "DONE"
+}
+
+# End of functions
+
+# Start of script
+
+if [ $# -ne 1 ] || [ ! -e "$1" -o -d "$1" ]; then
+	echo "USAGE: $0 [linux_with_debugging_symbols]"
+	exit 1
+fi
+
+export LANG=C
+
+# For gdb-multiarch or toolchain-provided gdb
+
+[ -z "$GDB" ] && GDB="gdb"
+
+linux="$1"
+arch="$(readelf -h "$linux" | sed -ne '/Machine:/{s/^[[:space:]]*Machine:[[:space:]]*//;P}')"
+class="$(readelf -h "$linux" | sed -ne '/Class:/{s/^[[:space:]]*Class:[[:space:]]*//;P}')"
+
+if [ "$arch" = "Advanced Micro Devices X86-64" ]; then
+	arch="AMD64"
+elif [ "$arch" = "Intel 80386" ]; then
+	arch="i386"
+elif [ "$arch" = "MIPS R3000" ]; then
+        [ "$class" = "ELF32" ] && arch="mipso32" || arch="mips64"
+fi
+
+if [ "$arch" = "AMD64" ]; then
+	generate_syscall_file "$linux" amd64
+	generate_syscall_file "$linux" i386 ia32_sys_call_table 0
+	generate_syscall_file "$linux" x32 x32_sys_call_table 1073741824
+else
+	generate_syscall_file "$linux" "$arch"
+fi