Automatically generate user space syscall stubs

This requires adding flags to the magic syscall comment so that we can mark sys_exec as using INT instead of SYSCALL for entry.

Automatically generate user space syscall stubs
203de796 · Austin Clements · 860627e6 · 203de796 · 203de796 · 203de796
--- a/Makefile
+++ b/Makefile
@@ -68,6 +68,11 @@ $(O)/%.o: %.S
 	$(Q)mkdir -p $(@D)
 	$(Q)$(CC) $(ASFLAGS) -c -o $@ $<

+$(O)/%.o: $(O)/%.S
+	@echo "  CC     $@"
+	$(Q)mkdir -p $(@D)
+	$(Q)$(CC) $(ASFLAGS) -c -o $@ $<
+
 xv6memfs.img: bootblock kernelmemfs
 	dd if=/dev/zero of=xv6memfs.img count=10000
 	dd if=bootblock of=xv6memfs.img conv=notrunc

--- a/kernel/sysfile.cc
+++ b/kernel/sysfile.cc
@@ -431,7 +431,7 @@ sys_chdir(const char *path)
  return 0;
 }

-//SYSCALL
+//SYSCALL INT
 int
 sys_exec(const char *upath, userptr<userptr<const char> > uargv)
 {

--- a/lib/Makefrag
+++ b/lib/Makefrag
 $(O)/lib/%.o: CFLAGS:=$(CFLAGS) -DXV6_USER
 $(O)/lib/%.o: CXXFLAGS:=$(CXXFLAGS) -DXV6_USER -fno-exceptions -fno-rtti

-ULIB = ulib.o usys.o printf.o umalloc.o uthread.o fmt.o stream.o ipc.o \
-       threads.o crt.o wqlib.o wquser.o perf.o wqalloc.o
+ULIB = ulib.o printf.o umalloc.o uthread.o fmt.o stream.o ipc.o \
+       threads.o crt.o wqlib.o wquser.o perf.o wqalloc.o sysstubs.o
 ULIB := $(addprefix $(O)/lib/, $(ULIB))

+$(O)/lib/sysstubs.S: tools/syscalls.py kernel/*.cc
+	@echo "  GEN    $@"
+	$(Q)mkdir -p $(@D)
+	$(Q)python $^ --ustubs > $@
+
 .PRECIOUS: $(O)/lib/%.o
 -include $(O)/lib/*.d
--- a/lib/usys.S
+++ b/lib/usys.S
-#include "syscall.h"
-#include "traps.h"
-
-#define SYSCALL_INT(name) \
-  .globl name; \
-  name: \
-    movq $SYS_ ## name, %rax; \
-    int $T_SYSCALL; \
-    ret
-
-#define SYSCALL(name) \
-  .globl name; \
-  name: \
-    movq $SYS_ ## name, %rax; \
-    movq %rcx, %r10; \
-    syscall; \
-    ret
-
-SYSCALL(fork)
-SYSCALL(exit)
-SYSCALL(wait)
-SYSCALL(pipe)
-SYSCALL(read)
-SYSCALL(write)
-SYSCALL(close)
-SYSCALL(kill)
-SYSCALL_INT(exec)
-SYSCALL(openat)
-SYSCALL(mknod)
-SYSCALL(unlink)
-SYSCALL(fstat)
-SYSCALL(link)
-SYSCALL(mkdirat)
-SYSCALL(chdir)
-SYSCALL(dup)
-SYSCALL(getpid)
-SYSCALL(sbrk)
-SYSCALL(nsleep)
-SYSCALL(uptime)
-SYSCALL(map)
-SYSCALL(unmap)
-SYSCALL(halt)
-SYSCALL(socket)
-SYSCALL(bind)
-SYSCALL(listen)
-SYSCALL(accept)
-SYSCALL(pread)
-SYSCALL(async)
-SYSCALL(script)
-SYSCALL(setfs)
-SYSCALL(wqwait)
-SYSCALL(setaffinity)
-SYSCALL(futex)
--- a/tools/syscalls.py
+++ b/tools/syscalls.py
@@ -5,6 +5,8 @@ def main():
    parser = OptionParser(usage="usage: %prog [options] source...")
    parser.add_option("--kvectors", action="store_true",
                      help="output kernel syscall vectors")
+    parser.add_option("--ustubs", action="store_true",
+                      help="output user syscall stubs")
    (options, args) = parser.parse_args()

    if len(args) < 1:
@@ -42,16 +44,34 @@ def main():
        print
        print "extern const int nsyscalls = %d;" % (max(bynum.keys()) + 1)

+    if options.ustubs:
+        print "#include \"traps.h\""
+        print
+        for syscall in syscalls:
+            print """\
+.globl %(uname)s
+%(uname)s:
+  movq $%(num)d, %%rax""" % syscall.__dict__
+            if "INT" in syscall.flags:
+                print "  int $T_SYSCALL"
+            else:
+                print "  movq %rcx, %r10\n  syscall"
+            print "  ret"
+            print
+
 class Syscall(object):
-    def __init__(self, kname, rettype, kargs, num=None):
-        self.kname, self.rettype, self.kargs, self.num = \
-            kname, rettype, kargs, num
+    def __init__(self, kname, rettype, kargs, flags, num=None):
+        self.kname, self.rettype, self.kargs, self.flags, self.num = \
+            kname, rettype, kargs, flags, num

        self.basename = kname[4:]

+        # Construct user space prototype
+        self.uname = self.basename
+
    def __repr__(self):
-        return "Syscall(%r,%r,%r,%r)" % (
-            self.kname, self.rettype, self.kargs, self.num)
+        return "Syscall(%r,%r,%r,%r,%r)" % (
+            self.kname, self.rettype, self.kargs, self.flags, self.num)

 class ParseError(RuntimeError):
    def __init__(self, fname, msg):
@@ -60,7 +80,7 @@ class ParseError(RuntimeError):
 def parse(fp):
    res = []

-    for proto in re.findall(r"//SYSCALL\n([^{]*)", fp.read()):
+    for flags, proto in re.findall(r"//SYSCALL(.*)([^{]*)", fp.read()):
        # Parse the prototype
        proto = " ".join(proto.split())
        m = re.match(r"(.+) ([a-z_]+) *\(([^)]+)\)", proto)
@@ -69,7 +89,7 @@ def parse(fp):
        rettype, name, kargs = m.groups()
        kargs = re.split(" *, *", kargs)

-        res.append(Syscall(name, rettype, kargs))
+        res.append(Syscall(name, rettype, kargs, flags.split()))

    return res