syscall overhaul part two - unify public and internal syscall interface

with this patch, the syscallN() functions are no longer needed; a
variadic syscall() macro allows syscalls with anywhere from 0 to 6
arguments to be made with a single macro name. also, manually casting
each non-integer argument with (long) is no longer necessary; the
casts are hidden in the macros.

some source files which depended on being able to define the old macro
SYSCALL_RETURNS_ERRNO have been modified to directly use __syscall()
instead of syscall(). references to SYSCALL_SIGSET_SIZE and SYSCALL_LL
have also been changed.

x86_64 has not been tested, and may need a follow-up commit to fix any
minor bugs/oversights.

src/thread/__lock.c

@@ -1,4 +1,3 @@
-#define SYSCALL_RETURN_ERRNO
 #include "pthread_impl.h"
 
 void __lock(volatile int *l)
@@ -8,5 +7,5 @@ void __lock(volatile int *l)
 	 * assignment to optimize non-pathological code with no contention. */
 	while (a_xchg(l, 1))
 		if (spins) spins--, a_spin();
-		else syscall0(__NR_sched_yield);
+		else __syscall(__NR_sched_yield);
 }

src/thread/__timedwait.c

@@ -1,7 +1,6 @@
 #include <time.h>
 #include <errno.h>
 #include "futex.h"
-#define SYSCALL_RETURN_ERRNO
 #include "syscall.h"
 #include <stdio.h>
 int __timedwait(volatile int *addr, int val, clockid_t clk, const struct timespec *at, int priv)
@@ -18,7 +17,7 @@ int __timedwait(volatile int *addr, int val, clockid_t clk, const struct timespe
 		if (to.tv_sec < 0) return ETIMEDOUT;
 	}
 	if (priv) priv = 128; priv=0;
-	r = syscall4(__NR_futex, (long)addr, FUTEX_WAIT | priv, val, at ? (long)&to : 0);
+	r = __syscall(__NR_futex, (long)addr, FUTEX_WAIT | priv, val, at ? (long)&to : 0);
 	if (r == ETIMEDOUT) return r;
 	return 0;
 }

src/thread/__wait.c

@@ -1,4 +1,3 @@
-#define SYSCALL_RETURN_ERRNO
 #include "pthread_impl.h"
 
 void __wait(volatile int *addr, volatile int *waiters, int val, int priv)
@@ -11,6 +10,6 @@ void __wait(volatile int *addr, volatile int *waiters, int val, int priv)
 	}
 	if (waiters) a_inc(waiters);
 	while (*addr==val)
-		syscall4(__NR_futex, (long)addr, FUTEX_WAIT|priv, val, 0);
+		__syscall(__NR_futex, (long)addr, FUTEX_WAIT|priv, val, 0);
 	if (waiters) a_dec(waiters);
 }

src/thread/__wake.c

@@ -1,9 +1,8 @@
-#define SYSCALL_RETURN_ERRNO
 #include "pthread_impl.h"
 
 void __wake(volatile int *addr, int cnt, int priv)
 {
 	if (priv) priv = 128; priv=0;
 	if (cnt<0) cnt = INT_MAX;
-	syscall3(__NR_futex, (long)addr, FUTEX_WAKE | priv, cnt);
+	__syscall(__NR_futex, (long)addr, FUTEX_WAKE | priv, cnt);
 }

src/thread/pthread_cancel.c

@@ -1,7 +1,6 @@
-#define SYSCALL_RETURN_ERRNO
 #include "pthread_impl.h"
 
 int pthread_cancel(pthread_t t)
 {
-	return syscall3(__NR_tgkill, t->pid, t->tid, SIGCANCEL);
+	return pthread_kill(t, SIGCANCEL);
 }

src/thread/pthread_create.c

@@ -32,7 +32,7 @@ void __pthread_unwind_next(struct __ptcb *cb)
 		exit(0);
 
 	if (self->detached && self->map_base) {
-		syscall4(__NR_rt_sigprocmask, SIG_BLOCK, (long)(uint64_t[1]){-1},0,8);
+		syscall(__NR_rt_sigprocmask, SIG_BLOCK, (long)(uint64_t[1]){-1},0,8);
 		__unmapself(self->map_base, self->map_size);
 	}
 
@@ -91,7 +91,7 @@ static void rsyscall_handler(int sig, siginfo_t *si, void *ctx)
 		return;
 	}
 
-	if (__syscall(rs.nr, rs.arg[0], rs.arg[1], rs.arg[2],
+	if (syscall(rs.nr, rs.arg[0], rs.arg[1], rs.arg[2],
 		rs.arg[3], rs.arg[4], rs.arg[5]) < 0 && !rs.err) rs.err=errno;
 
 	a_inc(&rs.cnt);
@@ -140,7 +140,7 @@ static int rsyscall(int nr, long a, long b, long c, long d, long e, long f)
 	while((i=rs.cnt)) __wait(&rs.cnt, 0, i, 1);
 
 	if (rs.err) errno = rs.err, ret = -1;
-	else ret = __syscall(nr, a, b, c, d, e, f);
+	else ret = syscall(nr, a, b, c, d, e, f);
 
 	UNLOCK(&rs.lock);
 	return ret;

src/thread/pthread_kill.c

@@ -1,7 +1,6 @@
-#define SYSCALL_RETURN_ERRNO
 #include "pthread_impl.h"
 
 int pthread_kill(pthread_t t, int sig)
 {
-	return syscall3(__NR_tgkill, t->pid, t->tid, sig);
+	return __syscall(__NR_tgkill, t->pid, t->tid, sig);
 }