internal/syscall.h: use a macro for the syscall args casts

this allows syscall_arch.h to define the macro __scc if special
casting is needed, as is the case for x32, where the actual syscall
arguments are 64bit, but, in case of pointers, would get sign-extended
and thus become invalid.

src/internal/syscall.h

@@ -10,13 +10,17 @@ long __syscall_ret(unsigned long), __syscall(long, ...),
 #include <sys/syscall.h>
 #include "syscall_arch.h"
 
-#define __syscall1(n,a) __syscall1(n,(long)(a))
-#define __syscall2(n,a,b) __syscall2(n,(long)(a),(long)(b))
-#define __syscall3(n,a,b,c) __syscall3(n,(long)(a),(long)(b),(long)(c))
-#define __syscall4(n,a,b,c,d) __syscall4(n,(long)(a),(long)(b),(long)(c),(long)(d))
-#define __syscall5(n,a,b,c,d,e) __syscall5(n,(long)(a),(long)(b),(long)(c),(long)(d),(long)(e))
-#define __syscall6(n,a,b,c,d,e,f) __syscall6(n,(long)(a),(long)(b),(long)(c),(long)(d),(long)(e),(long)(f))
-#define __syscall7(n,a,b,c,d,e,f,g) (__syscall)(n,(long)(a),(long)(b),(long)(c),(long)(d),(long)(e),(long)(f),(long)g)
+#ifndef __scc
+#define __scc(X) (long) (X)
+#endif
+
+#define __syscall1(n,a) __syscall1(n,__scc(a))
+#define __syscall2(n,a,b) __syscall2(n,__scc(a),__scc(b))
+#define __syscall3(n,a,b,c) __syscall3(n,__scc(a),__scc(b),__scc(c))
+#define __syscall4(n,a,b,c,d) __syscall4(n,__scc(a),__scc(b),__scc(c),__scc(d))
+#define __syscall5(n,a,b,c,d,e) __syscall5(n,__scc(a),__scc(b),__scc(c),__scc(d),__scc(e))
+#define __syscall6(n,a,b,c,d,e,f) __syscall6(n,__scc(a),__scc(b),__scc(c),__scc(d),__scc(e),__scc(f))
+#define __syscall7(n,a,b,c,d,e,f,g) (__syscall)(n,__scc(a),__scc(b),__scc(c),__scc(d),__scc(e),__scc(f),__scc(g))
 
 #define __SYSCALL_NARGS_X(a,b,c,d,e,f,g,h,n,...) n
 #define __SYSCALL_NARGS(...) __SYSCALL_NARGS_X(__VA_ARGS__,7,6,5,4,3,2,1,0,)
@@ -31,12 +35,12 @@ long __syscall_ret(unsigned long), __syscall(long, ...),
 #define socketcall_cp __socketcall_cp
 
 #define __syscall_cp0(n) (__syscall_cp)(n,0,0,0,0,0,0)
-#define __syscall_cp1(n,a) (__syscall_cp)(n,(long)(a),0,0,0,0,0)
-#define __syscall_cp2(n,a,b) (__syscall_cp)(n,(long)(a),(long)(b),0,0,0,0)
-#define __syscall_cp3(n,a,b,c) (__syscall_cp)(n,(long)(a),(long)(b),(long)(c),0,0,0)
-#define __syscall_cp4(n,a,b,c,d) (__syscall_cp)(n,(long)(a),(long)(b),(long)(c),(long)(d),0,0)
-#define __syscall_cp5(n,a,b,c,d,e) (__syscall_cp)(n,(long)(a),(long)(b),(long)(c),(long)(d),(long)(e),0)
-#define __syscall_cp6(n,a,b,c,d,e,f) (__syscall_cp)(n,(long)(a),(long)(b),(long)(c),(long)(d),(long)(e),(long)(f))
+#define __syscall_cp1(n,a) (__syscall_cp)(n,__scc(a),0,0,0,0,0)
+#define __syscall_cp2(n,a,b) (__syscall_cp)(n,__scc(a),__scc(b),0,0,0,0)
+#define __syscall_cp3(n,a,b,c) (__syscall_cp)(n,__scc(a),__scc(b),__scc(c),0,0,0)
+#define __syscall_cp4(n,a,b,c,d) (__syscall_cp)(n,__scc(a),__scc(b),__scc(c),__scc(d),0,0)
+#define __syscall_cp5(n,a,b,c,d,e) (__syscall_cp)(n,__scc(a),__scc(b),__scc(c),__scc(d),__scc(e),0)
+#define __syscall_cp6(n,a,b,c,d,e,f) (__syscall_cp)(n,__scc(a),__scc(b),__scc(c),__scc(d),__scc(e),__scc(f))
 
 #define __syscall_cp(...) __SYSCALL_DISP(__syscall_cp,__VA_ARGS__)
 #define syscall_cp(...) __syscall_ret(__syscall_cp(__VA_ARGS__))