fusl/arch/arm/syscall_arch.h

#define __SYSCALL_LL_E(x) \
  ((union {               \
    long long ll;         \
    long l[2];            \
  }){.ll = x})            \
      .l[0],              \
      ((union {           \
        long long ll;     \
        long l[2];        \
      }){.ll = x})        \
          .l[1]
#define __SYSCALL_LL_O(x) 0, __SYSCALL_LL_E((x))

#define __asm_syscall(...)                                             \
  do {                                                                 \
    __asm__ __volatile__("svc 0" : "=r"(r0) : __VA_ARGS__ : "memory"); \
    return r0;                                                         \
  } while (0)

static inline long __syscall0(long n) {
  register long r7 __asm__("r7") = n;
  register long r0 __asm__("r0");
  __asm_syscall("r"(r7));
}

static inline long __syscall1(long n, long a) {
  register long r7 __asm__("r7") = n;
  register long r0 __asm__("r0") = a;
  __asm_syscall("r"(r7), "0"(r0));
}

static inline long __syscall2(long n, long a, long b) {
  register long r7 __asm__("r7") = n;
  register long r0 __asm__("r0") = a;
  register long r1 __asm__("r1") = b;
  __asm_syscall("r"(r7), "0"(r0), "r"(r1));
}

static inline long __syscall3(long n, long a, long b, long c) {
  register long r7 __asm__("r7") = n;
  register long r0 __asm__("r0") = a;
  register long r1 __asm__("r1") = b;
  register long r2 __asm__("r2") = c;
  __asm_syscall("r"(r7), "0"(r0), "r"(r1), "r"(r2));
}

static inline long __syscall4(long n, long a, long b, long c, long d) {
  register long r7 __asm__("r7") = n;
  register long r0 __asm__("r0") = a;
  register long r1 __asm__("r1") = b;
  register long r2 __asm__("r2") = c;
  register long r3 __asm__("r3") = d;
  __asm_syscall("r"(r7), "0"(r0), "r"(r1), "r"(r2), "r"(r3));
}

static inline long __syscall5(long n, long a, long b, long c, long d, long e) {
  register long r7 __asm__("r7") = n;
  register long r0 __asm__("r0") = a;
  register long r1 __asm__("r1") = b;
  register long r2 __asm__("r2") = c;
  register long r3 __asm__("r3") = d;
  register long r4 __asm__("r4") = e;
  __asm_syscall("r"(r7), "0"(r0), "r"(r1), "r"(r2), "r"(r3), "r"(r4));
}

static inline long
__syscall6(long n, long a, long b, long c, long d, long e, long f) {
  register long r7 __asm__("r7") = n;
  register long r0 __asm__("r0") = a;
  register long r1 __asm__("r1") = b;
  register long r2 __asm__("r2") = c;
  register long r3 __asm__("r3") = d;
  register long r4 __asm__("r4") = e;
  register long r5 __asm__("r5") = f;
  __asm_syscall("r"(r7), "0"(r0), "r"(r1), "r"(r2), "r"(r3), "r"(r4), "r"(r5));
}

#define VDSO_USEFUL
#define VDSO_CGT_SYM "__vdso_clock_gettime"
#define VDSO_CGT_VER "LINUX_2.6"