man 2 syscall :

Arch/ABI    Instruction           System  Ret  Ret  Error    Notes 
                                  call #  val  val2
───────────────────────────────────────────────────────────────────
alpha       callsys               v0      v0   a4   a3       1, 6
arc         trap0                 r8      r0   -    -
arm/OABI    swi NR                -       r0   -    -        2
arm/EABI    swi 0x0               r7      r0   r1   -
arm64       svc #0                w8      x0   x1   -
blackfin    excpt 0x0             P0      R0   -    -
i386        int $0x80             eax     eax  edx  -
ia64        break 0x100000        r15     r8   r9   r10      1, 6
loongarch   syscall 0             a7      a0   -    -
m68k        trap #0               d0      d0   -    -
microblaze  brki r14,8            r12     r3   -    -
mips        syscall               v0      v0   v1   a3       1, 6
nios2       trap                  r2      r2   -    r7
parisc      ble 0x100(%sr2, %r0)  r20     r28  -    -
powerpc     sc                    r0      r3   -    r0       1
powerpc64   sc                    r0      r3   -    cr0.SO   1
riscv       ecall                 a7      a0   a1   -
s390        svc 0                 r1      r2   r3   -        3
s390x       svc 0                 r1      r2   r3   -        3
superh      trapa #31             r3      r0   r1   -        4, 6
sparc/32    t 0x10                g1      o0   o1   psr/csr  1, 6
sparc/64    t 0x6d                g1      o0   o1   psr/csr  1, 6
tile        swint1                R10     R00  -    R01      1
x86-64      syscall               rax     rax  rdx  -        5
x32         syscall               rax     rax  rdx  -        5
xtensa      syscall               a2      a2   -    -