Fix nonexistent sync_file_range2 syscall bug in aarch64,loongarch64 and riscv*

[Fearyncess]

This PR will fix sync_file_range2 corruption in codes.

During these days, I have discovered a bug in syscall-gen. It has mistakenly marked some architectures using sync_file_range2 instead of sync_file_range.

Because of registers alignment, on a few architectures, sync_file_range2 swaps the argument order to avoid requiring 7 arguments instead of sync_file_range. After my investigation, only 32-bit ARM¹, SH², PowerPC³, CSKY⁴ and Hexagon⁵ use sync_file_range2. Specifically, arm_sync_file_range is aliased to sync_file_range on 32-bit ARM¹.

For aarch64, this architectures use sync_file_range actually. However, ARMv8 has a compatibility mode called aarch32, which will let 32bit ARM programs running on aarch64 machines. So there is a unistd32.h syscall compat header in arch/arm64⁶. It also have sync_file_range2 syscall name, aliased to arm_sync_file_range.

For other architectures which use unistd.h for syscalls definition, we should filter out sync_file_range2 if not defined. That follows their definitions in Linux kernel.

Footnotes

1. https://github.com/torvalds/linux/blob/176000734ee2978121fde22a954eb1eabb204329/arch/arm/tools/syscall.tbl#L359 ↩ ↩²

2. https://github.com/torvalds/linux/blob/30766f1105d6d2459c3b9fe34a3e52b637a72950/arch/sh/kernel/syscalls/syscall.tbl#L398 ↩

3. https://github.com/torvalds/linux/blob/b1e31c134a8ab2e8f5fd62323b6b45a950ac704d/arch/powerpc/kernel/syscalls/syscall.tbl#L401 ↩

4. https://github.com/torvalds/linux/blob/f840cab63efe802638bf536221deecfbf3f569ed/arch/csky/include/uapi/asm/unistd.h#L5 ↩

5. https://github.com/torvalds/linux/blob/36d69c29759ec2299c1537e292a466eab3824087/arch/hexagon/include/uapi/asm/unistd.h ↩

6. https://github.com/torvalds/linux/blob/7fe33e9f662c0a2f5110be4afff0a24e0c123540/arch/arm64/include/asm/unistd32.h#L7 ↩

[jasonwhite]

Thanks! Looks good.