fix alignment for new-style ctors when using riscv64

[wbx-github]

Recently uClibc-ng enabled UCLIBC_CTOR_DTOR for riscv64, so that f.e. C++ applications are running fine. As a side effect this breaks noMMU support. The problem is the alignment for the ctors in elf2flt. This patch fixes it.

Tested with Qemu for ARM, M68k and Xtensa with no regressions.

Thanks to sorear for the fix.

[gregungerer]

I don't have a problem with the change as-is.
Just wondering though if there is an argument you can use with ALIGN() to make it align to the natural word size of the machine?

[wbx-github]

Hi Greg,

I don't have a problem with the change as-is. Just wondering though if there is an argument you can use with ALIGN() to make it align to the natural word size of the machine?

With just ALIGN() I get a syntax error with ld. Did you mean something else?

[sorear]

I don't see anything in or under https://sourceware.org/binutils/docs/ld/Expressions.html that would give the target word size. I had hoped that if there was a better way to do this, a linker script expert could find it, which I am not.

The other reason I suggested using a fixed 8 instead of messing with ld-elf2flt.c is that it's consistent with the other places where FLAT is using an alignment that works for all architectures (RV64IMAC would be happy with ALIGN(2) for _stext and ALIGN(0x10) for .data, but 4 / 0x20 is the least common multiple of supported architectures, at least until someone adds tile or ia64).

[gregungerer]

Yes I can't see any better way than just using ALIGN(8).