Simplify the code to allocate stack for auxv, argv[], and environment vectors.
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Authored by jhb on Apr 17 2018, 10:58 PM.

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emaste

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Summary

Remove auxarg_size as it was only used once right after a confusing
assignment in each of the variants of exec_copyout_strings().

Test Plan

booted a patched FreeBSD/amd64 kernel and was able to run FreeBSD/amd64, FreeBSD/i386, and Linux/x86-64 binaries.

Lint

Lint Passed

Unit

No Test Coverage

Build Status

Buildable 16219
Build 16170: arc lint + arc unit

emaste added inline comments.

sys/amd64/linux/linux_sysvec.c
337–338	Maybe capital-A Auxargs follows from struct Elf64_Auxargs?
340–342	Perhaps a `_Static_assert` that `sizeof(Elf_Auxinfo)` is some multiple of `sizeof (char *)`?
348	Thanks, I think this comment is much improved.

This revision is now accepted and ready to land.Apr 18 2018, 7:44 PM

sys/amd64/linux/linux_sysvec.c
340–342	I started down that path and then tried an alternate approach of decrementing vectp directly using howmany(). This doesn't require the casts and is shorter and looks more like the math to handle the argv and env vectors. Will update after some more testing. This also needs to use Elf64_Auxinfo.
sys/amd64/linux32/linux32_sysvec.c
792	Just noticed these roundup/rounddown's are probably wrong (just need to be aligned to uint32_t) but it doesn't hurt beyond a few bytes of wasted space.