K 10
svn:author
V 4
mmel
K 8
svn:date
V 27
2017-12-12T11:25:30.658898Z
K 7
svn:log
V 890
Rework alignment handling in __libc_allocate_tls() for Variant I of TLS layout.

There are two versions of variant I of TLS
- ARM and aarch64 uses original version of variant I here TP points to
  start of TCB followed by aligned TLS segment. Both TCB and TLS must
  be aligned to alignment of TLS section. The TCB[0] points to DTV vector
  and DTV values are real addresses (without bias).

- MIPS, PowerPC and RISC-V use modified version of variant I,
  where TP points (with bias) to TLS and TCB immediately precedes TLS
  without any alignment gap. Only TLS should be aligned. The TCB[0]
  points to DTV vector and DTV values are biased by constant value (0x8000)
  from real addresses.

Take all this in account when allocating memory for TLS structures.

MFC after:	1 month
Reviewed by:	kib, mizhka
Tested by:	mizhka(on mips)
Differential Revision:	https://reviews.freebsd.org/D13378

END