git: DragonFly_RELEASE_5_4 kernel - MFC portions of the MAP_STACK fix

[Matthew Dillon]

commit e4d1cf393dcb622f98963a123fc0ccac30a9ed1d
Author: Matthew Dillon <dillon at apollo.backplane.com>
Date:   Fri May 3 15:19:43 2019 -0700

    kernel - MFC portions of the MAP_STACK fix
    
    * MFC portions of d6924570fb and 4837705ef8 from master.  This changes
      MAP_STACK semantics to better-align with application expectations.
    
      In particular, we finish the transition to requiring MAP_TRYFIXED
      in order to allow a mapping to use the ungrown area of a MAP_STACK
      mapping, and we basically kill userland's ability to create auto-grow
      mappings by converting MAP_STACK to a normal anonymous mmap.
    
    * The original auto-grow feature for the primary user stack as created
      by the kernel's exec() code remains intact in order to remain compatible
      with the pthreads library in -release.

Summary of changes:
 sys/kern/kern_exec.c |  2 +-
 sys/vm/vm_map.c      | 22 +++++++++++-----------
 sys/vm/vm_map.h      |  2 +-
 sys/vm/vm_mmap.c     | 33 ++++++++++++++++++++++++++++++---
 4 files changed, 43 insertions(+), 16 deletions(-)

http://gitweb.dragonflybsd.org/dragonfly.git/commitdiff/e4d1cf393dcb622f98963a123fc0ccac30a9ed1d


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