*setarch* modifies execution domains and process personality flags.
The execution domains currently only affects the output of *uname -m*. For example, on an AMD64 system, running *setarch i386* _program_ will cause _program_ to see i686 instead of _x86_64_ as the machine type. It can also be used to set various personality options. The default _program_ is */bin/sh*.
Since version 2.33 the _arch_ command line argument is optional and *setarch* may be used to change personality flags (ADDR_LIMIT_*, SHORT_INODE, etc) without modification of the execution domain.
Treat user-space function pointers to signal handlers as pointers to address descriptors. This option has no effect on architectures that do not support *FDPIC* ELF binaries. In kernel v4.14 support is limited to ARM, Blackfin, Fujitsu FR-V, and SuperH CPU architectures.
This makes *select*(2), *pselect*(2), and *ppoll*(2) system calls preserve the timeout value instead of modifying it to reflect the amount of time not slept when interrupted by a signal handler. Use when _program_ depends on this behavior. For more details see the timeout description in *select*(2) manual page. Turns on *STICKY_TIMEOUTS*.
If this is set then *mmap*(3p) *PROT_READ* will also add the *PROT_EXEC* bit - as expected by legacy x86 binaries. Notice that the ELF loader will automatically set this bit when it encounters a legacy binary. Turns on *READ_IMPLIES_EXEC*.
SVr4 bug emulation that will set *mmap*(3p) page zero as read-only. Use when _program_ depends on this behavior, and the source code is not available to be fixed. Turns on *MMAP_PAGE_ZERO*.