fba2689ee7
* 'remove-h8300' of git://git.infradead.org/users/hch/misc:
remove the h8300 architecture
This is clearly the least actively maintained architecture we have at
the moment, and probably the least useful. It is now the only one that
does not support MMUs at all, and most of the boards only support 4MB
of RAM, out of which the defconfig kernel needs more than half just
for .text/.data.
Guenter Roeck did the original patch to remove the architecture in 2013
after it had already been obsolete for a while, and Yoshinori Sato brought
it back in a much more modern form in 2015. Looking at the git history
since the reinstantiation, it's clear that almost all commits in the tree
are build fixes or cross-architecture cleanups:
$ git log --no-merges --format=%an v4.5.. arch/h8300/ | sort | uniq
-c | sort -rn | head -n 12
25 Masahiro Yamada
18 Christoph Hellwig
14 Mike Rapoport
9 Arnd Bergmann
8 Mark Rutland
7 Peter Zijlstra
6 Kees Cook
6 Ingo Molnar
6 Al Viro
5 Randy Dunlap
4 Yury Norov
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
54 lines
1.8 KiB
Plaintext
54 lines
1.8 KiB
Plaintext
#
|
|
# Feature name: membarrier-sync-core
|
|
# Kconfig: ARCH_HAS_MEMBARRIER_SYNC_CORE
|
|
# description: arch supports core serializing membarrier
|
|
#
|
|
# Architecture requirements
|
|
#
|
|
# * arm/arm64/powerpc
|
|
#
|
|
# Rely on implicit context synchronization as a result of exception return
|
|
# when returning from IPI handler, and when returning to user-space.
|
|
#
|
|
# * x86
|
|
#
|
|
# x86-32 uses IRET as return from interrupt, which takes care of the IPI.
|
|
# However, it uses both IRET and SYSEXIT to go back to user-space. The IRET
|
|
# instruction is core serializing, but not SYSEXIT.
|
|
#
|
|
# x86-64 uses IRET as return from interrupt, which takes care of the IPI.
|
|
# However, it can return to user-space through either SYSRETL (compat code),
|
|
# SYSRETQ, or IRET.
|
|
#
|
|
# Given that neither SYSRET{L,Q}, nor SYSEXIT, are core serializing, we rely
|
|
# instead on write_cr3() performed by switch_mm() to provide core serialization
|
|
# after changing the current mm, and deal with the special case of kthread ->
|
|
# uthread (temporarily keeping current mm into active_mm) by issuing a
|
|
# sync_core_before_usermode() in that specific case.
|
|
#
|
|
-----------------------
|
|
| arch |status|
|
|
-----------------------
|
|
| alpha: | TODO |
|
|
| arc: | TODO |
|
|
| arm: | ok |
|
|
| arm64: | ok |
|
|
| csky: | TODO |
|
|
| hexagon: | TODO |
|
|
| ia64: | TODO |
|
|
| m68k: | TODO |
|
|
| microblaze: | TODO |
|
|
| mips: | TODO |
|
|
| nios2: | TODO |
|
|
| openrisc: | TODO |
|
|
| parisc: | TODO |
|
|
| powerpc: | ok |
|
|
| riscv: | TODO |
|
|
| s390: | TODO |
|
|
| sh: | TODO |
|
|
| sparc: | TODO |
|
|
| um: | TODO |
|
|
| x86: | ok |
|
|
| xtensa: | TODO |
|
|
-----------------------
|