summaryrefslogtreecommitdiffstats
path: root/Documentation
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2018-02-15 09:28:47 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2018-02-15 09:28:47 -0800
commit1388c80438e69fc01d83fbe98da3cac24c3c8731 (patch)
tree5014b653431a4b4fafb1e952dddf0ffcce9387a2 /Documentation
parente9e3b3002fc3c9ef665628bd85a8c1b5a3424f23 (diff)
parent43d1b29b27c76e7454cd6c85bec4d0e9cbb039f3 (diff)
downloadlinux-1388c80438e69fc01d83fbe98da3cac24c3c8731.tar.bz2
Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fixes from Ingo Molnar: "Misc fixes: - fix rq->lock lockdep annotation bug - fix/improve update_curr_rt() and update_curr_dl() accounting - update documentation - remove unused macro" * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/cpufreq: Remove unused SUGOV_KTHREAD_PRIORITY macro sched/core: Fix DEBUG_SPINLOCK annotation for rq->lock sched/rt: Make update_curr_rt() more accurate sched/deadline: Make update_curr_dl() more accurate membarrier-sync-core: Document architecture support
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/features/sched/membarrier-sync-core/arch-support.txt62
1 files changed, 62 insertions, 0 deletions
diff --git a/Documentation/features/sched/membarrier-sync-core/arch-support.txt b/Documentation/features/sched/membarrier-sync-core/arch-support.txt
new file mode 100644
index 000000000000..2c815a7f1ba7
--- /dev/null
+++ b/Documentation/features/sched/membarrier-sync-core/arch-support.txt
@@ -0,0 +1,62 @@
+#
+# Feature name: membarrier-sync-core
+# Kconfig: ARCH_HAS_MEMBARRIER_SYNC_CORE
+# description: arch supports core serializing membarrier
+#
+# Architecture requirements
+#
+# * arm64
+#
+# Rely on eret context synchronization 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: | TODO |
+ | arm64: | ok |
+ | blackfin: | TODO |
+ | c6x: | TODO |
+ | cris: | TODO |
+ | frv: | TODO |
+ | h8300: | TODO |
+ | hexagon: | TODO |
+ | ia64: | TODO |
+ | m32r: | TODO |
+ | m68k: | TODO |
+ | metag: | TODO |
+ | microblaze: | TODO |
+ | mips: | TODO |
+ | mn10300: | TODO |
+ | nios2: | TODO |
+ | openrisc: | TODO |
+ | parisc: | TODO |
+ | powerpc: | TODO |
+ | s390: | TODO |
+ | score: | TODO |
+ | sh: | TODO |
+ | sparc: | TODO |
+ | tile: | TODO |
+ | um: | TODO |
+ | unicore32: | TODO |
+ | x86: | ok |
+ | xtensa: | TODO |
+ -----------------------