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authorLinus Torvalds <torvalds@linux-foundation.org>2019-05-06 16:57:52 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-05-06 16:57:52 -0700
commitdd4e5d6106b2380e2c1238406d26df8b2fe1c42c (patch)
tree33eb172237dd8873de02d5b881bf17cf58d05fab /kernel
parent14be4c61c205dcb0a72251c1e2790814181bd9ba (diff)
parent9726840d9cf0d42377e1591263d7c1d9ae0988ac (diff)
downloadlinux-dd4e5d6106b2380e2c1238406d26df8b2fe1c42c.tar.bz2
Merge tag 'arm64-mmiowb' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull mmiowb removal from Will Deacon: "Remove Mysterious Macro Intended to Obscure Weird Behaviours (mmiowb()) Remove mmiowb() from the kernel memory barrier API and instead, for architectures that need it, hide the barrier inside spin_unlock() when MMIO has been performed inside the critical section. The only relatively recent changes have been addressing review comments on the documentation, which is in a much better shape thanks to the efforts of Ben and Ingo. I was initially planning to split this into two pull requests so that you could run the coccinelle script yourself, however it's been plain sailing in linux-next so I've just included the whole lot here to keep things simple" * tag 'arm64-mmiowb' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (23 commits) docs/memory-barriers.txt: Update I/O section to be clearer about CPU vs thread docs/memory-barriers.txt: Fix style, spacing and grammar in I/O section arch: Remove dummy mmiowb() definitions from arch code net/ethernet/silan/sc92031: Remove stale comment about mmiowb() i40iw: Redefine i40iw_mmiowb() to do nothing scsi/qla1280: Remove stale comment about mmiowb() drivers: Remove explicit invocations of mmiowb() drivers: Remove useless trailing comments from mmiowb() invocations Documentation: Kill all references to mmiowb() riscv/mmiowb: Hook up mmwiob() implementation to asm-generic code powerpc/mmiowb: Hook up mmwiob() implementation to asm-generic code ia64/mmiowb: Add unconditional mmiowb() to arch_spin_unlock() mips/mmiowb: Add unconditional mmiowb() to arch_spin_unlock() sh/mmiowb: Add unconditional mmiowb() to arch_spin_unlock() m68k/io: Remove useless definition of mmiowb() nds32/io: Remove useless definition of mmiowb() x86/io: Remove useless definition of mmiowb() arm64/io: Remove useless definition of mmiowb() ARM/io: Remove useless definition of mmiowb() mmiowb: Hook up mmiowb helpers to spinlocks and generic I/O accessors ...
Diffstat (limited to 'kernel')
-rw-r--r--kernel/Kconfig.locks7
-rw-r--r--kernel/locking/spinlock.c7
-rw-r--r--kernel/locking/spinlock_debug.c6
3 files changed, 19 insertions, 1 deletions
diff --git a/kernel/Kconfig.locks b/kernel/Kconfig.locks
index e335953fa704..bf770d7556f7 100644
--- a/kernel/Kconfig.locks
+++ b/kernel/Kconfig.locks
@@ -251,3 +251,10 @@ config ARCH_USE_QUEUED_RWLOCKS
config QUEUED_RWLOCKS
def_bool y if ARCH_USE_QUEUED_RWLOCKS
depends on SMP
+
+config ARCH_HAS_MMIOWB
+ bool
+
+config MMIOWB
+ def_bool y if ARCH_HAS_MMIOWB
+ depends on SMP
diff --git a/kernel/locking/spinlock.c b/kernel/locking/spinlock.c
index 936f3d14dd6b..0ff08380f531 100644
--- a/kernel/locking/spinlock.c
+++ b/kernel/locking/spinlock.c
@@ -22,6 +22,13 @@
#include <linux/debug_locks.h>
#include <linux/export.h>
+#ifdef CONFIG_MMIOWB
+#ifndef arch_mmiowb_state
+DEFINE_PER_CPU(struct mmiowb_state, __mmiowb_state);
+EXPORT_PER_CPU_SYMBOL(__mmiowb_state);
+#endif
+#endif
+
/*
* If lockdep is enabled then we use the non-preemption spin-ops
* even on CONFIG_PREEMPT, because lockdep assumes that interrupts are
diff --git a/kernel/locking/spinlock_debug.c b/kernel/locking/spinlock_debug.c
index 9aa0fccd5d43..399669f7eba8 100644
--- a/kernel/locking/spinlock_debug.c
+++ b/kernel/locking/spinlock_debug.c
@@ -111,6 +111,7 @@ void do_raw_spin_lock(raw_spinlock_t *lock)
{
debug_spin_lock_before(lock);
arch_spin_lock(&lock->raw_lock);
+ mmiowb_spin_lock();
debug_spin_lock_after(lock);
}
@@ -118,8 +119,10 @@ int do_raw_spin_trylock(raw_spinlock_t *lock)
{
int ret = arch_spin_trylock(&lock->raw_lock);
- if (ret)
+ if (ret) {
+ mmiowb_spin_lock();
debug_spin_lock_after(lock);
+ }
#ifndef CONFIG_SMP
/*
* Must not happen on UP:
@@ -131,6 +134,7 @@ int do_raw_spin_trylock(raw_spinlock_t *lock)
void do_raw_spin_unlock(raw_spinlock_t *lock)
{
+ mmiowb_spin_unlock();
debug_spin_unlock(lock);
arch_spin_unlock(&lock->raw_lock);
}