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authorLinus Torvalds <torvalds@linux-foundation.org>2012-03-28 15:58:21 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-03-28 15:58:21 -0700
commit0195c00244dc2e9f522475868fa278c473ba7339 (patch)
treef97ca98ae64ede2c33ad3de05ed7bbfa4f4495ed /arch/ia64/include/asm/barrier.h
parentf21ce8f8447c8be8847dadcfdbcc76b0d7365fa5 (diff)
parent141124c02059eee9dbc5c86ea797b1ca888e77f7 (diff)
Merge tag 'split-asm_system_h-for-linus-20120328' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-asm_system
Pull "Disintegrate and delete asm/system.h" from David Howells: "Here are a bunch of patches to disintegrate asm/system.h into a set of separate bits to relieve the problem of circular inclusion dependencies. I've built all the working defconfigs from all the arches that I can and made sure that they don't break. The reason for these patches is that I recently encountered a circular dependency problem that came about when I produced some patches to optimise get_order() by rewriting it to use ilog2(). This uses bitops - and on the SH arch asm/bitops.h drags in asm-generic/get_order.h by a circuituous route involving asm/system.h. The main difficulty seems to be asm/system.h. It holds a number of low level bits with no/few dependencies that are commonly used (eg. memory barriers) and a number of bits with more dependencies that aren't used in many places (eg. switch_to()). These patches break asm/system.h up into the following core pieces: (1) asm/barrier.h Move memory barriers here. This already done for MIPS and Alpha. (2) asm/switch_to.h Move switch_to() and related stuff here. (3) asm/exec.h Move arch_align_stack() here. Other process execution related bits could perhaps go here from asm/processor.h. (4) asm/cmpxchg.h Move xchg() and cmpxchg() here as they're full word atomic ops and frequently used by atomic_xchg() and atomic_cmpxchg(). (5) asm/bug.h Move die() and related bits. (6) asm/auxvec.h Move AT_VECTOR_SIZE_ARCH here. Other arch headers are created as needed on a per-arch basis." Fixed up some conflicts from other header file cleanups and moving code around that has happened in the meantime, so David's testing is somewhat weakened by that. We'll find out anything that got broken and fix it.. * tag 'split-asm_system_h-for-linus-20120328' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-asm_system: (38 commits) Delete all instances of asm/system.h Remove all #inclusions of asm/system.h Add #includes needed to permit the removal of asm/system.h Move all declarations of free_initmem() to linux/mm.h Disintegrate asm/system.h for OpenRISC Split arch_align_stack() out from asm-generic/system.h Split the switch_to() wrapper out of asm-generic/system.h Move the asm-generic/system.h xchg() implementation to asm-generic/cmpxchg.h Create asm-generic/barrier.h Make asm-generic/cmpxchg.h #include asm-generic/cmpxchg-local.h Disintegrate asm/system.h for Xtensa Disintegrate asm/system.h for Unicore32 [based on ver #3, changed by gxt] Disintegrate asm/system.h for Tile Disintegrate asm/system.h for Sparc Disintegrate asm/system.h for SH Disintegrate asm/system.h for Score Disintegrate asm/system.h for S390 Disintegrate asm/system.h for PowerPC Disintegrate asm/system.h for PA-RISC Disintegrate asm/system.h for MN10300 ...
Diffstat (limited to 'arch/ia64/include/asm/barrier.h')
-rw-r--r--arch/ia64/include/asm/barrier.h68
1 files changed, 68 insertions, 0 deletions
diff --git a/arch/ia64/include/asm/barrier.h b/arch/ia64/include/asm/barrier.h
new file mode 100644
index 000000000000..60576e06b6fb
--- /dev/null
+++ b/arch/ia64/include/asm/barrier.h
@@ -0,0 +1,68 @@
+/*
+ * Memory barrier definitions. This is based on information published
+ * in the Processor Abstraction Layer and the System Abstraction Layer
+ * manual.
+ *
+ * Copyright (C) 1998-2003 Hewlett-Packard Co
+ * David Mosberger-Tang <davidm@hpl.hp.com>
+ * Copyright (C) 1999 Asit Mallick <asit.k.mallick@intel.com>
+ * Copyright (C) 1999 Don Dugger <don.dugger@intel.com>
+ */
+#ifndef _ASM_IA64_BARRIER_H
+#define _ASM_IA64_BARRIER_H
+
+#include <linux/compiler.h>
+
+/*
+ * Macros to force memory ordering. In these descriptions, "previous"
+ * and "subsequent" refer to program order; "visible" means that all
+ * architecturally visible effects of a memory access have occurred
+ * (at a minimum, this means the memory has been read or written).
+ *
+ * wmb(): Guarantees that all preceding stores to memory-
+ * like regions are visible before any subsequent
+ * stores and that all following stores will be
+ * visible only after all previous stores.
+ * rmb(): Like wmb(), but for reads.
+ * mb(): wmb()/rmb() combo, i.e., all previous memory
+ * accesses are visible before all subsequent
+ * accesses and vice versa. This is also known as
+ * a "fence."
+ *
+ * Note: "mb()" and its variants cannot be used as a fence to order
+ * accesses to memory mapped I/O registers. For that, mf.a needs to
+ * be used. However, we don't want to always use mf.a because (a)
+ * it's (presumably) much slower than mf and (b) mf.a is supported for
+ * sequential memory pages only.
+ */
+#define mb() ia64_mf()
+#define rmb() mb()
+#define wmb() mb()
+#define read_barrier_depends() do { } while(0)
+
+#ifdef CONFIG_SMP
+# define smp_mb() mb()
+# define smp_rmb() rmb()
+# define smp_wmb() wmb()
+# define smp_read_barrier_depends() read_barrier_depends()
+#else
+# define smp_mb() barrier()
+# define smp_rmb() barrier()
+# define smp_wmb() barrier()
+# define smp_read_barrier_depends() do { } while(0)
+#endif
+
+/*
+ * XXX check on this ---I suspect what Linus really wants here is
+ * acquire vs release semantics but we can't discuss this stuff with
+ * Linus just yet. Grrr...
+ */
+#define set_mb(var, value) do { (var) = (value); mb(); } while (0)
+
+/*
+ * The group barrier in front of the rsm & ssm are necessary to ensure
+ * that none of the previous instructions in the same group are
+ * affected by the rsm/ssm.
+ */
+
+#endif /* _ASM_IA64_BARRIER_H */