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
  ...

1 files changed, 90 insertions, 0 deletions

diff --git a/arch/hexagon/include/asm/cmpxchg.h b/arch/hexagon/include/asm/cmpxchg.h
new file mode 100644
index 000000000000..c5f9527e1df6
--- /dev/null
+++ b/arch/hexagon/include/asm/cmpxchg.h
@@ -0,0 +1,90 @@
+/*
+ * xchg/cmpxchg operations for the Hexagon architecture
+ *
+ * Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.
+ *
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+#ifndef _ASM_CMPXCHG_H
+#define _ASM_CMPXCHG_H
+
+/*
+ * __xchg - atomically exchange a register and a memory location
+ * @x: value to swap
+ * @ptr: pointer to memory
+ * @size:  size of the value
+ *
+ * Only 4 bytes supported currently.
+ *
+ * Note:  there was an errata for V2 about .new's and memw_locked.
+ *
+ */
+static inline unsigned long __xchg(unsigned long x, volatile void *ptr,
+				   int size)
+{
+	unsigned long retval;
+
+	/*  Can't seem to use printk or panic here, so just stop  */
+	if (size != 4) do { asm volatile("brkpt;\n"); } while (1);
+
+	__asm__ __volatile__ (
+	"1:	%0 = memw_locked(%1);\n"    /*  load into retval */
+	"	memw_locked(%1,P0) = %2;\n" /*  store into memory */
+	"	if !P0 jump 1b;\n"
+	: "=&r" (retval)
+	: "r" (ptr), "r" (x)
+	: "memory", "p0"
+	);
+	return retval;
+}
+
+/*
+ * Atomically swap the contents of a register with memory.  Should be atomic
+ * between multiple CPU's and within interrupts on the same CPU.
+ */
+#define xchg(ptr, v) ((__typeof__(*(ptr)))__xchg((unsigned long)(v), (ptr), \
+	sizeof(*(ptr))))
+
+/*
+ *  see rt-mutex-design.txt; cmpxchg supposedly checks if *ptr == A and swaps.
+ *  looks just like atomic_cmpxchg on our arch currently with a bunch of
+ *  variable casting.
+ */
+#define __HAVE_ARCH_CMPXCHG 1
+
+#define cmpxchg(ptr, old, new)					\
+({								\
+	__typeof__(ptr) __ptr = (ptr);				\
+	__typeof__(*(ptr)) __old = (old);			\
+	__typeof__(*(ptr)) __new = (new);			\
+	__typeof__(*(ptr)) __oldval = 0;			\
+								\
+	asm volatile(						\
+		"1:	%0 = memw_locked(%1);\n"		\
+		"	{ P0 = cmp.eq(%0,%2);\n"		\
+		"	  if (!P0.new) jump:nt 2f; }\n"		\
+		"	memw_locked(%1,p0) = %3;\n"		\
+		"	if (!P0) jump 1b;\n"			\
+		"2:\n"						\
+		: "=&r" (__oldval)				\
+		: "r" (__ptr), "r" (__old), "r" (__new)		\
+		: "memory", "p0"				\
+	);							\
+	__oldval;						\
+})
+
+#endif /* _ASM_CMPXCHG_H */