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, 124 insertions, 0 deletions

diff --git a/arch/mips/include/asm/cmpxchg.h b/arch/mips/include/asm/cmpxchg.h
index d8d1c2805ac..285a41fa0b1 100644
--- a/arch/mips/include/asm/cmpxchg.h
+++ b/arch/mips/include/asm/cmpxchg.h
@@ -9,6 +9,130 @@
 #define __ASM_CMPXCHG_H
 
 #include <linux/irqflags.h>
+#include <asm/war.h>
+
+static inline unsigned long __xchg_u32(volatile int * m, unsigned int val)
+{
+	__u32 retval;
+
+	smp_mb__before_llsc();
+
+	if (kernel_uses_llsc && R10000_LLSC_WAR) {
+		unsigned long dummy;
+
+		__asm__ __volatile__(
+		"	.set	mips3					\n"
+		"1:	ll	%0, %3			# xchg_u32	\n"
+		"	.set	mips0					\n"
+		"	move	%2, %z4					\n"
+		"	.set	mips3					\n"
+		"	sc	%2, %1					\n"
+		"	beqzl	%2, 1b					\n"
+		"	.set	mips0					\n"
+		: "=&r" (retval), "=m" (*m), "=&r" (dummy)
+		: "R" (*m), "Jr" (val)
+		: "memory");
+	} else if (kernel_uses_llsc) {
+		unsigned long dummy;
+
+		do {
+			__asm__ __volatile__(
+			"	.set	mips3				\n"
+			"	ll	%0, %3		# xchg_u32	\n"
+			"	.set	mips0				\n"
+			"	move	%2, %z4				\n"
+			"	.set	mips3				\n"
+			"	sc	%2, %1				\n"
+			"	.set	mips0				\n"
+			: "=&r" (retval), "=m" (*m), "=&r" (dummy)
+			: "R" (*m), "Jr" (val)
+			: "memory");
+		} while (unlikely(!dummy));
+	} else {
+		unsigned long flags;
+
+		raw_local_irq_save(flags);
+		retval = *m;
+		*m = val;
+		raw_local_irq_restore(flags);	/* implies memory barrier  */
+	}
+
+	smp_llsc_mb();
+
+	return retval;
+}
+
+#ifdef CONFIG_64BIT
+static inline __u64 __xchg_u64(volatile __u64 * m, __u64 val)
+{
+	__u64 retval;
+
+	smp_mb__before_llsc();
+
+	if (kernel_uses_llsc && R10000_LLSC_WAR) {
+		unsigned long dummy;
+
+		__asm__ __volatile__(
+		"	.set	mips3					\n"
+		"1:	lld	%0, %3			# xchg_u64	\n"
+		"	move	%2, %z4					\n"
+		"	scd	%2, %1					\n"
+		"	beqzl	%2, 1b					\n"
+		"	.set	mips0					\n"
+		: "=&r" (retval), "=m" (*m), "=&r" (dummy)
+		: "R" (*m), "Jr" (val)
+		: "memory");
+	} else if (kernel_uses_llsc) {
+		unsigned long dummy;
+
+		do {
+			__asm__ __volatile__(
+			"	.set	mips3				\n"
+			"	lld	%0, %3		# xchg_u64	\n"
+			"	move	%2, %z4				\n"
+			"	scd	%2, %1				\n"
+			"	.set	mips0				\n"
+			: "=&r" (retval), "=m" (*m), "=&r" (dummy)
+			: "R" (*m), "Jr" (val)
+			: "memory");
+		} while (unlikely(!dummy));
+	} else {
+		unsigned long flags;
+
+		raw_local_irq_save(flags);
+		retval = *m;
+		*m = val;
+		raw_local_irq_restore(flags);	/* implies memory barrier  */
+	}
+
+	smp_llsc_mb();
+
+	return retval;
+}
+#else
+extern __u64 __xchg_u64_unsupported_on_32bit_kernels(volatile __u64 * m, __u64 val);
+#define __xchg_u64 __xchg_u64_unsupported_on_32bit_kernels
+#endif
+
+static inline unsigned long __xchg(unsigned long x, volatile void * ptr, int size)
+{
+	switch (size) {
+	case 4:
+		return __xchg_u32(ptr, x);
+	case 8:
+		return __xchg_u64(ptr, x);
+	}
+
+	return x;
+}
+
+#define xchg(ptr, x)							\
+({									\
+	BUILD_BUG_ON(sizeof(*(ptr)) & ~0xc);				\
+									\
+	((__typeof__(*(ptr)))						\
+		__xchg((unsigned long)(x), (ptr), sizeof(*(ptr))));	\
+})
 
 #define __HAVE_ARCH_CMPXCHG 1