[SPARC64]: Inline membar()'s again.

Since GCC has to emit a call and a delay slot to the
out-of-line "membar" routines in arch/sparc64/lib/mb.S
it is much better to just do the necessary predicted
branch inline instead as:

	ba,pt	%xcc, 1f
	 membar	#whatever
1:

instead of the current:

	call	membar_foo
	 dslot

because this way GCC is not required to allocate a stack
frame if the function can be a leaf function.

This also makes this bug fix easier to backport to 2.4.x

Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 1 insertions, 74 deletions

diff --git a/arch/sparc64/lib/Makefile b/arch/sparc64/lib/Makefile
index 6201f1040982..40dbeec7e5d6 100644
--- a/arch/sparc64/lib/Makefile
+++ b/arch/sparc64/lib/Makefile
@@ -12,7 +12,7 @@ lib-y := PeeCeeI.o copy_page.o clear_page.o strlen.o strncmp.o \
          U1memcpy.o U1copy_from_user.o U1copy_to_user.o \
          U3memcpy.o U3copy_from_user.o U3copy_to_user.o U3patch.o \
          copy_in_user.o user_fixup.o memmove.o \
-         mcount.o ipcsum.o rwsem.o xor.o find_bit.o delay.o mb.o
+         mcount.o ipcsum.o rwsem.o xor.o find_bit.o delay.o
 
 lib-$(CONFIG_DEBUG_SPINLOCK) += debuglocks.o
 lib-$(CONFIG_HAVE_DEC_LOCK) += dec_and_lock.o
diff --git a/arch/sparc64/lib/mb.S b/arch/sparc64/lib/mb.S
deleted file mode 100644
index 4004f748619f..000000000000
--- a/arch/sparc64/lib/mb.S
+++ /dev/null
@@ -1,73 +0,0 @@
-/* mb.S: Out of line memory barriers.
- *
- * Copyright (C) 2005 David S. Miller (davem@davemloft.net)
- */
-
-        /* These are here in an effort to more fully work around
-         * Spitfire Errata #51.  Essentially, if a memory barrier
-         * occurs soon after a mispredicted branch, the chip can stop
-         * executing instructions until a trap occurs.  Therefore, if
-         * interrupts are disabled, the chip can hang forever.
-         *
-         * It used to be believed that the memory barrier had to be
-         * right in the delay slot, but a case has been traced
-         * recently wherein the memory barrier was one instruction
-         * after the branch delay slot and the chip still hung.  The
-         * offending sequence was the following in sym_wakeup_done()
-         * of the sym53c8xx_2 driver:
-         *
-         *      call    sym_ccb_from_dsa, 0
-         *       movge  %icc, 0, %l0
-         *      brz,pn  %o0, .LL1303
-         *       mov    %o0, %l2
-         *      membar  #LoadLoad
-         *
-         * The branch has to be mispredicted for the bug to occur.
-         * Therefore, we put the memory barrier explicitly into a
-         * "branch always, predicted taken" delay slot to avoid the
-         * problem case.
-         */
-
-        .text
-
-99:     retl
-         nop
-
-        .globl  mb
-mb:     ba,pt   %xcc, 99b
-         membar #LoadLoad | #LoadStore | #StoreStore | #StoreLoad
-        .size   mb, .-mb
-
-        .globl  rmb
-rmb:    ba,pt   %xcc, 99b
-         membar #LoadLoad
-        .size   rmb, .-rmb
-
-        .globl  wmb
-wmb:    ba,pt   %xcc, 99b
-         membar #StoreStore
-        .size   wmb, .-wmb
-
-        .globl  membar_storeload
-membar_storeload:
-        ba,pt   %xcc, 99b
-         membar #StoreLoad
-        .size   membar_storeload, .-membar_storeload
-
-        .globl  membar_storeload_storestore
-membar_storeload_storestore:
-        ba,pt   %xcc, 99b
-         membar #StoreLoad | #StoreStore
-        .size   membar_storeload_storestore, .-membar_storeload_storestore
-
-        .globl  membar_storeload_loadload
-membar_storeload_loadload:
-        ba,pt   %xcc, 99b
-         membar #StoreLoad | #LoadLoad
-        .size   membar_storeload_loadload, .-membar_storeload_loadload
-
-        .globl  membar_storestore_loadstore
-membar_storestore_loadstore:
-        ba,pt   %xcc, 99b
-         membar #StoreStore | #LoadStore
-        .size   membar_storestore_loadstore, .-membar_storestore_loadstore