1 files changed, 103 insertions, 0 deletions
diff --git a/arch/sparc/lib/clear_page.S b/arch/sparc/lib/clear_page.S
new file mode 100644
index 000000000..46272dfc2
--- /dev/null
+++ b/arch/sparc/lib/clear_page.S
@@ -0,0 +1,103 @@
+/* clear_page.S: UltraSparc optimized clear page.
+ *
+ * Copyright (C) 1996, 1998, 1999, 2000, 2004 David S. Miller (davem@redhat.com)
+ * Copyright (C) 1997 Jakub Jelinek (jakub@redhat.com)
+ */
+
+#include <asm/visasm.h>
+#include <asm/thread_info.h>
+#include <asm/page.h>
+#include <asm/pgtable.h>
+#include <asm/spitfire.h>
+#include <asm/head.h>
+
+	/* What we used to do was lock a TLB entry into a specific
+	 * TLB slot, clear the page with interrupts disabled, then
+	 * restore the original TLB entry.  This was great for
+	 * disturbing the TLB as little as possible, but it meant
+	 * we had to keep interrupts disabled for a long time.
+	 *
+	 * Now, we simply use the normal TLB loading mechanism,
+	 * and this makes the cpu choose a slot all by itself.
+	 * Then we do a normal TLB flush on exit.  We need only
+	 * disable preemption during the clear.
+	 */
+
+	.text
+
+	.globl		_clear_page
+_clear_page:		/* %o0=dest */
+	ba,pt		%xcc, clear_page_common
+	 clr		%o4
+
+	/* This thing is pretty important, it shows up
+	 * on the profiles via do_anonymous_page().
+	 */
+	.align		32
+	.globl		clear_user_page
+clear_user_page:	/* %o0=dest, %o1=vaddr */
+	lduw		[%g6 + TI_PRE_COUNT], %o2
+	sethi		%hi(PAGE_OFFSET), %g2
+	sethi		%hi(PAGE_SIZE), %o4
+
+	ldx		[%g2 + %lo(PAGE_OFFSET)], %g2
+	sethi		%hi(PAGE_KERNEL_LOCKED), %g3
+
+	ldx		[%g3 + %lo(PAGE_KERNEL_LOCKED)], %g3
+	sub		%o0, %g2, %g1		! paddr
+
+	and		%o1, %o4, %o0		! vaddr D-cache alias bit
+
+	or		%g1, %g3, %g1		! TTE data
+	sethi		%hi(TLBTEMP_BASE), %o3
+
+	add		%o2, 1, %o4
+	add		%o0, %o3, %o0		! TTE vaddr
+
+	/* Disable preemption.  */
+	mov		TLB_TAG_ACCESS, %g3
+	stw		%o4, [%g6 + TI_PRE_COUNT]
+
+	/* Load TLB entry.  */
+	rdpr		%pstate, %o4
+	wrpr		%o4, PSTATE_IE, %pstate
+	stxa		%o0, [%g3] ASI_DMMU
+	stxa		%g1, [%g0] ASI_DTLB_DATA_IN
+	sethi		%hi(KERNBASE), %g1
+	flush		%g1
+	wrpr		%o4, 0x0, %pstate
+
+	mov		1, %o4
+
+clear_page_common:
+	VISEntryHalf
+	membar		#StoreLoad | #StoreStore | #LoadStore
+	fzero		%f0
+	sethi		%hi(PAGE_SIZE/64), %o1
+	mov		%o0, %g1		! remember vaddr for tlbflush
+	fzero		%f2
+	or		%o1, %lo(PAGE_SIZE/64), %o1
+	faddd		%f0, %f2, %f4
+	fmuld		%f0, %f2, %f6
+	faddd		%f0, %f2, %f8
+	fmuld		%f0, %f2, %f10
+
+	faddd		%f0, %f2, %f12
+	fmuld		%f0, %f2, %f14
+1:	stda		%f0, [%o0 + %g0] ASI_BLK_P
+	subcc		%o1, 1, %o1
+	bne,pt		%icc, 1b
+	 add		%o0, 0x40, %o0
+	membar		#Sync
+	VISExitHalf
+
+	brz,pn		%o4, out
+	 nop
+
+	stxa		%g0, [%g1] ASI_DMMU_DEMAP
+	membar		#Sync
+	stw		%o2, [%g6 + TI_PRE_COUNT]
+
+out:	retl
+	 nop
+