sparc64: Niagara-4 bzero/memset, plus use MRU stores in page copy.

This adds optimized memset/bzero/page-clear routines for Niagara-4.

We basically can do what powerpc has been able to do for a decade (via
the "dcbz" instruction), which is use cache line clearing stores for
bzero and memsets with a 'c' argument of zero.

As long as we make the cache initializing store to each 32-byte
subblock of the L2 cache line, it works.

As with other Niagara-4 optimized routines, the key is to make sure to
avoid any usage of the %asi register, as reads and writes to it cost
at least 50 cycles.

For the user clear cases, we don't use these new routines, we use the
Niagara-1 variants instead.  Those have to use %asi in an unavoidable
way.

A Niagara-4 8K page clear costs just under 600 cycles.

Add definitions of the MRU variants of the cache initializing store
ASIs.  By default, cache initializing stores install the line as Least
Recently Used.  If we know we're going to use the data immediately
(which is true for page copies and clears) we can use the Most
Recently Used variant, to decrease the likelyhood of the lines being
evicted before they get used.

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

5 files changed, 156 insertions, 11 deletions

diff --git a/arch/sparc/lib/Makefile b/arch/sparc/lib/Makefile
index 30f6ab51c551..8410065f2862 100644
--- a/arch/sparc/lib/Makefile
+++ b/arch/sparc/lib/Makefile
@@ -33,7 +33,7 @@ lib-$(CONFIG_SPARC64) += NG2memcpy.o NG2copy_from_user.o NG2copy_to_user.o
 lib-$(CONFIG_SPARC64) +=  NG2patch.o
 
 lib-$(CONFIG_SPARC64) += NG4memcpy.o NG4copy_from_user.o NG4copy_to_user.o
-lib-$(CONFIG_SPARC64) +=  NG4patch.o NG4copy_page.o
+lib-$(CONFIG_SPARC64) +=  NG4patch.o NG4copy_page.o NG4clear_page.o NG4memset.o
 
 lib-$(CONFIG_SPARC64) += GENmemcpy.o GENcopy_from_user.o GENcopy_to_user.o
 lib-$(CONFIG_SPARC64) += GENpatch.o GENpage.o GENbzero.o
diff --git a/arch/sparc/lib/NG4clear_page.S b/arch/sparc/lib/NG4clear_page.S
new file mode 100644
index 000000000000..e16c88204a42
--- /dev/null
+++ b/arch/sparc/lib/NG4clear_page.S
@@ -0,0 +1,29 @@
+/* NG4copy_page.S: Niagara-4 optimized clear page.
+ *
+ * Copyright (C) 2012 (davem@davemloft.net)
+ */
+
+#include <asm/asi.h>
+#include <asm/page.h>
+
+	.text
+
+	.register	%g3, #scratch
+
+	.align		32
+	.globl		NG4clear_page
+	.globl		NG4clear_user_page
+NG4clear_page:		/* %o0=dest */
+NG4clear_user_page:	/* %o0=dest, %o1=vaddr */
+	set		PAGE_SIZE, %g7
+	mov		0x20, %g3
+1:	stxa		%g0, [%o0 + %g0] ASI_ST_BLKINIT_MRU_P
+	subcc		%g7, 0x40, %g7
+	stxa		%g0, [%o0 + %g3] ASI_ST_BLKINIT_MRU_P
+	bne,pt		%xcc, 1b
+	 add		%o0, 0x40, %o0
+	membar		#StoreLoad|#StoreStore
+	retl
+	 nop
+	.size		NG4clear_page,.-NG4clear_page
+	.size		NG4clear_user_page,.-NG4clear_user_page
\ No newline at end of file
diff --git a/arch/sparc/lib/NG4copy_page.S b/arch/sparc/lib/NG4copy_page.S
index f30ec10bbcac..28504e88c535 100644
--- a/arch/sparc/lib/NG4copy_page.S
+++ b/arch/sparc/lib/NG4copy_page.S
@@ -30,25 +30,25 @@ NG4copy_user_page:	/* %o0=dest, %o1=src, %o2=vaddr */
 	ldx		[%o1 + 0x10], %o4
 	ldx		[%o1 + 0x18], %o5
 	ldx		[%o1 + 0x20], %g1
-	stxa		%o2, [%o0] ASI_BLK_INIT_QUAD_LDD_P
+	stxa		%o2, [%o0] ASI_ST_BLKINIT_MRU_P
 	add		%o0, 0x08, %o0
 	ldx		[%o1 + 0x28], %g2
-	stxa		%o3, [%o0] ASI_BLK_INIT_QUAD_LDD_P
+	stxa		%o3, [%o0] ASI_ST_BLKINIT_MRU_P
 	add		%o0, 0x08, %o0
 	ldx		[%o1 + 0x30], %g3
-	stxa		%o4, [%o0] ASI_BLK_INIT_QUAD_LDD_P
+	stxa		%o4, [%o0] ASI_ST_BLKINIT_MRU_P
 	add		%o0, 0x08, %o0
 	ldx		[%o1 + 0x38], %o2
 	add		%o1, 0x40, %o1
-	stxa		%o5, [%o0] ASI_BLK_INIT_QUAD_LDD_P
+	stxa		%o5, [%o0] ASI_ST_BLKINIT_MRU_P
 	add		%o0, 0x08, %o0
-	stxa		%g1, [%o0] ASI_BLK_INIT_QUAD_LDD_P
+	stxa		%g1, [%o0] ASI_ST_BLKINIT_MRU_P
 	add		%o0, 0x08, %o0
-	stxa		%g2, [%o0] ASI_BLK_INIT_QUAD_LDD_P
+	stxa		%g2, [%o0] ASI_ST_BLKINIT_MRU_P
 	add		%o0, 0x08, %o0
-	stxa		%g3, [%o0] ASI_BLK_INIT_QUAD_LDD_P
+	stxa		%g3, [%o0] ASI_ST_BLKINIT_MRU_P
 	add		%o0, 0x08, %o0
-	stxa		%o2, [%o0] ASI_BLK_INIT_QUAD_LDD_P
+	stxa		%o2, [%o0] ASI_ST_BLKINIT_MRU_P
 	add		%o0, 0x08, %o0
 	bne,pt		%icc, 1b
 	 prefetch	[%o1 + 0x200], #n_reads_strong
diff --git a/arch/sparc/lib/NG4memset.S b/arch/sparc/lib/NG4memset.S
new file mode 100644
index 000000000000..41da4bdd95cb
--- /dev/null
+++ b/arch/sparc/lib/NG4memset.S
@@ -0,0 +1,105 @@
+/* NG4memset.S: Niagara-4 optimized memset/bzero.
+ *
+ * Copyright (C) 2012 David S. Miller (davem@davemloft.net)
+ */
+
+#include <asm/asi.h>
+
+	.register	%g2, #scratch
+	.register	%g3, #scratch
+
+	.text
+	.align		32
+	.globl		NG4memset
+NG4memset:
+	andcc		%o1, 0xff, %o4
+	be,pt		%icc, 1f
+	 mov		%o2, %o1
+	sllx		%o4, 8, %g1
+	or		%g1, %o4, %o2
+	sllx		%o2, 16, %g1
+	or		%g1, %o2, %o2
+	sllx		%o2, 32, %g1
+	ba,pt		%icc, 1f
+	 or		%g1, %o2, %o4
+	.size		NG4memset,.-NG4memset
+
+	.align		32
+	.globl		NG4bzero
+NG4bzero:
+	clr		%o4
+1:	cmp		%o1, 16
+	ble		%icc, .Ltiny
+	 mov		%o0, %o3
+	sub		%g0, %o0, %g1
+	and		%g1, 0x7, %g1
+	brz,pt		%g1, .Laligned8
+	 sub		%o1, %g1, %o1
+1:	stb		%o4, [%o0 + 0x00]
+	subcc		%g1, 1, %g1
+	bne,pt		%icc, 1b
+	 add		%o0, 1, %o0
+.Laligned8:
+	cmp		%o1, 64 + (64 - 8)
+	ble		.Lmedium
+	 sub		%g0, %o0, %g1
+	andcc		%g1, (64 - 1), %g1
+	brz,pn		%g1, .Laligned64
+	 sub		%o1, %g1, %o1
+1:	stx		%o4, [%o0 + 0x00]
+	subcc		%g1, 8, %g1
+	bne,pt		%icc, 1b
+	 add		%o0, 0x8, %o0
+.Laligned64:
+	andn		%o1, 64 - 1, %g1
+	sub		%o1, %g1, %o1
+	brnz,pn		%o4, .Lnon_bzero_loop
+	 mov		0x20, %g2
+1:	stxa		%o4, [%o0 + %g0] ASI_BLK_INIT_QUAD_LDD_P
+	subcc		%g1, 0x40, %g1
+	stxa		%o4, [%o0 + %g2] ASI_BLK_INIT_QUAD_LDD_P
+	bne,pt		%icc, 1b
+	 add		%o0, 0x40, %o0
+.Lpostloop:
+	cmp		%o1, 8
+	bl,pn		%icc, .Ltiny
+	 membar		#StoreStore|#StoreLoad
+.Lmedium:
+	andn		%o1, 0x7, %g1
+	sub		%o1, %g1, %o1
+1:	stx		%o4, [%o0 + 0x00]
+	subcc		%g1, 0x8, %g1
+	bne,pt		%icc, 1b
+	 add		%o0, 0x08, %o0
+	andcc		%o1, 0x4, %g1
+	be,pt		%icc, .Ltiny
+	 sub		%o1, %g1, %o1
+	stw		%o4, [%o0 + 0x00]
+	add		%o0, 0x4, %o0
+.Ltiny:
+	cmp		%o1, 0
+	be,pn		%icc, .Lexit
+1:	 subcc		%o1, 1, %o1
+	stb		%o4, [%o0 + 0x00]
+	bne,pt		%icc, 1b
+	 add		%o0, 1, %o0
+.Lexit:
+	retl
+	 mov		%o3, %o0
+.Lnon_bzero_loop:
+	mov		0x08, %g3
+	mov		0x28, %o5
+1:	stxa		%o4, [%o0 + %g0] ASI_BLK_INIT_QUAD_LDD_P
+	subcc		%g1, 0x40, %g1
+	stxa		%o4, [%o0 + %g2] ASI_BLK_INIT_QUAD_LDD_P
+	stxa		%o4, [%o0 + %g3] ASI_BLK_INIT_QUAD_LDD_P
+	stxa		%o4, [%o0 + %o5] ASI_BLK_INIT_QUAD_LDD_P
+	add		%o0, 0x10, %o0
+	stxa		%o4, [%o0 + %g0] ASI_BLK_INIT_QUAD_LDD_P
+	stxa		%o4, [%o0 + %g2] ASI_BLK_INIT_QUAD_LDD_P
+	stxa		%o4, [%o0 + %g3] ASI_BLK_INIT_QUAD_LDD_P
+	stxa		%o4, [%o0 + %o5] ASI_BLK_INIT_QUAD_LDD_P
+	bne,pt		%icc, 1b
+	 add		%o0, 0x30, %o0
+	ba,a,pt		%icc, .Lpostloop
+	.size		NG4bzero,.-NG4bzero
diff --git a/arch/sparc/lib/NG4patch.S b/arch/sparc/lib/NG4patch.S
index c21c34c61dda..a114cbcf2a48 100644
--- a/arch/sparc/lib/NG4patch.S
+++ b/arch/sparc/lib/NG4patch.S
@@ -32,12 +32,23 @@ niagara4_patch_copyops:
 	 nop
 	.size	niagara4_patch_copyops,.-niagara4_patch_copyops
 
+	.globl	niagara4_patch_bzero
+	.type	niagara4_patch_bzero,#function
+niagara4_patch_bzero:
+	NG_DO_PATCH(memset, NG4memset)
+	NG_DO_PATCH(__bzero, NG4bzero)
+	NG_DO_PATCH(__clear_user, NGclear_user)
+	NG_DO_PATCH(tsb_init, NGtsb_init)
+	retl
+	 nop
+	.size	niagara4_patch_bzero,.-niagara4_patch_bzero
+
 	.globl	niagara4_patch_pageops
 	.type	niagara4_patch_pageops,#function
 niagara4_patch_pageops:
 	NG_DO_PATCH(copy_user_page, NG4copy_user_page)
-	NG_DO_PATCH(_clear_page, NGclear_page)
-	NG_DO_PATCH(clear_user_page, NGclear_user_page)
+	NG_DO_PATCH(_clear_page, NG4clear_page)
+	NG_DO_PATCH(clear_user_page, NG4clear_user_page)
 	retl
 	 nop
 	.size	niagara4_patch_pageops,.-niagara4_patch_pageops