sparc64: Multi-page size support

Add support for using multiple hugepage sizes simultaneously
on mainline. Currently, support for 256M has been added which
can be used along with 8M pages.

Page tables are set like this (e.g. for 256M page):
    VA + (8M * x) -> PA + (8M * x) (sz bit = 256M) where x in [0, 31]

and TSB is set similarly:
    VA + (4M * x) -> PA + (4M * x) (sz bit = 256M) where x in [0, 63]

- Testing

Tested on Sonoma (which supports 256M pages) by running stream
benchmark instances in parallel: one instance uses 8M pages and
another uses 256M pages, consuming 48G each.

Boot params used:

default_hugepagesz=256M hugepagesz=256M hugepages=300 hugepagesz=8M
hugepages=10000

Signed-off-by: Nitin Gupta <nitin.m.gupta@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

arch/sparc/kernel/tsb.S

@@ -117,26 +117,11 @@ tsb_miss_page_table_walk_sun4v_fastpath:
 	/* Valid PTE is now in %g5.  */
 
 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
-661:	sethi		%uhi(_PAGE_SZALL_4U), %g7
+	sethi		%uhi(_PAGE_PMD_HUGE), %g7
 	sllx		%g7, 32, %g7
-	.section	.sun4v_2insn_patch, "ax"
-	.word		661b
-	mov		_PAGE_SZALL_4V, %g7
-	nop
-	.previous
 
-	and		%g5, %g7, %g2
-
-661:	sethi		%uhi(_PAGE_SZHUGE_4U), %g7
-	sllx		%g7, 32, %g7
-	.section	.sun4v_2insn_patch, "ax"
-	.word		661b
-	mov		_PAGE_SZHUGE_4V, %g7
-	nop
-	.previous
-
-	cmp		%g2, %g7
-	bne,pt		%xcc, 60f
+	andcc		%g5, %g7, %g0
+	be,pt		%xcc, 60f
 	 nop
 
 	/* It is a huge page, use huge page TSB entry address we