1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * Copyright (C) 1999-2002 Hewlett-Packard Co
4 *	Stephane Eranian <eranian@hpl.hp.com>
5 *	David Mosberger-Tang <davidm@hpl.hp.com>
6 * Copyright (C) 2002 Ken Chen <kenneth.w.chen@intel.com>
7 *
8 * 1/06/01 davidm	Tuned for Itanium.
9 * 2/12/02 kchen	Tuned for both Itanium and McKinley
10 * 3/08/02 davidm	Some more tweaking
11 */
12
13#include <asm/asmmacro.h>
14#include <asm/page.h>
15#include <asm/export.h>
16
17#ifdef CONFIG_ITANIUM
18# define L3_LINE_SIZE	64	// Itanium L3 line size
19# define PREFETCH_LINES	9	// magic number
20#else
21# define L3_LINE_SIZE	128	// McKinley L3 line size
22# define PREFETCH_LINES	12	// magic number
23#endif
24
25#define saved_lc	r2
26#define dst_fetch	r3
27#define dst1		r8
28#define dst2		r9
29#define dst3		r10
30#define dst4		r11
31
32#define dst_last	r31
33
34GLOBAL_ENTRY(clear_page)
35	.prologue
36	.regstk 1,0,0,0
37	mov r16 = PAGE_SIZE/L3_LINE_SIZE-1	// main loop count, -1=repeat/until
38	.save ar.lc, saved_lc
39	mov saved_lc = ar.lc
40
41	.body
42	mov ar.lc = (PREFETCH_LINES - 1)
43	mov dst_fetch = in0
44	adds dst1 = 16, in0
45	adds dst2 = 32, in0
46	;;
47.fetch:	stf.spill.nta [dst_fetch] = f0, L3_LINE_SIZE
48	adds dst3 = 48, in0		// executing this multiple times is harmless
49	br.cloop.sptk.few .fetch
50	;;
51	addl dst_last = (PAGE_SIZE - PREFETCH_LINES*L3_LINE_SIZE), dst_fetch
52	mov ar.lc = r16			// one L3 line per iteration
53	adds dst4 = 64, in0
54	;;
55#ifdef CONFIG_ITANIUM
56	// Optimized for Itanium
571:	stf.spill.nta [dst1] = f0, 64
58	stf.spill.nta [dst2] = f0, 64
59	cmp.lt p8,p0=dst_fetch, dst_last
60	;;
61#else
62	// Optimized for McKinley
631:	stf.spill.nta [dst1] = f0, 64
64	stf.spill.nta [dst2] = f0, 64
65	stf.spill.nta [dst3] = f0, 64
66	stf.spill.nta [dst4] = f0, 128
67	cmp.lt p8,p0=dst_fetch, dst_last
68	;;
69	stf.spill.nta [dst1] = f0, 64
70	stf.spill.nta [dst2] = f0, 64
71#endif
72	stf.spill.nta [dst3] = f0, 64
73(p8)	stf.spill.nta [dst_fetch] = f0, L3_LINE_SIZE
74	br.cloop.sptk.few 1b
75	;;
76	mov ar.lc = saved_lc		// restore lc
77	br.ret.sptk.many rp
78END(clear_page)
79EXPORT_SYMBOL(clear_page)
80