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-rw-r--r--arch/ia64/lib/clear_page.S79
1 files changed, 79 insertions, 0 deletions
diff --git a/arch/ia64/lib/clear_page.S b/arch/ia64/lib/clear_page.S
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+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 1999-2002 Hewlett-Packard Co
+ * Stephane Eranian <eranian@hpl.hp.com>
+ * David Mosberger-Tang <davidm@hpl.hp.com>
+ * Copyright (C) 2002 Ken Chen <kenneth.w.chen@intel.com>
+ *
+ * 1/06/01 davidm Tuned for Itanium.
+ * 2/12/02 kchen Tuned for both Itanium and McKinley
+ * 3/08/02 davidm Some more tweaking
+ */
+
+#include <linux/export.h>
+#include <asm/asmmacro.h>
+#include <asm/page.h>
+
+#ifdef CONFIG_ITANIUM
+# define L3_LINE_SIZE 64 // Itanium L3 line size
+# define PREFETCH_LINES 9 // magic number
+#else
+# define L3_LINE_SIZE 128 // McKinley L3 line size
+# define PREFETCH_LINES 12 // magic number
+#endif
+
+#define saved_lc r2
+#define dst_fetch r3
+#define dst1 r8
+#define dst2 r9
+#define dst3 r10
+#define dst4 r11
+
+#define dst_last r31
+
+GLOBAL_ENTRY(clear_page)
+ .prologue
+ .regstk 1,0,0,0
+ mov r16 = PAGE_SIZE/L3_LINE_SIZE-1 // main loop count, -1=repeat/until
+ .save ar.lc, saved_lc
+ mov saved_lc = ar.lc
+
+ .body
+ mov ar.lc = (PREFETCH_LINES - 1)
+ mov dst_fetch = in0
+ adds dst1 = 16, in0
+ adds dst2 = 32, in0
+ ;;
+.fetch: stf.spill.nta [dst_fetch] = f0, L3_LINE_SIZE
+ adds dst3 = 48, in0 // executing this multiple times is harmless
+ br.cloop.sptk.few .fetch
+ ;;
+ addl dst_last = (PAGE_SIZE - PREFETCH_LINES*L3_LINE_SIZE), dst_fetch
+ mov ar.lc = r16 // one L3 line per iteration
+ adds dst4 = 64, in0
+ ;;
+#ifdef CONFIG_ITANIUM
+ // Optimized for Itanium
+1: stf.spill.nta [dst1] = f0, 64
+ stf.spill.nta [dst2] = f0, 64
+ cmp.lt p8,p0=dst_fetch, dst_last
+ ;;
+#else
+ // Optimized for McKinley
+1: stf.spill.nta [dst1] = f0, 64
+ stf.spill.nta [dst2] = f0, 64
+ stf.spill.nta [dst3] = f0, 64
+ stf.spill.nta [dst4] = f0, 128
+ cmp.lt p8,p0=dst_fetch, dst_last
+ ;;
+ stf.spill.nta [dst1] = f0, 64
+ stf.spill.nta [dst2] = f0, 64
+#endif
+ stf.spill.nta [dst3] = f0, 64
+(p8) stf.spill.nta [dst_fetch] = f0, L3_LINE_SIZE
+ br.cloop.sptk.few 1b
+ ;;
+ mov ar.lc = saved_lc // restore lc
+ br.ret.sptk.many rp
+END(clear_page)
+EXPORT_SYMBOL(clear_page)