Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / arch / arm / mm / copypage-v4mc.c

diff --git a/kernel/arch/arm/mm/copypage-v4mc.c b/kernel/arch/arm/mm/copypage-v4mc.c
new file mode 100644 (file)
index 0000000..1267e64
--- /dev/null
+++ b/kernel/arch/arm/mm/copypage-v4mc.c
@@ -0,0 +1,115 @@
+/*
+ *  linux/arch/arm/lib/copypage-armv4mc.S
+ *
+ *  Copyright (C) 1995-2005 Russell King
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This handles the mini data cache, as found on SA11x0 and XScale
+ * processors.  When we copy a user page page, we map it in such a way
+ * that accesses to this page will not touch the main data cache, but
+ * will be cached in the mini data cache.  This prevents us thrashing
+ * the main data cache on page faults.
+ */
+#include <linux/init.h>
+#include <linux/mm.h>
+#include <linux/highmem.h>
+
+#include <asm/pgtable.h>
+#include <asm/tlbflush.h>
+#include <asm/cacheflush.h>
+
+#include "mm.h"
+
+#define minicache_pgprot __pgprot(L_PTE_PRESENT | L_PTE_YOUNG | \
+                                 L_PTE_MT_MINICACHE)
+
+static DEFINE_RAW_SPINLOCK(minicache_lock);
+
+/*
+ * ARMv4 mini-dcache optimised copy_user_highpage
+ *
+ * We flush the destination cache lines just before we write the data into the
+ * corresponding address.  Since the Dcache is read-allocate, this removes the
+ * Dcache aliasing issue.  The writes will be forwarded to the write buffer,
+ * and merged as appropriate.
+ *
+ * Note: We rely on all ARMv4 processors implementing the "invalidate D line"
+ * instruction.  If your processor does not supply this, you have to write your
+ * own copy_user_highpage that does the right thing.
+ */
+static void __naked
+mc_copy_user_page(void *from, void *to)
+{
+       asm volatile(
+       "stmfd  sp!, {r4, lr}                   @ 2\n\
+       mov     r4, %2                          @ 1\n\
+       ldmia   %0!, {r2, r3, ip, lr}           @ 4\n\
+1:     mcr     p15, 0, %1, c7, c6, 1           @ 1   invalidate D line\n\
+       stmia   %1!, {r2, r3, ip, lr}           @ 4\n\
+       ldmia   %0!, {r2, r3, ip, lr}           @ 4+1\n\
+       stmia   %1!, {r2, r3, ip, lr}           @ 4\n\
+       ldmia   %0!, {r2, r3, ip, lr}           @ 4\n\
+       mcr     p15, 0, %1, c7, c6, 1           @ 1   invalidate D line\n\
+       stmia   %1!, {r2, r3, ip, lr}           @ 4\n\
+       ldmia   %0!, {r2, r3, ip, lr}           @ 4\n\
+       subs    r4, r4, #1                      @ 1\n\
+       stmia   %1!, {r2, r3, ip, lr}           @ 4\n\
+       ldmneia %0!, {r2, r3, ip, lr}           @ 4\n\
+       bne     1b                              @ 1\n\
+       ldmfd   sp!, {r4, pc}                   @ 3"
+       :
+       : "r" (from), "r" (to), "I" (PAGE_SIZE / 64));
+}
+
+void v4_mc_copy_user_highpage(struct page *to, struct page *from,
+       unsigned long vaddr, struct vm_area_struct *vma)
+{
+       void *kto = kmap_atomic(to);
+
+       if (!test_and_set_bit(PG_dcache_clean, &from->flags))
+               __flush_dcache_page(page_mapping(from), from);
+
+       raw_spin_lock(&minicache_lock);
+
+       set_top_pte(COPYPAGE_MINICACHE, mk_pte(from, minicache_pgprot));
+
+       mc_copy_user_page((void *)COPYPAGE_MINICACHE, kto);
+
+       raw_spin_unlock(&minicache_lock);
+
+       kunmap_atomic(kto);
+}
+
+/*
+ * ARMv4 optimised clear_user_page
+ */
+void v4_mc_clear_user_highpage(struct page *page, unsigned long vaddr)
+{
+       void *ptr, *kaddr = kmap_atomic(page);
+       asm volatile("\
+       mov     r1, %2                          @ 1\n\
+       mov     r2, #0                          @ 1\n\
+       mov     r3, #0                          @ 1\n\
+       mov     ip, #0                          @ 1\n\
+       mov     lr, #0                          @ 1\n\
+1:     mcr     p15, 0, %0, c7, c6, 1           @ 1   invalidate D line\n\
+       stmia   %0!, {r2, r3, ip, lr}           @ 4\n\
+       stmia   %0!, {r2, r3, ip, lr}           @ 4\n\
+       mcr     p15, 0, %0, c7, c6, 1           @ 1   invalidate D line\n\
+       stmia   %0!, {r2, r3, ip, lr}           @ 4\n\
+       stmia   %0!, {r2, r3, ip, lr}           @ 4\n\
+       subs    r1, r1, #1                      @ 1\n\
+       bne     1b                              @ 1"
+       : "=r" (ptr)
+       : "0" (kaddr), "I" (PAGE_SIZE / 64)
+       : "r1", "r2", "r3", "ip", "lr");
+       kunmap_atomic(kaddr);
+}
+
+struct cpu_user_fns v4_mc_user_fns __initdata = {
+       .cpu_clear_user_highpage = v4_mc_clear_user_highpage,
+       .cpu_copy_user_highpage = v4_mc_copy_user_highpage,
+};