1 files changed, 271 insertions, 0 deletions
diff --git a/arch/tile/lib/memcpy_tile64.c b/arch/tile/lib/memcpy_tile64.c
new file mode 100644
index 000000000000..4f0047342469
--- /dev/null
+++ b/arch/tile/lib/memcpy_tile64.c
@@ -0,0 +1,271 @@
+/*
+ * Copyright 2010 Tilera Corporation. All Rights Reserved.
+ *
+ *   This program is free software; you can redistribute it and/or
+ *   modify it under the terms of the GNU General Public License
+ *   as published by the Free Software Foundation, version 2.
+ *
+ *   This program is distributed in the hope that it will be useful, but
+ *   WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
+ *   NON INFRINGEMENT.  See the GNU General Public License for
+ *   more details.
+ */
+
+#include <linux/string.h>
+#include <linux/smp.h>
+#include <linux/module.h>
+#include <linux/uaccess.h>
+#include <asm/fixmap.h>
+#include <asm/kmap_types.h>
+#include <asm/tlbflush.h>
+#include <hv/hypervisor.h>
+#include <arch/chip.h>
+
+
+#if !CHIP_HAS_COHERENT_LOCAL_CACHE()
+
+/* Defined in memcpy.S */
+extern unsigned long __memcpy_asm(void *to, const void *from, unsigned long n);
+extern unsigned long __copy_to_user_inatomic_asm(
+	void __user *to, const void *from, unsigned long n);
+extern unsigned long __copy_from_user_inatomic_asm(
+	void *to, const void __user *from, unsigned long n);
+extern unsigned long __copy_from_user_zeroing_asm(
+	void *to, const void __user *from, unsigned long n);
+
+typedef unsigned long (*memcpy_t)(void *, const void *, unsigned long);
+
+/* Size above which to consider TLB games for performance */
+#define LARGE_COPY_CUTOFF 2048
+
+/* Communicate to the simulator what we are trying to do. */
+#define sim_allow_multiple_caching(b) \
+  __insn_mtspr(SPR_SIM_CONTROL, \
+   SIM_CONTROL_ALLOW_MULTIPLE_CACHING | ((b) << _SIM_CONTROL_OPERATOR_BITS))
+
+/*
+ * Copy memory by briefly enabling incoherent cacheline-at-a-time mode.
+ *
+ * We set up our own source and destination PTEs that we fully control.
+ * This is the only way to guarantee that we don't race with another
+ * thread that is modifying the PTE; we can't afford to try the
+ * copy_{to,from}_user() technique of catching the interrupt, since
+ * we must run with interrupts disabled to avoid the risk of some
+ * other code seeing the incoherent data in our cache.  (Recall that
+ * our cache is indexed by PA, so even if the other code doesn't use
+ * our KM_MEMCPY virtual addresses, they'll still hit in cache using
+ * the normal VAs that aren't supposed to hit in cache.)
+ */
+static void memcpy_multicache(void *dest, const void *source,
+			      pte_t dst_pte, pte_t src_pte, int len)
+{
+	int idx, i;
+	unsigned long flags, newsrc, newdst, endsrc;
+	pmd_t *pmdp;
+	pte_t *ptep;
+	int cpu = get_cpu();
+
+	/*
+	 * Disable interrupts so that we don't recurse into memcpy()
+	 * in an interrupt handler, nor accidentally reference
+	 * the PA of the source from an interrupt routine.  Also
+	 * notify the simulator that we're playing games so we don't
+	 * generate spurious coherency warnings.
+	 */
+	local_irq_save(flags);
+	sim_allow_multiple_caching(1);
+
+	/* Set up the new dest mapping */
+	idx = FIX_KMAP_BEGIN + (KM_TYPE_NR * cpu) + KM_MEMCPY0;
+	newdst = __fix_to_virt(idx) + ((unsigned long)dest & (PAGE_SIZE-1));
+	pmdp = pmd_offset(pud_offset(pgd_offset_k(newdst), newdst), newdst);
+	ptep = pte_offset_kernel(pmdp, newdst);
+	if (pte_val(*ptep) != pte_val(dst_pte)) {
+		set_pte(ptep, dst_pte);
+		local_flush_tlb_page(NULL, newdst, PAGE_SIZE);
+	}
+
+	/* Set up the new source mapping */
+	idx += (KM_MEMCPY0 - KM_MEMCPY1);
+	src_pte = hv_pte_set_nc(src_pte);
+	src_pte = hv_pte_clear_writable(src_pte);  /* be paranoid */
+	newsrc = __fix_to_virt(idx) + ((unsigned long)source & (PAGE_SIZE-1));
+	pmdp = pmd_offset(pud_offset(pgd_offset_k(newsrc), newsrc), newsrc);
+	ptep = pte_offset_kernel(pmdp, newsrc);
+	*ptep = src_pte;   /* set_pte() would be confused by this */
+	local_flush_tlb_page(NULL, newsrc, PAGE_SIZE);
+
+	/* Actually move the data. */
+	__memcpy_asm((void *)newdst, (const void *)newsrc, len);
+
+	/*
+	 * Remap the source as locally-cached and not OLOC'ed so that
+	 * we can inval without also invaling the remote cpu's cache.
+	 * This also avoids known errata with inv'ing cacheable oloc data.
+	 */
+	src_pte = hv_pte_set_mode(src_pte, HV_PTE_MODE_CACHE_NO_L3);
+	src_pte = hv_pte_set_writable(src_pte); /* need write access for inv */
+	*ptep = src_pte;   /* set_pte() would be confused by this */
+	local_flush_tlb_page(NULL, newsrc, PAGE_SIZE);
+
+	/*
+	 * Do the actual invalidation, covering the full L2 cache line
+	 * at the end since __memcpy_asm() is somewhat aggressive.
+	 */
+	__inv_buffer((void *)newsrc, len);
+
+	/*
+	 * We're done: notify the simulator that all is back to normal,
+	 * and re-enable interrupts and pre-emption.
+	 */
+	sim_allow_multiple_caching(0);
+	local_irq_restore(flags);
+	put_cpu_no_resched();
+}
+
+/*
+ * Identify large copies from remotely-cached memory, and copy them
+ * via memcpy_multicache() if they look good, otherwise fall back
+ * to the particular kind of copying passed as the memcpy_t function.
+ */
+static unsigned long fast_copy(void *dest, const void *source, int len,
+			       memcpy_t func)
+{
+	/*
+	 * Check if it's big enough to bother with.  We may end up doing a
+	 * small copy via TLB manipulation if we're near a page boundary,
+	 * but presumably we'll make it up when we hit the second page.
+	 */
+	while (len >= LARGE_COPY_CUTOFF) {
+		int copy_size, bytes_left_on_page;
+		pte_t *src_ptep, *dst_ptep;
+		pte_t src_pte, dst_pte;
+		struct page *src_page, *dst_page;
+
+		/* Is the source page oloc'ed to a remote cpu? */
+retry_source:
+		src_ptep = virt_to_pte(current->mm, (unsigned long)source);
+		if (src_ptep == NULL)
+			break;
+		src_pte = *src_ptep;
+		if (!hv_pte_get_present(src_pte) ||
+		    !hv_pte_get_readable(src_pte) ||
+		    hv_pte_get_mode(src_pte) != HV_PTE_MODE_CACHE_TILE_L3)
+			break;
+		if (get_remote_cache_cpu(src_pte) == smp_processor_id())
+			break;
+		src_page = pfn_to_page(hv_pte_get_pfn(src_pte));
+		get_page(src_page);
+		if (pte_val(src_pte) != pte_val(*src_ptep)) {
+			put_page(src_page);
+			goto retry_source;
+		}
+		if (pte_huge(src_pte)) {
+			/* Adjust the PTE to correspond to a small page */
+			int pfn = hv_pte_get_pfn(src_pte);
+			pfn += (((unsigned long)source & (HPAGE_SIZE-1))
+				>> PAGE_SHIFT);
+			src_pte = pfn_pte(pfn, src_pte);
+			src_pte = pte_mksmall(src_pte);
+		}
+
+		/* Is the destination page writable? */
+retry_dest:
+		dst_ptep = virt_to_pte(current->mm, (unsigned long)dest);
+		if (dst_ptep == NULL) {
+			put_page(src_page);
+			break;
+		}
+		dst_pte = *dst_ptep;
+		if (!hv_pte_get_present(dst_pte) ||
+		    !hv_pte_get_writable(dst_pte)) {
+			put_page(src_page);
+			break;
+		}
+		dst_page = pfn_to_page(hv_pte_get_pfn(dst_pte));
+		if (dst_page == src_page) {
+			/*
+			 * Source and dest are on the same page; this
+			 * potentially exposes us to incoherence if any
+			 * part of src and dest overlap on a cache line.
+			 * Just give up rather than trying to be precise.
+			 */
+			put_page(src_page);
+			break;
+		}
+		get_page(dst_page);
+		if (pte_val(dst_pte) != pte_val(*dst_ptep)) {
+			put_page(dst_page);
+			goto retry_dest;
+		}
+		if (pte_huge(dst_pte)) {
+			/* Adjust the PTE to correspond to a small page */
+			int pfn = hv_pte_get_pfn(dst_pte);
+			pfn += (((unsigned long)dest & (HPAGE_SIZE-1))
+				>> PAGE_SHIFT);
+			dst_pte = pfn_pte(pfn, dst_pte);
+			dst_pte = pte_mksmall(dst_pte);
+		}
+
+		/* All looks good: create a cachable PTE and copy from it */
+		copy_size = len;
+		bytes_left_on_page =
+			PAGE_SIZE - (((int)source) & (PAGE_SIZE-1));
+		if (copy_size > bytes_left_on_page)
+			copy_size = bytes_left_on_page;
+		bytes_left_on_page =
+			PAGE_SIZE - (((int)dest) & (PAGE_SIZE-1));
+		if (copy_size > bytes_left_on_page)
+			copy_size = bytes_left_on_page;
+		memcpy_multicache(dest, source, dst_pte, src_pte, copy_size);
+
+		/* Release the pages */
+		put_page(dst_page);
+		put_page(src_page);
+
+		/* Continue on the next page */
+		dest += copy_size;
+		source += copy_size;
+		len -= copy_size;
+	}
+
+	return func(dest, source, len);
+}
+
+void *memcpy(void *to, const void *from, __kernel_size_t n)
+{
+	if (n < LARGE_COPY_CUTOFF)
+		return (void *)__memcpy_asm(to, from, n);
+	else
+		return (void *)fast_copy(to, from, n, __memcpy_asm);
+}
+
+unsigned long __copy_to_user_inatomic(void __user *to, const void *from,
+				      unsigned long n)
+{
+	if (n < LARGE_COPY_CUTOFF)
+		return __copy_to_user_inatomic_asm(to, from, n);
+	else
+		return fast_copy(to, from, n, __copy_to_user_inatomic_asm);
+}
+
+unsigned long __copy_from_user_inatomic(void *to, const void __user *from,
+					unsigned long n)
+{
+	if (n < LARGE_COPY_CUTOFF)
+		return __copy_from_user_inatomic_asm(to, from, n);
+	else
+		return fast_copy(to, from, n, __copy_from_user_inatomic_asm);
+}
+
+unsigned long __copy_from_user_zeroing(void *to, const void __user *from,
+				       unsigned long n)
+{
+	if (n < LARGE_COPY_CUTOFF)
+		return __copy_from_user_zeroing_asm(to, from, n);
+	else
+		return fast_copy(to, from, n, __copy_from_user_zeroing_asm);
+}
+
+#endif /* !CHIP_HAS_COHERENT_LOCAL_CACHE() */