Patch "parisc: Optimize flush_kernel_vmap_range and invalidate_kernel_vmap_range" has been added to the 4.9-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    parisc: Optimize flush_kernel_vmap_range and invalidate_kernel_vmap_range

to the 4.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     parisc-optimize-flush_kernel_vmap_range-and-invalidate_kernel_vmap_range.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 316ec0624f951166daedbe446988ef92ae72b59f Mon Sep 17 00:00:00 2001
From: John David Anglin <dave.anglin@bell.net>
Date: Sat, 11 Mar 2017 18:03:34 -0500
Subject: parisc: Optimize flush_kernel_vmap_range and invalidate_kernel_vmap_range

From: John David Anglin <dave.anglin@bell.net>

commit 316ec0624f951166daedbe446988ef92ae72b59f upstream.

The previously submitted patch did not resolve the random segmentation
faults observed on the phantom buildd system.  There are still
unresolved problems with the Debian 4.8 and 4.9 kernels on C8000.

The attached patch removes the flush of the offset map pages and does a
whole data cache flush for large ranges.  No other arch flushes the
offset map in these routines as far as I can tell.

I have not observed any random segmentation faults on rp3440 in two
weeks of testing with 4.10.0 and 4.10.1.

Signed-off-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/parisc/include/asm/cacheflush.h |   23 ++---------------------
 arch/parisc/kernel/cache.c           |   22 ++++++++++++++++++++++
 2 files changed, 24 insertions(+), 21 deletions(-)

--- a/arch/parisc/include/asm/cacheflush.h
+++ b/arch/parisc/include/asm/cacheflush.h
@@ -45,28 +45,9 @@ static inline void flush_kernel_dcache_p
 
 #define flush_kernel_dcache_range(start,size) \
 	flush_kernel_dcache_range_asm((start), (start)+(size));
-/* vmap range flushes and invalidates.  Architecturally, we don't need
- * the invalidate, because the CPU should refuse to speculate once an
- * area has been flushed, so invalidate is left empty */
-static inline void flush_kernel_vmap_range(void *vaddr, int size)
-{
-	unsigned long start = (unsigned long)vaddr;
 
-	flush_kernel_dcache_range_asm(start, start + size);
-}
-static inline void invalidate_kernel_vmap_range(void *vaddr, int size)
-{
-	unsigned long start = (unsigned long)vaddr;
-	void *cursor = vaddr;
-
-	for ( ; cursor < vaddr + size; cursor += PAGE_SIZE) {
-		struct page *page = vmalloc_to_page(cursor);
-
-		if (test_and_clear_bit(PG_dcache_dirty, &page->flags))
-			flush_kernel_dcache_page(page);
-	}
-	flush_kernel_dcache_range_asm(start, start + size);
-}
+void flush_kernel_vmap_range(void *vaddr, int size);
+void invalidate_kernel_vmap_range(void *vaddr, int size);
 
 #define flush_cache_vmap(start, end)		flush_cache_all()
 #define flush_cache_vunmap(start, end)		flush_cache_all()
--- a/arch/parisc/kernel/cache.c
+++ b/arch/parisc/kernel/cache.c
@@ -633,3 +633,25 @@ flush_cache_page(struct vm_area_struct *
 		__flush_cache_page(vma, vmaddr, PFN_PHYS(pfn));
 	}
 }
+
+void flush_kernel_vmap_range(void *vaddr, int size)
+{
+	unsigned long start = (unsigned long)vaddr;
+
+	if ((unsigned long)size > parisc_cache_flush_threshold)
+		flush_data_cache();
+	else
+		flush_kernel_dcache_range_asm(start, start + size);
+}
+EXPORT_SYMBOL(flush_kernel_vmap_range);
+
+void invalidate_kernel_vmap_range(void *vaddr, int size)
+{
+	unsigned long start = (unsigned long)vaddr;
+
+	if ((unsigned long)size > parisc_cache_flush_threshold)
+		flush_data_cache();
+	else
+		flush_kernel_dcache_range_asm(start, start + size);
+}
+EXPORT_SYMBOL(invalidate_kernel_vmap_range);


Patches currently in stable-queue which might be from dave.anglin@bell.net are

queue-4.9/parisc-optimize-flush_kernel_vmap_range-and-invalidate_kernel_vmap_range.patch