parisc: change value of SHMLBA from 0x00400000 to PAGE_SIZE

On parisc, SHMLBA was defined to 0x00400000 (4MB) to reflect that we need to
take care of our caches for shared mappings. But actually, we can map a file at
any multiple address of PAGE_SIZE, so let us correct that now with a value of
PAGE_SIZE for SHMLBA.  Instead we now take care of this cache colouring via the
constant SHM_COLOUR while we map shared pages.

Signed-off-by: Helge Deller <deller@gmx.de>
CC: Jeroen Roovers <jer@gentoo.org>
CC: John David Anglin <dave.anglin@bell.net>
CC: Carlos O'Donell <carlos@systemhalted.org>
Cc: stable@kernel.org [3.13+]

arch/parisc/include/asm/shmparam.h

@@ -1,8 +1,7 @@
 #ifndef _ASMPARISC_SHMPARAM_H
 #define _ASMPARISC_SHMPARAM_H
 
-#define __ARCH_FORCE_SHMLBA 	1
-
-#define SHMLBA 0x00400000   /* attach addr needs to be 4 Mb aligned */
+#define SHMLBA	   PAGE_SIZE	/* attach addr a multiple of this */
+#define SHM_COLOUR 0x00400000	/* shared mappings colouring */
 
 #endif /* _ASMPARISC_SHMPARAM_H */

arch/parisc/kernel/cache.c

@@ -323,7 +323,8 @@ void flush_dcache_page(struct page *page)
 		 * specifically accesses it, of course) */
 
 		flush_tlb_page(mpnt, addr);
-		if (old_addr == 0 || (old_addr & (SHMLBA - 1)) != (addr & (SHMLBA - 1))) {
+		if (old_addr == 0 || (old_addr & (SHM_COLOUR - 1))
+				      != (addr & (SHM_COLOUR - 1))) {
 			__flush_cache_page(mpnt, addr, page_to_phys(page));
 			if (old_addr)
 				printk(KERN_ERR "INEQUIVALENT ALIASES 0x%lx and 0x%lx in file %s\n", old_addr, addr, mpnt->vm_file ? (char *)mpnt->vm_file->f_path.dentry->d_name.name : "(null)");

arch/parisc/kernel/sys_parisc.c

@@ -45,7 +45,7 @@
 
 static int get_offset(unsigned int last_mmap)
 {
-	return (last_mmap & (SHMLBA-1)) >> PAGE_SHIFT;
+	return (last_mmap & (SHM_COLOUR-1)) >> PAGE_SHIFT;
 }
 
 static unsigned long shared_align_offset(unsigned int last_mmap,
@@ -57,8 +57,8 @@ static unsigned long shared_align_offset(unsigned int last_mmap,
 static inline unsigned long COLOR_ALIGN(unsigned long addr,
 			 unsigned int last_mmap, unsigned long pgoff)
 {
-	unsigned long base = (addr+SHMLBA-1) & ~(SHMLBA-1);
-	unsigned long off  = (SHMLBA-1) &
+	unsigned long base = (addr+SHM_COLOUR-1) & ~(SHM_COLOUR-1);
+	unsigned long off  = (SHM_COLOUR-1) &
 		(shared_align_offset(last_mmap, pgoff) << PAGE_SHIFT);
 
 	return base + off;
@@ -101,7 +101,7 @@ unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
 	if (flags & MAP_FIXED) {
 		if ((flags & MAP_SHARED) && last_mmap &&
 		    (addr - shared_align_offset(last_mmap, pgoff))
-				& (SHMLBA - 1))
+				& (SHM_COLOUR - 1))
 			return -EINVAL;
 		goto found_addr;
 	}
@@ -122,7 +122,7 @@ unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
 	info.length = len;
 	info.low_limit = mm->mmap_legacy_base;
 	info.high_limit = mmap_upper_limit();
-	info.align_mask = last_mmap ? (PAGE_MASK & (SHMLBA - 1)) : 0;
+	info.align_mask = last_mmap ? (PAGE_MASK & (SHM_COLOUR - 1)) : 0;
 	info.align_offset = shared_align_offset(last_mmap, pgoff);
 	addr = vm_unmapped_area(&info);
 
@@ -161,7 +161,7 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
 	if (flags & MAP_FIXED) {
 		if ((flags & MAP_SHARED) && last_mmap &&
 		    (addr - shared_align_offset(last_mmap, pgoff))
-			& (SHMLBA - 1))
+			& (SHM_COLOUR - 1))
 			return -EINVAL;
 		goto found_addr;
 	}
@@ -182,7 +182,7 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
 	info.length = len;
 	info.low_limit = PAGE_SIZE;
 	info.high_limit = mm->mmap_base;
-	info.align_mask = last_mmap ? (PAGE_MASK & (SHMLBA - 1)) : 0;
+	info.align_mask = last_mmap ? (PAGE_MASK & (SHM_COLOUR - 1)) : 0;
 	info.align_offset = shared_align_offset(last_mmap, pgoff);
 	addr = vm_unmapped_area(&info);
 	if (!(addr & ~PAGE_MASK))