powerpc ioremap_prot

This adds ioremap_prot and pte_pgprot() so that one can extract protection
bits from a PTE and use them to ioremap_prot() (in order to support ptrace
of VM_IO | VM_PFNMAP as per Rik's patch).

This moves a couple of flag checks around in the ioremap implementations
of arch/powerpc.  There's a side effect of allowing non-cacheable and
non-guarded mappings on ppc32 which before would always have _PAGE_GUARDED
set whenever _PAGE_NO_CACHE is.

(standard ioremap will still set _PAGE_GUARDED, but ioremap_prot will be
capable of setting such a non guarded mapping).

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Rik van Riel <riel@redhat.com>
Cc: Dave Airlie <airlied@linux.ie>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 4 insertions, 1 deletions

diff --git a/include/asm-powerpc/io.h b/include/asm-powerpc/io.h
index 8b627823f5f9..77c7fa025e65 100644
--- a/include/asm-powerpc/io.h
+++ b/include/asm-powerpc/io.h
@@ -617,7 +617,8 @@ static inline void iosync(void)
  *   and can be hooked by the platform via ppc_md
  *
  * * ioremap_flags allows to specify the page flags as an argument and can
- *   also be hooked by the platform via ppc_md
+ *   also be hooked by the platform via ppc_md. ioremap_prot is the exact
+ *   same thing as ioremap_flags.
  *
  * * ioremap_nocache is identical to ioremap
  *
@@ -639,6 +640,8 @@ extern void __iomem *ioremap(phys_addr_t address, unsigned long size);
 extern void __iomem *ioremap_flags(phys_addr_t address, unsigned long size,
                                    unsigned long flags);
 #define ioremap_nocache(addr, size)     ioremap((addr), (size))
+#define ioremap_prot(addr, size, prot)  ioremap_flags((addr), (size), (prot))
+
 extern void iounmap(volatile void __iomem *addr);
 
 extern void __iomem *__ioremap(phys_addr_t, unsigned long size,