powerpc/mm: Cleanup handling of execute permission

This is an attempt at cleaning up a bit the way we handle execute
permission on powerpc. _PAGE_HWEXEC is gone, _PAGE_EXEC is now only
defined by CPUs that can do something with it, and the myriad of
#ifdef's in the I$/D$ coherency code is reduced to 2 cases that
hopefully should cover everything.

The logic on BookE is a little bit different than what it was though
not by much. Since now, _PAGE_EXEC will be set by the generic code
for executable pages, we need to filter out if they are unclean and
recover it. However, I don't expect the code to be more bloated than
it already was in that area due to that change.

I could boast that this brings proper enforcing of per-page execute
permissions to all BookE and 40x but in fact, we've had that now for
some time as a side effect of my previous rework in that area (and
I didn't even know it :-) We would only enable execute permission if
the page was cache clean and we would only cache clean it if we took
and exec fault. Since we now enforce that the later only work if
VM_EXEC is part of the VMA flags, we de-fact already enforce per-page
execute permissions... Unless I missed something

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 11 insertions, 11 deletions

diff --git a/arch/powerpc/include/asm/pte-common.h b/arch/powerpc/include/asm/pte-common.h
index 8bb6464ba619..c3b65076a263 100644
--- a/arch/powerpc/include/asm/pte-common.h
+++ b/arch/powerpc/include/asm/pte-common.h
@@ -13,9 +13,6 @@
 #ifndef _PAGE_HWWRITE
 #define _PAGE_HWWRITE   0
 #endif
-#ifndef _PAGE_HWEXEC
-#define _PAGE_HWEXEC    0
-#endif
 #ifndef _PAGE_EXEC
 #define _PAGE_EXEC      0
 #endif
@@ -48,10 +45,16 @@
 #define PMD_PAGE_SIZE(pmd)      bad_call_to_PMD_PAGE_SIZE()
 #endif
 #ifndef _PAGE_KERNEL_RO
-#define _PAGE_KERNEL_RO 0
+#define _PAGE_KERNEL_RO         0
+#endif
+#ifndef _PAGE_KERNEL_ROX
+#define _PAGE_KERNEL_ROX        (_PAGE_EXEC)
 #endif
 #ifndef _PAGE_KERNEL_RW
-#define _PAGE_KERNEL_RW (_PAGE_DIRTY | _PAGE_RW | _PAGE_HWWRITE)
+#define _PAGE_KERNEL_RW         (_PAGE_DIRTY | _PAGE_RW | _PAGE_HWWRITE)
+#endif
+#ifndef _PAGE_KERNEL_RWX
+#define _PAGE_KERNEL_RWX        (_PAGE_DIRTY | _PAGE_RW | _PAGE_HWWRITE | _PAGE_EXEC)
 #endif
 #ifndef _PAGE_HPTEFLAGS
 #define _PAGE_HPTEFLAGS _PAGE_HASHPTE
@@ -96,8 +99,7 @@ extern unsigned long bad_call_to_PMD_PAGE_SIZE(void);
 #define PAGE_PROT_BITS  (_PAGE_GUARDED | _PAGE_COHERENT | _PAGE_NO_CACHE | \
                          _PAGE_WRITETHRU | _PAGE_ENDIAN | _PAGE_4K_PFN | \
                          _PAGE_USER | _PAGE_ACCESSED | \
-                         _PAGE_RW | _PAGE_HWWRITE | _PAGE_DIRTY | \
-                         _PAGE_EXEC | _PAGE_HWEXEC)
+                         _PAGE_RW | _PAGE_HWWRITE | _PAGE_DIRTY | _PAGE_EXEC)
 
 /*
  * We define 2 sets of base prot bits, one for basic pages (ie,
@@ -154,11 +156,9 @@ extern unsigned long bad_call_to_PMD_PAGE_SIZE(void);
                                  _PAGE_NO_CACHE)
 #define PAGE_KERNEL_NCG __pgprot(_PAGE_BASE_NC | _PAGE_KERNEL_RW | \
                                  _PAGE_NO_CACHE | _PAGE_GUARDED)
-#define PAGE_KERNEL_X   __pgprot(_PAGE_BASE | _PAGE_KERNEL_RW | _PAGE_EXEC | \
-                                 _PAGE_HWEXEC)
+#define PAGE_KERNEL_X   __pgprot(_PAGE_BASE | _PAGE_KERNEL_RWX)
 #define PAGE_KERNEL_RO  __pgprot(_PAGE_BASE | _PAGE_KERNEL_RO)
-#define PAGE_KERNEL_ROX __pgprot(_PAGE_BASE | _PAGE_KERNEL_RO | _PAGE_EXEC | \
-                                 _PAGE_HWEXEC)
+#define PAGE_KERNEL_ROX __pgprot(_PAGE_BASE | _PAGE_KERNEL_ROX)
 
 /* Protection used for kernel text. We want the debuggers to be able to
  * set breakpoints anywhere, so don't write protect the kernel text