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powerpc/mm: Cleanup handling of execute permission

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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>
This commit is contained in:
Benjamin Herrenschmidt
2009-08-18 19:00:34 +00:00
parent f480fe3916
commit ea3cc330ac
15 changed files with 149 additions and 87 deletions
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13
arch/powerpc/include/asm/pte-book3e.h
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@@ -37,12 +37,13 @@
#define _PAGE_WRITETHRU 0x800000 /* W: cache write-through */
/* "Higher level" linux bit combinations */
#define _PAGE_EXEC _PAGE_BAP_SX /* Can be executed from potentially */
#define _PAGE_HWEXEC _PAGE_BAP_UX /* .. and was cache cleaned */
#define _PAGE_RW (_PAGE_BAP_SW | _PAGE_BAP_UW) /* User write permission */
#define _PAGE_KERNEL_RW (_PAGE_BAP_SW | _PAGE_BAP_SR | _PAGE_DIRTY)
#define _PAGE_KERNEL_RO (_PAGE_BAP_SR)
#define _PAGE_USER (_PAGE_BAP_UR | _PAGE_BAP_SR) /* Can be read */
#define _PAGE_EXEC _PAGE_BAP_UX /* .. and was cache cleaned */
#define _PAGE_RW (_PAGE_BAP_SW | _PAGE_BAP_UW) /* User write permission */
#define _PAGE_KERNEL_RW (_PAGE_BAP_SW | _PAGE_BAP_SR | _PAGE_DIRTY)
#define _PAGE_KERNEL_RO (_PAGE_BAP_SR)
#define _PAGE_KERNEL_RWX (_PAGE_BAP_SW | _PAGE_BAP_SR | _PAGE_DIRTY | _PAGE_BAP_SX)
#define _PAGE_KERNEL_ROX (_PAGE_BAP_SR | _PAGE_BAP_SX)
#define _PAGE_USER (_PAGE_BAP_UR | _PAGE_BAP_SR) /* Can be read */
#define _PAGE_HASHPTE 0
#define _PAGE_BUSY 0