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>
diff --git a/arch/powerpc/mm/pgtable_32.c b/arch/powerpc/mm/pgtable_32.c
index c758407..2001abd 100644
--- a/arch/powerpc/mm/pgtable_32.c
+++ b/arch/powerpc/mm/pgtable_32.c
@@ -145,13 +145,20 @@
void __iomem *
ioremap(phys_addr_t addr, unsigned long size)
{
- return __ioremap(addr, size, _PAGE_NO_CACHE);
+ return __ioremap(addr, size, _PAGE_NO_CACHE | _PAGE_GUARDED);
}
EXPORT_SYMBOL(ioremap);
void __iomem *
ioremap_flags(phys_addr_t addr, unsigned long size, unsigned long flags)
{
+ /* writeable implies dirty for kernel addresses */
+ if (flags & _PAGE_RW)
+ flags |= _PAGE_DIRTY | _PAGE_HWWRITE;
+
+ /* we don't want to let _PAGE_USER and _PAGE_EXEC leak out */
+ flags &= ~(_PAGE_USER | _PAGE_EXEC | _PAGE_HWEXEC);
+
return __ioremap(addr, size, flags);
}
EXPORT_SYMBOL(ioremap_flags);
@@ -163,6 +170,14 @@
phys_addr_t p;
int err;
+ /* Make sure we have the base flags */
+ if ((flags & _PAGE_PRESENT) == 0)
+ flags |= _PAGE_KERNEL;
+
+ /* Non-cacheable page cannot be coherent */
+ if (flags & _PAGE_NO_CACHE)
+ flags &= ~_PAGE_COHERENT;
+
/*
* Choose an address to map it to.
* Once the vmalloc system is running, we use it.
@@ -219,11 +234,6 @@
v = (ioremap_bot -= size);
}
- if ((flags & _PAGE_PRESENT) == 0)
- flags |= _PAGE_KERNEL;
- if (flags & _PAGE_NO_CACHE)
- flags |= _PAGE_GUARDED;
-
/*
* Should check if it is a candidate for a BAT mapping
*/