2009-07-15 07:39:15

by Michal Simek

Subject: asm-generic pgtable.h

Hi Arnd,

I found that we should simplify pgtable.h. There are a lot of generic
functions which use
all archs. Have you look at it or not?

Thanks,
Michal

--
Michal Simek, Ing. (M.Eng)
PetaLogix - Linux Solutions for a Reconfigurable World
w: http://www.petalogix.com p: +61-7-30090663,+42-0-721842854 f: +61-7-30090663

2009-07-15 09:25:59

by Arnd Bergmann

Subject: [PATCH] asm-generic: add pgtable-nommu.h

All nommu architectures have almost identical pgtable.h implementations,
so we should have a common file for them.

I must have missed this in the earlier asm-generic submission.

Signed-off-by: Arnd Bergmann <[email protected]>
---
On Wednesday 15 July 2009, Michal Simek wrote:

> I found that we should simplify pgtable.h. There are a lot of generic
> functions which use all archs. Have you look at it or not?

I have missed this one for some reason, maybe because it looked too
complicated at some point, or because it is already very complex with
a lot of different helper header files.

For the nommu case, it should be trivial to add something. Can you
try if the patch below gives you something useful?

diff --git a/include/asm-generic/pgtable-nommu.h b/include/asm-generic/pgtable-nommu.h
new file mode 100644
index 0000000..c194f85
--- /dev/null
+++ b/include/asm-generic/pgtable-nommu.h
@@ -0,0 +1,74 @@
+#ifndef __ASM_GENERIC_PGTABLE_H
+#define __ASM_GENERIC_PGTABLE_H
+
+#include <asm-generic/4level-fixup.h>
+
+#include <asm/processor.h>
+#include <asm/page.h>
+#include <asm/io.h>
+
+/*
+ * Trivial page table functions.
+ */
+#define pgd_present(pgd) (1)
+#define pgd_none(pgd) (0)
+#define pgd_bad(pgd) (0)
+#define pgd_clear(pgdp)
+#define kern_addr_valid(addr) (1)
+#define pmd_offset(a, b) ((void *)0)
+
+#define PAGE_NONE __pgprot(0)
+#define PAGE_SHARED __pgprot(0)
+#define PAGE_COPY __pgprot(0)
+#define PAGE_READONLY __pgprot(0)
+#define PAGE_KERNEL __pgprot(0)
+
+extern void paging_init(void);
+#define swapper_pg_dir ((pgd_t *) 0)
+
+#define __swp_type(x) (0)
+#define __swp_offset(x) (0)
+#define __swp_entry(typ,off) ((swp_entry_t) { ((typ) | ((off) << 7)) })
+#define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
+#define __swp_entry_to_pte(x) ((pte_t) { (x).val })
+
+static inline int pte_file(pte_t pte)
+{
+ return 0;
+}
+
+/*
+ * ZERO_PAGE is a global shared page that is always zero: used
+ * for zero-mapped memory areas etc..
+ */
+#define ZERO_PAGE(vaddr) (virt_to_page(0))
+
+/*
+ * Mark the prot value as uncacheable and unbufferable.
+ */
+#define pgprot_noncached(prot) __pgprot(0)
+#define pgprot_writecombine(prot) __pgprot(0)
+
+/*
+ * These would be in other places but having them here reduces the diffs.
+ */
+extern unsigned int kobjsize(const void *objp);
+
+/*
+ * No page table caches to initialise.
+ */
+#define pgtable_cache_init() do { } while (0)
+
+#define io_remap_pfn_range(vma, vaddr, pfn, size, prot) \
+ remap_pfn_range(vma, vaddr, pfn, size, prot)
+
+/*
+ * All 32bit addresses are effectively valid for vmalloc...
+ * Sort of meaningless for non-VM targets.
+ */
+#define VMALLOC_START 0
+#define VMALLOC_END 0xffffffff
+
+#include <asm-generic/pgtable.h>
+
+#endif /* __ASM_GENERIC_PGTABLE_H */