[PATCH 2/17] Generic backward compatibility includes for 4level

[PATCH 2/17] Generic backward compatibility includes for 4level

[Andreas Kleen]

Generic backward compatibility includes for 4level

This adds some asm-generic file to allow conversion of 2level
and 3level architectures to 4levels without much duplicated code.

The pml4 is simply a pointer to the pgd.


Signed-off-by: Andi Kleen <ak@suse.de>

diff -urpN -X ../KDIFX linux-2.6.10rc1/include/asm-generic/nopml4-page.h linux-2.6.10rc1-4level/include/asm-generic/nopml4-page.h
--- linux-2.6.10rc1/include/asm-generic/nopml4-page.h	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.10rc1-4level/include/asm-generic/nopml4-page.h	2004-10-25 04:48:10.000000000 +0200
@@ -0,0 +1,14 @@
+#ifndef _NOPML4_PAGE_H
+#define _NOPML4_PAGE_H 1
+
+#ifndef __ASSEMBLY__
+
+/* 
+ * Generic page.h declarations for architectures without four level
+ * page tables 
+ */
+
+typedef struct { pgd_t pgd; } pml4_t; 
+#endif
+
+#endif
diff -urpN -X ../KDIFX linux-2.6.10rc1/include/asm-generic/nopml4-pgalloc.h linux-2.6.10rc1-4level/include/asm-generic/nopml4-pgalloc.h
--- linux-2.6.10rc1/include/asm-generic/nopml4-pgalloc.h	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.10rc1-4level/include/asm-generic/nopml4-pgalloc.h	2004-10-25 04:48:10.000000000 +0200
@@ -0,0 +1,21 @@
+#ifndef _NOPML4_PGALLOC_H
+#define _NOPML4_PGALLOC_H 1
+
+/* Fallback used for architectures without 4 level pagetables */
+
+#define pml4_populate(mm, pml4, pgd) ((mm)->pml4 = (pml4_t *)(pgd)) 
+
+static inline pml4_t *pml4_alloc(struct mm_struct *mm)
+{
+	pml4_t dummy;
+	return (pml4_t *)__pgd_alloc(mm, &dummy, 0);
+} 
+
+static inline void pml4_free(pml4_t *pml4)
+{
+	pgd_free((pgd_t *)pml4);
+}
+
+#define __pgd_free_tlb(tlb,x)   do {} while(0)
+
+#endif
diff -urpN -X ../KDIFX linux-2.6.10rc1/include/asm-generic/nopml4-pgtable.h linux-2.6.10rc1-4level/include/asm-generic/nopml4-pgtable.h
--- linux-2.6.10rc1/include/asm-generic/nopml4-pgtable.h	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.10rc1-4level/include/asm-generic/nopml4-pgtable.h	2004-10-25 04:48:10.000000000 +0200
@@ -0,0 +1,43 @@
+#ifndef _NOPML4_H
+#define _NOPML4_H 1
+
+#ifndef __ASSEMBLY__
+
+/* Included by architectures that don't have a fourth page table level.
+
+   pml4 is simply casted to pgd */
+
+#define pml4_ERROR(x) 
+#define pml4_bad(x) 0
+#define pml4_clear(x) 
+
+/* Covers all address room. This implies that walks will usually wrap.
+   The code has to handle this. 
+
+   Could use TASK_SIZE here, but a lot of architectures make it different
+   for 32bit and 64bit tasks. */
+#define PML4_SIZE (~0UL)
+#define PML4_MASK 0UL
+
+#define pml4_offset(mm, addr) ((mm)->pml4)
+#define pml4_offset_k(addr) (init_mm.pml4)
+#define pml4_pgd_offset(pml4, addr) ((pgd_t *)(pml4) + pgd_index(addr))
+#define pml4_pgd_offset_k(pml4, addr) ((pgd_t *)(pml4) + pgd_index_k(addr))
+
+#define pml4_none(pml4) 0
+#define pml4_present(pml4) 1
+#define pml4_index(pml4) 0
+
+#define swapper_pml4 ((pml4_t *)swapper_pg_dir)
+
+/* Use pml4_pgd_offset and pml4_offset_k instead */
+
+#undef pgd_offset
+#define pgd_offset pgd_offset_is_obsolete
+
+#undef pgd_offset_k
+#define pgd_offset_k pgd_offset_k_is_obsolete
+
+#endif
+
+#endif
diff -urpN -X ../KDIFX linux-2.6.10rc1/include/asm-generic/pgtable.h linux-2.6.10rc1-4level/include/asm-generic/pgtable.h
--- linux-2.6.10rc1/include/asm-generic/pgtable.h	2004-10-19 01:55:32.000000000 +0200
+++ linux-2.6.10rc1-4level/include/asm-generic/pgtable.h	2004-10-25 04:48:10.000000000 +0200
@@ -131,7 +131,7 @@ static inline void ptep_mkdirty(pte_t *p
 #endif
 
 #ifndef __HAVE_ARCH_PGD_OFFSET_GATE
-#define pgd_offset_gate(mm, addr)	pgd_offset(mm, addr)
+#define pml4_offset_gate(mm, addr)	pml4_offset(mm, addr)
 #endif
 
 #endif /* _ASM_GENERIC_PGTABLE_H */
diff -urpN -X ../KDIFX linux-2.6.10rc1/include/asm-generic/tlb.h linux-2.6.10rc1-4level/include/asm-generic/tlb.h
--- linux-2.6.10rc1/include/asm-generic/tlb.h	2004-08-15 19:45:46.000000000 +0200
+++ linux-2.6.10rc1-4level/include/asm-generic/tlb.h	2004-10-25 04:48:10.000000000 +0200
@@ -147,6 +147,12 @@ static inline void tlb_remove_page(struc
 		__pmd_free_tlb(tlb, pmdp);			\
 	} while (0)
 
+#define pgd_free_tlb(tlb, pgdp)					\
+	do {							\
+		tlb->need_flush = 1;				\
+		__pgd_free_tlb(tlb, pgdp);			\
+	} while (0)
+
 #define tlb_migrate_finish(mm) do {} while (0)
 
 #endif /* _ASM_GENERIC__TLB_H */

Re: [PATCH 2/17] Generic backward compatibility includes for 4level

[Russell King]

On Mon, Oct 25, 2004 at 09:23:49AM +0200, Andreas Kleen wrote:
> +/* Included by architectures that don't have a fourth page table level.
> +
> +   pml4 is simply casted to pgd */
> +
> +#define pml4_ERROR(x) 

Don't we normally add do { } while (0) after empty macros which look like
a function?

-- 
Russell King
 Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
 maintainer of:  2.6 PCMCIA      - http://pcmcia.arm.linux.org.uk/
                 2.6 Serial core

Re: [PATCH 2/17] Generic backward compatibility includes for 4level

[Andi Kleen]

On Mon, Oct 25, 2004 at 10:39:26AM +0100, Russell King wrote:
> On Mon, Oct 25, 2004 at 09:23:49AM +0200, Andreas Kleen wrote:
> > +/* Included by architectures that don't have a fourth page table level.
> > +
> > +   pml4 is simply casted to pgd */
> > +
> > +#define pml4_ERROR(x) 
> 
> Don't we normally add do { } while (0) after empty macros which look like
> a function?

iirc Rusty tried to come up with an example some time ago where it actually 
made a difference, but failed. But I can change it. 

-Andi

Re: [PATCH 2/17] Generic backward compatibility includes for 4level

[Arjan van de Ven]

> > 
> > Don't we normally add do { } while (0) after empty macros which look like
> > a function?
> 
> iirc Rusty tried to come up with an example some time ago where it actually 
> made a difference, but failed. But I can change it. 


if (foo) 
	bar(); 
else 
	pml4_ERROR(x);
something_else();

-- 

Re: [PATCH 2/17] Generic backward compatibility includes for 4level

[Andi Kleen]

On Mon, Oct 25, 2004 at 06:50:34PM +0200, Arjan van de Ven wrote:
> > > 
> > > Don't we normally add do { } while (0) after empty macros which look like
> > > a function?
> > 
> > iirc Rusty tried to come up with an example some time ago where it actually 
> > made a difference, but failed. But I can change it. 
> 
> 
> if (foo) 
> 	bar(); 
> else 
> 	pml4_ERROR(x);
> something_else();

Doesn't make any difference. Try it. With a double else it may make 
a difference, but that is extremly bad style imho and better resolved
with a {}. Also you'll get a clear compile error. 

-Andi