[PATCH v8 07/16] ARM: LPAE: Introduce the 3-level page table format definitions

On Mon, 7 Nov 2011, Catalin Marinas wrote:

This patch introduces the pgtable-3level*.h files with definitions
specific to the LPAE page table format (3 levels of page tables).

[...]

[...]

+#ifdef __ASSEMBLY__
+/* avoid 'shift count out of range' warning */
+#define PMD_SECT_XN		(0)
+#else
+#define PMD_SECT_XN		((pmdval_t)1 << 54)
+#endif

Please don't do that.  Having a symbol that changes value depending on 
the type of code is evil.  If PMD_SECT_XN is actually used in assembly 
code then you have to deal with it, not blindly redefine it as zero.
In my compilation test I didn't see any such warning anyway.

[...]

+typedef u64 pteval_t;
+typedef u64 pmdval_t;
+typedef u64 pgdval_t;
+
+#undef STRICT_MM_TYPECHECKS
+
+#ifdef STRICT_MM_TYPECHECKS
+
+/*
+ * These are used to make use of C type-checking..
+ */
+typedef struct { pteval_t pte; } pte_t;
+typedef struct { pmdval_t pmd; } pmd_t;
+typedef struct { pgdval_t pgd; } pgd_t;
+typedef struct { pteval_t pgprot; } pgprot_t;
+
+#define pte_val(x)      ((x).pte)
+#define pmd_val(x)      ((x).pmd)
+#define pgd_val(x)	((x).pgd)
+#define pgprot_val(x)   ((x).pgprot)
+
+#define __pte(x)        ((pte_t) { (x) } )
+#define __pmd(x)        ((pmd_t) { (x) } )
+#define __pgd(x)	((pgd_t) { (x) } )
+#define __pgprot(x)     ((pgprot_t) { (x) } )
+
+#else	/* !STRICT_MM_TYPECHECKS */
+
+typedef pteval_t pte_t;
+typedef pmdval_t pmd_t;
+typedef pgdval_t pgd_t;
+typedef pteval_t pgprot_t;
+
+#define pte_val(x)	(x)
+#define pmd_val(x)	(x)
+#define pgd_val(x)	(x)
+#define pgprot_val(x)	(x)
+
+#define __pte(x)	(x)
+#define __pmd(x)	(x)
+#define __pgd(x)	(x)
+#define __pgprot(x)	(x)
+
+#endif	/* STRICT_MM_TYPECHECKS */

Isn't the vast majority of this file actually common with the content of 
pgtable-2level-types.h?  Except for the basic types and pgd handling, 
this looks pretty similar.


Nicolas