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authorWill Deacon <will.deacon@arm.com>2011-09-30 11:43:29 +0100
committerWill Deacon <will.deacon@arm.com>2011-12-06 14:04:14 +0000
commit8903826d0cd99aed9267e792d38284cf3092042b (patch)
treeec75fed09f62c215e2057d8c5e82c343e627c8fe /arch/arm/include
parentba8bb18a03f8c7508565c385576a5431a4ad804a (diff)
ARM: idmap: populate identity map pgd at init time using .init.text
When disabling and re-enabling the MMU, it is necessary to take out an identity mapping for the code that manipulates the SCTLR in order to avoid it disappearing from under our feet. This is useful when soft rebooting and returning from CPU suspend. This patch allocates a set of page tables during boot and populates them with an identity mapping for the .idmap.text section. This means that users of the identity map do not need to manage their own pgd and can instead annotate their functions with __idmap or, in the case of assembly code, place them in the correct section. Acked-by: Dave Martin <dave.martin@linaro.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Tested-by: Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'arch/arm/include')
-rw-r--r--arch/arm/include/asm/idmap.h17
-rw-r--r--arch/arm/include/asm/pgtable.h3
2 files changed, 17 insertions, 3 deletions
diff --git a/arch/arm/include/asm/idmap.h b/arch/arm/include/asm/idmap.h
new file mode 100644
index 00000000000..62e3d19c9ad
--- /dev/null
+++ b/arch/arm/include/asm/idmap.h
@@ -0,0 +1,17 @@
+#ifndef __ASM_IDMAP_H
+#define __ASM_IDMAP_H
+
+#include <linux/compiler.h>
+#include <asm/pgtable.h>
+
+/* Tag a function as requiring to be executed via an identity mapping. */
+#define __idmap __section(.idmap.text) noinline notrace
+
+extern pgd_t *idmap_pgd;
+
+void identity_mapping_add(pgd_t *, unsigned long, unsigned long);
+void identity_mapping_del(pgd_t *, unsigned long, unsigned long);
+
+void setup_mm_for_reboot(void);
+
+#endif /* __ASM_IDMAP_H */
diff --git a/arch/arm/include/asm/pgtable.h b/arch/arm/include/asm/pgtable.h
index 9451dce3a55..03893a55e68 100644
--- a/arch/arm/include/asm/pgtable.h
+++ b/arch/arm/include/asm/pgtable.h
@@ -346,9 +346,6 @@ static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
#define pgtable_cache_init() do { } while (0)
-void identity_mapping_add(pgd_t *, unsigned long, unsigned long);
-void identity_mapping_del(pgd_t *, unsigned long, unsigned long);
-
#endif /* !__ASSEMBLY__ */
#endif /* CONFIG_MMU */