summaryrefslogtreecommitdiff
path: root/arch
diff options
context:
space:
mode:
authorCatalin Marinas <catalin.marinas@arm.com>2013-04-29 15:07:45 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-05-07 19:51:53 -0700
commit0907fdff86010806099f872de9fff2b86d6b18fe (patch)
tree86879a15384eeeca368a1af6bb1608ddf56b8437 /arch
parentbe2300f0961d43c4d92f2a7aa716811383ebbeb2 (diff)
arm: set the page table freeing ceiling to TASK_SIZE
commit 104ad3b32d7a71941c8ab2dee78eea38e8a23309 upstream. ARM processors with LPAE enabled use 3 levels of page tables, with an entry in the top level (pgd) covering 1GB of virtual space. Because of the branch relocation limitations on ARM, the loadable modules are mapped 16MB below PAGE_OFFSET, making the corresponding 1GB pgd shared between kernel modules and user space. If free_pgtables() is called with the default ceiling 0, free_pgd_range() (and subsequently called functions) also frees the page table shared between user space and kernel modules (which is normally handled by the ARM-specific pgd_free() function). This patch changes defines the ARM USER_PGTABLES_CEILING to TASK_SIZE when CONFIG_ARM_LPAE is enabled. Note that the pgd_free() function already checks the presence of the shared pmd page allocated by pgd_alloc() and frees it, though with ceiling 0 this wasn't necessary. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/arm/include/asm/pgtable.h9
1 files changed, 9 insertions, 0 deletions
diff --git a/arch/arm/include/asm/pgtable.h b/arch/arm/include/asm/pgtable.h
index 41dc31f834c3..cc5e50fd7fe6 100644
--- a/arch/arm/include/asm/pgtable.h
+++ b/arch/arm/include/asm/pgtable.h
@@ -61,6 +61,15 @@ extern void __pgd_error(const char *file, int line, pgd_t);
#define FIRST_USER_ADDRESS PAGE_SIZE
/*
+ * Use TASK_SIZE as the ceiling argument for free_pgtables() and
+ * free_pgd_range() to avoid freeing the modules pmd when LPAE is enabled (pmd
+ * page shared between user and kernel).
+ */
+#ifdef CONFIG_ARM_LPAE
+#define USER_PGTABLES_CEILING TASK_SIZE
+#endif
+
+/*
* The pgprot_* and protection_map entries will be fixed up in runtime
* to include the cachable and bufferable bits based on memory policy,
* as well as any architecture dependent bits like global/ASID and SMP