parisc: add flexible mmap memory layout support

Add support for the flexible mmap memory layout (as described in
http://lwn.net/Articles/91829). This is especially very interesting on
parisc since we currently only support 32bit userspace (even with a
64bit Linux kernel).

Signed-off-by: Helge Deller <deller@gmx.de>

4 files changed, 17 insertions, 0 deletions

diff --git a/arch/parisc/include/asm/elf.h b/arch/parisc/include/asm/elf.h
index ad2b50397894..3391d061eccc 100644
--- a/arch/parisc/include/asm/elf.h
+++ b/arch/parisc/include/asm/elf.h
@@ -348,4 +348,8 @@ struct pt_regs;	/* forward declaration... */
 
 #define ELF_HWCAP       0
 
+struct mm_struct;
+extern unsigned long arch_randomize_brk(struct mm_struct *);
+#define arch_randomize_brk arch_randomize_brk
+
 #endif
diff --git a/arch/parisc/include/asm/pgtable.h b/arch/parisc/include/asm/pgtable.h
index 34899b5d959a..22b89d1edba7 100644
--- a/arch/parisc/include/asm/pgtable.h
+++ b/arch/parisc/include/asm/pgtable.h
@@ -511,6 +511,7 @@ static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr,
 /* We provide our own get_unmapped_area to provide cache coherency */
 
 #define HAVE_ARCH_UNMAPPED_AREA
+#define HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
 
 #define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
 #define __HAVE_ARCH_PTEP_GET_AND_CLEAR
diff --git a/arch/parisc/include/asm/processor.h b/arch/parisc/include/asm/processor.h
index cc2290a3cace..198a86feb574 100644
--- a/arch/parisc/include/asm/processor.h
+++ b/arch/parisc/include/asm/processor.h
@@ -30,6 +30,8 @@
 #endif
 #define current_text_addr() ({ void *pc; current_ia(pc); pc; })
 
+#define HAVE_ARCH_PICK_MMAP_LAYOUT
+
 #define TASK_SIZE_OF(tsk)       ((tsk)->thread.task_size)
 #define TASK_SIZE               TASK_SIZE_OF(current)
 #define TASK_UNMAPPED_BASE      (current->thread.map_base)
diff --git a/arch/parisc/include/asm/thread_info.h b/arch/parisc/include/asm/thread_info.h
index d5f97ea3a4e1..4b9b10ce1f9d 100644
--- a/arch/parisc/include/asm/thread_info.h
+++ b/arch/parisc/include/asm/thread_info.h
@@ -76,6 +76,16 @@ struct thread_info {
 #define _TIF_SYSCALL_TRACE_MASK (_TIF_SYSCALL_TRACE | _TIF_SINGLESTEP | \
                                  _TIF_BLOCKSTEP | _TIF_SYSCALL_AUDIT)
 
+#ifdef CONFIG_64BIT
+# ifdef CONFIG_COMPAT
+#  define is_32bit_task()       (test_thread_flag(TIF_32BIT))
+# else
+#  define is_32bit_task()       (0)
+# endif
+#else
+# define is_32bit_task()        (1)
+#endif
+
 #endif /* __KERNEL__ */
 
 #endif /* _ASM_PARISC_THREAD_INFO_H */