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Commit 9dabf60d authored by Helge Deller's avatar Helge Deller
Browse files

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: default avatarHelge Deller <deller@gmx.de>
parent f5a408d5

arch/parisc/include/asm/elf.h

+4 −0
Original line number Diff line number Diff line
@@ -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

arch/parisc/include/asm/pgtable.h

+1 −0
Original line number Diff line number Diff line
@@ -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

arch/parisc/include/asm/processor.h

+2 −0
Original line number Diff line number Diff line
@@ -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)

arch/parisc/include/asm/thread_info.h

+10 −0
Original line number Diff line number Diff line
@@ -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 */

arch/parisc/kernel/process.c

+20 −1
Original line number Diff line number Diff line
@@ -13,7 +13,7 @@ 
 *    Copyright (C) 2000 Grant Grundler <grundler with parisc-linux.org>

 *    Copyright (C) 2001 Alan Modra <amodra at parisc-linux.org>

 *    Copyright (C) 2001-2002 Ryan Bradetich <rbrad at parisc-linux.org>

 *    Copyright (C) 2001-2007 Helge Deller <deller at parisc-linux.org>

 *    Copyright (C) 2001-2014 Helge Deller <deller@gmx.de>

 *    Copyright (C) 2002 Randolph Chung <tausq with parisc-linux.org>

 *

 *
@@ -49,6 +49,7 @@ 
#include <linux/kallsyms.h>

#include <linux/uaccess.h>

#include <linux/rcupdate.h>

#include <linux/random.h>



#include <asm/io.h>

#include <asm/asm-offsets.h>
@@ -286,3 +287,21 @@ void *dereference_function_descriptor(void *ptr) 
	return ptr;

}

#endif



static inline unsigned long brk_rnd(void)

{

	/* 8MB for 32bit, 1GB for 64bit */

	if (is_32bit_task())

		return (get_random_int() & 0x7ffUL) << PAGE_SHIFT;

	else

		return (get_random_int() & 0x3ffffUL) << PAGE_SHIFT;

}



unsigned long arch_randomize_brk(struct mm_struct *mm)

{

	unsigned long ret = PAGE_ALIGN(mm->brk + brk_rnd());



	if (ret < mm->brk)

		return mm->brk;

	return ret;

}