Commit 3033cd43 authored by Helge Deller's avatar Helge Deller
Browse files

parisc: Use generic mmap top-down layout and brk randomization 



parisc uses a top-down layout by default that exactly fits the generic
functions, so get rid of arch specific code and use the generic version
by selecting ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT.

Note that on parisc the stack always grows up and a "unlimited stack"
simply means that the value as defined in CONFIG_STACK_MAX_DEFAULT_SIZE_MB
should be used. So RLIM_INFINITY is not an indicator to use the legacy
memory layout.

Signed-off-by: default avatarHelge Deller <deller@gmx.de>
parent 9f5ba4b3

arch/parisc/Kconfig

+17 −0
Original line number Diff line number Diff line
@@ -49,6 +49,9 @@ config PARISC 
	select TTY # Needed for pdc_cons.c

	select HAS_IOPORT if PCI || EISA

	select HAVE_DEBUG_STACKOVERFLOW

	select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT

	select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT

	select HAVE_ARCH_MMAP_RND_BITS

	select HAVE_ARCH_AUDITSYSCALL

	select HAVE_ARCH_HASH

	select HAVE_ARCH_JUMP_LABEL
@@ -124,6 +127,20 @@ config TIME_LOW_RES 
	depends on SMP

	default y



config ARCH_MMAP_RND_BITS_MIN

	default 18 if 64BIT

	default 8



config ARCH_MMAP_RND_COMPAT_BITS_MIN

	default 8



config ARCH_MMAP_RND_BITS_MAX

	default 24 if 64BIT

	default 17



config ARCH_MMAP_RND_COMPAT_BITS_MAX

	default 17



# unless you want to implement ACPI on PA-RISC ... ;-)

config PM

	bool

arch/parisc/kernel/process.c

+0 −14
Original line number Diff line number Diff line
@@ -278,17 +278,3 @@ __get_wchan(struct task_struct *p) 
	} while (count++ < MAX_UNWIND_ENTRIES);

	return 0;

}
 


static inline unsigned long brk_rnd(void)

{

	return (get_random_u32() & BRK_RND_MASK) << 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;

}

arch/parisc/kernel/sys_parisc.c

+1 −53
Original line number Diff line number Diff line
@@ -161,7 +161,7 @@ static unsigned long arch_get_unmapped_area_common(struct file *filp, 
	}



	info.flags = 0;

	info.low_limit = mm->mmap_legacy_base;

	info.low_limit = mm->mmap_base;

	info.high_limit = mmap_upper_limit(NULL);

	return vm_unmapped_area(&info);

}
@@ -181,58 +181,6 @@ unsigned long arch_get_unmapped_area_topdown(struct file *filp, 
			addr, len, pgoff, flags, DOWN);

}



static int mmap_is_legacy(void)

{

	if (current->personality & ADDR_COMPAT_LAYOUT)

		return 1;



	/* parisc stack always grows up - so a unlimited stack should

	 * not be an indicator to use the legacy memory layout.

	 * if (rlimit(RLIMIT_STACK) == RLIM_INFINITY)

	 *	return 1;

	 */



	return sysctl_legacy_va_layout;

}



static unsigned long mmap_rnd(void)

{

	unsigned long rnd = 0;



	if (current->flags & PF_RANDOMIZE)

		rnd = get_random_u32() & MMAP_RND_MASK;



	return rnd << PAGE_SHIFT;

}



unsigned long arch_mmap_rnd(void)

{

	return (get_random_u32() & MMAP_RND_MASK) << PAGE_SHIFT;

}



static unsigned long mmap_legacy_base(void)

{

	return TASK_UNMAPPED_BASE + mmap_rnd();

}



/*

 * This function, called very early during the creation of a new

 * process VM image, sets up which VM layout function to use:

 */

void arch_pick_mmap_layout(struct mm_struct *mm, struct rlimit *rlim_stack)

{

	mm->mmap_legacy_base = mmap_legacy_base();

	mm->mmap_base = mmap_upper_limit(rlim_stack);



	if (mmap_is_legacy()) {

		mm->mmap_base = mm->mmap_legacy_base;

		mm->get_unmapped_area = arch_get_unmapped_area;

	} else {

		mm->get_unmapped_area = arch_get_unmapped_area_topdown;

	}

}





asmlinkage unsigned long sys_mmap2(unsigned long addr, unsigned long len,

	unsigned long prot, unsigned long flags, unsigned long fd,

	unsigned long pgoff)

mm/util.c

+4 −1
Original line number Diff line number Diff line
@@ -396,7 +396,10 @@ static int mmap_is_legacy(struct rlimit *rlim_stack) 
	if (current->personality & ADDR_COMPAT_LAYOUT)

		return 1;



	if (rlim_stack->rlim_cur == RLIM_INFINITY)

	/* On parisc the stack always grows up - so a unlimited stack should

	 * not be an indicator to use the legacy memory layout. */

	if (rlim_stack->rlim_cur == RLIM_INFINITY &&

		!IS_ENABLED(CONFIG_STACK_GROWSUP))

		return 1;



	return sysctl_legacy_va_layout;