Commit 76a345ed authored by Christophe Leroy's avatar Christophe Leroy Committed by Michael Ellerman
Browse files

powerpc/mm: Use generic_get_unmapped_area() and call it from arch_get_unmapped_area() 



Use the generic version of arch_get_unmapped_area() which
is now available at all time instead of its copy
radix__arch_get_unmapped_area()

To allow that for PPC64, add arch_get_mmap_base() and
arch_get_mmap_end() macros.

Instead of setting mm->get_unmapped_area() to either
arch_get_unmapped_area() or generic_get_unmapped_area(),
always set it to arch_get_unmapped_area() and call
generic_get_unmapped_area() from there when radix is enabled.

Do the same with radix__arch_get_unmapped_area_topdown()

Signed-off-by: default avatarChristophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/393be1fa386446443682fdb74544d733f68ef3bb.1649523076.git.christophe.leroy@csgroup.eu
parent f693d38d

arch/powerpc/include/asm/task_size_64.h

+8 −0
Original line number Diff line number Diff line
@@ -72,4 +72,12 @@ 
#define STACK_TOP_MAX TASK_SIZE_USER64

#define STACK_TOP (is_32bit_task() ? STACK_TOP_USER32 : STACK_TOP_USER64)



#define arch_get_mmap_base(addr, base) \

	(((addr) > DEFAULT_MAP_WINDOW) ? (base) + TASK_SIZE - DEFAULT_MAP_WINDOW : (base))



#define arch_get_mmap_end(addr, len, flags) \

	(((addr) > DEFAULT_MAP_WINDOW) || \

	 (((flags) & MAP_FIXED) && ((addr) + (len) > DEFAULT_MAP_WINDOW)) ? TASK_SIZE : \

									    DEFAULT_MAP_WINDOW)



#endif /* _ASM_POWERPC_TASK_SIZE_64_H */

arch/powerpc/mm/mmap.c

+6 −121
Original line number Diff line number Diff line
@@ -81,115 +81,15 @@ static inline unsigned long mmap_base(unsigned long rnd, 
}



#ifdef HAVE_ARCH_UNMAPPED_AREA

#ifdef CONFIG_PPC_RADIX_MMU

/*

 * Same function as generic code used only for radix, because we don't need to overload

 * the generic one. But we will have to duplicate, because hash select

 * HAVE_ARCH_UNMAPPED_AREA

 */

static unsigned long

radix__arch_get_unmapped_area(struct file *filp, unsigned long addr,

			     unsigned long len, unsigned long pgoff,

			     unsigned long flags)

{

	struct mm_struct *mm = current->mm;

	struct vm_area_struct *vma;

	int fixed = (flags & MAP_FIXED);

	unsigned long high_limit;

	struct vm_unmapped_area_info info;



	high_limit = DEFAULT_MAP_WINDOW;

	if (addr >= high_limit || (fixed && (addr + len > high_limit)))

		high_limit = TASK_SIZE;



	if (len > high_limit)

		return -ENOMEM;



	if (fixed) {

		if (addr > high_limit - len)

			return -ENOMEM;

		return addr;

	}



	if (addr) {

		addr = PAGE_ALIGN(addr);

		vma = find_vma(mm, addr);

		if (high_limit - len >= addr && addr >= mmap_min_addr &&

		    (!vma || addr + len <= vm_start_gap(vma)))

			return addr;

	}



	info.flags = 0;

	info.length = len;

	info.low_limit = mm->mmap_base;

	info.high_limit = high_limit;

	info.align_mask = 0;



	return vm_unmapped_area(&info);

}



static unsigned long

radix__arch_get_unmapped_area_topdown(struct file *filp,

				     const unsigned long addr0,

				     const unsigned long len,

				     const unsigned long pgoff,

				     const unsigned long flags)

{

	struct vm_area_struct *vma;

	struct mm_struct *mm = current->mm;

	unsigned long addr = addr0;

	int fixed = (flags & MAP_FIXED);

	unsigned long high_limit;

	struct vm_unmapped_area_info info;



	high_limit = DEFAULT_MAP_WINDOW;

	if (addr >= high_limit || (fixed && (addr + len > high_limit)))

		high_limit = TASK_SIZE;



	if (len > high_limit)

		return -ENOMEM;



	if (fixed) {

		if (addr > high_limit - len)

			return -ENOMEM;

		return addr;

	}



	if (addr) {

		addr = PAGE_ALIGN(addr);

		vma = find_vma(mm, addr);

		if (high_limit - len >= addr && addr >= mmap_min_addr &&

		    (!vma || addr + len <= vm_start_gap(vma)))

			return addr;

	}



	info.flags = VM_UNMAPPED_AREA_TOPDOWN;

	info.length = len;

	info.low_limit = max(PAGE_SIZE, mmap_min_addr);

	info.high_limit = mm->mmap_base + (high_limit - DEFAULT_MAP_WINDOW);

	info.align_mask = 0;



	addr = vm_unmapped_area(&info);

	if (!(addr & ~PAGE_MASK))

		return addr;

	VM_BUG_ON(addr != -ENOMEM);



	/*

	 * A failed mmap() very likely causes application failure,

	 * so fall back to the bottom-up function here. This scenario

	 * can happen with large stack limits and large mmap()

	 * allocations.

	 */

	return radix__arch_get_unmapped_area(filp, addr0, len, pgoff, flags);

}

#endif



unsigned long arch_get_unmapped_area(struct file *filp,

				     unsigned long addr,

				     unsigned long len,

				     unsigned long pgoff,

				     unsigned long flags)

{

	if (radix_enabled())

		return generic_get_unmapped_area(filp, addr, len, pgoff, flags);



#ifdef CONFIG_PPC_64S_HASH_MMU

	return slice_get_unmapped_area(addr, len, flags,

				       mm_ctx_user_psize(&current->mm->context), 0);
@@ -204,6 +104,9 @@ unsigned long arch_get_unmapped_area_topdown(struct file *filp, 
					     const unsigned long pgoff,

					     const unsigned long flags)

{

	if (radix_enabled())

		return generic_get_unmapped_area_topdown(filp, addr0, len, pgoff, flags);



#ifdef CONFIG_PPC_64S_HASH_MMU

	return slice_get_unmapped_area(addr0, len, flags,

				       mm_ctx_user_psize(&current->mm->context), 1);
@@ -213,21 +116,6 @@ unsigned long arch_get_unmapped_area_topdown(struct file *filp, 
}

#endif /* HAVE_ARCH_UNMAPPED_AREA */



static void radix__arch_pick_mmap_layout(struct mm_struct *mm,

					unsigned long random_factor,

					struct rlimit *rlim_stack)

{

#ifdef CONFIG_PPC_RADIX_MMU

	if (mmap_is_legacy(rlim_stack)) {

		mm->mmap_base = TASK_UNMAPPED_BASE;

		mm->get_unmapped_area = radix__arch_get_unmapped_area;

	} else {

		mm->mmap_base = mmap_base(random_factor, rlim_stack);

		mm->get_unmapped_area = radix__arch_get_unmapped_area_topdown;

	}

#endif

}



/*

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

 * process VM image, sets up which VM layout function to use:
@@ -239,9 +127,6 @@ void arch_pick_mmap_layout(struct mm_struct *mm, struct rlimit *rlim_stack) 
	if (current->flags & PF_RANDOMIZE)

		random_factor = arch_mmap_rnd();



	if (radix_enabled())

		return radix__arch_pick_mmap_layout(mm, random_factor,

						    rlim_stack);

	/*

	 * Fall back to the standard layout if the personality

	 * bit is set, or if the expected stack growth is unlimited: