Commit 9e37a2e8 authored by Sven Schnelle's avatar Sven Schnelle Committed by Heiko Carstens
Browse files

s390/vdso: map vdso above stack 



In the current code vdso is mapped below the stack. This is
problematic when programs mapped to the top of the address space
are allocating a lot of memory, because the heap will clash with
the vdso. To avoid this map the vdso above the stack and move
STACK_TOP so that it all fits into three level paging.

Signed-off-by: default avatarSven Schnelle <svens@linux.ibm.com>
Reviewed-by: default avatarHeiko Carstens <hca@linux.ibm.com>
Signed-off-by: default avatarHeiko Carstens <hca@linux.ibm.com>
parent 57761da4

arch/s390/include/asm/processor.h

+4 −3
Original line number Original line Diff line number Diff line
@@ -95,9 +95,10 @@ unsigned long vdso_size(void); 
					(_REGION3_SIZE >> 1) : (_REGION2_SIZE >> 1))

					(_REGION3_SIZE >> 1) : (_REGION2_SIZE >> 1))

#define TASK_SIZE_MAX		(-PAGE_SIZE)

#define TASK_SIZE_MAX		(-PAGE_SIZE)





#define STACK_TOP		(test_thread_flag(TIF_31BIT) ? \

#define VDSO_BASE		(STACK_TOP + PAGE_SIZE)

					_REGION3_SIZE : _REGION2_SIZE)

#define VDSO_LIMIT		(test_thread_flag(TIF_31BIT) ? _REGION3_SIZE : _REGION2_SIZE)

#define STACK_TOP_MAX		_REGION2_SIZE

#define STACK_TOP		(VDSO_LIMIT - vdso_size() - PAGE_SIZE)

#define STACK_TOP_MAX		(_REGION2_SIZE - vdso_size() - PAGE_SIZE)





#define HAVE_ARCH_PICK_MMAP_LAYOUT

#define HAVE_ARCH_PICK_MMAP_LAYOUT

arch/s390/kernel/vdso.c

+1 −1
Original line number Original line Diff line number Diff line
@@ -221,7 +221,7 @@ unsigned long vdso_size(void) 




int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)

int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)

{

{

	return map_vdso(0, vdso_size());

	return map_vdso(VDSO_BASE, vdso_size());

}

}





static struct page ** __init vdso_setup_pages(void *start, void *end)

static struct page ** __init vdso_setup_pages(void *start, void *end)