leandrof/linux
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

s390/vdso: map vdso above stack

Browse Source 
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: Sven Schnelle <svens@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
This commit is contained in:
Sven Schnelle 2022-04-06 08:44:49 +02:00 committed by Heiko Carstens
parent 57761da4dc
commit 9e37a2e854
2 changed files with 5 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
arch/s390/include/asm/processor.h
View File

@ -95,9 +95,10 @@ unsigned long vdso_size(void);
(_REGION3_SIZE >> 1) : (_REGION2_SIZE >> 1))
#define TASK_SIZE_MAX (-PAGE_SIZE)
#define STACK_TOP (test_thread_flag(TIF_31BIT) ? \
_REGION3_SIZE : _REGION2_SIZE)
#define STACK_TOP_MAX _REGION2_SIZE
#define VDSO_BASE (STACK_TOP + PAGE_SIZE)
#define VDSO_LIMIT (test_thread_flag(TIF_31BIT) ? _REGION3_SIZE : _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

2
arch/s390/kernel/vdso.c
View File

@ -221,7 +221,7 @@ unsigned long vdso_size(void)
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)