diff options
| author | Alexander Gordeev <agordeev@linux.ibm.com> | 2023-07-06 12:28:17 +0200 |
|---|---|---|
| committer | Heiko Carstens <hca@linux.ibm.com> | 2023-08-16 15:13:02 +0200 |
| commit | 8ddccc8a7d06f7ea4d8579970c95609d1b1de77b (patch) | |
| tree | 582f01214e1f4a8da3c4f945a68c660c741db2b7 /arch/s390/boot/startup.c | |
| parent | ee4ac5275fd82a877e2fe6aeefcc3c4268f43388 (diff) | |
s390/boot: cleanup number of page table levels setup
The separate vmalloc area size check against _REGION2_SIZE
is needed in case user provided insanely large value using
vmalloc= kernel command line parameter. That could lead to
overflow and selecting 3 page table levels instead of 4.
Use size_add() for the overflow check and get rid of the
extra vmalloc area check.
With the current values of CONFIG_MAX_PHYSMEM_BITS and
PAGES_PER_SECTION the sum of maximal possible size of
identity mapping and vmemmap area (derived from these
macros) plus modules area size MODULES_LEN can not
overflow. Thus, that sum is used as first addend while
vmalloc area size is second addend for size_add().
Suggested-by: Heiko Carstens <hca@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Diffstat (limited to 'arch/s390/boot/startup.c')
| -rw-r--r-- | arch/s390/boot/startup.c | 9 |
1 files changed, 4 insertions, 5 deletions
diff --git a/arch/s390/boot/startup.c b/arch/s390/boot/startup.c index a1f792fcc710..b058e2a575c1 100644 --- a/arch/s390/boot/startup.c +++ b/arch/s390/boot/startup.c @@ -177,6 +177,7 @@ static unsigned long setup_kernel_memory_layout(void) unsigned long asce_limit; unsigned long rte_size; unsigned long pages; + unsigned long vsize; unsigned long vmax; pages = ident_map_size / PAGE_SIZE; @@ -184,11 +185,9 @@ static unsigned long setup_kernel_memory_layout(void) vmemmap_size = SECTION_ALIGN_UP(pages) * sizeof(struct page); /* choose kernel address space layout: 4 or 3 levels. */ - vmemmap_start = round_up(ident_map_size, _REGION3_SIZE); - if (IS_ENABLED(CONFIG_KASAN) || - vmalloc_size > _REGION2_SIZE || - vmemmap_start + vmemmap_size + vmalloc_size + MODULES_LEN > - _REGION2_SIZE) { + vsize = round_up(ident_map_size, _REGION3_SIZE) + vmemmap_size + MODULES_LEN; + vsize = size_add(vsize, vmalloc_size); + if (IS_ENABLED(CONFIG_KASAN) || (vsize > _REGION2_SIZE)) { asce_limit = _REGION1_SIZE; rte_size = _REGION2_SIZE; } else { |