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s390/kasan: avoid kasan crash with standby memory defined

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Kasan early memory allocator simply chops off memory blocks from the
end of the physical memory. Reuse mem_detect info to identify actual
online memory end rather than using max_physmem_end. This allows to run
the kernel with kasan enabled and standby memory defined.

Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Vasily Gorbik 2018-09-13 10:59:25 +02:00 committed by Martin Schwidefsky
parent 19733fe872
commit 296352397d
1 changed files with 18 additions and 1 deletions
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19
arch/s390/mm/kasan_init.c
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@ -5,6 +5,7 @@
#include <asm/pgalloc.h>
#include <asm/pgtable.h>
#include <asm/kasan.h>
#include <asm/mem_detect.h>
#include <asm/processor.h>
#include <asm/sclp.h>
#include <asm/facility.h>
@ -233,6 +234,18 @@ static void __init kasan_early_detect_facilities(void)
}
}
static unsigned long __init get_mem_detect_end(void)
{
unsigned long start;
unsigned long end;
if (mem_detect.count) {
__get_mem_detect_block(mem_detect.count - 1, &start, &end);
return end;
}
return 0;
}
void __init kasan_early_init(void)
{
unsigned long untracked_mem_end;
@ -252,6 +265,11 @@ void __init kasan_early_init(void)
pgt_prot &= ~_PAGE_NOEXEC;
pte_z = __pte(__pa(kasan_zero_page) | pgt_prot);
memsize = get_mem_detect_end();
if (!memsize)
kasan_early_panic("cannot detect physical memory size\n");
memsize = min(memsize, KASAN_SHADOW_START);
if (IS_ENABLED(CONFIG_KASAN_S390_4_LEVEL_PAGING)) {
/* 4 level paging */
BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_START, P4D_SIZE));
@ -276,7 +294,6 @@ void __init kasan_early_init(void)
crst_table_init((unsigned long *)kasan_zero_pmd, pmd_val(pmd_z));
memset64((u64 *)kasan_zero_pte, pte_val(pte_z), PTRS_PER_PTE);
memsize = min(max_physmem_end, KASAN_SHADOW_START);
shadow_alloc_size = memsize >> KASAN_SHADOW_SCALE_SHIFT;
pgalloc_low = round_up((unsigned long)_end, _SEGMENT_SIZE);
if (IS_ENABLED(CONFIG_BLK_DEV_INITRD)) {