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Commit 29635239 authored by Vasily Gorbik's avatar Vasily Gorbik Committed by Martin Schwidefsky
Browse files

s390/kasan: avoid kasan crash with standby memory defined 



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: default avatarVasily Gorbik <gor@linux.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 19733fe8

arch/s390/mm/kasan_init.c

+18 −1
Original line number Diff line number Diff line
@@ -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)) {