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Commit 135ff163 authored by Vasily Gorbik's avatar Vasily Gorbik Committed by Martin Schwidefsky
Browse files

s390/kasan: free early identity mapping structures 



Kasan initialization code is changed to populate persistent shadow
first, save allocator position into pgalloc_freeable and proceed with
early identity mapping creation. This way early identity mapping paging
structures could be freed at once after switching to swapper_pg_dir
when early identity mapping is not needed anymore.

Reviewed-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: default avatarVasily Gorbik <gor@linux.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 5e785963

arch/s390/include/asm/kasan.h

+2 −0
Original line number Diff line number Diff line
@@ -15,9 +15,11 @@ 


extern void kasan_early_init(void);

extern void kasan_copy_shadow(pgd_t *dst);

extern void kasan_free_early_identity(void);

#else

static inline void kasan_early_init(void) { }

static inline void kasan_copy_shadow(pgd_t *dst) { }

static inline void kasan_free_early_identity(void) { }

#endif



#endif

arch/s390/mm/init.c

+1 −0
Original line number Diff line number Diff line
@@ -109,6 +109,7 @@ void __init paging_init(void) 
	psw_bits(psw).dat = 1;

	psw_bits(psw).as = PSW_BITS_AS_HOME;

	__load_psw_mask(psw.mask);

	kasan_free_early_identity();



	sparse_memory_present_with_active_regions(MAX_NUMNODES);

	sparse_init();

arch/s390/mm/kasan_init.c

+10 −2
Original line number Diff line number Diff line
@@ -15,6 +15,7 @@ static unsigned long segment_pos __initdata; 
static unsigned long segment_low __initdata;

static unsigned long pgalloc_pos __initdata;

static unsigned long pgalloc_low __initdata;

static unsigned long pgalloc_freeable __initdata;

static bool has_edat __initdata;

static bool has_nx __initdata;
@@ -298,14 +299,16 @@ void __init kasan_early_init(void) 
	 * | 2Gb	     |	\|	unmapped  | allocated per module

	 * +-----------------+	 +- shadow end ---+

	 */

	/* populate identity mapping */

	kasan_early_vmemmap_populate(0, memsize, POPULATE_ONE2ONE);

	/* populate kasan shadow (for identity mapping and zero page mapping) */

	kasan_early_vmemmap_populate(__sha(0), __sha(memsize), POPULATE_MAP);

	if (IS_ENABLED(CONFIG_MODULES))

		untracked_mem_end = vmax - MODULES_LEN;

	kasan_early_vmemmap_populate(__sha(memsize), __sha(untracked_mem_end),

				     POPULATE_ZERO_SHADOW);

	/* memory allocated for identity mapping structs will be freed later */

	pgalloc_freeable = pgalloc_pos;

	/* populate identity mapping */

	kasan_early_vmemmap_populate(0, memsize, POPULATE_ONE2ONE);

	kasan_set_pgd(early_pg_dir, asce_type);

	kasan_enable_dat();

	/* enable kasan */
@@ -345,3 +348,8 @@ void __init kasan_copy_shadow(pgd_t *pg_dir) 
	memcpy(pu_dir_dst, pu_dir_src,

	       (KASAN_SHADOW_SIZE >> PUD_SHIFT) * sizeof(pud_t));

}



void __init kasan_free_early_identity(void)

{

	memblock_free(pgalloc_pos, pgalloc_freeable - pgalloc_pos);

}