From 135ff163939294f5573927ca890699ed619c0031 Mon Sep 17 00:00:00 2001
From: Vasily Gorbik <gor@linux.ibm.com>
Date: Mon, 20 Nov 2017 12:56:10 +0100
Subject: [PATCH] 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: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
---
arch/s390/include/asm/kasan.h | 2 ++
arch/s390/mm/init.c | 1 +
arch/s390/mm/kasan_init.c | 12 ++++++++++--
3 files changed, 13 insertions(+), 2 deletions(-)
diff --git a/arch/s390/include/asm/kasan.h b/arch/s390/include/asm/kasan.h
index 892f4585c663f..8b9ae18430ad1 100644
--- a/arch/s390/include/asm/kasan.h
+++ b/arch/s390/include/asm/kasan.h
@@ -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
diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
index 50ebda9b3d0ca..92d7a153e72a0 100644
--- a/arch/s390/mm/init.c
+++ b/arch/s390/mm/init.c
@@ -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();
diff --git a/arch/s390/mm/kasan_init.c b/arch/s390/mm/kasan_init.c
index e4697900e884d..40748afc43fa5 100644
--- a/arch/s390/mm/kasan_init.c
+++ b/arch/s390/mm/kasan_init.c
@@ -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);
+}
--
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