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authorVasily Gorbik <gor@linux.ibm.com>2020-10-05 13:53:36 +0200
committerHeiko Carstens <hca@linux.ibm.com>2020-11-09 11:20:59 +0100
commit0c4ec024a481774df98910c79a4b3a105d1bb996 (patch)
treefee5cfbcb8c2558986b7a5408a649f5de27a8cb8 /arch/s390
parente385b550faf356db47234083c53e9841e8ec05c5 (diff)
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s390/kasan: move memory needs estimation into a function
Also correct rounding downs in estimation calculations. Reviewed-by: Alexander Egorenkov <egorenar@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Diffstat (limited to 'arch/s390')
-rw-r--r--arch/s390/boot/kaslr.c30
-rw-r--r--arch/s390/include/asm/kasan.h26
2 files changed, 34 insertions, 22 deletions
diff --git a/arch/s390/boot/kaslr.c b/arch/s390/boot/kaslr.c
index d844a5ef9089..987a9eaf228a 100644
--- a/arch/s390/boot/kaslr.c
+++ b/arch/s390/boot/kaslr.c
@@ -7,6 +7,7 @@
#include <asm/cpacf.h>
#include <asm/timex.h>
#include <asm/sclp.h>
+#include <asm/kasan.h>
#include "compressed/decompressor.h"
#include "boot.h"
@@ -179,34 +180,19 @@ unsigned long get_random_base(unsigned long safe_addr)
if (memory_end_set)
memory_limit = min(memory_limit, memory_end);
+ /*
+ * Avoid putting kernel in the end of physical memory
+ * which kasan will use for shadow memory and early pgtable
+ * mapping allocations.
+ */
+ memory_limit -= kasan_estimate_memory_needs(memory_limit);
+
if (IS_ENABLED(CONFIG_BLK_DEV_INITRD) && INITRD_START && INITRD_SIZE) {
if (safe_addr < INITRD_START + INITRD_SIZE)
safe_addr = INITRD_START + INITRD_SIZE;
}
safe_addr = ALIGN(safe_addr, THREAD_SIZE);
- if ((IS_ENABLED(CONFIG_KASAN))) {
- /*
- * Estimate kasan memory requirements, which it will reserve
- * at the very end of available physical memory. To estimate
- * that, we take into account that kasan would require
- * 1/8 of available physical memory (for shadow memory) +
- * creating page tables for the whole memory + shadow memory
- * region (1 + 1/8). To keep page tables estimates simple take
- * the double of combined ptes size.
- */
- memory_limit = get_mem_detect_end();
- if (memory_end_set && memory_limit > memory_end)
- memory_limit = memory_end;
-
- /* for shadow memory */
- kasan_needs = memory_limit / 8;
- /* for paging structures */
- kasan_needs += (memory_limit + kasan_needs) / PAGE_SIZE /
- _PAGE_ENTRIES * _PAGE_TABLE_SIZE * 2;
- memory_limit -= kasan_needs;
- }
-
kernel_size = vmlinux.image_size + vmlinux.bss_size;
if (safe_addr + kernel_size > memory_limit)
return 0;
diff --git a/arch/s390/include/asm/kasan.h b/arch/s390/include/asm/kasan.h
index eea62586e719..76f351bd6645 100644
--- a/arch/s390/include/asm/kasan.h
+++ b/arch/s390/include/asm/kasan.h
@@ -17,10 +17,36 @@ extern void kasan_early_init(void);
extern void kasan_copy_shadow_mapping(void);
extern void kasan_free_early_identity(void);
extern unsigned long kasan_vmax;
+
+/*
+ * Estimate kasan memory requirements, which it will reserve
+ * at the very end of available physical memory. To estimate
+ * that, we take into account that kasan would require
+ * 1/8 of available physical memory (for shadow memory) +
+ * creating page tables for the whole memory + shadow memory
+ * region (1 + 1/8). To keep page tables estimates simple take
+ * the double of combined ptes size.
+ *
+ * physmem parameter has to be already adjusted if not entire physical memory
+ * would be used (e.g. due to effect of "mem=" option).
+ */
+static inline unsigned long kasan_estimate_memory_needs(unsigned long physmem)
+{
+ unsigned long kasan_needs;
+ unsigned long pages;
+ /* for shadow memory */
+ kasan_needs = round_up(physmem / 8, PAGE_SIZE);
+ /* for paging structures */
+ pages = DIV_ROUND_UP(physmem + kasan_needs, PAGE_SIZE);
+ kasan_needs += DIV_ROUND_UP(pages, _PAGE_ENTRIES) * _PAGE_TABLE_SIZE * 2;
+
+ return kasan_needs;
+}
#else
static inline void kasan_early_init(void) { }
static inline void kasan_copy_shadow_mapping(void) { }
static inline void kasan_free_early_identity(void) { }
+static inline unsigned long kasan_estimate_memory_needs(unsigned long physmem) { return 0; }
#endif
#endif