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s390/kasan: dynamic shadow mem allocation for modules 

Move from modules area entire shadow memory preallocation to dynamic
allocation per module load.

This behaivior has been introduced for x86 with bebf56a1b: "This patch
also forces module_alloc() to return 8*PAGE_SIZE aligned address making
shadow memory handling ( kasan_module_alloc()/kasan_module_free() )
more simple. Such alignment guarantees that each shadow page backing
modules address space correspond to only one module_alloc() allocation"

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 2017-11-17 18:22:24 +01:00 committed by Martin Schwidefsky
parent 0dac8f6bc3
commit 793213a82d
2 changed files with 14 additions and 12 deletions
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15
arch/s390/kernel/module.c
View File

@ -16,6 +16,7 @@
#include <linux/fs.h>
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/kasan.h>
#include <linux/moduleloader.h>
#include <linux/bug.h>
#include <asm/alternative.h>
@ -32,12 +33,18 @@
void *module_alloc(unsigned long size)
{
void *p;
if (PAGE_ALIGN(size) > MODULES_LEN)
return NULL;
return __vmalloc_node_range(size, 1, MODULES_VADDR, MODULES_END,
GFP_KERNEL, PAGE_KERNEL_EXEC,
0, NUMA_NO_NODE,
__builtin_return_address(0));
p = __vmalloc_node_range(size, MODULE_ALIGN, MODULES_VADDR, MODULES_END,
GFP_KERNEL, PAGE_KERNEL_EXEC, 0, NUMA_NO_NODE,
__builtin_return_address(0));
if (p && (kasan_module_alloc(p, size) < 0)) {
vfree(p);
return NULL;
}
return p;
}
void module_arch_freeing_init(struct module *mod)

11
arch/s390/mm/kasan_init.c
View File

@ -214,8 +214,6 @@ void __init kasan_early_init(void)
memsize = min(max_physmem_end, KASAN_SHADOW_START);
shadow_alloc_size = memsize >> KASAN_SHADOW_SCALE_SHIFT;
if (IS_ENABLED(CONFIG_MODULES))
shadow_alloc_size += MODULES_LEN >> KASAN_SHADOW_SCALE_SHIFT;
pgalloc_low = round_up((unsigned long)_end, _SEGMENT_SIZE);
if (IS_ENABLED(CONFIG_BLK_DEV_INITRD)) {
initrd_end =
@ -239,18 +237,15 @@ void __init kasan_early_init(void)
* +- shadow end -+ | mapping |
* | ... gap ... |\ | (untracked) |
* +- modules vaddr -+ \ +----------------+
* | 2Gb | \| 256Mb |
* | 2Gb | \| unmapped | allocated per module
* +-----------------+ +- shadow end ---+
*/
/* populate identity mapping */
kasan_early_vmemmap_populate(0, memsize, POPULATE_ONE2ONE);
/* populate kasan shadow (for identity mapping / modules / zero page) */
/* 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)) {
if (IS_ENABLED(CONFIG_MODULES))
untracked_mem_end = vmax - MODULES_LEN;
kasan_early_vmemmap_populate(__sha(untracked_mem_end),
__sha(vmax), POPULATE_MAP);
}
kasan_early_vmemmap_populate(__sha(memsize), __sha(untracked_mem_end),
POPULATE_ZERO_SHADOW);
kasan_set_pgd(early_pg_dir, asce_type);