Commit 793213a8 authored by Vasily Gorbik's avatar Vasily Gorbik Committed by Martin Schwidefsky
Browse files

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 bebf56a1: "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: default avatarVasily Gorbik <gor@linux.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 0dac8f6b

arch/s390/kernel/module.c

+11 −4
Original line number Diff line number Diff line
@@ -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,

	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)

arch/s390/mm/kasan_init.c

+3 −8
Original line number Diff line number Diff line
@@ -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);

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