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>

diff --git a/arch/s390/kernel/module.c b/arch/s390/kernel/module.c
index d298d3cb46d0e716c7093324f0e04bc6b5f7b593..31889db609e904cbafbc2bdab9aa9500fe793b09 100644 (file)
--- a/arch/s390/kernel/module.c
+++ b/arch/s390/kernel/module.c
@@ -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)

diff --git a/arch/s390/mm/kasan_init.c b/arch/s390/mm/kasan_init.c
index b888cbbbcf0dab0c9755e5686315fe77348ba693..714ac41e3ee57ffc38745a762c7074196d3bef2b 100644 (file)
--- a/arch/s390/mm/kasan_init.c
+++ b/arch/s390/mm/kasan_init.c
@@ -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);