s390/kasan: add KASAN_VMALLOC support

Add KASAN_VMALLOC support which now enables vmalloc memory area access
checks as well as enables usage of VMAP_STACK under kasan.

KASAN_VMALLOC changes the way vmalloc and modules areas shadow memory
is handled. With this new approach only top level page tables are
pre-populated and lower levels are filled dynamically upon memory
allocation.

Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index d4051e88e6250ddbb621b18c0dc6f8356411ffd8..bc88841d335d20816596d354060341d2377c4df8 100644 (file)
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -124,6 +124,7 @@ config S390
        select HAVE_ARCH_JUMP_LABEL
        select HAVE_ARCH_JUMP_LABEL_RELATIVE
        select HAVE_ARCH_KASAN
+       select HAVE_ARCH_KASAN_VMALLOC
        select CPU_NO_EFFICIENT_FFS if !HAVE_MARCH_Z9_109_FEATURES
        select HAVE_ARCH_SECCOMP_FILTER
        select HAVE_ARCH_SOFT_DIRTY

diff --git a/arch/s390/mm/kasan_init.c b/arch/s390/mm/kasan_init.c
index 460f2557294021f0f7bd49e1f31bcfbaed007f31..06345616a6466a921c9476ca6ecf6a0710a3638a 100644 (file)
--- a/arch/s390/mm/kasan_init.c
+++ b/arch/s390/mm/kasan_init.c
@@ -82,7 +82,8 @@ static pte_t * __init kasan_early_pte_alloc(void)
 enum populate_mode {
        POPULATE_ONE2ONE,
        POPULATE_MAP,
-       POPULATE_ZERO_SHADOW
+       POPULATE_ZERO_SHADOW,
+       POPULATE_SHALLOW
 };
 static void __init kasan_early_vmemmap_populate(unsigned long address,
                                                unsigned long end,
@@ -116,6 +117,12 @@ static void __init kasan_early_vmemmap_populate(unsigned long address,
                        pgd_populate(&init_mm, pg_dir, p4_dir);
                }
 
+               if (IS_ENABLED(CONFIG_KASAN_S390_4_LEVEL_PAGING) &&
+                   mode == POPULATE_SHALLOW) {
+                       address = (address + P4D_SIZE) & P4D_MASK;
+                       continue;
+               }
+
                p4_dir = p4d_offset(pg_dir, address);
                if (p4d_none(*p4_dir)) {
                        if (mode == POPULATE_ZERO_SHADOW &&
@@ -130,6 +137,12 @@ static void __init kasan_early_vmemmap_populate(unsigned long address,
                        p4d_populate(&init_mm, p4_dir, pu_dir);
                }
 
+               if (!IS_ENABLED(CONFIG_KASAN_S390_4_LEVEL_PAGING) &&
+                   mode == POPULATE_SHALLOW) {
+                       address = (address + PUD_SIZE) & PUD_MASK;
+                       continue;
+               }
+
                pu_dir = pud_offset(p4_dir, address);
                if (pud_none(*pu_dir)) {
                        if (mode == POPULATE_ZERO_SHADOW &&
@@ -195,6 +208,9 @@ static void __init kasan_early_vmemmap_populate(unsigned long address,
                                page = kasan_early_shadow_page;
                                pte_val(*pt_dir) = __pa(page) | pgt_prot_zero;
                                break;
+                       case POPULATE_SHALLOW:
+                               /* should never happen */
+                               break;
                        }
                }
                address += PAGE_SIZE;
@@ -313,22 +329,50 @@ void __init kasan_early_init(void)
        init_mm.pgd = early_pg_dir;
        /*
         * Current memory layout:
-        * +- 0 -------------+   +- shadow start -+
-        * | 1:1 ram mapping |  /| 1/8 ram        |
-        * +- end of ram ----+ / +----------------+
-        * | ... gap ...     |/  |      kasan     |
-        * +- shadow start --+   |      zero      |
-        * | 1/8 addr space  |   |      page      |
-        * +- shadow end    -+   |      mapping   |
-        * | ... gap ...     |\  |    (untracked) |
-        * +- modules vaddr -+ \ +----------------+
-        * | 2Gb             |  \|      unmapped  | allocated per module
-        * +-----------------+   +- shadow end ---+
+        * +- 0 -------------+     +- shadow start -+
+        * | 1:1 ram mapping |    /| 1/8 ram        |
+        * |                 |   / |                |
+        * +- end of ram ----+  /  +----------------+
+        * | ... gap ...     | /   |                |
+        * |                 |/    |    kasan       |
+        * +- shadow start --+     |    zero        |
+        * | 1/8 addr space  |     |    page        |
+        * +- shadow end    -+     |    mapping     |
+        * | ... gap ...     |\    |  (untracked)   |
+        * +- vmalloc area  -+ \   |                |
+        * | vmalloc_size    |  \  |                |
+        * +- modules vaddr -+   \ +----------------+
+        * | 2Gb             |    \|      unmapped  | allocated per module
+        * +-----------------+     +- shadow end ---+
+        *
+        * Current memory layout (KASAN_VMALLOC):
+        * +- 0 -------------+     +- shadow start -+
+        * | 1:1 ram mapping |    /| 1/8 ram        |
+        * |                 |   / |                |
+        * +- end of ram ----+  /  +----------------+
+        * | ... gap ...     | /   |    kasan       |
+        * |                 |/    |    zero        |
+        * +- shadow start --+     |    page        |
+        * | 1/8 addr space  |     |    mapping     |
+        * +- shadow end    -+     |  (untracked)   |
+        * | ... gap ...     |\    |                |
+        * +- vmalloc area  -+ \   +- vmalloc area -+
+        * | vmalloc_size    |  \  |shallow populate|
+        * +- modules vaddr -+   \ +- modules area -+
+        * | 2Gb             |    \|shallow populate|
+        * +-----------------+     +- shadow end ---+
         */
        /* 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;
+       if (IS_ENABLED(CONFIG_KASAN_VMALLOC)) {
+               untracked_mem_end = vmax - vmalloc_size - MODULES_LEN;
+               /* shallowly populate kasan shadow for vmalloc and modules */
+               kasan_early_vmemmap_populate(__sha(untracked_mem_end),
+                                            __sha(vmax), POPULATE_SHALLOW);
+       }
+       /* populate kasan shadow for untracked memory */
        kasan_early_vmemmap_populate(__sha(max_physmem_end),
                                     __sha(untracked_mem_end),
                                     POPULATE_ZERO_SHADOW);