@@ -428,11 +428,13 @@ endif
endif
ifdef CONFIG_KASAN
+ifndef CONFIG_PPC_BOOK3S_32
prepare: kasan_prepare
kasan_prepare: prepare0
$(eval KASAN_SHADOW_OFFSET = $(shell awk '{if ($$2 == "KASAN_SHADOW_OFFSET") print $$3;}' include/generated/asm-offsets.h))
endif
+endif
# Check toolchain versions:
# - gcc-4.6 is the minimum kernel-wide version so nothing required.
@@ -16,6 +16,7 @@
#include <asm/page.h>
#include <asm/pgtable-types.h>
+#include <linux/jump_label.h>
#define KASAN_SHADOW_SCALE_SHIFT 3
@@ -34,5 +35,17 @@
void kasan_early_init(void);
void kasan_init(void);
+extern struct static_key_false powerpc_kasan_enabled_key;
+
+static inline bool kasan_arch_is_ready(void)
+{
+ if (!IS_ENABLED(CONFIG_BOOK3S_32))
+ return true;
+ if (static_branch_likely(&powerpc_kasan_enabled_key))
+ return true;
+ return false;
+}
+#define kasan_arch_is_ready kasan_arch_is_ready
+
#endif /* __ASSEMBLY */
#endif
@@ -9,6 +9,9 @@
#include <linux/vmalloc.h>
#include <asm/pgalloc.h>
+/* Used by BOOK3S_32 only */
+DEFINE_STATIC_KEY_FALSE(powerpc_kasan_enabled_key);
+
void __init kasan_early_init(void)
{
unsigned long addr = KASAN_SHADOW_START;
@@ -21,7 +24,7 @@ void __init kasan_early_init(void)
BUILD_BUG_ON(KASAN_SHADOW_START & ~PGDIR_MASK);
if (early_mmu_has_feature(MMU_FTR_HPTE_TABLE))
- panic("KASAN not supported with Hash MMU\n");
+ return;
for (i = 0; i < PTRS_PER_PTE; i++)
__set_pte_at(&init_mm, (unsigned long)kasan_early_shadow_page,
@@ -32,6 +35,22 @@ void __init kasan_early_init(void)
next = pgd_addr_end(addr, end);
pmd_populate_kernel(&init_mm, pmd, kasan_early_shadow_pte);
} while (pmd++, addr = next, addr != end);
+
+ if (IS_ENABLED(CONFIG_PPC_BOOK3S_32)) {
+ jump_label_init();
+ static_branch_enable(&powerpc_kasan_enabled_key);
+ }
+}
+
+static void __init kasan_late_init(void)
+{
+ unsigned long addr;
+ phys_addr_t pa = __pa(kasan_early_shadow_page);
+
+ for (addr = KASAN_SHADOW_START; addr < KASAN_SHADOW_END; addr += PAGE_SIZE)
+ map_kernel_page(addr, pa, PAGE_KERNEL_RO);
+
+ static_branch_enable(&powerpc_kasan_enabled_key);
}
static void __ref *kasan_get_one_page(void)
@@ -113,6 +132,9 @@ void __init kasan_init(void)
{
struct memblock_region *reg;
+ if (early_mmu_has_feature(MMU_FTR_HPTE_TABLE))
+ kasan_late_init();
+
for_each_memblock(memory, reg) {
int ret = kasan_init_region(__va(reg->base), reg->size);
@@ -120,7 +142,8 @@ void __init kasan_init(void)
panic("kasan: kasan_init_region() failed");
}
- kasan_remap_early_shadow_ro();
+ if (!early_mmu_has_feature(MMU_FTR_HPTE_TABLE))
+ kasan_remap_early_shadow_ro();
clear_page(kasan_early_shadow_page);
The challenge with book3s/32 is that the hash table management has to be set up before being able to use KASAN. This patch adds a kasan_arch_is_ready() helper to defer the activation of KASAN until paging is ready. This limits KASAN to KASAN_MINIMAL mode. The downside of it is that the 603, which doesn't use hash table, also gets downgraded to KASAN_MINIMAL because this is no way to activate full support dynamically because that's compiled-in. Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> --- arch/powerpc/Makefile | 2 ++ arch/powerpc/include/asm/kasan.h | 13 +++++++++++++ arch/powerpc/mm/kasan/kasan_init_32.c | 27 +++++++++++++++++++++++++-- 3 files changed, 40 insertions(+), 2 deletions(-)