From c633544a6154146a210cf158157a1ae7c55473b6 Mon Sep 17 00:00:00 2001 From: Max Filippov Date: Sun, 3 Dec 2017 13:28:52 -0800 Subject: xtensa: add support for KASAN Cover kernel addresses above 0x90000000 by the shadow map. Enable HAVE_ARCH_KASAN when MMU is enabled. Provide kasan_early_init that fills shadow map with writable copies of kasan_zero_page. Call kasan_early_init right after mmu initialization in the setup_arch. Provide kasan_init that allocates proper shadow map pages from the memblock and puts these pages into the shadow map for addresses from VMALLOC area to the end of KSEG. Call kasan_init right after memblock initialization. Don't use KASAN for the boot code, MMU and KASAN initialization and page fault handler. Make kernel stack size 4 times larger when KASAN is enabled to avoid stack overflows. GCC 7.3, 8 or newer is required to build the xtensa kernel with KASAN. Signed-off-by: Max Filippov --- arch/xtensa/kernel/setup.c | 7 ++++++- arch/xtensa/kernel/xtensa_ksyms.c | 3 +++ 2 files changed, 9 insertions(+), 1 deletion(-) (limited to 'arch/xtensa/kernel') diff --git a/arch/xtensa/kernel/setup.c b/arch/xtensa/kernel/setup.c index 960212e72a70..a931af9075f2 100644 --- a/arch/xtensa/kernel/setup.c +++ b/arch/xtensa/kernel/setup.c @@ -36,6 +36,7 @@ #endif #include +#include #include #include #include @@ -251,6 +252,10 @@ void __init init_arch(bp_tag_t *bp_start) init_mmu(); + /* Initialize initial KASAN shadow map */ + + kasan_early_init(); + /* Parse boot parameters */ if (bp_start) @@ -388,7 +393,7 @@ void __init setup_arch(char **cmdline_p) #endif parse_early_param(); bootmem_init(); - + kasan_init(); unflatten_and_copy_device_tree(); #ifdef CONFIG_SMP diff --git a/arch/xtensa/kernel/xtensa_ksyms.c b/arch/xtensa/kernel/xtensa_ksyms.c index 672391003e40..3a443f83ae87 100644 --- a/arch/xtensa/kernel/xtensa_ksyms.c +++ b/arch/xtensa/kernel/xtensa_ksyms.c @@ -41,6 +41,9 @@ EXPORT_SYMBOL(memset); EXPORT_SYMBOL(memcpy); EXPORT_SYMBOL(memmove); +EXPORT_SYMBOL(__memset); +EXPORT_SYMBOL(__memcpy); +EXPORT_SYMBOL(__memmove); EXPORT_SYMBOL(__strncpy_user); EXPORT_SYMBOL(clear_page); EXPORT_SYMBOL(copy_page); -- cgit v1.2.3