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/Kconfig | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'arch/xtensa/Kconfig') diff --git a/arch/xtensa/Kconfig b/arch/xtensa/Kconfig index fffe05b698ac..f9f95d6e8da8 100644 --- a/arch/xtensa/Kconfig +++ b/arch/xtensa/Kconfig @@ -15,6 +15,7 @@ config XTENSA select GENERIC_IRQ_SHOW select GENERIC_PCI_IOMAP select GENERIC_SCHED_CLOCK + select HAVE_ARCH_KASAN if MMU select HAVE_CC_STACKPROTECTOR select HAVE_DEBUG_KMEMLEAK select HAVE_DMA_API_DEBUG @@ -80,6 +81,10 @@ config VARIANT_IRQ_SWITCH config HAVE_XTENSA_GPIO32 def_bool n +config KASAN_SHADOW_OFFSET + hex + default 0x6e400000 + menu "Processor type and features" choice -- cgit v1.2.3