From 0773495b1f5f1c5e23551843f87b5ff37e7af8f7 Mon Sep 17 00:00:00 2001 From: Max Filippov <jcmvbkbc@gmail.com> Date: Sun, 4 Nov 2018 01:46:00 -0700 Subject: [PATCH 1/2] xtensa: make sure bFLT stack is 16 byte aligned Xtensa ABI requires stack alignment to be at least 16. In noMMU configuration ARCH_SLAB_MINALIGN is used to align stack. Make it at least 16. This fixes the following runtime error in noMMU configuration, caused by interaction between insufficiently aligned stack and alloca function, that results in corruption of on-stack variable in the libc function glob: Caught unhandled exception in 'sh' (pid = 47, pc = 0x02d05d65) - should not happen EXCCAUSE is 15 Cc: stable@vger.kernel.org Signed-off-by: Max Filippov <jcmvbkbc@gmail.com> --- arch/xtensa/include/asm/processor.h | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/arch/xtensa/include/asm/processor.h b/arch/xtensa/include/asm/processor.h index e4ccb88b7996..677bc76c1d70 100644 --- a/arch/xtensa/include/asm/processor.h +++ b/arch/xtensa/include/asm/processor.h @@ -23,7 +23,11 @@ # error Linux requires the Xtensa Windowed Registers Option. #endif -#define ARCH_SLAB_MINALIGN XCHAL_DATA_WIDTH +/* Xtensa ABI requires stack alignment to be at least 16 */ + +#define STACK_ALIGN (XCHAL_DATA_WIDTH > 16 ? XCHAL_DATA_WIDTH : 16) + +#define ARCH_SLAB_MINALIGN STACK_ALIGN /* * User space process size: 1 GB. From 40dc948f234b73497c3278875eb08a01d5854d3f Mon Sep 17 00:00:00 2001 From: Max Filippov <jcmvbkbc@gmail.com> Date: Tue, 13 Nov 2018 23:46:42 -0800 Subject: [PATCH 2/2] xtensa: fix boot parameters address translation The bootloader may pass physical address of the boot parameters structure to the MMUv3 kernel in the register a2. Code in the _SetupMMU block in the arch/xtensa/kernel/head.S is supposed to map that physical address to the virtual address in the configured virtual memory layout. This code haven't been updated when additional 256+256 and 512+512 memory layouts were introduced and it may produce wrong addresses when used with these layouts. Cc: stable@vger.kernel.org Signed-off-by: Max Filippov <jcmvbkbc@gmail.com> --- arch/xtensa/kernel/head.S | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/arch/xtensa/kernel/head.S b/arch/xtensa/kernel/head.S index 2f76118ecf62..9053a5622d2c 100644 --- a/arch/xtensa/kernel/head.S +++ b/arch/xtensa/kernel/head.S @@ -88,9 +88,12 @@ _SetupMMU: initialize_mmu #if defined(CONFIG_MMU) && XCHAL_HAVE_PTP_MMU && XCHAL_HAVE_SPANNING_WAY rsr a2, excsave1 - movi a3, 0x08000000 + movi a3, XCHAL_KSEG_PADDR + bltu a2, a3, 1f + sub a2, a2, a3 + movi a3, XCHAL_KSEG_SIZE bgeu a2, a3, 1f - movi a3, 0xd0000000 + movi a3, XCHAL_KSEG_CACHED_VADDR add a2, a2, a3 wsr a2, excsave1 1: