From 1a27f7d9c27671e7ae3cd0a3ee316149fa0824dc Mon Sep 17 00:00:00 2001 From: Vitaly Kuzmichev Date: Tue, 15 Jun 2010 22:18:11 +0400 Subject: ARM: Align stack to 8 bytes The ARM ABI requires that the stack be aligned to 8 bytes as it is noted in Procedure Call Standard for the ARM Architecture: http://infocenter.arm.com/help/topic/com.arm.doc.ihi0042d/index.html Unaligned SP also causes the problem with variable-length arrays allocation when VLA address becomes less than stack pointer during aligning of this address, so the next 'push' in the stack overwrites first 4 bytes of VLA. Signed-off-by: Vitaly Kuzmichev --- arch/arm/cpu/pxa/start.S | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) (limited to 'arch/arm/cpu/pxa') diff --git a/arch/arm/cpu/pxa/start.S b/arch/arm/cpu/pxa/start.S index 3989fa61bc..e07c8c2e0e 100644 --- a/arch/arm/cpu/pxa/start.S +++ b/arch/arm/cpu/pxa/start.S @@ -140,10 +140,8 @@ stack_setup: #ifdef CONFIG_USE_IRQ sub r0, r0, #(CONFIG_STACKSIZE_IRQ+CONFIG_STACKSIZE_FIQ) #endif /* CONFIG_USE_IRQ */ - sub r0, r0, #12 /* leave 3 words for abort-stack */ - bic sp, r0, #7 /* NOTE: stack MUST be aligned to */ - /* 8 bytes in case we want to use */ - /* 64bit datatypes (eg. VSPRINTF64) */ + sub sp, r0, #12 /* leave 3 words for abort-stack */ + bic sp, sp, #7 /* 8-byte alignment for ABI compliance */ clear_bss: ldr r0, _bss_start /* find start of bss segment */ -- cgit