From: Samuel Thibault Subject: [PATCH] [Mini-OS] Fix x86 initial stack alignment Date: Fri, 23 Nov 2007 14:14:22 +0000 Message-ID: <20071123141422.GK4207@implementation.uk.xensource.com> References: <20071123135541.GA10153@implementation.uk.xensource.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Resent-Message-ID: <20071123154335.GL4207@implementation.uk.xensource.com> Resent-To: xen-devel@lists.xensource.com Content-Disposition: inline In-Reply-To: <20071123135541.GA10153@implementation.uk.xensource.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: xen-devel@xensource.com List-Id: xen-devel@lists.xenproject.org This fixes the initial stack alignment for x86, which is required for current to return a fine NULL instead of a random value or possibly crash during initialization. Signed-off-by: Grzegorz Milos Signed-off-by: Samuel Thibault diff -r 2e05a6173be0 extras/mini-os/arch/x86/setup.c --- a/extras/mini-os/arch/x86/setup.c Fri Nov 23 11:58:11 2007 +0000 +++ b/extras/mini-os/arch/x86/setup.c Fri Nov 23 13:31:36 2007 +0000 @@ -45,7 +45,7 @@ union start_info_union start_info_union; * Just allocate the kernel stack here. SS:ESP is set up to point here * in head.S. */ -char stack[8192]; +char stack[2*8192]; extern char shared_info[PAGE_SIZE]; @@ -102,7 +102,7 @@ void void arch_print_info(void) { - printk(" stack: %p-%p\n", stack, stack + 8192); + printk(" stack: %p-%p\n", stack, stack + 2*8192); } diff -r 2e05a6173be0 extras/mini-os/arch/x86/x86_32.S --- a/extras/mini-os/arch/x86/x86_32.S Fri Nov 23 11:58:11 2007 +0000 +++ b/extras/mini-os/arch/x86/x86_32.S Fri Nov 23 13:31:36 2007 +0000 @@ -21,11 +21,12 @@ _start: _start: cld lss stack_start,%esp + andl $(~(8192-1)), %esp push %esi call start_kernel stack_start: - .long stack+8192, __KERNEL_SS + .long stack+(2*8192), __KERNEL_SS /* Unpleasant -- the PTE that maps this page is actually overwritten */ /* to map the real shared-info page! :-) */ diff -r 2e05a6173be0 extras/mini-os/arch/x86/x86_64.S --- a/extras/mini-os/arch/x86/x86_64.S Fri Nov 23 11:58:11 2007 +0000 +++ b/extras/mini-os/arch/x86/x86_64.S Fri Nov 23 13:31:36 2007 +0000 @@ -18,11 +18,12 @@ _start: _start: cld movq stack_start(%rip),%rsp + andq $(~(8192-1)), %rsp movq %rsi,%rdi call start_kernel stack_start: - .quad stack+8192 + .quad stack+(2*8192) /* Unpleasant -- the PTE that maps this page is actually overwritten */ /* to map the real shared-info page! :-) */