From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mx1.redhat.com ([209.132.183.28]) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1WQUzT-0002tq-Ge for kexec@lists.infradead.org; Thu, 20 Mar 2014 04:54:05 +0000 Date: Thu, 20 Mar 2014 12:53:35 +0800 From: WANG Chao Subject: Re: [kexec-tools PATCH] x86: extend kernel text size up to 1GB Message-ID: <20140320045335.GD24486@dhcp-17-89.nay.redhat.com> References: <20140312031309.GA14477@dhcp-17-89.nay.redhat.com> <20140314061232.GA8248@dhcp-16-126.nay.redhat.com> <20140314064757.GB8248@dhcp-16-126.nay.redhat.com> <20140314070357.GA22782@dhcp-17-89.nay.redhat.com> <20140314070852.GC8248@dhcp-16-126.nay.redhat.com> <20140314072929.GB22782@dhcp-17-89.nay.redhat.com> <20140320034428.GA10601@verge.net.au> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20140320034428.GA10601@verge.net.au> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+dwmw2=twosheds.infradead.org@lists.infradead.org To: Simon Horman Cc: kexec@lists.infradead.org, Dave Young , ebiederm@xmission.com, vgoyal@redhat.com On 03/20/14 at 12:44pm, Simon Horman wrote: > On Fri, Mar 14, 2014 at 03:29:29PM +0800, WANG Chao wrote: > > On 03/14/14 at 03:08pm, Dave Young wrote: > > > On 03/14/14 at 03:03pm, WANG Chao wrote: > > > > On 03/14/14 at 02:47pm, Dave Young wrote: > > > > > On 03/14/14 at 02:12pm, Dave Young wrote: > > > > > > On 03/12/14 at 11:13am, WANG Chao wrote: > > > > > > > Currently kexec hard code X86_64_KERNEL_TEXT_SIZE to 512M. With kASLR > > > > > > > enabled (CONFIG_RANDOMIZED_BASE=y), kernel image base offset could be > > > > > > > randomized from 0 to 1GB and kexec-tools fails to get kernel virtual > > > > > > > address from /proc/kcore when the offset is >512M. > > > > > > > > > > > > > > Now extend X86_64_KERNEL_TEXT_SIZE to 1GB to adapt kASLR. > > > > > > > > > > > > > > Signed-off-by: WANG Chao > > > > > > > --- > > > > > > > kexec/arch/i386/crashdump-x86.h | 2 +- > > > > > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > > > > > > > > > diff --git a/kexec/arch/i386/crashdump-x86.h b/kexec/arch/i386/crashdump-x86.h > > > > > > > index e68b626..a5b2dfd 100644 > > > > > > > --- a/kexec/arch/i386/crashdump-x86.h > > > > > > > +++ b/kexec/arch/i386/crashdump-x86.h > > > > > > > @@ -18,7 +18,7 @@ int load_crashdump_segments(struct kexec_info *info, char *mod_cmdline, > > > > > > > #define X86_64_MAXMEM 0x3fffffffffffUL > > > > > > > > > > > > > > /* Kernel text size */ > > > > > > > -#define X86_64_KERNEL_TEXT_SIZE (512UL*1024*1024) > > > > > > > +#define X86_64_KERNEL_TEXT_SIZE (1UL*1024*1024*1024) > > > > > > > > > > > > Should define a new macro such as: X86_KERNEL_TEXT_START_LIMIT (1UL*1024*1024*1024) > > > > > > and then check end addr with X86_64_KERNEL_TEXT_SIZE + X86_64_KERNEL_TEXT_SIZE > > > > > > > > > > I means check ktext with range <1G - 1.5G> > > > > > > > > You're right. > > > > > > > > I think it's fine adding new macro X86_64_RANDOMIZE_BASE_MAX_OFFSET > > > > as 0x40000000 (1G) and doing the following check: > > > > > > > > (start >= X86_64__START_KERNEL_map) && > > > > (start <= X86_64__START_KERNEL_map + X86_64_RANDOMIZE_MAX_BASE_OFFSET) && > > > > (end - start <= X86_64_KERNEL_TEXT_SIZE) > > > > > > end - start < X86_64_KERNEL_TEXT_SIZE should be right, other wise I'm fine. > > > > Right. size = end - start + 1. > > > > I'll post v2. > > Hi, > > I'd like to enquire about the status of this as I don't see v2 in my inbox. Hi, Simon I'd like to hold off for such fix. Fixing kaslr issue is not trivial as I thought. You can find the discussion on kexec mail list or here: http://thread.gmane.org/gmane.linux.kernel.kexec/11103 Sorry. I'll CC you next time. Thanks WANG Chao _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec