From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Petazzoni Date: Mon, 3 Nov 2008 09:31:10 +0100 Subject: [Buildroot] External toolchain support improvements In-Reply-To: References: <20081030094501.66983ff9@surf> Message-ID: <20081103093110.13e43438@surf> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: buildroot@busybox.net Le Fri, 31 Oct 2008 14:42:14 -0400, "hartleys" a ?crit : > What are the side effects if you use an external toolchain that was > built with a given kernel version, say 2.6.20.4, but use a newer > kernel, say 2.6.27.3? The kernel <-> userspace interface is backward compatible. So if you use a toolchain that was compiled against the headers of kernel 2.6.20.4 and run the binaries under 2.6.27.3, them it will work perfectly fine. The only thing is that you won't be able to use the new system calls, data structures, headers, defines, that have been added in the kernel between 2.6.20.4 and 2.6.27.3. The reverse side: if you generate binaries with a toolchain that has been compiled against the headers of kernel 2.6.27.3 and run it on a 2.6.20.4 kernel, then there are two cases : * You don't use any of the new features of the kernel <-> userspace interface added between 2.6.20.4 and 2.6.27.3 : everything will work correctly ; * You use one of these new features: your binary might fail to run properly (for example if they use a new system call, that isn't available in your kernel). Sincerly, Thomas -- Thomas Petazzoni, Free Electrons Kernel, drivers and embedded Linux development, consulting, training and support. http://free-electrons.com