On Tuesday 21 August 2012, Catalin Marinas wrote: > On Thu, Aug 16, 2012 at 01:37:53PM +0100, Arnd Bergmann wrote: > > On Thursday 16 August 2012, Will Deacon wrote: > > > > This looks wrong: PER_LINUX/PER_LINUX32 decides over the output of the > > > > uname system call, while TIF_32BIT decides over the instruction set > > > > when returning to user space. You definitely should not set the personality > > > > to the value you pass from the elf loader. Instead, just do > > > > > > > > #define SET_PERSONALITY(ex) clear_thread_flag(TIF_32BIT); > > > > #defined COMPAT_SET_PERSONALITY(ex) set_thread_flag(TIF_32BIT); > > > > > > In this case, won't uname be incorrect (aarch64l) for aarch32 tasks (which > > > expect something like armv8l)? > > > > No, the uname output is meant to tell you about the system, not the > > instruction set that you are using (you already know that in compiled > > code). > > OK, so we assumed that compat tasks should get a uname as close as > possible to a 32-bit system, i.e. armv8l, for full compatibility. This > would allow us to run something like 32-bit Debian on an AArch64 kernel > without worrying about any scripts failing. You can still do that, just boot with init="/sbin/setarch armv7 /sbin/init". > But I can see on x86 that it always reports x86_64 even if the task is > x86_32. Not just x86, the same behavior is used on powerpc, s390, mips, sparc and parisc. Not sure about tile though. Arnd -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
