On 7/2/2014 8:47 PM, Stuart Hayes wrote: > A page fault can crash the kernel very early if an NX bit is set in a > page table entry, if the CPU doesn't support NX (or if NX support is > disabled in the CPU). Move the call to x86_configure_nx() earlier > than parse_setup_data(), since that calls early_memremap(). > > Signed-off-by: Stuart Hayes <stuart.w.ha...@gmail.com> > --- > > --- linux-3.16-rc3/arch/x86/kernel/setup.c.orig 2014-07-02 > 12:14:50.196308719 -0400 > +++ linux-3.16-rc3/arch/x86/kernel/setup.c 2014-07-02 12:11:11.240301228 > -0400 > @@ -940,6 +940,17 @@ void __init setup_arch(char **cmdline_p) > > iomem_resource.end = (1ULL << boot_cpu_data.x86_phys_bits) - 1; > setup_memory_map(); > + > + /* > + * x86_configure_nx() is called before parse_setup_data() to detect > + * whether hardware doesn't support NX (so that parse_setup_data() > + * can safely call early_memremap() without setting the XD bit in > + * the PTE, which can cause an unrecoverable page fault). It may > + * then be called again from within noexec_setup() during parsing > + * early parameters to honor the respective command line option. > + */ > + x86_configure_nx(); > + > parse_setup_data(); > > copy_edd(); > @@ -974,15 +985,6 @@ void __init setup_arch(char **cmdline_p) > strlcpy(command_line, boot_command_line, COMMAND_LINE_SIZE); > *cmdline_p = command_line; > > - /* > - * x86_configure_nx() is called before parse_early_param() to detect > - * whether hardware doesn't support NX (so that the early EHCI debug > - * console setup can safely call set_fixmap()). It may then be called > - * again from within noexec_setup() during parsing early parameters > - * to honor the respective command line option. > - */ > - x86_configure_nx(); > - > parse_early_param(); > > x86_report_nx();
I haven't received any responses... is there a problem with the patch? Also CCing a couple people. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
