x86/boot/64: Verify alignment of the LOAD segment

Since the x86-64 kernel must be aligned to 2MB, refuse to boot the
kernel if the alignment of the LOAD segment isn't a multiple of 2MB.
Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/CAMe9rOrR7xSJgUfiCoZLuqWUwymRxXPoGBW38%2BpN%3D9g%2ByKNhZw@mail.gmail.comSigned-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/boot/compressed/misc.c

@@ -309,6 +309,10 @@ static void parse_elf(void *output)
 
 		switch (phdr->p_type) {
 		case PT_LOAD:
+#ifdef CONFIG_X86_64
+			if ((phdr->p_align % 0x200000) != 0)
+				error("Alignment of LOAD segment isn't multiple of 2MB");
+#endif
 #ifdef CONFIG_RELOCATABLE
 			dest = output;
 			dest += (phdr->p_paddr - LOAD_PHYSICAL_ADDR);