x86, boot: correct sanity checks in boot/compressed/misc.c

arch/x86/boot/compressed/misc.c contains several sanity checks on the
output address.  Correct constraints that are no longer correct:

- the alignment test should be MIN_KERNEL_ALIGN on both 32 and 64
  bits.
- the 64 bit maximum address was set to 2^40, which was the limit of
  one specific x86-64 implementation.  Change the test to 2^46, the
  current Linux limit, and at least try to test the end rather than
  the beginning.
- for non-relocatable kernels, test against LOAD_PHYSICAL_ADDR on both
  32 and 64 bits.

[ Impact: fix potential boot failure due to invalid tests ]

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

1 files changed, 5 insertions, 7 deletions

diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c
index e45be73684f..842b2a36174 100644
--- a/arch/x86/boot/compressed/misc.c
+++ b/arch/x86/boot/compressed/misc.c
@@ -325,21 +325,19 @@ asmlinkage void decompress_kernel(void *rmode, memptr heap,
 	free_mem_ptr     = heap;	/* Heap */
 	free_mem_end_ptr = heap + BOOT_HEAP_SIZE;
 
+	if ((unsigned long)output & (MIN_KERNEL_ALIGN - 1))
+		error("Destination address inappropriately aligned");
 #ifdef CONFIG_X86_64
-	if ((unsigned long)output & (__KERNEL_ALIGN - 1))
-		error("Destination address not 2M aligned");
-	if ((unsigned long)output >= 0xffffffffffUL)
+	if (heap > 0x3fffffffffffUL)
 		error("Destination address too large");
 #else
-	if ((u32)output & (CONFIG_PHYSICAL_ALIGN - 1))
-		error("Destination address not CONFIG_PHYSICAL_ALIGN aligned");
 	if (heap > ((-__PAGE_OFFSET-(512<<20)-1) & 0x7fffffff))
 		error("Destination address too large");
+#endif
 #ifndef CONFIG_RELOCATABLE
-	if ((u32)output != LOAD_PHYSICAL_ADDR)
+	if ((unsigned long)output != LOAD_PHYSICAL_ADDR)
 		error("Wrong destination address");
 #endif
-#endif
 
 	if (!quiet)
 		putstr("\nDecompressing Linux... ");