Make the loader runs on 16k page size kernel with SCons (2)

[illwieckz]

Replay of:

• Make the loader runs on 16k page size kernel with SCons #11

[slipher]

I think it is breaking the bootstrap loader memory mapping somehow based on nacl_bootstrap_prereservation_test. I'm testing just on a 4k page system. The test also doesn't work on master because mmap is buggy and refuses to allocate the page starting right at vm.mmap_min_addr but the test can be made to work by modifying IsPageMappable to accept EINVAL with any address. So with that change, the mappings from master are like

00002000-00010000 ---p 00000000 00:00 0 
00010000-00012000 r-xp 00000000 b3:02 137384     /home/me/elsewhere/scons-out/opt-linux-arm/staging/nacl_helper_bootstrap
00012000-00014000 rw-p 00000000 00:00 0 
00014000-40002000 ---p 00000000 b3:02 137384     /home/me/elsewhere/scons-out/opt-linux-arm/staging/nacl_helper_bootstrap
40002000-40003000 rw-p 00002000 b3:02 137384     /home/me/elsewhere/scons-out/opt-linux-arm/staging/nacl_helper_bootstrap
4112a000-4114b000 rw-p 00000000 00:00 0          [heap]

The test, which checks that the first 1 GiB is reserved, passes. With this branch, the patched test fails and shows there was no additional memory reserved:

00002000-00010000 ---p 00000000 00:00 0 
00010000-00012000 r-xp 00000000 b3:02 146288     /home/me/elsewhere/scons-out/opt-linux-arm/staging/nacl_helper_bootstrap
00020000-00022000 rw-p 00000000 00:00 0 

The patch to the test:

diff --git a/src/trusted/service_runtime/linux/nacl_bootstrap_prereservation_test.c b/src/trusted/service_runtime/linux/nacl_bootstrap_prereservation_test.c
index 9f0a888e2..10812bcfa 100644
--- a/src/trusted/service_runtime/linux/nacl_bootstrap_prereservation_test.c
+++ b/src/trusted/service_runtime/linux/nacl_bootstrap_prereservation_test.c
@@ -28,7 +28,7 @@ int ParseMapsLine(FILE *fp, uintptr_t *start, uintptr_t *end) {
   if (!fgets(buf, sizeof(buf), fp)) {
     return 0;
   }
-
+ printf("%s", buf);
   if (sscanf(buf, "%"SCNxPTR"-%"SCNxPTR" %*4[-rwxp] %*8x %*2x:%*2x %*16x",
              start, end) != 2) {
     return 0;
@@ -62,9 +62,10 @@ int IsPageMappable(uintptr_t addr) {
                       MAP_ANONYMOUS | MAP_NORESERVE,
                       -1, 0);
   if (retval != (void *) addr)   {
+printf("addr=%p retval=%p errno=%d\n", (void*)addr, retval, errno);
     CHECK(MAP_FAILED == retval &&
           (EPERM == errno || EACCES == errno ||
-           (EINVAL == errno && 0 == addr)));
+           (EINVAL == errno /*&& 0 == addr*/)));
     return 0;
   }
   return 1;