build breaks when checkpoint unimplemented by arch

[Oren Laadan]

On Mon, 6 Jul 2009, Nathan Lynch wrote:

> Oren Laadan <orenl at cs.columbia.edu> writes:
> 
> > On Mon, 6 Jul 2009, Nathan Lynch wrote:
> >
> >> Hi Oren,
> >> 
> >> With ckpt-v17-rc1 (as well as ckpt-v16-dev) the powerpc build is broken:
> >> 
> >> In file included from include/linux/checkpoint.h:28,
> >>                  from kernel/exit.c:53:
> >> include/linux/checkpoint_hdr.h:42:32: error: asm/checkpoint_hdr.h: No such file or directory
> >> In file included from include/linux/checkpoint.h:28,
> >>                  from kernel/exit.c:53:
> >> include/linux/checkpoint_hdr.h:410: error: 'CKPT_ARCH_NSIG' undeclared here (not in a function)
> >> make[1]: *** [kernel/exit.o] Error 1
> >> 
> >> 
> >> It appears that any architecture which does not supply
> >> asm/checkpoint_hdr.h is broken in the same way.
> >> 
> >> Either all architectures need to supply asm/checkpoint_hdr.h (and define
> >> CKPT_ARCH_NSIG), or there needs to be some other fix which allows
> >> as-yet-unsupported arches to build..
> >> 
> >
> > I see... well - maybe it's time to resend the powerpc port :p
> 
> I'm working on that, but the powerpc port won't be of any help to the
> twenty-odd other architectures that are broken.
> 

[...]

That's what I tried initially, but the problem is that sigset_t may
be defined differently for userspace - see /usr/include/asm/sigset_t.h.
In fact, for x86_32, it it is different, defined as 'unsigned long' 
(and NSIG defined as 32, so only 32 bits).

Moreover, if you include <asm/sigset.h> in checkpoint_hdr.h, which is
also included by userspace, you get lots of compilations warnings,
because of other stuff included from the kernel's asm/sigset.h that
isn't supposed to be included by userspace.

So the introduction of CKPT_ARCH_NSIG is a workaround that.

And back to the other problem - I agree, kernel should only include
<linux/checkpoint.h>, which in turn will include <checkpoint_hdr.h>
if defined CONFIG_CHECKPOINT.

Can you try this patch:

(Hallyn: note that there is some checkpoint-related code within
kerbel/capability.c that should be inside #ifdef CONFIG_CHECKPOINT).

Oren.


diff --git a/fs/pipe.c b/fs/pipe.c
index 5d4c1c8..68fdab4 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -19,12 +19,11 @@
 #include <linux/pagemap.h>
 #include <linux/audit.h>
 #include <linux/syscalls.h>
+#include <linux/checkpoint.h>
 
 #include <asm/uaccess.h>
 #include <asm/ioctls.h>
 
-#include <linux/checkpoint.h>
-#include <linux/checkpoint_hdr.h>
 
 /*
  * We use a start+len construction, which provides full use of the 
diff --git a/include/linux/checkpoint.h b/include/linux/checkpoint.h
index c47e796..b8f99be 100644
--- a/include/linux/checkpoint.h
+++ b/include/linux/checkpoint.h
@@ -19,6 +19,7 @@
 #define RESTART_TASKSELF	0x1
 
 #ifdef __KERNEL__
+#ifdef CONFIG_CHECKPOINT
 
 #include <linux/sched.h>
 #include <linux/nsproxy.h>
@@ -299,6 +300,7 @@ extern unsigned long ckpt_debug_level;
 
 #endif /* CONFIG_CHECKPOINT_DEBUG */
 
+#endif /* CONFIG_CHECKPOINT */
 #endif /* __KERNEL__ */
 
 #endif /* _LINUX_CHECKPOINT_H_ */
diff --git a/ipc/shm.c b/ipc/shm.c
index 0991134..516b179 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -40,7 +40,6 @@
 #include <linux/mount.h>
 #include <linux/ipc_namespace.h>
 #include <linux/ima.h>
-#include <linux/checkpoint_hdr.h>
 #include <linux/checkpoint.h>
 
 #include <asm/uaccess.h>
diff --git a/kernel/capability.c b/kernel/capability.c
index 90cc7b4..4f58454 100644
--- a/kernel/capability.c
+++ b/kernel/capability.c
@@ -15,7 +15,7 @@
 #include <linux/syscalls.h>
 #include <linux/pid_namespace.h>
 #include <linux/securebits.h>
-#include <linux/checkpoint_hdr.h>
+#include <linux/checkpoint.h>
 #include <asm/uaccess.h>
 #include "cred-internals.h"
 
@@ -375,6 +375,7 @@ static inline int restore_cap_bset(kernel_cap_t bset, struct cred *cred)
 }
 #endif /* CONFIG_SECURITY_FILE_CAPABILITIES */
 
+#ifdef CONFIG_CHECKPOINT
 static int do_restore_caps(struct ckpt_capabilities *h, struct cred *cred)
 {
 	kernel_cap_t effective, inheritable, permitted, bset;
@@ -428,6 +429,7 @@ int restore_capabilities(struct ckpt_capabilities *h, struct cred *new)
 
 	return ret;
 }
+#endif /* CONFIG_CHECKPOINT */
 
 /**
  * capable - Determine if the current task has a superior capability in effect
diff --git a/mm/filemap.c b/mm/filemap.c
index 782664d..202bd74 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -34,11 +34,9 @@
 #include <linux/hardirq.h> /* for BUG_ON(!in_atomic()) only */
 #include <linux/memcontrol.h>
 #include <linux/mm_inline.h> /* for page_is_file_cache() */
+#include <linux/checkpoint.h>
 #include "internal.h"
 
-#include <linux/checkpoint_types.h>
-#include <linux/checkpoint_hdr.h>
-#include <linux/checkpoint.h>
 
 /*
  * FIXME: remove all knowledge of the buffer layer from the core VM
diff --git a/mm/mmap.c b/mm/mmap.c
index e60424b..4c01a90 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -29,16 +29,13 @@
 #include <linux/rmap.h>
 #include <linux/mmu_notifier.h>
 #include <linux/perf_counter.h>
+#include <linux/checkpoint.h>
 
 #include <asm/uaccess.h>
 #include <asm/cacheflush.h>
 #include <asm/tlb.h>
 #include <asm/mmu_context.h>
 
-#include <linux/checkpoint_types.h>
-#include <linux/checkpoint_hdr.h>
-#include <linux/checkpoint.h>
-
 #include "internal.h"
 
 #ifndef arch_mmap_check
diff --git a/mm/shmem.c b/mm/shmem.c
index e123ec2..9334810 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -30,9 +30,6 @@
 #include <linux/module.h>
 #include <linux/swap.h>
 #include <linux/ima.h>
-
-#include <linux/checkpoint_types.h>
-#include <linux/checkpoint_hdr.h>
 #include <linux/checkpoint.h>
 
 static struct vfsmount *shm_mnt;