ipc: add COMPAT_SHMLBA support
If the SHMLBA definition for a native task differs from the definition for
a compat task, the do_shmat() function would need to handle both.
This patch introduces COMPAT_SHMLBA, which is used by the compat shmat
syscall when calling the ipc code and allows architectures such as AArch64
(where the native SHMLBA is 64k but the compat (AArch32) definition is
16k) to provide the correct semantics for compat IPC system calls.
Cc: David S. Miller <davem@davemloft.net>
Cc: Chris Zankel <chris@zankel.net>
Cc: Arnd Bergmann <arnd@arndb.de>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/shm.h b/include/linux/shm.h
index 92808b8..edd0868 100644
--- a/include/linux/shm.h
+++ b/include/linux/shm.h
@@ -107,12 +107,14 @@
#define SHM_NORESERVE 010000 /* don't check for reservations */
#ifdef CONFIG_SYSVIPC
-long do_shmat(int shmid, char __user *shmaddr, int shmflg, unsigned long *addr);
+long do_shmat(int shmid, char __user *shmaddr, int shmflg, unsigned long *addr,
+ unsigned long shmlba);
extern int is_file_shm_hugepages(struct file *file);
extern void exit_shm(struct task_struct *task);
#else
static inline long do_shmat(int shmid, char __user *shmaddr,
- int shmflg, unsigned long *addr)
+ int shmflg, unsigned long *addr,
+ unsigned long shmlba)
{
return -ENOSYS;
}