shmget: add "shmflg" checks for SHM_HUGE*

arch/x86/kernel/include/arch/shm.h

@@ -13,6 +13,11 @@
 #ifndef HEADER_ARCH_SHM_H
 #define HEADER_ARCH_SHM_H
 
+/* shmflg */
+#define SHM_HUGE_SHIFT  26
+#define SHM_HUGE_2MB    (21 << SHM_HUGE_SHIFT)
+#define SHM_HUGE_1GB    (30 << SHM_HUGE_SHIFT)
+
 struct ipc_perm {
 	key_t		key;
 	uid_t		uid;

arch/x86/kernel/syscall.c

@@ -1332,13 +1332,33 @@ SYSCALL_DECLARE(shmget)
 {
 	const key_t key = ihk_mc_syscall_arg0(ctx);
 	const size_t size = ihk_mc_syscall_arg1(ctx);
-	const int shmflg = ihk_mc_syscall_arg2(ctx);
+	const int shmflg0 = ihk_mc_syscall_arg2(ctx);
 	int shmid;
+	int error;
+	int shmflg = shmflg0;
 
-	dkprintf("shmget(%#lx,%#lx,%#x)\n", key, size, shmflg);
+	dkprintf("shmget(%#lx,%#lx,%#x)\n", key, size, shmflg0);
+
+	if (shmflg & SHM_HUGETLB) {
+		switch (shmflg & (0x3F << SHM_HUGE_SHIFT)) {
+		case 0:
+			shmflg |= SHM_HUGE_2MB;	/* default hugepage size */
+			break;
+
+		case SHM_HUGE_2MB:
+		case SHM_HUGE_1GB:
+			break;
+
+		default:
+			error = -EINVAL;
+			goto out;
+		}
+	}
 
 	shmid = do_shmget(key, size, shmflg);
 
-	dkprintf("shmget(%#lx,%#lx,%#x): %d\n", key, size, shmflg, shmid);
-	return shmid;
+	error = 0;
+out:
+	dkprintf("shmget(%#lx,%#lx,%#x): %d %d\n", key, size, shmflg0, error, shmid);
+	return (error)?: shmid;
 } /* sys_shmget() */

kernel/include/shm.h

@@ -25,6 +25,7 @@ enum {
 	IPC_CREAT	= 01000,
 	IPC_EXCL	= 02000,
 
+	SHM_HUGETLB	= 04000,
 	SHM_RDONLY	= 010000,
 	SHM_RND		= 020000,
 	SHM_REMAP	= 040000,
@@ -49,7 +50,7 @@ enum {
 struct shmobj {
 	struct memobj		memobj;		/* must be first */
 	int			index;
-	uint8_t			padding[4];
+	int			pgshift;
 	size_t			real_segsz;
 	struct shmid_ds		ds;
 	struct list_head	page_list;

kernel/shmobj.c

@@ -136,6 +136,7 @@ int shmobj_create(struct shmid_ds *ds, struct memobj **objp)
 	obj->ds.shm_perm.seq = the_seq++;
 	obj->ds.shm_nattch = 1;
 	obj->index = -1;
+	obj->pgshift = PAGE_SHIFT;
 	obj->real_segsz = (obj->ds.shm_segsz + PAGE_SIZE - 1) & PAGE_MASK;
 	page_list_init(obj);
 	ihk_mc_spinlock_init(&obj->memobj.lock);

kernel/syscall.c

@@ -3536,6 +3536,7 @@ int do_shmget(const key_t key, const size_t size, const int shmflg)
 	int error;
 	struct shmid_ds ads;
 	struct shmobj *obj;
+	int pgshift;
 
 	dkprintf("do_shmget(%#lx,%#lx,%#x)\n", key, size, shmflg);
 
@@ -3610,6 +3611,11 @@ int do_shmget(const key_t key, const size_t size, const int shmflg)
 		return -ENOSPC;
 	}
 
+	pgshift = PAGE_SHIFT;
+	if (shmflg & SHM_HUGETLB) {
+		pgshift = (shmflg >> SHM_HUGE_SHIFT) & 0x3F;
+	}
+
 	memset(&ads, 0, sizeof(ads));
 	ads.shm_perm.key = key;
 	ads.shm_perm.uid = proc->euid;
@@ -3629,6 +3635,7 @@ int do_shmget(const key_t key, const size_t size, const int shmflg)
 	}
 
 	obj->index = ++the_maxi;
+	obj->pgshift = pgshift;
 
 	list_add(&obj->chain, &kds_list);
 	++the_shm_info.used_ids;