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/arch/sparc/kernel/sys_sparc_64.c b/arch/sparc/kernel/sys_sparc_64.c
index c38e5aa..0dc1f57 100644
--- a/arch/sparc/kernel/sys_sparc_64.c
+++ b/arch/sparc/kernel/sys_sparc_64.c
@@ -470,7 +470,7 @@
switch (call) {
case SHMAT: {
ulong raddr;
- err = do_shmat(first, ptr, (int)second, &raddr);
+ err = do_shmat(first, ptr, (int)second, &raddr, SHMLBA);
if (!err) {
if (put_user(raddr,
(ulong __user *) third))
diff --git a/arch/xtensa/kernel/syscall.c b/arch/xtensa/kernel/syscall.c
index 816e6d0..05b3f09 100644
--- a/arch/xtensa/kernel/syscall.c
+++ b/arch/xtensa/kernel/syscall.c
@@ -44,7 +44,7 @@
unsigned long ret;
long err;
- err = do_shmat(shmid, shmaddr, shmflg, &ret);
+ err = do_shmat(shmid, shmaddr, shmflg, &ret, SHMLBA);
if (err)
return err;
return (long)ret;
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;
}
diff --git a/ipc/compat.c b/ipc/compat.c
index a6df704..53cebdf 100644
--- a/ipc/compat.c
+++ b/ipc/compat.c
@@ -514,6 +514,10 @@
return err;
}
+#ifndef COMPAT_SHMLBA
+#define COMPAT_SHMLBA SHMLBA
+#endif
+
#ifdef CONFIG_ARCH_WANT_OLD_COMPAT_IPC
long compat_sys_shmat(int first, int second, compat_uptr_t third, int version,
void __user *uptr)
@@ -524,7 +528,7 @@
if (version == 1)
return -EINVAL;
- err = do_shmat(first, uptr, second, &raddr);
+ err = do_shmat(first, uptr, second, &raddr, COMPAT_SHMLBA);
if (err < 0)
return err;
uaddr = compat_ptr(third);
@@ -536,7 +540,7 @@
unsigned long ret;
long err;
- err = do_shmat(shmid, compat_ptr(shmaddr), shmflg, &ret);
+ err = do_shmat(shmid, compat_ptr(shmaddr), shmflg, &ret, COMPAT_SHMLBA);
if (err)
return err;
force_successful_syscall_return();
diff --git a/ipc/shm.c b/ipc/shm.c
index 41c1285..00faa05 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -953,7 +953,8 @@
* "raddr" thing points to kernel space, and there has to be a wrapper around
* this.
*/
-long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
+long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr,
+ unsigned long shmlba)
{
struct shmid_kernel *shp;
unsigned long addr;
@@ -973,9 +974,9 @@
if (shmid < 0)
goto out;
else if ((addr = (ulong)shmaddr)) {
- if (addr & (SHMLBA-1)) {
+ if (addr & (shmlba - 1)) {
if (shmflg & SHM_RND)
- addr &= ~(SHMLBA-1); /* round down */
+ addr &= ~(shmlba - 1); /* round down */
else
#ifndef __ARCH_FORCE_SHMLBA
if (addr & ~PAGE_MASK)
@@ -1107,7 +1108,7 @@
unsigned long ret;
long err;
- err = do_shmat(shmid, shmaddr, shmflg, &ret);
+ err = do_shmat(shmid, shmaddr, shmflg, &ret, SHMLBA);
if (err)
return err;
force_successful_syscall_return();
diff --git a/ipc/syscall.c b/ipc/syscall.c
index 1d6f53f..0d1e32ce 100644
--- a/ipc/syscall.c
+++ b/ipc/syscall.c
@@ -73,7 +73,7 @@
default: {
unsigned long raddr;
ret = do_shmat(first, (char __user *)ptr,
- second, &raddr);
+ second, &raddr, SHMLBA);
if (ret)
return ret;
return put_user(raddr, (unsigned long __user *) third);