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authorWill Deacon <will.deacon@arm.com>2012-07-30 14:42:38 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-07-30 17:25:20 -0700
commit079a96ae3871f0ed9083aac2218136ccec5b9877 (patch)
tree52acdeda67006d3d85eee0a17d6241657ba270dc /ipc
parent63dca8d5b5ef7effb58b8d6892a024125c0fab0b (diff)
downloadlinux-079a96ae3871f0ed9083aac2218136ccec5b9877.tar.gz
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>
Diffstat (limited to 'ipc')
-rw-r--r--ipc/compat.c8
-rw-r--r--ipc/shm.c9
-rw-r--r--ipc/syscall.c2
3 files changed, 12 insertions, 7 deletions
diff --git a/ipc/compat.c b/ipc/compat.c
index a6df704f521..53cebdf80e3 100644
--- a/ipc/compat.c
+++ b/ipc/compat.c
@@ -514,6 +514,10 @@ long compat_sys_msgctl(int first, int second, void __user *uptr)
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 @@ long compat_sys_shmat(int first, int second, compat_uptr_t third, int version,
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 @@ long compat_sys_shmat(int shmid, compat_uptr_t shmaddr, int shmflg)
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 41c1285d697..00faa05cf72 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -953,7 +953,8 @@ out:
* "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 @@ long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
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 @@ SYSCALL_DEFINE3(shmat, int, shmid, char __user *, shmaddr, int, shmflg)
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 1d6f53f6b56..0d1e32ce048 100644
--- a/ipc/syscall.c
+++ b/ipc/syscall.c
@@ -73,7 +73,7 @@ SYSCALL_DEFINE6(ipc, unsigned int, call, int, first, unsigned long, second,
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);