From: Will Deacon <will.dea...@arm.com>
If the SHMLBA for a 64-bit applications differs from the SHMLBA for
32-bit (compat) applications, do_shmat() would need to handle both. This
patch introduces COMPAT_SHMLBA which is used only if is_compat_task().
The reason for this patch is that we want SHMLBA to be 64K on AArch64
but still provide a compat equivalent of 4K (and allow LTP tests to
pass).
Signed-off-by: Will Deacon <will.dea...@arm.com>
Signed-off-by: Catalin Marinas <catalin.mari...@arm.com>
---
arch/sparc/kernel/sys_sparc_64.c | 2 +-
arch/xtensa/kernel/syscall.c | 2 +-
include/linux/shm.h | 6 ++++--
ipc/compat.c | 8 ++++++--
ipc/shm.c | 9 +++++----
ipc/syscall.c | 2 +-
6 files changed, 18 insertions(+), 11 deletions(-)
diff --git a/arch/sparc/kernel/sys_sparc_64.c b/arch/sparc/kernel/sys_sparc_64.c
index 275f74f..65203ff 100644
--- a/arch/sparc/kernel/sys_sparc_64.c
+++ b/arch/sparc/kernel/sys_sparc_64.c
@@ -487,7 +487,7 @@ SYSCALL_DEFINE6(sparc_ipc, unsigned int, call, int, first,
unsigned long, second
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 @@ asmlinkage long xtensa_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;
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 @@ struct shmid_kernel /* private to the kernel */
#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 @@ 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 41c1285..00faa05 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 1d6f53f..0d1e32ce 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);
--
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