staging: android: ashmem: Add support for 32bit ashmem calls in a 64bit kernel

Android's shared memory subsystem, Ashmem, does not support calls from a
32bit userspace in a 64 bit kernel. This patch adds support for syscalls
coming from a 32bit userspace in a 64bit kernel.

The patch has been successfully tested on ARMv8 AEM(64bit
platform model) and Versatile Express A9(32bit platform).

v2: Fix missing compat.h include.

Signed-off-by: Serban Constantinescu <serban.constantinescu@arm.com>
Acked-by: Arve Hjønnevåg <arve@android.com>
Acked-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Serban Constantinescu 2013-03-05 15:27:38 +00:00 committed by Greg Kroah-Hartman
parent 5db5a20a50
commit e9f5b8145a
2 changed files with 27 additions and 1 deletions

View file

@ -702,6 +702,23 @@ static long ashmem_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
return ret;
}
/* support of 32bit userspace on 64bit platforms */
#ifdef CONFIG_COMPAT
static long compat_ashmem_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
switch (cmd) {
case COMPAT_ASHMEM_SET_SIZE:
cmd = ASHMEM_SET_SIZE;
break;
case COMPAT_ASHMEM_SET_PROT_MASK:
cmd = ASHMEM_SET_PROT_MASK;
break;
}
return ashmem_ioctl(file, cmd, arg);
}
#endif
static const struct file_operations ashmem_fops = {
.owner = THIS_MODULE,
.open = ashmem_open,
@ -710,7 +727,9 @@ static const struct file_operations ashmem_fops = {
.llseek = ashmem_llseek,
.mmap = ashmem_mmap,
.unlocked_ioctl = ashmem_ioctl,
.compat_ioctl = ashmem_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = compat_ashmem_ioctl,
#endif
};
static struct miscdevice ashmem_misc = {

View file

@ -14,6 +14,7 @@
#include <linux/limits.h>
#include <linux/ioctl.h>
#include <linux/compat.h>
#define ASHMEM_NAME_LEN 256
@ -45,4 +46,10 @@ struct ashmem_pin {
#define ASHMEM_GET_PIN_STATUS _IO(__ASHMEMIOC, 9)
#define ASHMEM_PURGE_ALL_CACHES _IO(__ASHMEMIOC, 10)
/* support of 32bit userspace on 64bit platforms */
#ifdef CONFIG_COMPAT
#define COMPAT_ASHMEM_SET_SIZE _IOW(__ASHMEMIOC, 3, compat_size_t)
#define COMPAT_ASHMEM_SET_PROT_MASK _IOW(__ASHMEMIOC, 5, unsigned int)
#endif
#endif /* _LINUX_ASHMEM_H */