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Date: Fri, 1 Feb 2013 16:08:01 +0000
From: Serban Constantinescu <serban.constantinescu@....com>
To: linux-kernel@...r.kernel.org, gregkh@...uxfoundation.org,
kernel-team@...roid.com, arve@...roid.com, john.stultz@...aro.org,
Dave.Butcher@....com
Cc: Serban Constantinescu <serban.constantinescu@....com>
Subject: [PATCH 2/2] 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).
Signed-off-by: Serban Constantinescu <serban.constantinescu@....com>
---
drivers/staging/android/ashmem.c | 65 ++++++++++++++++++++++++++++++--------
drivers/staging/android/ashmem.h | 15 +++++++++
2 files changed, 66 insertions(+), 14 deletions(-)
diff --git a/drivers/staging/android/ashmem.c b/drivers/staging/android/ashmem.c
index aa52646..75b08a9 100644
--- a/drivers/staging/android/ashmem.c
+++ b/drivers/staging/android/ashmem.c
@@ -577,33 +577,29 @@ static int ashmem_get_pin_status(struct ashmem_area *asma, size_t pgstart,
}
static int ashmem_pin_unpin(struct ashmem_area *asma, unsigned long cmd,
- void __user *p)
+ struct ashmem_pin *pin)
{
- struct ashmem_pin pin;
size_t pgstart, pgend;
int ret = -EINVAL;
if (unlikely(!asma->file))
return -EINVAL;
- if (unlikely(copy_from_user(&pin, p, sizeof(pin))))
- return -EFAULT;
-
/* per custom, you can pass zero for len to mean "everything onward" */
- if (!pin.len)
- pin.len = PAGE_ALIGN(asma->size) - pin.offset;
+ if (!pin->len)
+ pin->len = PAGE_ALIGN(asma->size) - pin->offset;
- if (unlikely((pin.offset | pin.len) & ~PAGE_MASK))
+ if (unlikely((pin->offset | pin->len) & ~PAGE_MASK))
return -EINVAL;
- if (unlikely(((size_t) -1) - pin.offset < pin.len))
+ if (unlikely(((size_t) -1) - pin->offset < pin->len))
return -EINVAL;
- if (unlikely(PAGE_ALIGN(asma->size) < pin.offset + pin.len))
+ if (unlikely(PAGE_ALIGN(asma->size) < pin->offset + pin->len))
return -EINVAL;
- pgstart = pin.offset / PAGE_SIZE;
- pgend = pgstart + (pin.len / PAGE_SIZE) - 1;
+ pgstart = pin->offset / PAGE_SIZE;
+ pgend = pgstart + (pin->len / PAGE_SIZE) - 1;
mutex_lock(&ashmem_mutex);
@@ -627,6 +623,7 @@ static int ashmem_pin_unpin(struct ashmem_area *asma, unsigned long cmd,
static long ashmem_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
struct ashmem_area *asma = file->private_data;
+ struct ashmem_pin pin;
long ret = -ENOTTY;
switch (cmd) {
@@ -655,7 +652,9 @@ static long ashmem_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
case ASHMEM_PIN:
case ASHMEM_UNPIN:
case ASHMEM_GET_PIN_STATUS:
- ret = ashmem_pin_unpin(asma, cmd, (void __user *) arg);
+ if (unlikely(copy_from_user(&pin, (void __user *)arg, sizeof(pin))))
+ return -EFAULT;
+ ret = ashmem_pin_unpin(asma, cmd, &pin);
break;
case ASHMEM_PURGE_ALL_CACHES:
ret = -EPERM;
@@ -674,6 +673,42 @@ 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)
+{
+ struct compat_ashmem_pin c_pin;
+ struct ashmem_pin pin;
+
+ switch (cmd) {
+ case COMPAT_ASHMEM_SET_SIZE:
+ cmd = ASHMEM_SET_SIZE;
+ break;
+ case COMPAT_ASHMEM_SET_PROT_MASK:
+ cmd = ASHMEM_SET_PROT_MASK;
+ break;
+ case COMPAT_ASHMEM_PIN:
+ case COMPAT_ASHMEM_UNPIN:
+ case ASHMEM_GET_PIN_STATUS:
+ if (unlikely(copy_from_user(&c_pin, (void __user *)arg, sizeof(c_pin))))
+ return -EFAULT;
+ pin.offset = (size_t)c_pin.offset;
+ pin.len = (size_t)c_pin.len;
+ switch (cmd) {
+ case COMPAT_ASHMEM_PIN:
+ cmd = ASHMEM_PIN;
+ break;
+ case COMPAT_ASHMEM_UNPIN:
+ cmd = ASHMEM_UNPIN;
+ break;
+ }
+ return ashmem_pin_unpin(file->private_data, cmd, &pin);
+ }
+
+ return ashmem_ioctl(file, cmd, arg);
+}
+#endif /* CONFIG_COMPAT */
+
static const struct file_operations ashmem_fops = {
.owner = THIS_MODULE,
.open = ashmem_open,
@@ -682,7 +717,9 @@ 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 = {
diff --git a/drivers/staging/android/ashmem.h b/drivers/staging/android/ashmem.h
index c9b2eba..ff7328f 100644
--- a/drivers/staging/android/ashmem.h
+++ b/drivers/staging/android/ashmem.h
@@ -32,6 +32,13 @@ struct ashmem_pin {
size_t len; /* length forward from offset, in bytes, page-aligned */
};
+#ifdef CONFIG_COMPAT
+struct compat_ashmem_pin {
+ compat_size_t offset; /* offset into region, in bytes, page-aligned */
+ compat_size_t len; /* length forward from offset, in bytes, page-aligned */
+};
+#endif
+
#define __ASHMEMIOC 0x77
#define ASHMEM_SET_NAME _IOW(__ASHMEMIOC, 1, char[ASHMEM_NAME_LEN])
@@ -45,4 +52,12 @@ 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)
+#define COMPAT_ASHMEM_PIN _IOW(__ASHMEMIOC, 7, struct compat_ashmem_pin)
+#define COMPAT_ASHMEM_UNPIN _IOW(__ASHMEMIOC, 8, struct compat_ashmem_pin)
+#endif
+
#endif /* _LINUX_ASHMEM_H */
--
1.7.9.5
--
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