diff mbox series

[v2,6/6] misc: fastrpc: Add support for compat ioctls

Message ID 20181207163513.16412-7-srinivas.kandagatla@linaro.org
State New
Headers show
Series misc: Add support to Qualcomm FastRPC driver | expand

Commit Message

Srinivas Kandagatla Dec. 7, 2018, 4:35 p.m. UTC 
This patch adds support for compat ioctl from 32 bits userland to
Qualcomm fastrpc driver.

Supported ioctls in this change are INIT, INVOKE, and ALLOC/FREE_DMA.

Most of the work is derived from various downstream Qualcomm kernels.
Credits to various Qualcomm authors who have contributed to this code.
Specially Tharun Kumar Merugu <mtharu@codeaurora.org>

Co-developed-by: Thierry Escande <thierry.escande@linaro.org>
Signed-off-by: Thierry Escande <thierry.escande@linaro.org>

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>

---
 drivers/misc/fastrpc.c | 71 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 71 insertions(+)

-- 
2.19.2

Comments

Greg KH Dec. 12, 2018, 10:59 a.m. UTC | #1 
On Fri, Dec 07, 2018 at 04:35:13PM +0000, Srinivas Kandagatla wrote:
> This patch adds support for compat ioctl from 32 bits userland to

> Qualcomm fastrpc driver.


Ick, why?

Why not just fix up your ioctl structures to not need that at all?  For
new code being added to the kernel, there's no excuse to have to have
compat structures anymore, just make your api sane and all should be
fine.

What prevents you from doing that and requiring compat support?

thanks,

greg k-h
diff mbox series

Patch

diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
index 5ea2bba1e4bd..f36657263183 100644
--- a/drivers/misc/fastrpc.c
+++ b/drivers/misc/fastrpc.c
@@ -2,6 +2,7 @@ 
 // Copyright (c) 2011-2018, The Linux Foundation. All rights reserved.
 // Copyright (c) 2018, Linaro Limited
 
+#include <linux/compat.h>
 #include <linux/completion.h>
 #include <linux/device.h>
 #include <linux/dma-buf.h>
@@ -194,6 +195,22 @@  struct fastrpc_user {
 	struct mutex mutex;
 };
 
+#ifdef CONFIG_COMPAT
+
+#define FASTRPC_IOCTL_INVOKE32		_IOWR('R', 3, struct fastrpc_invoke32)
+struct fastrpc_invoke_args32 {
+	__s32 fd;
+	compat_size_t length;
+	compat_caddr_t ptr;
+};
+
+struct fastrpc_invoke32 {
+	__u32 handle;
+	__u32 sc;
+	compat_uptr_t args;
+};
+#endif
+
 static void fastrpc_free_map(struct kref *ref)
 {
 	struct fastrpc_map *map;
@@ -1092,6 +1109,52 @@  static long fastrpc_invoke(struct fastrpc_user *fl, char __user *argp)
 	return err;
 }
 
+#ifdef CONFIG_COMPAT
+static long fastrpc_invoke32(struct fastrpc_user *fl, compat_uptr_t arg)
+{
+	struct fastrpc_invoke_args32 *args32 = NULL;
+	struct fastrpc_invoke_args *args = NULL;
+	struct fastrpc_invoke32 inv32;
+	struct fastrpc_invoke inv;
+	int i, ret, nscalars;
+
+	if (copy_from_user(&inv32, compat_ptr(arg), sizeof(inv32)))
+		return -EFAULT;
+
+	inv.handle = inv32.handle;
+	inv.sc = inv32.sc;
+	inv.args = NULL;
+	nscalars = REMOTE_SCALARS_LENGTH(inv.sc);
+
+	if (nscalars) {
+		args32 = kcalloc(nscalars, sizeof(*args32), GFP_KERNEL);
+		if (!args32)
+			return -ENOMEM;
+
+		if (copy_from_user(args32, compat_ptr(inv32.args),
+				   nscalars * sizeof(*args32)))
+			return -EFAULT;
+
+		args = kcalloc(nscalars, sizeof(*args), GFP_KERNEL);
+		if (!args)
+			return -ENOMEM;
+
+		for (i = 0; i < nscalars; i++) {
+			args[i].length = args32[i].length;
+			args[i].ptr = (void *)(unsigned long)args32[i].ptr;
+			args[i].fd = args32[i].fd;
+		}
+		inv.args = &args[0];
+	}
+
+	ret = fastrpc_internal_invoke(fl, 0, &inv);
+	kfree(args32);
+	kfree(args);
+
+	return ret;
+}
+#endif
+
 static long fastrpc_device_ioctl(struct file *file, unsigned int cmd,
 				 unsigned long arg)
 {
@@ -1103,6 +1166,11 @@  static long fastrpc_device_ioctl(struct file *file, unsigned int cmd,
 	case FASTRPC_IOCTL_INVOKE:
 		err = fastrpc_invoke(fl, argp);
 		break;
+#ifdef CONFIG_COMPAT
+	case FASTRPC_IOCTL_INVOKE32:
+		err = fastrpc_invoke32(fl, ptr_to_compat(argp));
+		break;
+#endif
 	case FASTRPC_IOCTL_INIT_ATTACH:
 		err = fastrpc_init_attach(fl);
 		break;
@@ -1131,6 +1199,9 @@  static const struct file_operations fastrpc_fops = {
 	.open = fastrpc_device_open,
 	.release = fastrpc_device_release,
 	.unlocked_ioctl = fastrpc_device_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl = fastrpc_device_ioctl,
+#endif
 };
 
 static int fastrpc_cb_probe(struct platform_device *pdev)