Received-SPF: pass (google.com: domain of linux-wireless-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Jernej Skrabec <jernej.skrabec@gmail.com>
To:     pizza@shaftnet.org
Cc:     ulf.hansson@linaro.org, arnd@arndb.de, kvalo@codeaurora.org,
        davem@davemloft.net, kuba@kernel.org,
        linux-wireless@vger.kernel.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Jernej Skrabec <jernej.skrabec@gmail.com>
Subject: [RFC PATCH] cw1200: use kmalloc() allocation instead of stack
Date:   Tue, 22 Jun 2021 22:23:45 +0200
Message-Id: <20210622202345.795578-1-jernej.skrabec@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

It turns out that if CONFIG_VMAP_STACK is enabled and src or dst is
memory allocated on stack, SDIO operations fail due to invalid memory
address conversion:

cw1200_wlan_sdio: Probe called
sunxi-mmc 4021000.mmc: DMA addr 0x0000800051eab954+4 overflow (mask ffffffff, bus limit 0).
WARNING: CPU: 2 PID: 152 at kernel/dma/direct.h:97 dma_direct_map_sg+0x26c/0x28c
CPU: 2 PID: 152 Comm: kworker/2:2 Not tainted 5.13.0-rc1-00026-g84114ef026b9-dirty #85
Hardware name: X96 Mate (DT)
Workqueue: events_freezable mmc_rescan
pstate: 60000005 (nZCv daif -PAN -UAO -TCO BTYPE=--)
pc : dma_direct_map_sg+0x26c/0x28c
lr : dma_direct_map_sg+0x26c/0x28c
sp : ffff800011eab540
x29: ffff800011eab540 x28: ffff800011eab738 x27: 0000000000000000
x26: ffff000001daf010 x25: 0000000000000000 x24: 0000000000000000
x23: 0000000000000002 x22: fffffc0000000000 x21: ffff8000113b0ab0
x20: ffff80001181abb0 x19: 0000000000000001 x18: ffffffffffffffff
x17: 00000000fa97f83f x16: 00000000d2e01bf8 x15: ffff8000117ffb1d
x14: ffffffffffffffff x13: ffff8000117ffb18 x12: fffffffffffc593f
x11: ffff800011676ad0 x10: fffffffffffe0000 x9 : ffff800011eab540
x8 : 206b73616d282077 x7 : 000000000000000f x6 : 000000000000000c
x5 : 0000000000000000 x4 : 0000000000000000 x3 : 00000000ffffffff
x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff00000283b800
Call trace:
 dma_direct_map_sg+0x26c/0x28c
 dma_map_sg_attrs+0x2c/0x60
 sunxi_mmc_request+0x70/0x420
 __mmc_start_request+0x68/0x134
 mmc_start_request+0x84/0xac
 mmc_wait_for_req+0x70/0x100
 mmc_io_rw_extended+0x1cc/0x2c0
 sdio_io_rw_ext_helper+0x194/0x240
 sdio_memcpy_fromio+0x20/0x2c
 cw1200_sdio_memcpy_fromio+0x20/0x2c
 __cw1200_reg_read+0x34/0x60
 cw1200_reg_read+0x48/0x70
 cw1200_load_firmware+0x38/0x5d0
 cw1200_core_probe+0x794/0x970
 cw1200_sdio_probe+0x124/0x22c
 sdio_bus_probe+0xe8/0x1d0
 really_probe+0xe4/0x504
 driver_probe_device+0x64/0xcc
 __device_attach_driver+0xd0/0x14c
 bus_for_each_drv+0x78/0xd0
 __device_attach+0xdc/0x184
 device_initial_probe+0x14/0x20
 bus_probe_device+0x9c/0xa4
 device_add+0x350/0x83c
 sdio_add_func+0x6c/0x90
 mmc_attach_sdio+0x1b0/0x430
 mmc_rescan+0x254/0x2e0
 process_one_work+0x1d0/0x34c
 worker_thread+0x13c/0x470
 kthread+0x154/0x160
 ret_from_fork+0x10/0x34
sunxi-mmc 4021000.mmc: dma_map_sg failed
sunxi-mmc 4021000.mmc: map DMA failed
Can't read config register.

Fix that by using kmalloc() allocated memory for read/write 16/32
funtions.

Signed-off-by: Jernej Skrabec <jernej.skrabec@gmail.com>
---
 drivers/net/wireless/st/cw1200/hwio.c | 52 +++++++++++++++++++++------
 drivers/net/wireless/st/cw1200/hwio.h | 51 ++++++++++++++++++++------
 2 files changed, 83 insertions(+), 20 deletions(-)

diff --git a/drivers/net/wireless/st/cw1200/hwio.c b/drivers/net/wireless/st/cw1200/hwio.c
index 3ba462de8e91..5521cb7f2233 100644
--- a/drivers/net/wireless/st/cw1200/hwio.c
+++ b/drivers/net/wireless/st/cw1200/hwio.c
@@ -66,33 +66,65 @@ static int __cw1200_reg_write(struct cw1200_common *priv, u16 addr,
 static inline int __cw1200_reg_read_32(struct cw1200_common *priv,
 					u16 addr, u32 *val)
 {
-	__le32 tmp;
-	int i = __cw1200_reg_read(priv, addr, &tmp, sizeof(tmp), 0);
-	*val = le32_to_cpu(tmp);
+	__le32 *tmp;
+	int i;
+
+	tmp = kmalloc(sizeof(*tmp), GFP_KERNEL);
+	if (!tmp)
+		return -ENOMEM;
+
+	i = __cw1200_reg_read(priv, addr, tmp, sizeof(*tmp), 0);
+	*val = le32_to_cpu(*tmp);
+	kfree(tmp);
 	return i;
 }
 
 static inline int __cw1200_reg_write_32(struct cw1200_common *priv,
 					u16 addr, u32 val)
 {
-	__le32 tmp = cpu_to_le32(val);
-	return __cw1200_reg_write(priv, addr, &tmp, sizeof(tmp), 0);
+	__le32 *tmp;
+	int i;
+
+	tmp = kmalloc(sizeof(*tmp), GFP_KERNEL);
+	if (!tmp)
+		return -ENOMEM;
+
+	*tmp = cpu_to_le32(val);
+	i = __cw1200_reg_write(priv, addr, tmp, sizeof(*tmp), 0);
+	kfree(tmp);
+	return i;
 }
 
 static inline int __cw1200_reg_read_16(struct cw1200_common *priv,
 					u16 addr, u16 *val)
 {
-	__le16 tmp;
-	int i = __cw1200_reg_read(priv, addr, &tmp, sizeof(tmp), 0);
-	*val = le16_to_cpu(tmp);
+	__le16 *tmp;
+	int i;
+
+	tmp = kmalloc(sizeof(*tmp), GFP_KERNEL);
+	if (!tmp)
+		return -ENOMEM;
+
+	i = __cw1200_reg_read(priv, addr, tmp, sizeof(*tmp), 0);
+	*val = le16_to_cpu(*tmp);
+	kfree(tmp);
 	return i;
 }
 
 static inline int __cw1200_reg_write_16(struct cw1200_common *priv,
 					u16 addr, u16 val)
 {
-	__le16 tmp = cpu_to_le16(val);
-	return __cw1200_reg_write(priv, addr, &tmp, sizeof(tmp), 0);
+	__le16 *tmp;
+	int i;
+
+	tmp = kmalloc(sizeof(*tmp), GFP_KERNEL);
+	if (!tmp)
+		return -ENOMEM;
+
+	*tmp = cpu_to_le16(val);
+	i = __cw1200_reg_write(priv, addr, tmp, sizeof(*tmp), 0);
+	kfree(tmp);
+	return i;
 }
 
 int cw1200_reg_read(struct cw1200_common *priv, u16 addr, void *buf,
diff --git a/drivers/net/wireless/st/cw1200/hwio.h b/drivers/net/wireless/st/cw1200/hwio.h
index d1e629a566c2..088d2a1bacc0 100644
--- a/drivers/net/wireless/st/cw1200/hwio.h
+++ b/drivers/net/wireless/st/cw1200/hwio.h
@@ -166,34 +166,65 @@ int cw1200_reg_write(struct cw1200_common *priv, u16 addr,
 static inline int cw1200_reg_read_16(struct cw1200_common *priv,
 				     u16 addr, u16 *val)
 {
-	__le32 tmp;
+	__le32 *tmp;
 	int i;
-	i = cw1200_reg_read(priv, addr, &tmp, sizeof(tmp));
-	*val = le32_to_cpu(tmp) & 0xfffff;
+
+	tmp = kmalloc(sizeof(*tmp), GFP_KERNEL);
+	if (!tmp)
+		return -ENOMEM;
+
+	i = cw1200_reg_read(priv, addr, tmp, sizeof(*tmp));
+	*val = le32_to_cpu(*tmp) & 0xfffff;
+	kfree(tmp);
 	return i;
 }
 
 static inline int cw1200_reg_write_16(struct cw1200_common *priv,
 				      u16 addr, u16 val)
 {
-	__le32 tmp = cpu_to_le32((u32)val);
-	return cw1200_reg_write(priv, addr, &tmp, sizeof(tmp));
+	__le32 *tmp;
+	int i;
+
+	tmp = kmalloc(sizeof(*tmp), GFP_KERNEL);
+	if (!tmp)
+		return -ENOMEM;
+
+	*tmp = cpu_to_le32((u32)val);
+	i = cw1200_reg_write(priv, addr, tmp, sizeof(*tmp));
+	kfree(tmp);
+	return i;
 }
 
 static inline int cw1200_reg_read_32(struct cw1200_common *priv,
 				     u16 addr, u32 *val)
 {
-	__le32 tmp;
-	int i = cw1200_reg_read(priv, addr, &tmp, sizeof(tmp));
-	*val = le32_to_cpu(tmp);
+	__le32 *tmp;
+	int i;
+
+	tmp = kmalloc(sizeof(*tmp), GFP_KERNEL);
+	if (!tmp)
+		return -ENOMEM;
+
+	i = cw1200_reg_read(priv, addr, tmp, sizeof(*tmp));
+	*val = le32_to_cpu(*tmp);
+	kfree(tmp);
 	return i;
 }
 
 static inline int cw1200_reg_write_32(struct cw1200_common *priv,
 				      u16 addr, u32 val)
 {
-	__le32 tmp = cpu_to_le32(val);
-	return cw1200_reg_write(priv, addr, &tmp, sizeof(val));
+	__le32 *tmp;
+	int i;
+
+	tmp = kmalloc(sizeof(*tmp), GFP_KERNEL);
+	if (!tmp)
+		return -ENOMEM;
+
+	*tmp = cpu_to_le32(val);
+	i = cw1200_reg_write(priv, addr, tmp, sizeof(val));
+	kfree(tmp);
+	return i;
 }
 
 int cw1200_indirect_read(struct cw1200_common *priv, u32 addr, void *buf,
-- 
2.32.0