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Subject[PATCH v4] media: mtk-vpu: avoid unaligned access to DTCM buffer.
Date
media: mtk-vpu: avoid unaligned access to DTCM buffer.

Previously, vpu->recv_buf and send_buf are forced cast from
void __iomem *tcm. vpu->recv_buf->share_buf is passed to
vpu_ipi_desc.handler(). It's not able to do unaligned access. Otherwise
kernel would crash due to unable to handle kernel paging request.

struct vpu_run {
u32 signaled;
char fw_ver[VPU_FW_VER_LEN];
unsigned int dec_capability;
unsigned int enc_capability;
wait_queue_head_t wq;
};

fw_ver starts at 4 byte boundary. If system enables
CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS, strscpy() will do
read_word_at_a_time(), which tries to read 8-byte: *(unsigned long *)addr

vpu_init_ipi_handler() calls strscpy(), which would lead to crash.

vpu_init_ipi_handler() and several other handlers (eg.
vpu_dec_ipi_handler) only do read access to this data, so they can be
const, and we can use memcpy_fromio() to copy the buf to another non iomem
buffer then pass to handler.

Fixes: 85709cbf1524 ("media: replace strncpy() by strscpy()")
Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org>
---
Change in v4:
- Remove forced casting recv_buf from tcm. Copy iomem data before passing
to handler.
Change in v2, v3:
- fix sparse warnings.
---
drivers/media/platform/mtk-mdp/mtk_mdp_vpu.c | 9 ++--
.../media/platform/mtk-vcodec/vdec_vpu_if.c | 6 +--
.../media/platform/mtk-vcodec/venc_vpu_if.c | 12 ++---
drivers/media/platform/mtk-vpu/mtk_vpu.c | 45 ++++++++++---------
drivers/media/platform/mtk-vpu/mtk_vpu.h | 2 +-
5 files changed, 38 insertions(+), 36 deletions(-)

diff --git a/drivers/media/platform/mtk-mdp/mtk_mdp_vpu.c b/drivers/media/platform/mtk-mdp/mtk_mdp_vpu.c
index 6720d11f50cf..dc95b8a44759 100644
--- a/drivers/media/platform/mtk-mdp/mtk_mdp_vpu.c
+++ b/drivers/media/platform/mtk-mdp/mtk_mdp_vpu.c
@@ -15,7 +15,7 @@ static inline struct mtk_mdp_ctx *vpu_to_ctx(struct mtk_mdp_vpu *vpu)
return container_of(vpu, struct mtk_mdp_ctx, vpu);
}

-static void mtk_mdp_vpu_handle_init_ack(struct mdp_ipi_comm_ack *msg)
+static void mtk_mdp_vpu_handle_init_ack(const struct mdp_ipi_comm_ack *msg)
{
struct mtk_mdp_vpu *vpu = (struct mtk_mdp_vpu *)
(unsigned long)msg->ap_inst;
@@ -26,10 +26,11 @@ static void mtk_mdp_vpu_handle_init_ack(struct mdp_ipi_comm_ack *msg)
vpu->inst_addr = msg->vpu_inst_addr;
}

-static void mtk_mdp_vpu_ipi_handler(void *data, unsigned int len, void *priv)
+static void mtk_mdp_vpu_ipi_handler(const void *data, unsigned int len,
+ void *priv)
{
- unsigned int msg_id = *(unsigned int *)data;
- struct mdp_ipi_comm_ack *msg = (struct mdp_ipi_comm_ack *)data;
+ unsigned int msg_id = *(const unsigned int *)data;
+ const struct mdp_ipi_comm_ack *msg = data;
struct mtk_mdp_vpu *vpu = (struct mtk_mdp_vpu *)
(unsigned long)msg->ap_inst;
struct mtk_mdp_ctx *ctx;
diff --git a/drivers/media/platform/mtk-vcodec/vdec_vpu_if.c b/drivers/media/platform/mtk-vcodec/vdec_vpu_if.c
index 70abfd4cd4b9..948a12fd9d46 100644
--- a/drivers/media/platform/mtk-vcodec/vdec_vpu_if.c
+++ b/drivers/media/platform/mtk-vcodec/vdec_vpu_if.c
@@ -9,7 +9,7 @@
#include "vdec_ipi_msg.h"
#include "vdec_vpu_if.h"

-static void handle_init_ack_msg(struct vdec_vpu_ipi_init_ack *msg)
+static void handle_init_ack_msg(const struct vdec_vpu_ipi_init_ack *msg)
{
struct vdec_vpu_inst *vpu = (struct vdec_vpu_inst *)
(unsigned long)msg->ap_inst_addr;
@@ -34,9 +34,9 @@ static void handle_init_ack_msg(struct vdec_vpu_ipi_init_ack *msg)
* This function runs in interrupt context and it means there's an IPI MSG
* from VPU.
*/
-static void vpu_dec_ipi_handler(void *data, unsigned int len, void *priv)
+static void vpu_dec_ipi_handler(const void *data, unsigned int len, void *priv)
{
- struct vdec_vpu_ipi_ack *msg = data;
+ const struct vdec_vpu_ipi_ack *msg = data;
struct vdec_vpu_inst *vpu = (struct vdec_vpu_inst *)
(unsigned long)msg->ap_inst_addr;

diff --git a/drivers/media/platform/mtk-vcodec/venc_vpu_if.c b/drivers/media/platform/mtk-vcodec/venc_vpu_if.c
index 3e931b0ed096..9540709c1905 100644
--- a/drivers/media/platform/mtk-vcodec/venc_vpu_if.c
+++ b/drivers/media/platform/mtk-vcodec/venc_vpu_if.c
@@ -8,26 +8,26 @@
#include "venc_ipi_msg.h"
#include "venc_vpu_if.h"

-static void handle_enc_init_msg(struct venc_vpu_inst *vpu, void *data)
+static void handle_enc_init_msg(struct venc_vpu_inst *vpu, const void *data)
{
- struct venc_vpu_ipi_msg_init *msg = data;
+ const struct venc_vpu_ipi_msg_init *msg = data;

vpu->inst_addr = msg->vpu_inst_addr;
vpu->vsi = vpu_mapping_dm_addr(vpu->dev, msg->vpu_inst_addr);
}

-static void handle_enc_encode_msg(struct venc_vpu_inst *vpu, void *data)
+static void handle_enc_encode_msg(struct venc_vpu_inst *vpu, const void *data)
{
- struct venc_vpu_ipi_msg_enc *msg = data;
+ const struct venc_vpu_ipi_msg_enc *msg = data;

vpu->state = msg->state;
vpu->bs_size = msg->bs_size;
vpu->is_key_frm = msg->is_key_frm;
}

-static void vpu_enc_ipi_handler(void *data, unsigned int len, void *priv)
+static void vpu_enc_ipi_handler(const void *data, unsigned int len, void *priv)
{
- struct venc_vpu_ipi_msg_common *msg = data;
+ const struct venc_vpu_ipi_msg_common *msg = data;
struct venc_vpu_inst *vpu =
(struct venc_vpu_inst *)(unsigned long)msg->venc_inst;

diff --git a/drivers/media/platform/mtk-vpu/mtk_vpu.c b/drivers/media/platform/mtk-vpu/mtk_vpu.c
index a768707abb94..2fbccc9b247b 100644
--- a/drivers/media/platform/mtk-vpu/mtk_vpu.c
+++ b/drivers/media/platform/mtk-vpu/mtk_vpu.c
@@ -203,8 +203,8 @@ struct mtk_vpu {
struct vpu_run run;
struct vpu_wdt wdt;
struct vpu_ipi_desc ipi_desc[IPI_MAX];
- struct share_obj *recv_buf;
- struct share_obj *send_buf;
+ struct share_obj __iomem *recv_buf;
+ struct share_obj __iomem *send_buf;
struct device *dev;
struct clk *clk;
bool fw_loaded;
@@ -292,7 +292,7 @@ int vpu_ipi_send(struct platform_device *pdev,
unsigned int len)
{
struct mtk_vpu *vpu = platform_get_drvdata(pdev);
- struct share_obj *send_obj = vpu->send_buf;
+ struct share_obj __iomem *send_obj = vpu->send_buf;
unsigned long timeout;
int ret = 0;

@@ -325,9 +325,9 @@ int vpu_ipi_send(struct platform_device *pdev,
}
} while (vpu_cfg_readl(vpu, HOST_TO_VPU));

- memcpy((void *)send_obj->share_buf, buf, len);
- send_obj->len = len;
- send_obj->id = id;
+ memcpy_toio(send_obj->share_buf, buf, len);
+ writel(len, &send_obj->len);
+ writel(id, &send_obj->id);

vpu->ipi_id_ack[id] = false;
/* send the command to VPU */
@@ -600,10 +600,10 @@ int vpu_load_firmware(struct platform_device *pdev)
}
EXPORT_SYMBOL_GPL(vpu_load_firmware);

-static void vpu_init_ipi_handler(void *data, unsigned int len, void *priv)
+static void vpu_init_ipi_handler(const void *data, unsigned int len, void *priv)
{
- struct mtk_vpu *vpu = (struct mtk_vpu *)priv;
- struct vpu_run *run = (struct vpu_run *)data;
+ struct mtk_vpu *vpu = priv;
+ const struct vpu_run *run = data;

vpu->run.signaled = run->signaled;
strscpy(vpu->run.fw_ver, run->fw_ver, sizeof(vpu->run.fw_ver));
@@ -700,19 +700,21 @@ static int vpu_alloc_ext_mem(struct mtk_vpu *vpu, u32 fw_type)

static void vpu_ipi_handler(struct mtk_vpu *vpu)
{
- struct share_obj *rcv_obj = vpu->recv_buf;
+ struct share_obj __iomem *rcv_obj = vpu->recv_buf;
struct vpu_ipi_desc *ipi_desc = vpu->ipi_desc;
-
- if (rcv_obj->id < IPI_MAX && ipi_desc[rcv_obj->id].handler) {
- ipi_desc[rcv_obj->id].handler(rcv_obj->share_buf,
- rcv_obj->len,
- ipi_desc[rcv_obj->id].priv);
- if (rcv_obj->id > IPI_VPU_INIT) {
- vpu->ipi_id_ack[rcv_obj->id] = true;
+ unsigned char data[SHARE_BUF_SIZE];
+ s32 id = readl(&rcv_obj->id);
+
+ memcpy_fromio(data, rcv_obj->share_buf, sizeof(data));
+ if (id < IPI_MAX && ipi_desc[id].handler) {
+ ipi_desc[id].handler(data, readl(&rcv_obj->len),
+ ipi_desc[id].priv);
+ if (id > IPI_VPU_INIT) {
+ vpu->ipi_id_ack[id] = true;
wake_up(&vpu->ack_wq);
}
} else {
- dev_err(vpu->dev, "No such ipi id = %d\n", rcv_obj->id);
+ dev_err(vpu->dev, "No such ipi id = %d\n", id);
}
}

@@ -722,11 +724,10 @@ static int vpu_ipi_init(struct mtk_vpu *vpu)
vpu_cfg_writel(vpu, 0x0, VPU_TO_HOST);

/* shared buffer initialization */
- vpu->recv_buf = (__force struct share_obj *)(vpu->reg.tcm +
- VPU_DTCM_OFFSET);
+ vpu->recv_buf = vpu->reg.tcm + VPU_DTCM_OFFSET;
vpu->send_buf = vpu->recv_buf + 1;
- memset(vpu->recv_buf, 0, sizeof(struct share_obj));
- memset(vpu->send_buf, 0, sizeof(struct share_obj));
+ memset_io(vpu->recv_buf, 0, sizeof(struct share_obj));
+ memset_io(vpu->send_buf, 0, sizeof(struct share_obj));

return 0;
}
diff --git a/drivers/media/platform/mtk-vpu/mtk_vpu.h b/drivers/media/platform/mtk-vpu/mtk_vpu.h
index d4453b4bcee9..ee7c552ce928 100644
--- a/drivers/media/platform/mtk-vpu/mtk_vpu.h
+++ b/drivers/media/platform/mtk-vpu/mtk_vpu.h
@@ -15,7 +15,7 @@
* VPU interfaces with other blocks by share memory and interrupt.
**/

-typedef void (*ipi_handler_t) (void *data,
+typedef void (*ipi_handler_t) (const void *data,
unsigned int len,
void *priv);

--
2.25.0.265.gbab2e86ba0-goog
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