Re: [PATCH] ARM: qcom: Fix SCM interface for big-endian kernels

From: Kumar Gala
Date: Tue Sep 23 2014 - 12:48:09 EST



On Sep 22, 2014, at 5:36 PM, Stephen Boyd <sboyd@xxxxxxxxxxxxxx> wrote:

> The secure environment only runs in little-endian mode, so any
> buffers shared with the secure environment should have their
> contents converted to little-endian. We also mark such elements
> with __le32 to allow sparse to catch such problems.
>
> Signed-off-by: Stephen Boyd <sboyd@xxxxxxxxxxxxxx>
> ---
> drivers/soc/qcom/scm-boot.c | 8 ++++----
> drivers/soc/qcom/scm.c | 34 ++++++++++++++++++----------------
> 2 files changed, 22 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/soc/qcom/scm-boot.c b/drivers/soc/qcom/scm-boot.c
> index 60ff7b482141..3e4d77b371c6 100644
> --- a/drivers/soc/qcom/scm-boot.c
> +++ b/drivers/soc/qcom/scm-boot.c
> @@ -27,12 +27,12 @@
> int scm_set_boot_addr(phys_addr_t addr, int flags)
> {
> struct {
> - unsigned int flags;
> - phys_addr_t addr;
> + __le32 flags;
> + __le32 addr;

Hmm, was phys_addr_t wrong here before? I ask because don’t we support LPAE on some systems?

> } cmd;
>
> - cmd.addr = addr;
> - cmd.flags = flags;
> + cmd.addr = cpu_to_le32(addr);
> + cmd.flags = cpu_to_le32(flags);
> return scm_call(SCM_SVC_BOOT, SCM_BOOT_ADDR,
> &cmd, sizeof(cmd), NULL, 0);
> }
> diff --git a/drivers/soc/qcom/scm.c b/drivers/soc/qcom/scm.c
> index be1e2beec796..feeb4e4bb22d 100644
> --- a/drivers/soc/qcom/scm.c
> +++ b/drivers/soc/qcom/scm.c
> @@ -62,11 +62,11 @@ static DEFINE_MUTEX(scm_lock);
> * to access the buffers in a safe manner.
> */
> struct scm_command {
> - u32 len;
> - u32 buf_offset;
> - u32 resp_hdr_offset;
> - u32 id;
> - u32 buf[0];
> + __le32 len;
> + __le32 buf_offset;
> + __le32 resp_hdr_offset;
> + __le32 id;
> + __le32 buf[0];
> };
>
> /**
> @@ -76,9 +76,9 @@ struct scm_command {
> * @is_complete: indicates if the command has finished processing
> */
> struct scm_response {
> - u32 len;
> - u32 buf_offset;
> - u32 is_complete;
> + __le32 len;
> + __le32 buf_offset;
> + __le32 is_complete;
> };
>
> /**
> @@ -96,12 +96,14 @@ static struct scm_command *alloc_scm_command(size_t cmd_size, size_t resp_size)
> struct scm_command *cmd;
> size_t len = sizeof(*cmd) + sizeof(struct scm_response) + cmd_size +
> resp_size;
> + u32 offset;
>
> cmd = kzalloc(PAGE_ALIGN(len), GFP_KERNEL);
> if (cmd) {
> - cmd->len = len;
> - cmd->buf_offset = offsetof(struct scm_command, buf);
> - cmd->resp_hdr_offset = cmd->buf_offset + cmd_size;
> + cmd->len = cpu_to_le32(len);
> + offset = offsetof(struct scm_command, buf);
> + cmd->buf_offset = cpu_to_le32(offset);
> + cmd->resp_hdr_offset = cpu_to_le32(offset + cmd_size);
> }
> return cmd;
> }
> @@ -126,7 +128,7 @@ static inline void free_scm_command(struct scm_command *cmd)
> static inline struct scm_response *scm_command_to_response(
> const struct scm_command *cmd)
> {
> - return (void *)cmd + cmd->resp_hdr_offset;
> + return (void *)cmd + le32_to_cpu(cmd->resp_hdr_offset);
> }
>
> /**
> @@ -148,7 +150,7 @@ static inline void *scm_get_command_buffer(const struct scm_command *cmd)
> */
> static inline void *scm_get_response_buffer(const struct scm_response *rsp)
> {
> - return (void *)rsp + rsp->buf_offset;
> + return (void *)rsp + le32_to_cpu(rsp->buf_offset);
> }
>
> static int scm_remap_error(int err)
> @@ -201,8 +203,8 @@ static int __scm_call(const struct scm_command *cmd)
> * Flush the command buffer so that the secure world sees
> * the correct data.
> */
> - __cpuc_flush_dcache_area((void *)cmd, cmd->len);
> - outer_flush_range(cmd_addr, cmd_addr + cmd->len);
> + __cpuc_flush_dcache_area((void *)cmd, le32_to_cpu(cmd->len));
> + outer_flush_range(cmd_addr, cmd_addr + le32_to_cpu(cmd->len));
>
> ret = smc(cmd_addr);
> if (ret < 0)
> @@ -260,7 +262,7 @@ int scm_call(u32 svc_id, u32 cmd_id, const void *cmd_buf, size_t cmd_len,
> if (!cmd)
> return -ENOMEM;
>
> - cmd->id = (svc_id << 10) | cmd_id;
> + cmd->id = cpu_to_le32((svc_id << 10) | cmd_id);
> if (cmd_buf)
> memcpy(scm_get_command_buffer(cmd), cmd_buf, cmd_len);
>
> --
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> hosted by The Linux Foundation
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