Introduce a compat version of the struct mmc_ioc_cmd and struct mmc_ioc_multi_cmd. Also implement helper functions which convert between the native and compat versions of these two structs.

A subsequent patch will change the structs to enable it to support new architectures. On such architectures, the current struct layout must still be supported for compat tasks.

Signed-off-by: Akram Ahmad Akram.Ahmad@arm.com --- drivers/mmc/core/block.c | 96 +++++++++++++++++++++++++++++++++++++--- 1 file changed, 90 insertions(+), 6 deletions(-)

diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c index 2f8884e3d4c2..3333c4917028 100644 --- a/drivers/mmc/core/block.c +++ b/drivers/mmc/core/block.c @@ -101,6 +101,33 @@ struct mmc_blk_busy_data { u32 status; };

+static inline bool in_compat64(void) +{ + return IS_ENABLED(CONFIG_COMPAT64) && in_compat_syscall(); +} + +struct compat_mmc_ioc_cmd { + int write_flag; + int is_acmd; + __u32 opcode; + __u32 arg; + __u32 response[4]; + unsigned int flags; + unsigned int blksz; + unsigned int blocks; + unsigned int postsleep_min_us; + unsigned int postsleep_max_us; + unsigned int data_timeout_ns; + unsigned int cmd_timeout_ms; + __u32 __pad; + __u64 data_ptr; +}; + +struct compat_mmc_ioc_multi_cmd { + __u64 num_of_cmds; + struct compat_mmc_ioc_cmd cmds[]; +}; + /* * There is one mmc_blk_data per slot. */ @@ -401,6 +428,47 @@ struct mmc_blk_ioc_data { struct mmc_rpmb_data *rpmb; };

+/* + * Copy the data from a compat_mmc_ioc_cmd user pointer, src, + * to kernel space, storing it in native_cmd. Returns 0 for + * a successful copy. + */ +static int get_mmc_ioc_cmd_from_compat64(struct mmc_ioc_cmd *native_cmd, + void * __user src) +{ + struct compat_mmc_ioc_cmd compat_cmd; + + if (copy_from_user(&compat_cmd, src, sizeof(struct compat_mmc_ioc_cmd))) + return -EFAULT; + + native_cmd->arg = compat_cmd.arg; + native_cmd->is_acmd = compat_cmd.is_acmd; + native_cmd->opcode = compat_cmd.opcode; + native_cmd->arg = compat_cmd.arg; + memcpy(native_cmd->response, compat_cmd.response, sizeof(compat_cmd.response)); + native_cmd->flags = compat_cmd.flags; + native_cmd->blksz = compat_cmd.blksz; + native_cmd->blocks = compat_cmd.blocks; + native_cmd->postsleep_min_us = compat_cmd.postsleep_min_us; + native_cmd->postsleep_max_us = compat_cmd.postsleep_max_us; + native_cmd->data_timeout_ns = compat_cmd.data_timeout_ns; + native_cmd->cmd_timeout_ms = compat_cmd.cmd_timeout_ms; + native_cmd->__pad = compat_cmd.__pad; + native_cmd->data_ptr = compat_cmd.data_ptr; + + return 0; +} + +static int copy_mmc_ioc_cmd_from_user(struct mmc_ioc_cmd *to, void * __user src) +{ + if (in_compat64()) + return get_mmc_ioc_cmd_from_compat64(to, src); + + if (copy_from_user(to, src, sizeof(*to))) + return -EFAULT; + return 0; +} + static struct mmc_blk_ioc_data *mmc_blk_ioctl_copy_from_user( struct mmc_ioc_cmd __user *user) { @@ -413,7 +481,7 @@ static struct mmc_blk_ioc_data *mmc_blk_ioctl_copy_from_user( goto out; }

- if (copy_from_user(&idata->ic, user, sizeof(idata->ic))) { + if (copy_mmc_ioc_cmd_from_user(&idata->ic, user)) { err = -EFAULT; goto idata_err; } @@ -449,8 +517,11 @@ static int mmc_blk_ioctl_copy_to_user(struct mmc_ioc_cmd __user *ic_ptr, { struct mmc_ioc_cmd *ic = &idata->ic;

- if (copy_to_user(&(ic_ptr->response), ic->response, - sizeof(ic->response))) + __u32 __user *response_uptr = in_compat64() ? + &((struct compat_mmc_ioc_cmd __user *)ic_ptr)->response[0] : + &ic_ptr->response[0]; + + if (copy_to_user(response_uptr, ic->response, sizeof(ic->response))) return -EFAULT;

if (!idata->ic.write_flag) { @@ -666,12 +737,20 @@ static int mmc_blk_ioctl_cmd(struct mmc_blk_data *md, return ioc_err ? ioc_err : err; }

+static inline struct mmc_ioc_cmd __user *get_ith_mmc_ioc_cmd_uptr( + struct mmc_ioc_multi_cmd __user *user, + unsigned int i) +{ + if (in_compat64()) + return (struct mmc_ioc_cmd __user *)&((struct compat_mmc_ioc_multi_cmd __user *)user)->cmds[i]; + return &(user->cmds[i]); +} + static int mmc_blk_ioctl_multi_cmd(struct mmc_blk_data *md, struct mmc_ioc_multi_cmd __user *user, struct mmc_rpmb_data *rpmb) { struct mmc_blk_ioc_data **idata = NULL; - struct mmc_ioc_cmd __user *cmds = user->cmds; struct mmc_card *card; struct mmc_queue *mq; int err = 0, ioc_err = 0; @@ -679,6 +758,11 @@ static int mmc_blk_ioctl_multi_cmd(struct mmc_blk_data *md, unsigned int i, n; struct request *req;

+ /* + * Both native and compat64 versions of mmc_ioc_multi_cmd + * have num_of_cmds as the first field, so the offset does + * not need to be recalculated for compat64. + */ if (copy_from_user(&num_of_cmds, &user->num_of_cmds, sizeof(num_of_cmds))) return -EFAULT; @@ -695,7 +779,7 @@ static int mmc_blk_ioctl_multi_cmd(struct mmc_blk_data *md, return -ENOMEM;

for (i = 0; i < n; i++) { - idata[i] = mmc_blk_ioctl_copy_from_user(&cmds[i]); + idata[i] = mmc_blk_ioctl_copy_from_user(get_ith_mmc_ioc_cmd_uptr(user, i)); if (IS_ERR(idata[i])) { err = PTR_ERR(idata[i]); n = i; @@ -732,7 +816,7 @@ static int mmc_blk_ioctl_multi_cmd(struct mmc_blk_data *md,

/* copy to user if data and response */ for (i = 0; i < n && !err; i++) - err = mmc_blk_ioctl_copy_to_user(&cmds[i], idata[i]); + err = mmc_blk_ioctl_copy_to_user(get_ith_mmc_ioc_cmd_uptr(user, i), idata[i]);

blk_mq_free_request(req);