diff options
Diffstat (limited to 'drivers/gpio/gpiolib-cdev.c')
| -rw-r--r-- | drivers/gpio/gpiolib-cdev.c | 34 |
1 files changed, 30 insertions, 4 deletions
diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c index e6c9b78adfc2..fed5a3b2172f 100644 --- a/drivers/gpio/gpiolib-cdev.c +++ b/drivers/gpio/gpiolib-cdev.c @@ -423,6 +423,21 @@ static __poll_t lineevent_poll(struct file *file, return events; } +static ssize_t lineevent_get_size(void) +{ +#if defined(CONFIG_X86_64) && !defined(CONFIG_UML) + /* i386 has no padding after 'id' */ + if (in_ia32_syscall()) { + struct compat_gpioeevent_data { + compat_u64 timestamp; + u32 id; + }; + + return sizeof(struct compat_gpioeevent_data); + } +#endif + return sizeof(struct gpioevent_data); +} static ssize_t lineevent_read(struct file *file, char __user *buf, @@ -432,9 +447,20 @@ static ssize_t lineevent_read(struct file *file, struct lineevent_state *le = file->private_data; struct gpioevent_data ge; ssize_t bytes_read = 0; + ssize_t ge_size; int ret; - if (count < sizeof(ge)) + /* + * When compatible system call is being used the struct gpioevent_data, + * in case of at least ia32, has different size due to the alignment + * differences. Because we have first member 64 bits followed by one of + * 32 bits there is no gap between them. The only difference is the + * padding at the end of the data structure. Hence, we calculate the + * actual sizeof() and pass this as an argument to copy_to_user() to + * drop unneeded bytes from the output. + */ + ge_size = lineevent_get_size(); + if (count < ge_size) return -EINVAL; do { @@ -470,10 +496,10 @@ static ssize_t lineevent_read(struct file *file, break; } - if (copy_to_user(buf + bytes_read, &ge, sizeof(ge))) + if (copy_to_user(buf + bytes_read, &ge, ge_size)) return -EFAULT; - bytes_read += sizeof(ge); - } while (count >= bytes_read + sizeof(ge)); + bytes_read += ge_size; + } while (count >= bytes_read + ge_size); return bytes_read; } |