Re: [PATCH 03/12] linux-user: Add support for getting/setting RTC periodic interrupt and epoch using ioctls

[Laurent Vivier <laurent@vivier.eu>]

Le 09/01/2020 à 13:59, Filip Bozuta a écrit :
> This patch implements functionalities of following ioctls:
> 
> RTC_IRQP_READ, RTC_IRQP_SET - Getting/Setting IRQ rate
> 
>     Read and set the frequency for periodic interrupts, for RTCs
>     that support periodic interrupts. The periodic interrupt must
>     be separately enabled or disabled using the RTC_PIE_ON,
>     RTC_PIE_OFF requests. The third ioctl's argument is an
>     unsigned long * or an unsigned long, respectively. The value
>     is the frequency in interrupts per second. The set of allow‐
>     able frequencies is the multiples of two in the range 2 to
>     8192. Only a privileged process (i.e., one having the
>     CAP_SYS_RESOURCE capability) can set frequencies above the
>     value specified in /proc/sys/dev/rtc/max-user-freq. (This
>     file contains the value 64 by default.)
> 
> RTC_EPOCH_READ, RTC_EPOCH_SET - Getting/Setting epoch
> 
>     Many RTCs encode the year in an 8-bit register which is either
>     interpreted as an 8-bit binary number or as a BCD number. In
>     both cases, the number is interpreted relative to this RTC's
>     Epoch. The RTC's Epoch is initialized to 1900 on most systems
>     but on Alpha and MIPS it might also be initialized to 1952,
>     1980, or 2000, depending on the value of an RTC register for
>     the year. With some RTCs, these operations can be used to
>     read or to set the RTC's Epoch, respectively. The third
>     ioctl's argument is an unsigned long * or an unsigned long,
>     respectively, and the value returned (or assigned) is the
>     Epoch. To set the RTC's Epoch the process must be privileged
>     (i.e., have the CAP_SYS_TIME capability).
> 
> Implementation notes:
> 
>     All ioctls in this patch have a pointer to 'ulong' as their
>     third argument. That is the reason why corresponding parts
>     of added code in linux-user/syscall_defs.h contain special
>     handling related to 'ulong' type: they use 'abi_ulong' type
>     to make sure that ioctl's code is calculated correctly for
>     both 32-bit and 64-bit targets. Also, 'MK_PTR(TYPE_ULONG)'
>     is used for the similar reason in linux-user/ioctls.h.
> 
> Signed-off-by: Filip Bozuta <Filip.Bozuta@rt-rk.com>
> ---
>  linux-user/ioctls.h       | 4 ++++
>  linux-user/syscall_defs.h | 4 ++++
>  2 files changed, 8 insertions(+)
> 
> diff --git a/linux-user/ioctls.h b/linux-user/ioctls.h
> index f472794..accbdee 100644
> --- a/linux-user/ioctls.h
> +++ b/linux-user/ioctls.h
> @@ -81,6 +81,10 @@
>       IOCTL(RTC_ALM_SET, IOC_W, MK_PTR(MK_STRUCT(STRUCT_rtc_time)))
>       IOCTL(RTC_RD_TIME, IOC_R, MK_PTR(MK_STRUCT(STRUCT_rtc_time)))
>       IOCTL(RTC_SET_TIME, IOC_W, MK_PTR(MK_STRUCT(STRUCT_rtc_time)))
> +     IOCTL(RTC_IRQP_READ, IOC_R, MK_PTR(TYPE_ULONG))
> +     IOCTL(RTC_IRQP_SET, IOC_W, TYPE_ULONG)
> +     IOCTL(RTC_EPOCH_READ, IOC_R, MK_PTR(TYPE_ULONG))
> +     IOCTL(RTC_EPOCH_SET, IOC_W, TYPE_ULONG)
>  
>       IOCTL(BLKROSET, IOC_W, MK_PTR(TYPE_INT))
>       IOCTL(BLKROGET, IOC_R, MK_PTR(TYPE_INT))
> diff --git a/linux-user/syscall_defs.h b/linux-user/syscall_defs.h
> index f0bf09d..bbfa935 100644
> --- a/linux-user/syscall_defs.h
> +++ b/linux-user/syscall_defs.h
> @@ -776,6 +776,10 @@ struct target_pollfd {
>  #define TARGET_RTC_ALM_SET          TARGET_IOW('p', 0x07, struct rtc_time)
>  #define TARGET_RTC_RD_TIME          TARGET_IOR('p', 0x09, struct rtc_time)
>  #define TARGET_RTC_SET_TIME         TARGET_IOW('p', 0x0a, struct rtc_time)
> +#define TARGET_RTC_IRQP_READ        TARGET_IOR('p', 0x0b, abi_ulong)
> +#define TARGET_RTC_IRQP_SET         TARGET_IOW('p', 0x0c, abi_ulong)
> +#define TARGET_RTC_EPOCH_READ       TARGET_IOR('p', 0x0d, abi_ulong)
> +#define TARGET_RTC_EPOCH_SET        TARGET_IOW('p', 0x0e, abi_ulong)
>  
>  #if defined(TARGET_ALPHA) || defined(TARGET_MIPS) || defined(TARGET_SH4) ||    \
>         defined(TARGET_XTENSA)
> 

Reviewed-by: Laurent Vivier <laurent@vivier.eu>