Re: [RFC PATCH V3 01/43] rv64ilp32_abi: uapi: Reuse lp64 ABI interface

Jan Engelhardt
2025-03-25T20:31:01Z

On Tuesday 2025-03-25 13:15, guoren@kernel.org wrote:

>diff --git a/include/uapi/linux/netfilter/x_tables.h b/include/uapi/linux/netfilter/x_tables.h
>index 796af83a963a..7e02e34c6fad 100644
>--- a/include/uapi/linux/netfilter/x_tables.h
>+++ b/include/uapi/linux/netfilter/x_tables.h
>@@ -18,7 +18,11 @@ struct xt_entry_match {
> __u8 revision;
> } user;
> struct {
>+#if __riscv_xlen == 64
>+ __u64 match_size;
>+#else
> __u16 match_size;
>+#endif
>
> /* Used inside the kernel */
> struct xt_match *match;

The __u16 is the common prefix of the union which is exposed to userspace.
If anything, you need to use __attribute__((aligned(8))) to move
`match` to a fixed location.

However, that sub-struct is only used inside the kernel and never exposed,
so the alignment of `match` should not play a role.

Moreover, change from u16 to u64 would break RISC-V Big-Endian. Even if there
currently is no big-endian variant, let's not introduce such breakage.

>--- a/include/uapi/linux/netfilter_ipv4/ip_tables.h
>+++ b/include/uapi/linux/netfilter_ipv4/ip_tables.h
>@@ -200,7 +200,14 @@ struct ipt_replace {
> /* Number of counters (must be equal to current number of entries). */
> unsigned int num_counters;
> /* The old entries' counters. */
>+#if __riscv_xlen == 64
>+ union {
>+ struct xt_counters __user *counters;
>+ __u64 __counters;
>+ };
>+#else
> struct xt_counters __user *counters;
>+#endif
>
> /* The entries (hang off end: not really an array). */
> struct ipt_entry entries[];

This seems ok, but perhaps there is a better name for __riscv_xlen (ifdef
CONFIG_????ilp32), so it is not strictly tied to riscv,
in case other platform wants to try ilp32-self mode.

>+#if __riscv_xlen == 64
>+ union {
>+ int __user *auth_flavours; /* 1 */
>+ __u64 __auth_flavours;
>+ };
>+#else
> int __user *auth_flavours; /* 1 */
>+#endif
> };
>
> /* bits in the flags field */
>diff --git a/include/uapi/linux/ppp-ioctl.h b/include/uapi/linux/ppp-ioctl.h
>index 1cc5ce0ae062..8d48eab430c1 100644
>--- a/include/uapi/linux/ppp-ioctl.h
>+++ b/include/uapi/linux/ppp-ioctl.h
>@@ -59,7 +59,14 @@ struct npioctl {
>
> /* Structure describing a CCP configuration option, for PPPIOCSCOMPRESS */
> struct ppp_option_data {
>+#if __riscv_xlen == 64
>+ union {
>+ __u8 __user *ptr;
>+ __u64 __ptr;
>+ };
>+#else
> __u8 __user *ptr;
>+#endif
> __u32 length;
> int transmit;
> };
>diff --git a/include/uapi/linux/sctp.h b/include/uapi/linux/sctp.h
>index b7d91d4cf0db..46a06fddcd2f 100644
>--- a/include/uapi/linux/sctp.h
>+++ b/include/uapi/linux/sctp.h
>@@ -1024,6 +1024,9 @@ struct sctp_getaddrs_old {
> #else
> struct sockaddr *addrs;
> #endif
>+#if (__riscv_xlen == 64) && (__SIZEOF_LONG__ == 4)
>+ __u32 unused;
>+#endif
> };

>
> struct sctp_getaddrs {
>diff --git a/include/uapi/linux/sem.h b/include/uapi/linux/sem.h
>index 75aa3b273cd9..de9f441913cd 100644
>--- a/include/uapi/linux/sem.h
>+++ b/include/uapi/linux/sem.h
>@@ -26,10 +26,29 @@ struct semid_ds {
> struct ipc_perm sem_perm; /* permissions .. see ipc.h */
> __kernel_old_time_t sem_otime; /* last semop time */
> __kernel_old_time_t sem_ctime; /* create/last semctl() time */
>+#if __riscv_xlen == 64
>+ union {
>+ struct sem *sem_base; /* ptr to first semaphore in array */
>+ __u64 __sem_base;
>+ };
>+ union {
>+ struct sem_queue *sem_pending; /* pending operations to be processed */
>+ __u64 __sem_pending;
>+ };
>+ union {
>+ struct sem_queue **sem_pending_last; /* last pending operation */
>+ __u64 __sem_pending_last;
>+ };
>+ union {
>+ struct sem_undo *undo; /* undo requests on this array */
>+ __u64 __undo;
>+ };
>+#else
> struct sem *sem_base; /* ptr to first semaphore in array */
> struct sem_queue *sem_pending; /* pending operations to be processed */
> struct sem_queue **sem_pending_last; /* last pending operation */
> struct sem_undo *undo; /* undo requests on this array */
>+#endif
> unsigned short sem_nsems; /* no. of semaphores in array */
> };
>
>@@ -46,10 +65,29 @@ struct sembuf {
> /* arg for semctl system calls. */
> union semun {
> int val; /* value for SETVAL */
>+#if __riscv_xlen == 64
>+ union {
>+ struct semid_ds __user *buf; /* buffer for IPC_STAT & IPC_SET */
>+ __u64 ___buf;
>+ };
>+ union {
>+ unsigned short __user *array; /* array for GETALL & SETALL */
>+ __u64 __array;
>+ };
>+ union {
>+ struct seminfo __user *__buf; /* buffer for IPC_INFO */
>+ __u64 ____buf;
>+ };
>+ union {
>+ void __user *__pad;
>+ __u64 ____pad;
>+ };
>+#else
> struct semid_ds __user *buf; /* buffer for IPC_STAT & IPC_SET */
> unsigned short __user *array; /* array for GETALL & SETALL */
> struct seminfo __user *__buf; /* buffer for IPC_INFO */
> void __user *__pad;
>+#endif
> };
>
> struct seminfo {
>diff --git a/include/uapi/linux/socket.h b/include/uapi/linux/socket.h
>index d3fcd3b5ec53..5f7a83649395 100644
>--- a/include/uapi/linux/socket.h
>+++ b/include/uapi/linux/socket.h
>@@ -22,7 +22,14 @@ struct __kernel_sockaddr_storage {
> /* space to achieve desired size, */
> /* _SS_MAXSIZE value minus size of ss_family */
> };
>+#if __riscv_xlen == 64
>+ union {
>+ void *__align; /* implementation specific desired alignment */
>+ u64 ___align;
>+ };
>+#else
> void *__align; /* implementation specific desired alignment */
>+#endif
> };
> };
>
>diff --git a/include/uapi/linux/sysctl.h b/include/uapi/linux/sysctl.h
>index 8981f00204db..8ed7b29897f9 100644
>--- a/include/uapi/linux/sysctl.h
>+++ b/include/uapi/linux/sysctl.h
>@@ -33,13 +33,45 @@
> member of a struct __sysctl_args to have? */
>
> struct __sysctl_args {
>+#if __riscv_xlen == 64
>+ union {
>+ int __user *name;
>+ __u64 __name;
>+ };
>+#else
> int __user *name;
>+#endif
> int nlen;
>+#if __riscv_xlen == 64
>+ union {
>+ void __user *oldval;
>+ __u64 __oldval;
>+ };
>+#else
> void __user *oldval;
>+#endif
>+#if __riscv_xlen == 64
>+ union {
>+ size_t __user *oldlenp;
>+ __u64 __oldlenp;
>+ };
>+#else
> size_t __user *oldlenp;
>+#endif
>+#if __riscv_xlen == 64
>+ union {
>+ void __user *newval;
>+ __u64 __newval;
>+ };
>+#else
> void __user *newval;
>+#endif
> size_t newlen;
>+#if __riscv_xlen == 64
>+ unsigned long long __unused[4];
>+#else
> unsigned long __unused[4];
>+#endif
> };
>
> /* Define sysctl names first */
>diff --git a/include/uapi/linux/uhid.h b/include/uapi/linux/uhid.h
>index cef7534d2d19..4a774dbd3de8 100644
>--- a/include/uapi/linux/uhid.h
>+++ b/include/uapi/linux/uhid.h
>@@ -130,7 +130,14 @@ struct uhid_create_req {
> __u8 name[128];
> __u8 phys[64];
> __u8 uniq[64];
>+#if __riscv_xlen == 64
>+ union {
>+ __u8 __user *rd_data;
>+ __u64 __rd_data;
>+ };
>+#else
> __u8 __user *rd_data;
>+#endif
> __u16 rd_size;
>
> __u16 bus;
>diff --git a/include/uapi/linux/uio.h b/include/uapi/linux/uio.h
>index 649739e0c404..27dfd6032dc6 100644
>--- a/include/uapi/linux/uio.h
>+++ b/include/uapi/linux/uio.h
>@@ -16,8 +16,19 @@
>
> struct iovec
> {
>+#if __riscv_xlen == 64
>+ union {
>+ void __user *iov_base; /* BSD uses caddr_t (1003.1g requires void *) */
>+ __u64 __iov_base;
>+ };
>+ union {
>+ __kernel_size_t iov_len; /* Must be size_t (1003.1g) */
>+ __u64 __iov_len;
>+ };
>+#else
> void __user *iov_base; /* BSD uses caddr_t (1003.1g requires void *) */
> __kernel_size_t iov_len; /* Must be size_t (1003.1g) */
>+#endif
> };
>
> struct dmabuf_cmsg {
>diff --git a/include/uapi/linux/usb/tmc.h b/include/uapi/linux/usb/tmc.h
>index d791cc58a7f0..443ec5356caf 100644
>--- a/include/uapi/linux/usb/tmc.h
>+++ b/include/uapi/linux/usb/tmc.h
>@@ -51,7 +51,14 @@ struct usbtmc_request {
>
> struct usbtmc_ctrlrequest {
> struct usbtmc_request req;
>+#if __riscv_xlen == 64
>+ union {
>+ void __user *data; /* pointer to user space */
>+ __u64 __data; /* pointer to user space */
>+ };
>+#else
> void __user *data; /* pointer to user space */
>+#endif
> } __attribute__ ((packed));
>
> struct usbtmc_termchar {
>@@ -70,7 +77,14 @@ struct usbtmc_message {
> __u32 transfer_size; /* size of bytes to transfer */
> __u32 transferred; /* size of received/written bytes */
> __u32 flags; /* bit 0: 0 = synchronous; 1 = asynchronous */
>+#if __riscv_xlen == 64
>+ union {
>+ void __user *message; /* pointer to header and data in user space */
>+ __u64 __message;
>+ };
>+#else
> void __user *message; /* pointer to header and data in user space */
>+#endif
> } __attribute__ ((packed));
>
> /* Request values for USBTMC driver's ioctl entry point */
>diff --git a/include/uapi/linux/usbdevice_fs.h b/include/uapi/linux/usbdevice_fs.h
>index 74a84e02422a..8c8efef74c3c 100644
>--- a/include/uapi/linux/usbdevice_fs.h
>+++ b/include/uapi/linux/usbdevice_fs.h
>@@ -44,14 +44,28 @@ struct usbdevfs_ctrltransfer {
> __u16 wIndex;
> __u16 wLength;
> __u32 timeout; /* in milliseconds */
>+#if __riscv_xlen == 64
>+ union {
>+ void __user *data;
>+ __u64 __data;
>+ };
>+#else
> void __user *data;
>+#endif
> };
>
> struct usbdevfs_bulktransfer {
> unsigned int ep;
> unsigned int len;
> unsigned int timeout; /* in milliseconds */
>+#if __riscv_xlen == 64
>+ union {
>+ void __user *data;
>+ __u64 __data;
>+ };
>+#else
> void __user *data;
>+#endif
> };
>
> struct usbdevfs_setinterface {
>@@ -61,7 +75,14 @@ struct usbdevfs_setinterface {
>
> struct usbdevfs_disconnectsignal {
> unsigned int signr;
>+#if __riscv_xlen == 64
>+ union {
>+ void __user *context;
>+ __u64 __context;
>+ };
>+#else
> void __user *context;
>+#endif
> };
>
> #define USBDEVFS_MAXDRIVERNAME 255
>@@ -119,7 +140,14 @@ struct usbdevfs_urb {
> unsigned char endpoint;
> int status;
> unsigned int flags;
>+#if __riscv_xlen == 64
>+ union {
>+ void __user *buffer;
>+ __u64 __buffer;
>+ };
>+#else
> void __user *buffer;
>+#endif
> int buffer_length;
> int actual_length;
> int start_frame;
>@@ -130,7 +158,14 @@ struct usbdevfs_urb {
> int error_count;
> unsigned int signr; /* signal to be sent on completion,
> or 0 if none should be sent. */
>+#if __riscv_xlen == 64
>+ union {
>+ void __user *usercontext;
>+ __u64 __usercontext;
>+ };
>+#else
> void __user *usercontext;
>+#endif
> struct usbdevfs_iso_packet_desc iso_frame_desc[];
> };
>
>@@ -139,7 +174,14 @@ struct usbdevfs_ioctl {
> int ifno; /* interface 0..N ; negative numbers reserved */
> int ioctl_code; /* MUST encode size + direction of data so the
> * macros in <asm/ioctl.h> give correct values */
>+#if __riscv_xlen == 64
>+ union {
>+ void __user *data; /* param buffer (in, or out) */
>+ __u64 __pad;
>+ };
>+#else
> void __user *data; /* param buffer (in, or out) */
>+#endif
> };
>
> /* You can do most things with hubs just through control messages,
>@@ -195,9 +237,17 @@ struct usbdevfs_streams {
> #define USBDEVFS_SUBMITURB _IOR('U', 10, struct usbdevfs_urb)
> #define USBDEVFS_SUBMITURB32 _IOR('U', 10, struct usbdevfs_urb32)
> #define USBDEVFS_DISCARDURB _IO('U', 11)
>+#if __riscv_xlen == 64
>+#define USBDEVFS_REAPURB _IOW('U', 12, __u64)
>+#else
> #define USBDEVFS_REAPURB _IOW('U', 12, void *)
>+#endif
> #define USBDEVFS_REAPURB32 _IOW('U', 12, __u32)
>+#if __riscv_xlen == 64
>+#define USBDEVFS_REAPURBNDELAY _IOW('U', 13, __u64)
>+#else
> #define USBDEVFS_REAPURBNDELAY _IOW('U', 13, void *)
>+#endif
> #define USBDEVFS_REAPURBNDELAY32 _IOW('U', 13, __u32)
> #define USBDEVFS_DISCSIGNAL _IOR('U', 14, struct usbdevfs_disconnectsignal)
> #define USBDEVFS_DISCSIGNAL32 _IOR('U', 14, struct usbdevfs_disconnectsignal32)
>diff --git a/include/uapi/linux/uvcvideo.h b/include/uapi/linux/uvcvideo.h
>index f86185456dc5..3ccb99039a43 100644
>--- a/include/uapi/linux/uvcvideo.h
>+++ b/include/uapi/linux/uvcvideo.h
>@@ -54,7 +54,14 @@ struct uvc_xu_control_mapping {
> __u32 v4l2_type;
> __u32 data_type;
>
>+#if __riscv_xlen == 64
>+ union {
>+ struct uvc_menu_info __user *menu_info;
>+ __u64 __menu_info;
>+ };
>+#else
> struct uvc_menu_info __user *menu_info;
>+#endif
> __u32 menu_count;
>
> __u32 reserved[4];
>@@ -66,7 +73,14 @@ struct uvc_xu_control_query {
> __u8 query; /* Video Class-Specific Request Code, */
> /* defined in linux/usb/video.h A.8. */
> __u16 size;
>+#if __riscv_xlen == 64
>+ union {
>+ __u8 __user *data;
>+ __u64 __data;
>+ };
>+#else
> __u8 __user *data;
>+#endif
> };
>
> #define UVCIOC_CTRL_MAP _IOWR('u', 0x20, struct uvc_xu_control_mapping)
>diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
>index c8dbf8219c4f..0a1dc2a780fb 100644
>--- a/include/uapi/linux/vfio.h
>+++ b/include/uapi/linux/vfio.h
>@@ -1570,7 +1570,14 @@ struct vfio_iommu_type1_dma_map {
> struct vfio_bitmap {
> __u64 pgsize; /* page size for bitmap in bytes */
> __u64 size; /* in bytes */
>+ #if __riscv_xlen == 64
>+ union {
>+ __u64 __user *data; /* one bit per page */
>+ __u64 __data;
>+ };
>+ #else
> __u64 __user *data; /* one bit per page */
>+ #endif
> };
>
> /**
>diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
>index e7c4dce39007..8e5391f07626 100644
>--- a/include/uapi/linux/videodev2.h
>+++ b/include/uapi/linux/videodev2.h
>@@ -1898,7 +1898,14 @@ struct v4l2_ext_controls {
> __u32 error_idx;
> __s32 request_fd;
> __u32 reserved[1];
>+#if __riscv_xlen == 64
>+ union {
>+ struct v4l2_ext_control *controls;
>+ __u64 __controls;
>+ };
>+#else
> struct v4l2_ext_control *controls;
>+#endif
> };
>
> #define V4L2_CTRL_ID_MASK (0x0fffffff)
>--
>2.40.1
>
>