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

[Jan Engelhardt <ej@inai.de>]

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
>
>