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![Arnd Bergmann](/assets/img/avatar_default.png)
The behavior of these system calls is slightly different between architectures, as determined by the CONFIG_ARCH_WANT_IPC_PARSE_VERSION symbol. Most architectures that implement the split IPC syscalls don't set that symbol and only get the modern version, but alpha, arm, microblaze, mips-n32, mips-n64 and xtensa expect the caller to pass the IPC_64 flag. For the architectures that so far only implement sys_ipc(), i.e. m68k, mips-o32, powerpc, s390, sh, sparc, and x86-32, we want the new behavior when adding the split syscalls, so we need to distinguish between the two groups of architectures. The method I picked for this distinction is to have a separate system call entry point: sys_old_*ctl() now uses ipc_parse_version, while sys_*ctl() does not. The system call tables of the five architectures are changed accordingly. As an additional benefit, we no longer need the configuration specific definition for ipc_parse_version(), it always does the same thing now, but simply won't get called on architectures with the modern interface. A small downside is that on architectures that do set ARCH_WANT_IPC_PARSE_VERSION, we now have an extra set of entry points that are never called. They only add a few bytes of bloat, so it seems better to keep them compared to adding yet another Kconfig symbol. I considered adding new syscall numbers for the IPC_64 variants for consistency, but decided against that for now. Signed-off-by: Arnd Bergmann <arnd@arndb.de>
211 lines
5.1 KiB
C
211 lines
5.1 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* sys_ipc() is the old de-multiplexer for the SysV IPC calls.
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*
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* This is really horribly ugly, and new architectures should just wire up
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* the individual syscalls instead.
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*/
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#include <linux/unistd.h>
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#include <linux/syscalls.h>
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#include <linux/security.h>
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#include <linux/ipc_namespace.h>
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#include "util.h"
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#ifdef __ARCH_WANT_SYS_IPC
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#include <linux/errno.h>
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#include <linux/ipc.h>
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#include <linux/shm.h>
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#include <linux/uaccess.h>
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int ksys_ipc(unsigned int call, int first, unsigned long second,
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unsigned long third, void __user * ptr, long fifth)
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{
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int version, ret;
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version = call >> 16; /* hack for backward compatibility */
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call &= 0xffff;
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switch (call) {
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case SEMOP:
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return ksys_semtimedop(first, (struct sembuf __user *)ptr,
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second, NULL);
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case SEMTIMEDOP:
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if (IS_ENABLED(CONFIG_64BIT) || !IS_ENABLED(CONFIG_64BIT_TIME))
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return ksys_semtimedop(first, ptr, second,
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(const struct __kernel_timespec __user *)fifth);
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else if (IS_ENABLED(CONFIG_COMPAT_32BIT_TIME))
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return compat_ksys_semtimedop(first, ptr, second,
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(const struct old_timespec32 __user *)fifth);
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else
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return -ENOSYS;
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case SEMGET:
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return ksys_semget(first, second, third);
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case SEMCTL: {
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unsigned long arg;
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if (!ptr)
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return -EINVAL;
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if (get_user(arg, (unsigned long __user *) ptr))
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return -EFAULT;
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return ksys_old_semctl(first, second, third, arg);
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}
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case MSGSND:
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return ksys_msgsnd(first, (struct msgbuf __user *) ptr,
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second, third);
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case MSGRCV:
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switch (version) {
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case 0: {
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struct ipc_kludge tmp;
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if (!ptr)
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return -EINVAL;
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if (copy_from_user(&tmp,
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(struct ipc_kludge __user *) ptr,
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sizeof(tmp)))
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return -EFAULT;
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return ksys_msgrcv(first, tmp.msgp, second,
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tmp.msgtyp, third);
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}
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default:
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return ksys_msgrcv(first,
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(struct msgbuf __user *) ptr,
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second, fifth, third);
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}
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case MSGGET:
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return ksys_msgget((key_t) first, second);
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case MSGCTL:
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return ksys_old_msgctl(first, second,
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(struct msqid_ds __user *)ptr);
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case SHMAT:
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switch (version) {
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default: {
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unsigned long raddr;
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ret = do_shmat(first, (char __user *)ptr,
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second, &raddr, SHMLBA);
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if (ret)
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return ret;
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return put_user(raddr, (unsigned long __user *) third);
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}
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case 1:
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/*
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* This was the entry point for kernel-originating calls
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* from iBCS2 in 2.2 days.
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*/
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return -EINVAL;
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}
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case SHMDT:
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return ksys_shmdt((char __user *)ptr);
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case SHMGET:
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return ksys_shmget(first, second, third);
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case SHMCTL:
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return ksys_old_shmctl(first, second,
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(struct shmid_ds __user *) ptr);
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default:
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return -ENOSYS;
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}
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}
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SYSCALL_DEFINE6(ipc, unsigned int, call, int, first, unsigned long, second,
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unsigned long, third, void __user *, ptr, long, fifth)
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{
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return ksys_ipc(call, first, second, third, ptr, fifth);
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}
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#endif
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#ifdef CONFIG_COMPAT
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#include <linux/compat.h>
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#ifndef COMPAT_SHMLBA
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#define COMPAT_SHMLBA SHMLBA
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#endif
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struct compat_ipc_kludge {
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compat_uptr_t msgp;
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compat_long_t msgtyp;
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};
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#ifdef CONFIG_ARCH_WANT_OLD_COMPAT_IPC
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int compat_ksys_ipc(u32 call, int first, int second,
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u32 third, compat_uptr_t ptr, u32 fifth)
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{
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int version;
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u32 pad;
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version = call >> 16; /* hack for backward compatibility */
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call &= 0xffff;
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switch (call) {
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case SEMOP:
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/* struct sembuf is the same on 32 and 64bit :)) */
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return ksys_semtimedop(first, compat_ptr(ptr), second, NULL);
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case SEMTIMEDOP:
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if (!IS_ENABLED(CONFIG_COMPAT_32BIT_TIME))
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return -ENOSYS;
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return compat_ksys_semtimedop(first, compat_ptr(ptr), second,
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compat_ptr(fifth));
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case SEMGET:
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return ksys_semget(first, second, third);
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case SEMCTL:
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if (!ptr)
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return -EINVAL;
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if (get_user(pad, (u32 __user *) compat_ptr(ptr)))
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return -EFAULT;
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return compat_ksys_old_semctl(first, second, third, pad);
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case MSGSND:
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return compat_ksys_msgsnd(first, ptr, second, third);
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case MSGRCV: {
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void __user *uptr = compat_ptr(ptr);
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if (first < 0 || second < 0)
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return -EINVAL;
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if (!version) {
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struct compat_ipc_kludge ipck;
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if (!uptr)
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return -EINVAL;
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if (copy_from_user(&ipck, uptr, sizeof(ipck)))
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return -EFAULT;
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return compat_ksys_msgrcv(first, ipck.msgp, second,
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ipck.msgtyp, third);
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}
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return compat_ksys_msgrcv(first, ptr, second, fifth, third);
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}
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case MSGGET:
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return ksys_msgget(first, second);
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case MSGCTL:
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return compat_ksys_old_msgctl(first, second, compat_ptr(ptr));
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case SHMAT: {
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int err;
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unsigned long raddr;
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if (version == 1)
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return -EINVAL;
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err = do_shmat(first, compat_ptr(ptr), second, &raddr,
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COMPAT_SHMLBA);
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if (err < 0)
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return err;
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return put_user(raddr, (compat_ulong_t __user *)compat_ptr(third));
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}
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case SHMDT:
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return ksys_shmdt(compat_ptr(ptr));
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case SHMGET:
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return ksys_shmget(first, (unsigned int)second, third);
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case SHMCTL:
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return compat_ksys_old_shmctl(first, second, compat_ptr(ptr));
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}
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return -ENOSYS;
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}
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COMPAT_SYSCALL_DEFINE6(ipc, u32, call, int, first, int, second,
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u32, third, compat_uptr_t, ptr, u32, fifth)
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{
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return compat_ksys_ipc(call, first, second, third, ptr, fifth);
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}
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#endif
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#endif
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