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![Chris Metcalf](/assets/img/avatar_default.png)
When using the "compat" APIs, architectures will generally want to be able to make direct syscalls to msgsnd(), shmctl(), etc., and in the kernel we would want them to be handled directly by compat_sys_xxx() functions, as is true for other compat syscalls. However, for historical reasons, several of the existing compat IPC syscalls do not do this. semctl() expects a pointer to the fourth argument, instead of the fourth argument itself. msgsnd(), msgrcv() and shmat() expect arguments in different order. This change adds an ARCH_WANT_OLD_COMPAT_IPC config option that can be set to preserve this behavior for ports that use it (x86, sparc, powerpc, s390, and mips). No actual semantics are changed for those architectures, and there is only a minimal amount of code refactoring in ipc/compat.c. Newer architectures like tile (and perhaps future architectures such as arm64 and unicore64) should not select this option, and thus can avoid having any IPC-specific code at all in their architecture-specific compat layer. In the same vein, if this option is not selected, IPC_64 mode is assumed, since that's what the <asm-generic> headers expect. The workaround code in "tile" for msgsnd() and msgrcv() is removed with this change; it also fixes the bug that shmat() and semctl() were not being properly handled. Reviewed-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
118 lines
3.5 KiB
C
118 lines
3.5 KiB
C
/*
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* Copyright 2010 Tilera Corporation. All Rights Reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation, version 2.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
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* NON INFRINGEMENT. See the GNU General Public License for
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* more details.
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*/
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/* Adjust unistd.h to provide 32-bit numbers and functions. */
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#define __SYSCALL_COMPAT
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#include <linux/compat.h>
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#include <linux/syscalls.h>
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#include <linux/kdev_t.h>
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#include <linux/fs.h>
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#include <linux/fcntl.h>
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#include <linux/uaccess.h>
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#include <linux/signal.h>
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#include <asm/syscalls.h>
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/*
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* Syscalls that take 64-bit numbers traditionally take them in 32-bit
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* "high" and "low" value parts on 32-bit architectures.
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* In principle, one could imagine passing some register arguments as
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* fully 64-bit on TILE-Gx in 32-bit mode, but it seems easier to
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* adapt the usual convention.
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*/
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long compat_sys_truncate64(char __user *filename, u32 dummy, u32 low, u32 high)
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{
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return sys_truncate(filename, ((loff_t)high << 32) | low);
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}
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long compat_sys_ftruncate64(unsigned int fd, u32 dummy, u32 low, u32 high)
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{
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return sys_ftruncate(fd, ((loff_t)high << 32) | low);
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}
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long compat_sys_pread64(unsigned int fd, char __user *ubuf, size_t count,
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u32 dummy, u32 low, u32 high)
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{
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return sys_pread64(fd, ubuf, count, ((loff_t)high << 32) | low);
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}
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long compat_sys_pwrite64(unsigned int fd, char __user *ubuf, size_t count,
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u32 dummy, u32 low, u32 high)
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{
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return sys_pwrite64(fd, ubuf, count, ((loff_t)high << 32) | low);
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}
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long compat_sys_lookup_dcookie(u32 low, u32 high, char __user *buf, size_t len)
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{
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return sys_lookup_dcookie(((loff_t)high << 32) | low, buf, len);
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}
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long compat_sys_sync_file_range2(int fd, unsigned int flags,
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u32 offset_lo, u32 offset_hi,
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u32 nbytes_lo, u32 nbytes_hi)
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{
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return sys_sync_file_range(fd, ((loff_t)offset_hi << 32) | offset_lo,
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((loff_t)nbytes_hi << 32) | nbytes_lo,
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flags);
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}
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long compat_sys_fallocate(int fd, int mode,
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u32 offset_lo, u32 offset_hi,
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u32 len_lo, u32 len_hi)
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{
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return sys_fallocate(fd, mode, ((loff_t)offset_hi << 32) | offset_lo,
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((loff_t)len_hi << 32) | len_lo);
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}
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long compat_sys_sched_rr_get_interval(compat_pid_t pid,
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struct compat_timespec __user *interval)
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{
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struct timespec t;
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int ret;
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mm_segment_t old_fs = get_fs();
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set_fs(KERNEL_DS);
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ret = sys_sched_rr_get_interval(pid,
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(struct timespec __force __user *)&t);
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set_fs(old_fs);
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if (put_compat_timespec(&t, interval))
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return -EFAULT;
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return ret;
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}
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/* Provide the compat syscall number to call mapping. */
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#undef __SYSCALL
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#define __SYSCALL(nr, call) [nr] = (call),
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/* See comments in sys.c */
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#define compat_sys_fadvise64_64 sys32_fadvise64_64
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#define compat_sys_readahead sys32_readahead
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/* Call the trampolines to manage pt_regs where necessary. */
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#define compat_sys_execve _compat_sys_execve
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#define compat_sys_sigaltstack _compat_sys_sigaltstack
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#define compat_sys_rt_sigreturn _compat_sys_rt_sigreturn
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#define sys_clone _sys_clone
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/*
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* Note that we can't include <linux/unistd.h> here since the header
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* guard will defeat us; <asm/unistd.h> checks for __SYSCALL as well.
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*/
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void *compat_sys_call_table[__NR_syscalls] = {
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[0 ... __NR_syscalls-1] = sys_ni_syscall,
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#include <asm/unistd.h>
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};
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