2c7387ef99
The existing asm-generic/stat.h specifies st_mtime, etc., as a 32-value, and works well for 32-bit architectures (currently microblaze, score, and 32-bit tile). However, for 64-bit architectures it isn't sufficient to return 32 bits of time_t; this isn't good insurance against the 2037 rollover. (It also makes glibc support less convenient, since we can't use glibc's handy STAT_IS_KERNEL_STAT mode.) This change extends the two "timespec" fields for each of the three atime, mtime, and ctime fields from "int" to "long". As a result, on 32-bit platforms nothing changes, and 64-bit platforms will now work as expected. The only wrinkle is 32-bit userspace under 64-bit kernels taking advantage of COMPAT mode. For these, we leave the "struct stat64" definitions with the "int" versions of the time_t and nsec fields, so that architectures can implement compat_sys_stat64() and friends with sys_stat64(), etc., and get the expected 32-bit structure layout. This requires a field-by-field copy in the kernel, implemented by the code guarded under __ARCH_WANT_STAT64. This does mean that the shape of the "struct stat" and "struct stat64" structures is different on a 64-bit kernel, but only one of the two structures should ever be used by any given process: "struct stat" is meant for 64-bit userspace only, and "struct stat64" for 32-bit userspace only. (On a 32-bit kernel the two structures continue to have the same shape, since "long" is 32 bits.) The alternative is keeping the two structures the same shape on 64-bit kernels, which means a 64-bit time_t in "struct stat64" for 32-bit processes. This is a little unnatural since 32-bit userspace can't do anything with 64 bits of time_t information, since time_t is just "long", not "int64_t"; and in any case 32-bit userspace might expect to be running under a 32-bit kernel, which can't provide the high 32 bits anyway. In the case of a 32-bit kernel we'd then be extending the kernel's 32-bit time_t to 64 bits, then truncating it back to 32 bits again in userspace, for no particular reason. And, as mentioned above, if we have 64-bit time_t for 32-bit processes we can't easily use glibc's STAT_IS_KERNEL_STAT, since glibc's stat structure requires an embedded "struct timespec", which is a pair of "long" (32-bit) values in a 32-bit userspace. "Inventive" solutions are possible, but are pretty hacky. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com> Acked-by: Arnd Bergmann <arnd@arndb.de>
173 lines
4.9 KiB
C
173 lines
4.9 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/msg.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/smp_lock.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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/*
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* The usual compat_sys_msgsnd() and _msgrcv() seem to be assuming
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* some different calling convention than our normal 32-bit tile code.
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*/
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/* Already defined in ipc/compat.c, but we need it here. */
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struct compat_msgbuf {
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compat_long_t mtype;
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char mtext[1];
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};
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long tile_compat_sys_msgsnd(int msqid,
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struct compat_msgbuf __user *msgp,
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size_t msgsz, int msgflg)
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{
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compat_long_t mtype;
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if (get_user(mtype, &msgp->mtype))
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return -EFAULT;
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return do_msgsnd(msqid, mtype, msgp->mtext, msgsz, msgflg);
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}
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long tile_compat_sys_msgrcv(int msqid,
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struct compat_msgbuf __user *msgp,
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size_t msgsz, long msgtyp, int msgflg)
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{
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long err, mtype;
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err = do_msgrcv(msqid, &mtype, msgp->mtext, msgsz, msgtyp, msgflg);
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if (err < 0)
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goto out;
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if (put_user(mtype, &msgp->mtype))
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err = -EFAULT;
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out:
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return err;
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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] = (compat_##call),
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/* The generic versions of these don't work for Tile. */
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#define compat_sys_msgrcv tile_compat_sys_msgrcv
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#define compat_sys_msgsnd tile_compat_sys_msgsnd
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/* See comments in sys.c */
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#define compat_sys_fadvise64 sys32_fadvise64
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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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#define compat_sys_sync_file_range compat_sys_sync_file_range2
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/* We leverage the "struct stat64" type for 32-bit time_t/nsec. */
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#define compat_sys_stat64 sys_stat64
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#define compat_sys_lstat64 sys_lstat64
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#define compat_sys_fstat64 sys_fstat64
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#define compat_sys_fstatat64 sys_fstatat64
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/* The native sys_ptrace dynamically handles compat binaries. */
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#define compat_sys_ptrace sys_ptrace
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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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