Commit 687ad019 authored by Nicolas Pitre's avatar Nicolas Pitre Committed by Russell King
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[ARM] 3109/1: old ABI compat: syscall wrappers for ABI impedance matching

Patch from Nicolas Pitre

The difference between EABI and the legacy ABI may affect either
structure member alignment and/or argument register selection.

The patch has the details.

Included are wrappers for the following syscalls:

Signed-off-by: default avatarNicolas Pitre <>
Signed-off-by: default avatarRussell King <>
parent 713c4815
......@@ -20,6 +20,7 @@ obj-$(CONFIG_ARTHUR) += arthur.o
obj-$(CONFIG_ISA_DMA) += dma-isa.o
obj-$(CONFIG_PCI) += bios32.o
obj-$(CONFIG_SMP) += smp.o
obj-$(CONFIG_OABI_COMPAT) += sys_oabi-compat.o
obj-$(CONFIG_IWMMXT) += iwmmxt.o
AFLAGS_iwmmxt.o := -Wa,-mcpu=iwmmxt
......@@ -288,3 +288,35 @@ sys_mmap2:
str r5, [sp, #4]
b do_mmap2
* These are syscalls with argument register differences
stmia sp, {r3, r4}
b sys_pread64
stmia sp, {r3, r4}
b sys_pwrite64
mov r3, r2
mov r2, r1
b sys_truncate64
mov r3, r2
mov r2, r1
b sys_ftruncate64
str r3, [sp]
mov r3, r2
mov r2, r1
b sys_readahead
* arch/arm/kernel/sys_oabi-compat.c
* Compatibility wrappers for syscalls that are used from
* old ABI user space binaries with an EABI kernel.
* Author: Nicolas Pitre
* Created: Oct 7, 2005
* Copyright: MontaVista Software, Inc.
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
* The legacy ABI and the new ARM EABI have different rules making some
* syscalls incompatible especially with structure arguments.
* Most notably, Eabi says 64-bit members should be 64-bit aligned instead of
* simply word aligned. EABI also pads structures to the size of the largest
* member it contains instead of the invariant 32-bit.
* The following syscalls are affected:
* sys_stat64:
* sys_lstat64:
* sys_fstat64:
* struct stat64 has different sizes and some members are shifted
* Compatibility wrappers are needed for them and provided below.
* sys_fcntl64:
* struct flock64 has different sizes and some members are shifted
* A compatibility wrapper is needed and provided below.
* sys_statfs64:
* sys_fstatfs64:
* struct statfs64 has extra padding with EABI growing its size from
* 84 to 88. This struct is now __attribute__((packed,aligned(4)))
* with a small assembly wrapper to force the sz argument to 84 if it is 88
* to avoid copying the extra padding over user space unexpecting it.
* sys_newuname:
* struct new_utsname has no padding with EABI. No problem there.
* sys_epoll_ctl:
* sys_epoll_wait:
* struct epoll_event has its second member shifted also affecting the
* structure size. Compatibility wrappers are needed and provided below.
* sys_ipc:
* sys_semop:
* sys_semtimedop:
* struct sembuf loses its padding with EABI. Since arrays of them are
* used they have to be copyed to remove the padding. Compatibility wrappers
* provided below.
#include <linux/syscalls.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/fcntl.h>
#include <linux/eventpoll.h>
#include <linux/sem.h>
#include <asm/ipc.h>
#include <asm/uaccess.h>
struct oldabi_stat64 {
unsigned long long st_dev;
unsigned int __pad1;
unsigned long __st_ino;
unsigned int st_mode;
unsigned int st_nlink;
unsigned long st_uid;
unsigned long st_gid;
unsigned long long st_rdev;
unsigned int __pad2;
long long st_size;
unsigned long st_blksize;
unsigned long long st_blocks;
unsigned long st_atime;
unsigned long st_atime_nsec;
unsigned long st_mtime;
unsigned long st_mtime_nsec;
unsigned long st_ctime;
unsigned long st_ctime_nsec;
unsigned long long st_ino;
} __attribute__ ((packed,aligned(4)));
static long cp_oldabi_stat64(struct kstat *stat,
struct oldabi_stat64 __user *statbuf)
struct oldabi_stat64 tmp;
tmp.st_dev = huge_encode_dev(stat->dev);
tmp.__pad1 = 0;
tmp.__st_ino = stat->ino;
tmp.st_mode = stat->mode;
tmp.st_nlink = stat->nlink;
tmp.st_uid = stat->uid;
tmp.st_gid = stat->gid;
tmp.st_rdev = huge_encode_dev(stat->rdev);
tmp.st_size = stat->size;
tmp.st_blocks = stat->blocks;
tmp.__pad2 = 0;
tmp.st_blksize = stat->blksize;
tmp.st_atime = stat->atime.tv_sec;
tmp.st_atime_nsec = stat->atime.tv_nsec;
tmp.st_mtime = stat->mtime.tv_sec;
tmp.st_mtime_nsec = stat->mtime.tv_nsec;
tmp.st_ctime = stat->ctime.tv_sec;
tmp.st_ctime_nsec = stat->ctime.tv_nsec;
tmp.st_ino = stat->ino;
return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
asmlinkage long sys_oabi_stat64(char __user * filename,
struct oldabi_stat64 __user * statbuf)
struct kstat stat;
int error = vfs_stat(filename, &stat);
if (!error)
error = cp_oldabi_stat64(&stat, statbuf);
return error;
asmlinkage long sys_oabi_lstat64(char __user * filename,
struct oldabi_stat64 __user * statbuf)
struct kstat stat;
int error = vfs_lstat(filename, &stat);
if (!error)
error = cp_oldabi_stat64(&stat, statbuf);
return error;
asmlinkage long sys_oabi_fstat64(unsigned long fd,
struct oldabi_stat64 __user * statbuf)
struct kstat stat;
int error = vfs_fstat(fd, &stat);
if (!error)
error = cp_oldabi_stat64(&stat, statbuf);
return error;
struct oabi_flock64 {
short l_type;
short l_whence;
loff_t l_start;
loff_t l_len;
pid_t l_pid;
} __attribute__ ((packed,aligned(4)));
asmlinkage long sys_oabi_fcntl64(unsigned int fd, unsigned int cmd,
unsigned long arg)
struct oabi_flock64 user;
struct flock64 kernel;
mm_segment_t fs = USER_DS; /* initialized to kill a warning */
unsigned long local_arg = arg;
int ret;
switch (cmd) {
case F_GETLK64:
case F_SETLK64:
case F_SETLKW64:
if (copy_from_user(&user, (struct oabi_flock64 __user *)arg,
return -EFAULT;
kernel.l_type = user.l_type;
kernel.l_whence = user.l_whence;
kernel.l_start = user.l_start;
kernel.l_len = user.l_len;
kernel.l_pid = user.l_pid;
local_arg = (unsigned long)&kernel;
fs = get_fs();
ret = sys_fcntl64(fd, cmd, local_arg);
switch (cmd) {
case F_GETLK64:
if (!ret) {
user.l_type = kernel.l_type;
user.l_whence = kernel.l_whence;
user.l_start = kernel.l_start;
user.l_len = kernel.l_len;
user.l_pid = kernel.l_pid;
if (copy_to_user((struct oabi_flock64 __user *)arg,
&user, sizeof(user)))
ret = -EFAULT;
case F_SETLK64:
case F_SETLKW64:
return ret;
struct oabi_epoll_event {
__u32 events;
__u64 data;
} __attribute__ ((packed,aligned(4)));
asmlinkage long sys_oabi_epoll_ctl(int epfd, int op, int fd,
struct oabi_epoll_event __user *event)
struct oabi_epoll_event user;
struct epoll_event kernel;
mm_segment_t fs;
long ret;
if (op == EPOLL_CTL_DEL)
return sys_epoll_ctl(epfd, op, fd, NULL);
if (copy_from_user(&user, event, sizeof(user)))
return -EFAULT; =; =;
fs = get_fs();
ret = sys_epoll_ctl(epfd, op, fd, &kernel);
return ret;
asmlinkage long sys_oabi_epoll_wait(int epfd,
struct oabi_epoll_event __user *events,
int maxevents, int timeout)
struct epoll_event *kbuf;
mm_segment_t fs;
long ret, err, i;
if (maxevents <= 0 || maxevents > (INT_MAX/sizeof(struct epoll_event)))
return -EINVAL;
kbuf = kmalloc(sizeof(*kbuf) * maxevents, GFP_KERNEL);
if (!kbuf)
return -ENOMEM;
fs = get_fs();
ret = sys_epoll_wait(epfd, kbuf, maxevents, timeout);
err = 0;
for (i = 0; i < ret; i++) {
__put_user_error(kbuf[i].events, &events->events, err);
__put_user_error(kbuf[i].data, &events->data, err);
return err ? -EFAULT : ret;
struct oabi_sembuf {
unsigned short sem_num;
short sem_op;
short sem_flg;
unsigned short __pad;
asmlinkage long sys_oabi_semtimedop(int semid,
struct oabi_sembuf __user *tsops,
unsigned nsops,
const struct timespec __user *timeout)
struct sembuf *sops;
struct timespec local_timeout;
long err;
int i;
if (nsops < 1)
return -EINVAL;
sops = kmalloc(sizeof(*sops) * nsops, GFP_KERNEL);
if (!sops)
return -ENOMEM;
err = 0;
for (i = 0; i < nsops; i++) {
__get_user_error(sops[i].sem_num, &tsops->sem_num, err);
__get_user_error(sops[i].sem_op, &tsops->sem_op, err);
__get_user_error(sops[i].sem_flg, &tsops->sem_flg, err);
if (timeout) {
/* copy this as well before changing domain protection */
err |= copy_from_user(&local_timeout, timeout, sizeof(*timeout));
timeout = &local_timeout;
if (err) {
err = -EFAULT;
} else {
mm_segment_t fs = get_fs();
err = sys_semtimedop(semid, sops, nsops, timeout);
return err;
asmlinkage long sys_oabi_semop(int semid, struct oabi_sembuf __user *tsops,
unsigned nsops)
return sys_oabi_semtimedop(semid, tsops, nsops, NULL);
extern asmlinkage int sys_ipc(uint call, int first, int second, int third,
void __user *ptr, long fifth);
asmlinkage int sys_oabi_ipc(uint call, int first, int second, int third,
void __user *ptr, long fifth)
switch (call & 0xffff) {
case SEMOP:
return sys_oabi_semtimedop(first,
(struct oabi_sembuf __user *)ptr,
second, NULL);
return sys_oabi_semtimedop(first,
(struct oabi_sembuf __user *)ptr,
(const struct timespec __user *)fifth);
return sys_ipc(call, first, second, third, ptr, fifth);
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