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linux/arch/s390/kernel/compat_wrapper.c
Josh Triplett 3033f14ab7 clone: support passing tls argument via C rather than pt_regs magic 
clone has some of the quirkiest syscall handling in the kernel, with a
pile of special cases, historical curiosities, and architecture-specific
calling conventions.  In particular, clone with CLONE_SETTLS accepts a
parameter "tls" that the C entry point completely ignores and some
assembly entry points overwrite; instead, the low-level arch-specific
code pulls the tls parameter out of the arch-specific register captured
as part of pt_regs on entry to the kernel.  That's a massive hack, and
it makes the arch-specific code only work when called via the specific
existing syscall entry points; because of this hack, any new clone-like
system call would have to accept an identical tls argument in exactly
the same arch-specific position, rather than providing a unified system
call entry point across architectures.

The first patch allows architectures to handle the tls argument via
normal C parameter passing, if they opt in by selecting
HAVE_COPY_THREAD_TLS.  The second patch makes 32-bit and 64-bit x86 opt
into this.

These two patches came out of the clone4 series, which isn't ready for
this merge window, but these first two cleanup patches were entirely
uncontroversial and have acks.  I'd like to go ahead and submit these
two so that other architectures can begin building on top of this and
opting into HAVE_COPY_THREAD_TLS.  However, I'm also happy to wait and
send these through the next merge window (along with v3 of clone4) if
anyone would prefer that.

This patch (of 2):

clone with CLONE_SETTLS accepts an argument to set the thread-local
storage area for the new thread.  sys_clone declares an int argument
tls_val in the appropriate point in the argument list (based on the
various CLONE_BACKWARDS variants), but doesn't actually use or pass along
that argument.  Instead, sys_clone calls do_fork, which calls
copy_process, which calls the arch-specific copy_thread, and copy_thread
pulls the corresponding syscall argument out of the pt_regs captured at
kernel entry (knowing what argument of clone that architecture passes tls
in).

Apart from being awful and inscrutable, that also only works because only
one code path into copy_thread can pass the CLONE_SETTLS flag, and that
code path comes from sys_clone with its architecture-specific
argument-passing order.  This prevents introducing a new version of the
clone system call without propagating the same architecture-specific
position of the tls argument.

However, there's no reason to pull the argument out of pt_regs when
sys_clone could just pass it down via C function call arguments.

Introduce a new CONFIG_HAVE_COPY_THREAD_TLS for architectures to opt into,
and a new copy_thread_tls that accepts the tls parameter as an additional
unsigned long (syscall-argument-sized) argument.  Change sys_clone's tls
argument to an unsigned long (which does not change the ABI), and pass
that down to copy_thread_tls.

Architectures that don't opt into copy_thread_tls will continue to ignore
the C argument to sys_clone in favor of the pt_regs captured at kernel
entry, and thus will be unable to introduce new versions of the clone
syscall.

Patch co-authored by Josh Triplett and Thiago Macieira.

Signed-off-by: Josh Triplett <josh@joshtriplett.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Thiago Macieira <thiago.macieira@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-25 17:00:38 -07:00

223 lines
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/*
* Compat system call wrappers.
*
* Copyright IBM Corp. 2014
*/
#include <linux/syscalls.h>
#include <linux/compat.h>
#include "entry.h"
#define COMPAT_SYSCALL_WRAP1(name, ...) \
COMPAT_SYSCALL_WRAPx(1, _##name, __VA_ARGS__)
#define COMPAT_SYSCALL_WRAP2(name, ...) \
COMPAT_SYSCALL_WRAPx(2, _##name, __VA_ARGS__)
#define COMPAT_SYSCALL_WRAP3(name, ...) \
COMPAT_SYSCALL_WRAPx(3, _##name, __VA_ARGS__)
#define COMPAT_SYSCALL_WRAP4(name, ...) \
COMPAT_SYSCALL_WRAPx(4, _##name, __VA_ARGS__)
#define COMPAT_SYSCALL_WRAP5(name, ...) \
COMPAT_SYSCALL_WRAPx(5, _##name, __VA_ARGS__)
#define COMPAT_SYSCALL_WRAP6(name, ...) \
COMPAT_SYSCALL_WRAPx(6, _##name, __VA_ARGS__)
#define __SC_COMPAT_TYPE(t, a) \
__typeof(__builtin_choose_expr(sizeof(t) > 4, 0L, (t)0)) a
#define __SC_COMPAT_CAST(t, a) \
({ \
long __ReS = a; \
\
BUILD_BUG_ON((sizeof(t) > 4) && !__TYPE_IS_L(t) && \
!__TYPE_IS_UL(t) && !__TYPE_IS_PTR(t)); \
if (__TYPE_IS_L(t)) \
__ReS = (s32)a; \
if (__TYPE_IS_UL(t)) \
__ReS = (u32)a; \
if (__TYPE_IS_PTR(t)) \
__ReS = a & 0x7fffffff; \
(t)__ReS; \
})
/*
* The COMPAT_SYSCALL_WRAP macro generates system call wrappers to be used by
* compat tasks. These wrappers will only be used for system calls where only
* the system call arguments need sign or zero extension or zeroing of the upper
* 33 bits of pointers.
* Note: since the wrapper function will afterwards call a system call which
* again performs zero and sign extension for all system call arguments with
* a size of less than eight bytes, these compat wrappers only touch those
* system call arguments with a size of eight bytes ((unsigned) long and
* pointers). Zero and sign extension for e.g. int parameters will be done by
* the regular system call wrappers.
*/
#define COMPAT_SYSCALL_WRAPx(x, name, ...) \
asmlinkage long sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)); \
asmlinkage long compat_sys##name(__MAP(x,__SC_COMPAT_TYPE,__VA_ARGS__));\
asmlinkage long compat_sys##name(__MAP(x,__SC_COMPAT_TYPE,__VA_ARGS__)) \
{ \
return sys##name(__MAP(x,__SC_COMPAT_CAST,__VA_ARGS__)); \
}
COMPAT_SYSCALL_WRAP1(exit, int, error_code);
COMPAT_SYSCALL_WRAP1(close, unsigned int, fd);
COMPAT_SYSCALL_WRAP2(creat, const char __user *, pathname, umode_t, mode);
COMPAT_SYSCALL_WRAP2(link, const char __user *, oldname, const char __user *, newname);
COMPAT_SYSCALL_WRAP1(unlink, const char __user *, pathname);
COMPAT_SYSCALL_WRAP1(chdir, const char __user *, filename);
COMPAT_SYSCALL_WRAP3(mknod, const char __user *, filename, umode_t, mode, unsigned, dev);
COMPAT_SYSCALL_WRAP2(chmod, const char __user *, filename, umode_t, mode);
COMPAT_SYSCALL_WRAP1(oldumount, char __user *, name);
COMPAT_SYSCALL_WRAP1(alarm, unsigned int, seconds);
COMPAT_SYSCALL_WRAP2(access, const char __user *, filename, int, mode);
COMPAT_SYSCALL_WRAP1(nice, int, increment);
COMPAT_SYSCALL_WRAP2(kill, int, pid, int, sig);
COMPAT_SYSCALL_WRAP2(rename, const char __user *, oldname, const char __user *, newname);
COMPAT_SYSCALL_WRAP2(mkdir, const char __user *, pathname, umode_t, mode);
COMPAT_SYSCALL_WRAP1(rmdir, const char __user *, pathname);
COMPAT_SYSCALL_WRAP1(dup, unsigned int, fildes);
COMPAT_SYSCALL_WRAP1(pipe, int __user *, fildes);
COMPAT_SYSCALL_WRAP1(brk, unsigned long, brk);
COMPAT_SYSCALL_WRAP2(signal, int, sig, __sighandler_t, handler);
COMPAT_SYSCALL_WRAP1(acct, const char __user *, name);
COMPAT_SYSCALL_WRAP2(umount, char __user *, name, int, flags);
COMPAT_SYSCALL_WRAP2(setpgid, pid_t, pid, pid_t, pgid);
COMPAT_SYSCALL_WRAP1(umask, int, mask);
COMPAT_SYSCALL_WRAP1(chroot, const char __user *, filename);
COMPAT_SYSCALL_WRAP2(dup2, unsigned int, oldfd, unsigned int, newfd);
COMPAT_SYSCALL_WRAP3(sigsuspend, int, unused1, int, unused2, old_sigset_t, mask);
COMPAT_SYSCALL_WRAP2(sethostname, char __user *, name, int, len);
COMPAT_SYSCALL_WRAP2(symlink, const char __user *, old, const char __user *, new);
COMPAT_SYSCALL_WRAP3(readlink, const char __user *, path, char __user *, buf, int, bufsiz);
COMPAT_SYSCALL_WRAP1(uselib, const char __user *, library);
COMPAT_SYSCALL_WRAP2(swapon, const char __user *, specialfile, int, swap_flags);
COMPAT_SYSCALL_WRAP4(reboot, int, magic1, int, magic2, unsigned int, cmd, void __user *, arg);
COMPAT_SYSCALL_WRAP2(munmap, unsigned long, addr, size_t, len);
COMPAT_SYSCALL_WRAP2(fchmod, unsigned int, fd, umode_t, mode);
COMPAT_SYSCALL_WRAP2(getpriority, int, which, int, who);
COMPAT_SYSCALL_WRAP3(setpriority, int, which, int, who, int, niceval);
COMPAT_SYSCALL_WRAP3(syslog, int, type, char __user *, buf, int, len);
COMPAT_SYSCALL_WRAP1(swapoff, const char __user *, specialfile);
COMPAT_SYSCALL_WRAP1(fsync, unsigned int, fd);
COMPAT_SYSCALL_WRAP2(setdomainname, char __user *, name, int, len);
COMPAT_SYSCALL_WRAP1(newuname, struct new_utsname __user *, name);
COMPAT_SYSCALL_WRAP3(mprotect, unsigned long, start, size_t, len, unsigned long, prot);
COMPAT_SYSCALL_WRAP3(init_module, void __user *, umod, unsigned long, len, const char __user *, uargs);
COMPAT_SYSCALL_WRAP2(delete_module, const char __user *, name_user, unsigned int, flags);
COMPAT_SYSCALL_WRAP4(quotactl, unsigned int, cmd, const char __user *, special, qid_t, id, void __user *, addr);
COMPAT_SYSCALL_WRAP1(getpgid, pid_t, pid);
COMPAT_SYSCALL_WRAP1(fchdir, unsigned int, fd);
COMPAT_SYSCALL_WRAP2(bdflush, int, func, long, data);
COMPAT_SYSCALL_WRAP3(sysfs, int, option, unsigned long, arg1, unsigned long, arg2);
COMPAT_SYSCALL_WRAP1(s390_personality, unsigned int, personality);
COMPAT_SYSCALL_WRAP5(llseek, unsigned int, fd, unsigned long, high, unsigned long, low, loff_t __user *, result, unsigned int, whence);
COMPAT_SYSCALL_WRAP2(flock, unsigned int, fd, unsigned int, cmd);
COMPAT_SYSCALL_WRAP3(msync, unsigned long, start, size_t, len, int, flags);
COMPAT_SYSCALL_WRAP1(getsid, pid_t, pid);
COMPAT_SYSCALL_WRAP1(fdatasync, unsigned int, fd);
COMPAT_SYSCALL_WRAP2(mlock, unsigned long, start, size_t, len);
COMPAT_SYSCALL_WRAP2(munlock, unsigned long, start, size_t, len);
COMPAT_SYSCALL_WRAP1(mlockall, int, flags);
COMPAT_SYSCALL_WRAP2(sched_setparam, pid_t, pid, struct sched_param __user *, param);
COMPAT_SYSCALL_WRAP2(sched_getparam, pid_t, pid, struct sched_param __user *, param);
COMPAT_SYSCALL_WRAP3(sched_setscheduler, pid_t, pid, int, policy, struct sched_param __user *, param);
COMPAT_SYSCALL_WRAP1(sched_getscheduler, pid_t, pid);
COMPAT_SYSCALL_WRAP1(sched_get_priority_max, int, policy);
COMPAT_SYSCALL_WRAP1(sched_get_priority_min, int, policy);
COMPAT_SYSCALL_WRAP5(mremap, unsigned long, addr, unsigned long, old_len, unsigned long, new_len, unsigned long, flags, unsigned long, new_addr);
COMPAT_SYSCALL_WRAP3(poll, struct pollfd __user *, ufds, unsigned int, nfds, int, timeout);
COMPAT_SYSCALL_WRAP5(prctl, int, option, unsigned long, arg2, unsigned long, arg3, unsigned long, arg4, unsigned long, arg5);
COMPAT_SYSCALL_WRAP2(getcwd, char __user *, buf, unsigned long, size);
COMPAT_SYSCALL_WRAP2(capget, cap_user_header_t, header, cap_user_data_t, dataptr);
COMPAT_SYSCALL_WRAP2(capset, cap_user_header_t, header, const cap_user_data_t, data);
COMPAT_SYSCALL_WRAP3(lchown, const char __user *, filename, uid_t, user, gid_t, group);
COMPAT_SYSCALL_WRAP2(setreuid, uid_t, ruid, uid_t, euid);
COMPAT_SYSCALL_WRAP2(setregid, gid_t, rgid, gid_t, egid);
COMPAT_SYSCALL_WRAP2(getgroups, int, gidsetsize, gid_t __user *, grouplist);
COMPAT_SYSCALL_WRAP2(setgroups, int, gidsetsize, gid_t __user *, grouplist);
COMPAT_SYSCALL_WRAP3(fchown, unsigned int, fd, uid_t, user, gid_t, group);
COMPAT_SYSCALL_WRAP3(setresuid, uid_t, ruid, uid_t, euid, uid_t, suid);
COMPAT_SYSCALL_WRAP3(getresuid, uid_t __user *, ruid, uid_t __user *, euid, uid_t __user *, suid);
COMPAT_SYSCALL_WRAP3(setresgid, gid_t, rgid, gid_t, egid, gid_t, sgid);
COMPAT_SYSCALL_WRAP3(getresgid, gid_t __user *, rgid, gid_t __user *, egid, gid_t __user *, sgid);
COMPAT_SYSCALL_WRAP3(chown, const char __user *, filename, uid_t, user, gid_t, group);
COMPAT_SYSCALL_WRAP1(setuid, uid_t, uid);
COMPAT_SYSCALL_WRAP1(setgid, gid_t, gid);
COMPAT_SYSCALL_WRAP1(setfsuid, uid_t, uid);
COMPAT_SYSCALL_WRAP1(setfsgid, gid_t, gid);
COMPAT_SYSCALL_WRAP2(pivot_root, const char __user *, new_root, const char __user *, put_old);
COMPAT_SYSCALL_WRAP3(mincore, unsigned long, start, size_t, len, unsigned char __user *, vec);
COMPAT_SYSCALL_WRAP3(madvise, unsigned long, start, size_t, len, int, behavior);
COMPAT_SYSCALL_WRAP5(setxattr, const char __user *, path, const char __user *, name, const void __user *, value, size_t, size, int, flags);
COMPAT_SYSCALL_WRAP5(lsetxattr, const char __user *, path, const char __user *, name, const void __user *, value, size_t, size, int, flags);
COMPAT_SYSCALL_WRAP5(fsetxattr, int, fd, const char __user *, name, const void __user *, value, size_t, size, int, flags);
COMPAT_SYSCALL_WRAP3(getdents64, unsigned int, fd, struct linux_dirent64 __user *, dirent, unsigned int, count);
COMPAT_SYSCALL_WRAP4(getxattr, const char __user *, path, const char __user *, name, void __user *, value, size_t, size);
COMPAT_SYSCALL_WRAP4(lgetxattr, const char __user *, path, const char __user *, name, void __user *, value, size_t, size);
COMPAT_SYSCALL_WRAP4(fgetxattr, int, fd, const char __user *, name, void __user *, value, size_t, size);
COMPAT_SYSCALL_WRAP3(listxattr, const char __user *, path, char __user *, list, size_t, size);
COMPAT_SYSCALL_WRAP3(llistxattr, const char __user *, path, char __user *, list, size_t, size);
COMPAT_SYSCALL_WRAP3(flistxattr, int, fd, char __user *, list, size_t, size);
COMPAT_SYSCALL_WRAP2(removexattr, const char __user *, path, const char __user *, name);
COMPAT_SYSCALL_WRAP2(lremovexattr, const char __user *, path, const char __user *, name);
COMPAT_SYSCALL_WRAP2(fremovexattr, int, fd, const char __user *, name);
COMPAT_SYSCALL_WRAP1(exit_group, int, error_code);
COMPAT_SYSCALL_WRAP1(set_tid_address, int __user *, tidptr);
COMPAT_SYSCALL_WRAP1(epoll_create, int, size);
COMPAT_SYSCALL_WRAP4(epoll_ctl, int, epfd, int, op, int, fd, struct epoll_event __user *, event);
COMPAT_SYSCALL_WRAP4(epoll_wait, int, epfd, struct epoll_event __user *, events, int, maxevents, int, timeout);
COMPAT_SYSCALL_WRAP1(timer_getoverrun, timer_t, timer_id);
COMPAT_SYSCALL_WRAP1(timer_delete, compat_timer_t, compat_timer_id);
COMPAT_SYSCALL_WRAP1(io_destroy, aio_context_t, ctx);
COMPAT_SYSCALL_WRAP3(io_cancel, aio_context_t, ctx_id, struct iocb __user *, iocb, struct io_event __user *, result);
COMPAT_SYSCALL_WRAP1(mq_unlink, const char __user *, name);
COMPAT_SYSCALL_WRAP5(add_key, const char __user *, tp, const char __user *, dsc, const void __user *, pld, size_t, len, key_serial_t, id);
COMPAT_SYSCALL_WRAP4(request_key, const char __user *, tp, const char __user *, dsc, const char __user *, info, key_serial_t, id);
COMPAT_SYSCALL_WRAP5(remap_file_pages, unsigned long, start, unsigned long, size, unsigned long, prot, unsigned long, pgoff, unsigned long, flags);
COMPAT_SYSCALL_WRAP3(ioprio_set, int, which, int, who, int, ioprio);
COMPAT_SYSCALL_WRAP2(ioprio_get, int, which, int, who);
COMPAT_SYSCALL_WRAP3(inotify_add_watch, int, fd, const char __user *, path, u32, mask);
COMPAT_SYSCALL_WRAP2(inotify_rm_watch, int, fd, __s32, wd);
COMPAT_SYSCALL_WRAP3(mkdirat, int, dfd, const char __user *, pathname, umode_t, mode);
COMPAT_SYSCALL_WRAP4(mknodat, int, dfd, const char __user *, filename, umode_t, mode, unsigned, dev);
COMPAT_SYSCALL_WRAP5(fchownat, int, dfd, const char __user *, filename, uid_t, user, gid_t, group, int, flag);
COMPAT_SYSCALL_WRAP3(unlinkat, int, dfd, const char __user *, pathname, int, flag);
COMPAT_SYSCALL_WRAP4(renameat, int, olddfd, const char __user *, oldname, int, newdfd, const char __user *, newname);
COMPAT_SYSCALL_WRAP5(linkat, int, olddfd, const char __user *, oldname, int, newdfd, const char __user *, newname, int, flags);
COMPAT_SYSCALL_WRAP3(symlinkat, const char __user *, oldname, int, newdfd, const char __user *, newname);
COMPAT_SYSCALL_WRAP4(readlinkat, int, dfd, const char __user *, path, char __user *, buf, int, bufsiz);
COMPAT_SYSCALL_WRAP3(fchmodat, int, dfd, const char __user *, filename, umode_t, mode);
COMPAT_SYSCALL_WRAP3(faccessat, int, dfd, const char __user *, filename, int, mode);
COMPAT_SYSCALL_WRAP1(unshare, unsigned long, unshare_flags);
COMPAT_SYSCALL_WRAP6(splice, int, fd_in, loff_t __user *, off_in, int, fd_out, loff_t __user *, off_out, size_t, len, unsigned int, flags);
COMPAT_SYSCALL_WRAP4(tee, int, fdin, int, fdout, size_t, len, unsigned int, flags);
COMPAT_SYSCALL_WRAP3(getcpu, unsigned __user *, cpu, unsigned __user *, node, struct getcpu_cache __user *, cache);
COMPAT_SYSCALL_WRAP1(eventfd, unsigned int, count);
COMPAT_SYSCALL_WRAP2(timerfd_create, int, clockid, int, flags);
COMPAT_SYSCALL_WRAP2(eventfd2, unsigned int, count, int, flags);
COMPAT_SYSCALL_WRAP1(inotify_init1, int, flags);
COMPAT_SYSCALL_WRAP2(pipe2, int __user *, fildes, int, flags);
COMPAT_SYSCALL_WRAP3(dup3, unsigned int, oldfd, unsigned int, newfd, int, flags);
COMPAT_SYSCALL_WRAP1(epoll_create1, int, flags);
COMPAT_SYSCALL_WRAP2(tkill, int, pid, int, sig);
COMPAT_SYSCALL_WRAP3(tgkill, int, tgid, int, pid, int, sig);
COMPAT_SYSCALL_WRAP5(perf_event_open, struct perf_event_attr __user *, attr_uptr, pid_t, pid, int, cpu, int, group_fd, unsigned long, flags);
COMPAT_SYSCALL_WRAP5(clone, unsigned long, newsp, unsigned long, clone_flags, int __user *, parent_tidptr, int __user *, child_tidptr, unsigned long, tls);
COMPAT_SYSCALL_WRAP2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags);
COMPAT_SYSCALL_WRAP4(prlimit64, pid_t, pid, unsigned int, resource, const struct rlimit64 __user *, new_rlim, struct rlimit64 __user *, old_rlim);
COMPAT_SYSCALL_WRAP5(name_to_handle_at, int, dfd, const char __user *, name, struct file_handle __user *, handle, int __user *, mnt_id, int, flag);
COMPAT_SYSCALL_WRAP1(syncfs, int, fd);
COMPAT_SYSCALL_WRAP2(setns, int, fd, int, nstype);
COMPAT_SYSCALL_WRAP2(s390_runtime_instr, int, command, int, signum);
COMPAT_SYSCALL_WRAP5(kcmp, pid_t, pid1, pid_t, pid2, int, type, unsigned long, idx1, unsigned long, idx2);
COMPAT_SYSCALL_WRAP3(finit_module, int, fd, const char __user *, uargs, int, flags);
COMPAT_SYSCALL_WRAP3(sched_setattr, pid_t, pid, struct sched_attr __user *, attr, unsigned int, flags);
COMPAT_SYSCALL_WRAP4(sched_getattr, pid_t, pid, struct sched_attr __user *, attr, unsigned int, size, unsigned int, flags);
COMPAT_SYSCALL_WRAP5(renameat2, int, olddfd, const char __user *, oldname, int, newdfd, const char __user *, newname, unsigned int, flags);
COMPAT_SYSCALL_WRAP3(seccomp, unsigned int, op, unsigned int, flags, const char __user *, uargs)
COMPAT_SYSCALL_WRAP3(getrandom, char __user *, buf, size_t, count, unsigned int, flags)
COMPAT_SYSCALL_WRAP2(memfd_create, const char __user *, uname, unsigned int, flags)
COMPAT_SYSCALL_WRAP3(bpf, int, cmd, union bpf_attr *, attr, unsigned int, size);
COMPAT_SYSCALL_WRAP3(s390_pci_mmio_write, const unsigned long, mmio_addr, const void __user *, user_buffer, const size_t, length);
COMPAT_SYSCALL_WRAP3(s390_pci_mmio_read, const unsigned long, mmio_addr, void __user *, user_buffer, const size_t, length);
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