Revision 595d153dd1022392083ac93a1550382cbee127e0 authored by Michael Ellerman on 26 May 2020, 06:18:08 UTC, committed by Michael Ellerman on 26 May 2020, 07:32:37 UTC
Commit 702f09805222 ("powerpc/64s/exception: Remove lite interrupt
return") changed the interrupt return path to not restore non-volatile
registers by default, and explicitly restore them in paths where it is
required.
But it missed that the facility unavailable exception can sometimes
modify user registers, ie. when it does emulation of move from DSCR.
This is seen as a failure of the dscr_sysfs_thread_test:
test: dscr_sysfs_thread_test
[cpu 0] User DSCR should be 1 but is 0
failure: dscr_sysfs_thread_test
So restore non-volatile GPRs after facility unavailable exceptions.
Currently the hypervisor facility unavailable exception is also wired
up to call facility_unavailable_exception().
In practice we should never take a hypervisor facility unavailable
exception for the DSCR. On older bare metal systems we set HFSCR_DSCR
unconditionally in __init_HFSCR, or on newer systems it should be
enabled via the "data-stream-control-register" device tree CPU
feature.
Even if it's not, since commit f3c99f97a3cd ("KVM: PPC: Book3S HV:
Don't access HFSCR, LPIDR or LPCR when running nested"), the KVM code
has unconditionally set HFSCR_DSCR when running guests.
So we should only get a hypervisor facility unavailable for the DSCR
if skiboot has disabled the "data-stream-control-register" feature,
and we are somehow in guest context but not via KVM.
Given all that, it should be unnecessary to add a restore of
non-volatile GPRs after the hypervisor facility exception, because we
never expect to hit that path. But equally we may as well add the
restore, because we never expect to hit that path, and if we ever did,
at least we would correctly restore the registers to their post
emulation state.
In future we can split the non-HV and HV facility unavailable handling
so that there is no emulation in the HV handler, and then remove the
restore for the HV case.
Fixes: 702f09805222 ("powerpc/64s/exception: Remove lite interrupt return")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200526061808.2472279-1-mpe@ellerman.id.au
1 parent 8659a0e
sys_ni.c
// SPDX-License-Identifier: GPL-2.0
#include <linux/linkage.h>
#include <linux/errno.h>
#include <asm/unistd.h>
#ifdef CONFIG_ARCH_HAS_SYSCALL_WRAPPER
/* Architectures may override COND_SYSCALL and COND_SYSCALL_COMPAT */
#include <asm/syscall_wrapper.h>
#endif /* CONFIG_ARCH_HAS_SYSCALL_WRAPPER */
/* we can't #include <linux/syscalls.h> here,
but tell gcc to not warn with -Wmissing-prototypes */
asmlinkage long sys_ni_syscall(void);
/*
* Non-implemented system calls get redirected here.
*/
asmlinkage long sys_ni_syscall(void)
{
return -ENOSYS;
}
#ifndef COND_SYSCALL
#define COND_SYSCALL(name) cond_syscall(sys_##name)
#endif /* COND_SYSCALL */
#ifndef COND_SYSCALL_COMPAT
#define COND_SYSCALL_COMPAT(name) cond_syscall(compat_sys_##name)
#endif /* COND_SYSCALL_COMPAT */
/*
* This list is kept in the same order as include/uapi/asm-generic/unistd.h.
* Architecture specific entries go below, followed by deprecated or obsolete
* system calls.
*/
COND_SYSCALL(io_setup);
COND_SYSCALL_COMPAT(io_setup);
COND_SYSCALL(io_destroy);
COND_SYSCALL(io_submit);
COND_SYSCALL_COMPAT(io_submit);
COND_SYSCALL(io_cancel);
COND_SYSCALL(io_getevents_time32);
COND_SYSCALL(io_getevents);
COND_SYSCALL(io_pgetevents_time32);
COND_SYSCALL(io_pgetevents);
COND_SYSCALL_COMPAT(io_pgetevents_time32);
COND_SYSCALL_COMPAT(io_pgetevents);
COND_SYSCALL(io_uring_setup);
COND_SYSCALL(io_uring_enter);
COND_SYSCALL(io_uring_register);
/* fs/xattr.c */
/* fs/dcache.c */
/* fs/cookies.c */
COND_SYSCALL(lookup_dcookie);
COND_SYSCALL_COMPAT(lookup_dcookie);
/* fs/eventfd.c */
COND_SYSCALL(eventfd2);
/* fs/eventfd.c */
COND_SYSCALL(epoll_create1);
COND_SYSCALL(epoll_ctl);
COND_SYSCALL(epoll_pwait);
COND_SYSCALL_COMPAT(epoll_pwait);
/* fs/fcntl.c */
/* fs/inotify_user.c */
COND_SYSCALL(inotify_init1);
COND_SYSCALL(inotify_add_watch);
COND_SYSCALL(inotify_rm_watch);
/* fs/ioctl.c */
/* fs/ioprio.c */
COND_SYSCALL(ioprio_set);
COND_SYSCALL(ioprio_get);
/* fs/locks.c */
COND_SYSCALL(flock);
/* fs/namei.c */
/* fs/namespace.c */
/* fs/nfsctl.c */
/* fs/open.c */
/* fs/pipe.c */
/* fs/quota.c */
COND_SYSCALL(quotactl);
/* fs/readdir.c */
/* fs/read_write.c */
/* fs/sendfile.c */
/* fs/select.c */
/* fs/signalfd.c */
COND_SYSCALL(signalfd4);
COND_SYSCALL_COMPAT(signalfd4);
/* fs/splice.c */
/* fs/stat.c */
/* fs/sync.c */
/* fs/timerfd.c */
COND_SYSCALL(timerfd_create);
COND_SYSCALL(timerfd_settime);
COND_SYSCALL(timerfd_settime32);
COND_SYSCALL(timerfd_gettime);
COND_SYSCALL(timerfd_gettime32);
/* fs/utimes.c */
/* kernel/acct.c */
COND_SYSCALL(acct);
/* kernel/capability.c */
COND_SYSCALL(capget);
COND_SYSCALL(capset);
/* kernel/exec_domain.c */
/* kernel/exit.c */
/* kernel/fork.c */
/* __ARCH_WANT_SYS_CLONE3 */
COND_SYSCALL(clone3);
/* kernel/futex.c */
COND_SYSCALL(futex);
COND_SYSCALL(futex_time32);
COND_SYSCALL(set_robust_list);
COND_SYSCALL_COMPAT(set_robust_list);
COND_SYSCALL(get_robust_list);
COND_SYSCALL_COMPAT(get_robust_list);
/* kernel/hrtimer.c */
/* kernel/itimer.c */
/* kernel/kexec.c */
COND_SYSCALL(kexec_load);
COND_SYSCALL_COMPAT(kexec_load);
/* kernel/module.c */
COND_SYSCALL(init_module);
COND_SYSCALL(delete_module);
/* kernel/posix-timers.c */
/* kernel/printk.c */
COND_SYSCALL(syslog);
/* kernel/ptrace.c */
/* kernel/sched/core.c */
/* kernel/sys.c */
COND_SYSCALL(setregid);
COND_SYSCALL(setgid);
COND_SYSCALL(setreuid);
COND_SYSCALL(setuid);
COND_SYSCALL(setresuid);
COND_SYSCALL(getresuid);
COND_SYSCALL(setresgid);
COND_SYSCALL(getresgid);
COND_SYSCALL(setfsuid);
COND_SYSCALL(setfsgid);
COND_SYSCALL(setgroups);
COND_SYSCALL(getgroups);
/* kernel/time.c */
/* kernel/timer.c */
/* ipc/mqueue.c */
COND_SYSCALL(mq_open);
COND_SYSCALL_COMPAT(mq_open);
COND_SYSCALL(mq_unlink);
COND_SYSCALL(mq_timedsend);
COND_SYSCALL(mq_timedsend_time32);
COND_SYSCALL(mq_timedreceive);
COND_SYSCALL(mq_timedreceive_time32);
COND_SYSCALL(mq_notify);
COND_SYSCALL_COMPAT(mq_notify);
COND_SYSCALL(mq_getsetattr);
COND_SYSCALL_COMPAT(mq_getsetattr);
/* ipc/msg.c */
COND_SYSCALL(msgget);
COND_SYSCALL(old_msgctl);
COND_SYSCALL(msgctl);
COND_SYSCALL_COMPAT(msgctl);
COND_SYSCALL_COMPAT(old_msgctl);
COND_SYSCALL(msgrcv);
COND_SYSCALL_COMPAT(msgrcv);
COND_SYSCALL(msgsnd);
COND_SYSCALL_COMPAT(msgsnd);
/* ipc/sem.c */
COND_SYSCALL(semget);
COND_SYSCALL(old_semctl);
COND_SYSCALL(semctl);
COND_SYSCALL_COMPAT(semctl);
COND_SYSCALL_COMPAT(old_semctl);
COND_SYSCALL(semtimedop);
COND_SYSCALL(semtimedop_time32);
COND_SYSCALL(semop);
/* ipc/shm.c */
COND_SYSCALL(shmget);
COND_SYSCALL(old_shmctl);
COND_SYSCALL(shmctl);
COND_SYSCALL_COMPAT(shmctl);
COND_SYSCALL_COMPAT(old_shmctl);
COND_SYSCALL(shmat);
COND_SYSCALL_COMPAT(shmat);
COND_SYSCALL(shmdt);
/* net/socket.c */
COND_SYSCALL(socket);
COND_SYSCALL(socketpair);
COND_SYSCALL(bind);
COND_SYSCALL(listen);
COND_SYSCALL(accept);
COND_SYSCALL(connect);
COND_SYSCALL(getsockname);
COND_SYSCALL(getpeername);
COND_SYSCALL(setsockopt);
COND_SYSCALL_COMPAT(setsockopt);
COND_SYSCALL(getsockopt);
COND_SYSCALL_COMPAT(getsockopt);
COND_SYSCALL(sendto);
COND_SYSCALL(shutdown);
COND_SYSCALL(recvfrom);
COND_SYSCALL_COMPAT(recvfrom);
COND_SYSCALL(sendmsg);
COND_SYSCALL_COMPAT(sendmsg);
COND_SYSCALL(recvmsg);
COND_SYSCALL_COMPAT(recvmsg);
/* mm/filemap.c */
/* mm/nommu.c, also with MMU */
COND_SYSCALL(mremap);
/* security/keys/keyctl.c */
COND_SYSCALL(add_key);
COND_SYSCALL(request_key);
COND_SYSCALL(keyctl);
COND_SYSCALL_COMPAT(keyctl);
/* arch/example/kernel/sys_example.c */
/* mm/fadvise.c */
COND_SYSCALL(fadvise64_64);
/* mm/, CONFIG_MMU only */
COND_SYSCALL(swapon);
COND_SYSCALL(swapoff);
COND_SYSCALL(mprotect);
COND_SYSCALL(msync);
COND_SYSCALL(mlock);
COND_SYSCALL(munlock);
COND_SYSCALL(mlockall);
COND_SYSCALL(munlockall);
COND_SYSCALL(mincore);
COND_SYSCALL(madvise);
COND_SYSCALL(remap_file_pages);
COND_SYSCALL(mbind);
COND_SYSCALL_COMPAT(mbind);
COND_SYSCALL(get_mempolicy);
COND_SYSCALL_COMPAT(get_mempolicy);
COND_SYSCALL(set_mempolicy);
COND_SYSCALL_COMPAT(set_mempolicy);
COND_SYSCALL(migrate_pages);
COND_SYSCALL_COMPAT(migrate_pages);
COND_SYSCALL(move_pages);
COND_SYSCALL_COMPAT(move_pages);
COND_SYSCALL(perf_event_open);
COND_SYSCALL(accept4);
COND_SYSCALL(recvmmsg);
COND_SYSCALL(recvmmsg_time32);
COND_SYSCALL_COMPAT(recvmmsg_time32);
COND_SYSCALL_COMPAT(recvmmsg_time64);
/*
* Architecture specific syscalls: see further below
*/
/* fanotify */
COND_SYSCALL(fanotify_init);
COND_SYSCALL(fanotify_mark);
/* open by handle */
COND_SYSCALL(name_to_handle_at);
COND_SYSCALL(open_by_handle_at);
COND_SYSCALL_COMPAT(open_by_handle_at);
COND_SYSCALL(sendmmsg);
COND_SYSCALL_COMPAT(sendmmsg);
COND_SYSCALL(process_vm_readv);
COND_SYSCALL_COMPAT(process_vm_readv);
COND_SYSCALL(process_vm_writev);
COND_SYSCALL_COMPAT(process_vm_writev);
/* compare kernel pointers */
COND_SYSCALL(kcmp);
COND_SYSCALL(finit_module);
/* operate on Secure Computing state */
COND_SYSCALL(seccomp);
COND_SYSCALL(memfd_create);
/* access BPF programs and maps */
COND_SYSCALL(bpf);
/* execveat */
COND_SYSCALL(execveat);
COND_SYSCALL(userfaultfd);
/* membarrier */
COND_SYSCALL(membarrier);
COND_SYSCALL(mlock2);
COND_SYSCALL(copy_file_range);
/* memory protection keys */
COND_SYSCALL(pkey_mprotect);
COND_SYSCALL(pkey_alloc);
COND_SYSCALL(pkey_free);
/*
* Architecture specific weak syscall entries.
*/
/* pciconfig: alpha, arm, arm64, ia64, sparc */
COND_SYSCALL(pciconfig_read);
COND_SYSCALL(pciconfig_write);
COND_SYSCALL(pciconfig_iobase);
/* sys_socketcall: arm, mips, x86, ... */
COND_SYSCALL(socketcall);
COND_SYSCALL_COMPAT(socketcall);
/* compat syscalls for arm64, x86, ... */
COND_SYSCALL_COMPAT(sysctl);
COND_SYSCALL_COMPAT(fanotify_mark);
/* x86 */
COND_SYSCALL(vm86old);
COND_SYSCALL(modify_ldt);
COND_SYSCALL_COMPAT(quotactl32);
COND_SYSCALL(vm86);
COND_SYSCALL(kexec_file_load);
/* s390 */
COND_SYSCALL(s390_pci_mmio_read);
COND_SYSCALL(s390_pci_mmio_write);
COND_SYSCALL(s390_ipc);
COND_SYSCALL_COMPAT(s390_ipc);
/* powerpc */
COND_SYSCALL(rtas);
COND_SYSCALL(spu_run);
COND_SYSCALL(spu_create);
COND_SYSCALL(subpage_prot);
/*
* Deprecated system calls which are still defined in
* include/uapi/asm-generic/unistd.h and wanted by >= 1 arch
*/
/* __ARCH_WANT_SYSCALL_NO_FLAGS */
COND_SYSCALL(epoll_create);
COND_SYSCALL(inotify_init);
COND_SYSCALL(eventfd);
COND_SYSCALL(signalfd);
COND_SYSCALL_COMPAT(signalfd);
/* __ARCH_WANT_SYSCALL_OFF_T */
COND_SYSCALL(fadvise64);
/* __ARCH_WANT_SYSCALL_DEPRECATED */
COND_SYSCALL(epoll_wait);
COND_SYSCALL(recv);
COND_SYSCALL_COMPAT(recv);
COND_SYSCALL(send);
COND_SYSCALL(bdflush);
COND_SYSCALL(uselib);
/* optional: time32 */
COND_SYSCALL(time32);
COND_SYSCALL(stime32);
COND_SYSCALL(utime32);
COND_SYSCALL(adjtimex_time32);
COND_SYSCALL(sched_rr_get_interval_time32);
COND_SYSCALL(nanosleep_time32);
COND_SYSCALL(rt_sigtimedwait_time32);
COND_SYSCALL_COMPAT(rt_sigtimedwait_time32);
COND_SYSCALL(timer_settime32);
COND_SYSCALL(timer_gettime32);
COND_SYSCALL(clock_settime32);
COND_SYSCALL(clock_gettime32);
COND_SYSCALL(clock_getres_time32);
COND_SYSCALL(clock_nanosleep_time32);
COND_SYSCALL(utimes_time32);
COND_SYSCALL(futimesat_time32);
COND_SYSCALL(pselect6_time32);
COND_SYSCALL_COMPAT(pselect6_time32);
COND_SYSCALL(ppoll_time32);
COND_SYSCALL_COMPAT(ppoll_time32);
COND_SYSCALL(utimensat_time32);
COND_SYSCALL(clock_adjtime32);
/*
* The syscalls below are not found in include/uapi/asm-generic/unistd.h
*/
/* obsolete: SGETMASK_SYSCALL */
COND_SYSCALL(sgetmask);
COND_SYSCALL(ssetmask);
/* obsolete: SYSFS_SYSCALL */
COND_SYSCALL(sysfs);
/* obsolete: __ARCH_WANT_SYS_IPC */
COND_SYSCALL(ipc);
COND_SYSCALL_COMPAT(ipc);
/* obsolete: UID16 */
COND_SYSCALL(chown16);
COND_SYSCALL(fchown16);
COND_SYSCALL(getegid16);
COND_SYSCALL(geteuid16);
COND_SYSCALL(getgid16);
COND_SYSCALL(getgroups16);
COND_SYSCALL(getresgid16);
COND_SYSCALL(getresuid16);
COND_SYSCALL(getuid16);
COND_SYSCALL(lchown16);
COND_SYSCALL(setfsgid16);
COND_SYSCALL(setfsuid16);
COND_SYSCALL(setgid16);
COND_SYSCALL(setgroups16);
COND_SYSCALL(setregid16);
COND_SYSCALL(setresgid16);
COND_SYSCALL(setresuid16);
COND_SYSCALL(setreuid16);
COND_SYSCALL(setuid16);
/* restartable sequence */
COND_SYSCALL(rseq);
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