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
checksyscalls.sh
#!/bin/sh
# SPDX-License-Identifier: GPL-2.0
#
# Check if current architecture are missing any function calls compared
# to i386.
# i386 define a number of legacy system calls that are i386 specific
# and listed below so they are ignored.
#
# Usage:
# checksyscalls.sh gcc gcc-options
#
ignore_list() {
cat << EOF
#include <asm/types.h>
#include <asm/unistd.h>
/* *at */
#define __IGNORE_open /* openat */
#define __IGNORE_link /* linkat */
#define __IGNORE_unlink /* unlinkat */
#define __IGNORE_mknod /* mknodat */
#define __IGNORE_chmod /* fchmodat */
#define __IGNORE_chown /* fchownat */
#define __IGNORE_mkdir /* mkdirat */
#define __IGNORE_rmdir /* unlinkat */
#define __IGNORE_lchown /* fchownat */
#define __IGNORE_access /* faccessat */
#define __IGNORE_rename /* renameat2 */
#define __IGNORE_readlink /* readlinkat */
#define __IGNORE_symlink /* symlinkat */
#define __IGNORE_utimes /* futimesat */
#define __IGNORE_stat /* fstatat */
#define __IGNORE_lstat /* fstatat */
#define __IGNORE_stat64 /* fstatat64 */
#define __IGNORE_lstat64 /* fstatat64 */
#ifndef __ARCH_WANT_SET_GET_RLIMIT
#define __IGNORE_getrlimit /* getrlimit */
#define __IGNORE_setrlimit /* setrlimit */
#endif
/* Missing flags argument */
#define __IGNORE_renameat /* renameat2 */
/* CLOEXEC flag */
#define __IGNORE_pipe /* pipe2 */
#define __IGNORE_dup2 /* dup3 */
#define __IGNORE_epoll_create /* epoll_create1 */
#define __IGNORE_inotify_init /* inotify_init1 */
#define __IGNORE_eventfd /* eventfd2 */
#define __IGNORE_signalfd /* signalfd4 */
/* MMU */
#ifndef CONFIG_MMU
#define __IGNORE_madvise
#define __IGNORE_mbind
#define __IGNORE_mincore
#define __IGNORE_mlock
#define __IGNORE_mlockall
#define __IGNORE_munlock
#define __IGNORE_munlockall
#define __IGNORE_mprotect
#define __IGNORE_msync
#define __IGNORE_migrate_pages
#define __IGNORE_move_pages
#define __IGNORE_remap_file_pages
#define __IGNORE_get_mempolicy
#define __IGNORE_set_mempolicy
#define __IGNORE_swapoff
#define __IGNORE_swapon
#endif
/* System calls for 32-bit kernels only */
#if BITS_PER_LONG == 64
#define __IGNORE_sendfile64
#define __IGNORE_ftruncate64
#define __IGNORE_truncate64
#define __IGNORE_stat64
#define __IGNORE_lstat64
#define __IGNORE_fstat64
#define __IGNORE_fcntl64
#define __IGNORE_fadvise64_64
#define __IGNORE_fstatat64
#define __IGNORE_fstatfs64
#define __IGNORE_statfs64
#define __IGNORE_llseek
#define __IGNORE_mmap2
#define __IGNORE_clock_gettime64
#define __IGNORE_clock_settime64
#define __IGNORE_clock_adjtime64
#define __IGNORE_clock_getres_time64
#define __IGNORE_clock_nanosleep_time64
#define __IGNORE_timer_gettime64
#define __IGNORE_timer_settime64
#define __IGNORE_timerfd_gettime64
#define __IGNORE_timerfd_settime64
#define __IGNORE_utimensat_time64
#define __IGNORE_pselect6_time64
#define __IGNORE_ppoll_time64
#define __IGNORE_io_pgetevents_time64
#define __IGNORE_recvmmsg_time64
#define __IGNORE_mq_timedsend_time64
#define __IGNORE_mq_timedreceive_time64
#define __IGNORE_semtimedop_time64
#define __IGNORE_rt_sigtimedwait_time64
#define __IGNORE_futex_time64
#define __IGNORE_sched_rr_get_interval_time64
#else
#define __IGNORE_sendfile
#define __IGNORE_ftruncate
#define __IGNORE_truncate
#define __IGNORE_stat
#define __IGNORE_lstat
#define __IGNORE_fstat
#define __IGNORE_fcntl
#define __IGNORE_fadvise64
#define __IGNORE_newfstatat
#define __IGNORE_fstatfs
#define __IGNORE_statfs
#define __IGNORE_lseek
#define __IGNORE_mmap
#define __IGNORE_clock_gettime
#define __IGNORE_clock_settime
#define __IGNORE_clock_adjtime
#define __IGNORE_clock_getres
#define __IGNORE_clock_nanosleep
#define __IGNORE_timer_gettime
#define __IGNORE_timer_settime
#define __IGNORE_timerfd_gettime
#define __IGNORE_timerfd_settime
#define __IGNORE_utimensat
#define __IGNORE_pselect6
#define __IGNORE_ppoll
#define __IGNORE_io_pgetevents
#define __IGNORE_recvmmsg
#define __IGNORE_mq_timedsend
#define __IGNORE_mq_timedreceive
#define __IGNORE_semtimedop
#define __IGNORE_rt_sigtimedwait
#define __IGNORE_futex
#define __IGNORE_sched_rr_get_interval
#define __IGNORE_gettimeofday
#define __IGNORE_settimeofday
#define __IGNORE_wait4
#define __IGNORE_adjtimex
#define __IGNORE_nanosleep
#define __IGNORE_io_getevents
#define __IGNORE_recvmmsg
#endif
/* i386-specific or historical system calls */
#define __IGNORE_break
#define __IGNORE_stty
#define __IGNORE_gtty
#define __IGNORE_ftime
#define __IGNORE_prof
#define __IGNORE_lock
#define __IGNORE_mpx
#define __IGNORE_ulimit
#define __IGNORE_profil
#define __IGNORE_ioperm
#define __IGNORE_iopl
#define __IGNORE_idle
#define __IGNORE_modify_ldt
#define __IGNORE_ugetrlimit
#define __IGNORE_vm86
#define __IGNORE_vm86old
#define __IGNORE_set_thread_area
#define __IGNORE_get_thread_area
#define __IGNORE_madvise1
#define __IGNORE_oldstat
#define __IGNORE_oldfstat
#define __IGNORE_oldlstat
#define __IGNORE_oldolduname
#define __IGNORE_olduname
#define __IGNORE_umount
#define __IGNORE_waitpid
#define __IGNORE_stime
#define __IGNORE_nice
#define __IGNORE_signal
#define __IGNORE_sigaction
#define __IGNORE_sgetmask
#define __IGNORE_sigsuspend
#define __IGNORE_sigpending
#define __IGNORE_ssetmask
#define __IGNORE_readdir
#define __IGNORE_socketcall
#define __IGNORE_ipc
#define __IGNORE_sigreturn
#define __IGNORE_sigprocmask
#define __IGNORE_bdflush
#define __IGNORE__llseek
#define __IGNORE__newselect
#define __IGNORE_create_module
#define __IGNORE_query_module
#define __IGNORE_get_kernel_syms
#define __IGNORE_sysfs
#define __IGNORE_uselib
#define __IGNORE__sysctl
#define __IGNORE_arch_prctl
#define __IGNORE_nfsservctl
/* ... including the "new" 32-bit uid syscalls */
#define __IGNORE_lchown32
#define __IGNORE_getuid32
#define __IGNORE_getgid32
#define __IGNORE_geteuid32
#define __IGNORE_getegid32
#define __IGNORE_setreuid32
#define __IGNORE_setregid32
#define __IGNORE_getgroups32
#define __IGNORE_setgroups32
#define __IGNORE_fchown32
#define __IGNORE_setresuid32
#define __IGNORE_getresuid32
#define __IGNORE_setresgid32
#define __IGNORE_getresgid32
#define __IGNORE_chown32
#define __IGNORE_setuid32
#define __IGNORE_setgid32
#define __IGNORE_setfsuid32
#define __IGNORE_setfsgid32
/* these can be expressed using other calls */
#define __IGNORE_alarm /* setitimer */
#define __IGNORE_creat /* open */
#define __IGNORE_fork /* clone */
#define __IGNORE_futimesat /* utimensat */
#define __IGNORE_getpgrp /* getpgid */
#define __IGNORE_getdents /* getdents64 */
#define __IGNORE_pause /* sigsuspend */
#define __IGNORE_poll /* ppoll */
#define __IGNORE_select /* pselect6 */
#define __IGNORE_epoll_wait /* epoll_pwait */
#define __IGNORE_time /* gettimeofday */
#define __IGNORE_uname /* newuname */
#define __IGNORE_ustat /* statfs */
#define __IGNORE_utime /* utimes */
#define __IGNORE_vfork /* clone */
/* sync_file_range had a stupid ABI. Allow sync_file_range2 instead */
#ifdef __NR_sync_file_range2
#define __IGNORE_sync_file_range
#endif
/* Unmerged syscalls for AFS, STREAMS, etc. */
#define __IGNORE_afs_syscall
#define __IGNORE_getpmsg
#define __IGNORE_putpmsg
#define __IGNORE_vserver
EOF
}
syscall_list() {
grep '^[0-9]' "$1" | sort -n |
while read nr abi name entry ; do
echo "#if !defined(__NR_${name}) && !defined(__IGNORE_${name})"
echo "#warning syscall ${name} not implemented"
echo "#endif"
done
}
(ignore_list && syscall_list $(dirname $0)/../arch/x86/entry/syscalls/syscall_32.tbl) | \
$* -E -x c - > /dev/null
Computing file changes ...
