linux/arch/powerpc/kernel
Michael Ellerman b91eb51824 powerpc/64s: Fix crash in load_fp_state() due to fpexc_mode
The recent commit 01eb01877f ("powerpc/64s: Fix restore_math
unnecessarily changing MSR") changed some of the handling of floating
point/vector restore.

In particular it caused current->thread.fpexc_mode to be copied into
the current MSR (via msr_check_and_set()), rather than just into
regs->msr (which is moved into MSR on return to userspace).

This can lead to a crash in the kernel if we take a floating point
exception when restoring FPSCR:

  Oops: Exception in kernel mode, sig: 8 [#1]
  LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=2048 NUMA PowerNV
  Modules linked in:
  CPU: 3 PID: 101213 Comm: ld64.so.2 Not tainted 5.9.0-rc1-00098-g18445bf405cb-dirty #9
  NIP:  c00000000000fbb4 LR: c00000000001a7ac CTR: c000000000183570
  REGS: c0000016b7cfb3b0 TRAP: 0700   Not tainted  (5.9.0-rc1-00098-g18445bf405cb-dirty)
  MSR:  900000000290b933 <SF,HV,VEC,VSX,EE,FP,ME,IR,DR,RI,LE>  CR: 44002444  XER: 00000000
  CFAR: c00000000001a7a8 IRQMASK: 1
  GPR00: c00000000001ae40 c0000016b7cfb640 c0000000011b7f00 c000001542a0f740
  GPR04: c000001542a0f720 c000001542a0eb00 0000000000000900 c000001542a0eb00
  GPR08: 000000000000000a 0000000000002000 9000000000009033 0000000000000000
  GPR12: 0000000000004000 c0000017ffffd900 0000000000000001 c000000000df5a58
  GPR16: c000000000e19c18 c0000000010e1123 0000000000000001 c000000000e1a638
  GPR20: 0000000000000000 c0000000044b1d00 0000000000000000 c000001542a0f2a0
  GPR24: 00000016c7fe0000 c000001542a0f720 c000000001c93da0 c000000000fe5f28
  GPR28: c000001542a0f720 0000000000800000 c0000016b7cfbe90 0000000002802900
  NIP load_fp_state+0x4/0x214
  LR  restore_math+0x17c/0x1f0
  Call Trace:
    0xc0000016b7cfb680 (unreliable)
    __switch_to+0x330/0x460
    __schedule+0x318/0x920
    schedule+0x74/0x140
    schedule_timeout+0x318/0x3f0
    wait_for_completion+0xc8/0x210
    call_usermodehelper_exec+0x234/0x280
    do_coredump+0xedc/0x13c0
    get_signal+0x1d4/0xbe0
    do_notify_resume+0x1a0/0x490
    interrupt_exit_user_prepare+0x1c4/0x230
    interrupt_return+0x14/0x1c0
  Instruction dump:
  ebe10168 e88101a0 7c8ff120 382101e0 e8010010 7c0803a6 4e800020 790605c4
  782905c4 7c0008a8 7c0008a8 c8030200 <fffe058e> 48000088 c8030000 c8230010

Fix it by only loading the fpexc_mode value into regs->msr.

Also add a comment to explain that although VSX is subject to the
value of fpexc_mode, we don't have to handle that separately because
we only allow VSX to be enabled if FP is also enabled.

Fixes: 01eb01877f ("powerpc/64s: Fix restore_math unnecessarily changing MSR")
Reported-by: Milton Miller <miltonm@us.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Link: https://lore.kernel.org/r/20200825093424.3967813-1-mpe@ellerman.id.au
2020-08-27 17:41:39 +10:00
..
ptrace powerpc/ptrace: Fix build error in pkey_get() 2020-08-07 18:27:26 -07:00
syscalls all arch: remove system call sys_sysctl 2020-08-14 19:56:56 -07:00
trace powerpc: Add a ppc_inst_as_str() helper 2020-07-23 17:41:36 +10:00
vdso32 powerpc/build: vdso linker warning for orphan sections 2020-07-29 21:09:37 +10:00
vdso64 powerpc/build: vdso linker warning for orphan sections 2020-07-29 21:09:37 +10:00
.gitignore .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
align.c powerpc: Use fallthrough pseudo-keyword 2020-07-29 21:09:37 +10:00
asm-offsets.c KVM: PPC: Book3S HV: Save/restore new PMU registers 2020-07-22 21:56:41 +10:00
audit.c
btext.c mm: reorder includes after introduction of linux/pgtable.h 2020-06-09 09:39:13 -07:00
cacheinfo.c powerpc/cacheinfo: Warn if cache object chain becomes unordered 2020-07-30 22:53:48 +10:00
cacheinfo.h powerpc/cacheinfo: add cacheinfo_teardown, cacheinfo_rebuild 2019-06-15 16:52:06 +10:00
compat_audit.c
cpu_setup_6xx.S powerpc/32: Blacklist functions running with MMU disabled for kprobe 2020-06-02 20:59:11 +10:00
cpu_setup_44x.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
cpu_setup_fsl_booke.S powerpc/booke: Spelling s/date/data/ 2019-11-17 01:56:31 -06:00
cpu_setup_pa6t.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 333 2019-06-05 17:37:06 +02:00
cpu_setup_power.S powerpc/perf: Initialize power10 PMU registers in cpu setup routine 2020-07-26 23:34:23 +10:00
cpu_setup_ppc970.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
cputable.c powerpc/kernel: Cleanup machine check function declarations 2020-08-17 14:13:18 +10:00
crash_dump.c powerpc: Add prefixed instructions to instruction data type 2020-05-19 00:10:39 +10:00
dawr.c powerpc/watchpoint: Guest support for 2nd DAWR hcall 2020-07-26 23:34:19 +10:00
dbell.c powerpc: Inline doorbell sending functions 2020-07-29 21:02:09 +10:00
dma-iommu.c powerpc: use the generic dma_ops_bypass mode 2020-07-19 09:29:29 +02:00
dma-mask.c dma-mapping, powerpc: simplify the arch dma_set_mask override 2019-02-18 22:41:03 +11:00
dma-swiotlb.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
dt_cpu_ftrs.c Revert "powerpc/64s: Remove PROT_SAO support" 2020-08-24 14:12:53 +10:00
early_32.c powerpc/fsl_booke/32: implement KASLR infrastructure 2019-11-13 19:27:40 +11:00
eeh_cache.c powerpc/eeh_cache: Don't use pci_dn when inserting new ranges 2020-01-23 21:31:18 +11:00
eeh_driver.c pci-v5.9-changes 2020-08-07 18:48:15 -07:00
eeh_event.c powerpc/eeh: Fix build with STACKTRACE=n 2019-09-14 00:01:14 +10:00
eeh_pe.c powerpc/eeh: Move PE tree setup into the platform 2020-07-26 23:34:21 +10:00
eeh_sysfs.c powerpc/eeh: Pass eeh_dev to eeh_ops->resume_notify() 2020-07-26 23:34:20 +10:00
eeh.c powerpc/eeh: Rename eeh_{add_to|remove_from}_parent_pe() 2020-07-26 23:34:21 +10:00
entry_32.S powerpc: Select ARCH_HAS_MEMBARRIER_SYNC_CORE 2020-07-23 17:43:23 +10:00
entry_64.S powerpc/64s: scv entry should set PPR 2020-08-27 17:41:13 +10:00
epapr_hcalls.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
epapr_paravirt.c powerpc: Use a datatype for instructions 2020-05-19 00:10:37 +10:00
exceptions-64e.S powerpc/64s: Implement interrupt exit logic in C 2020-04-01 13:42:14 +11:00
exceptions-64s.S powerpc updates for 5.9 2020-08-07 10:33:50 -07:00
fadump.c powerpc/fadump: Fix build error with CONFIG_PRESERVE_FA_DUMP=y 2020-07-27 17:04:54 +10:00
firmware.c powerpc/pseries: Add KVM guest doorbell restrictions 2020-07-29 21:02:10 +10:00
fpu.S powerpc: re-initialise lazy FPU/VEC counters on every fault 2020-07-16 13:00:24 +10:00
fsl_booke_entry_mapping.S powerpc/fsl_booke/32: implement KASLR infrastructure 2019-11-13 19:27:40 +11:00
head_8xx.S mm: reorder includes after introduction of linux/pgtable.h 2020-06-09 09:39:13 -07:00
head_32.h Merge branch 'fixes' into next 2020-03-10 15:16:42 +11:00
head_32.S powerpc/32s: Remove TAUException wart in traps.c 2020-07-29 21:08:18 +10:00
head_40x.S powerpc/40x: Fix assembler warning about r0 2020-08-03 22:12:41 +10:00
head_44x.S mm: reorder includes after introduction of linux/pgtable.h 2020-06-09 09:39:13 -07:00
head_64.S powerpc/64: Don't initialise init_task->thread.regs 2020-05-15 11:58:54 +10:00
head_booke.h powerpc: Replace _ALIGN_UP() by ALIGN() 2020-05-11 23:15:15 +10:00
head_fsl_booke.S mm: reorder includes after introduction of linux/pgtable.h 2020-06-09 09:39:13 -07:00
hw_breakpoint.c powerpc/watchpoint: Remove 512 byte boundary 2020-07-26 23:34:19 +10:00
idle_6xx.S powerpc/32: Blacklist functions running with MMU disabled for kprobe 2020-06-02 20:59:11 +10:00
idle_book3e.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
idle_book3s.S powerpc/64s: Reimplement power4_idle code in C 2020-01-16 14:59:37 +10:00
idle_e500.S powerpc/32: Blacklist functions running with MMU disabled for kprobe 2020-06-02 20:59:11 +10:00
idle.c powerpc/64s: Reimplement power4_idle code in C 2020-01-16 14:59:37 +10:00
ima_arch.c powerpc/ima: Fix secure boot rules in ima arch policy 2020-05-07 17:25:54 +10:00
io-workarounds.c mm: reorder includes after introduction of linux/pgtable.h 2020-06-09 09:39:13 -07:00
io.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
iomap.c iomap: constify ioreadX() iomem argument (as in generic implementation) 2020-08-14 19:56:57 -07:00
iommu.c Merge branch 'topic/ppc-kvm' into next 2019-08-30 09:52:57 +10:00
irq.c powerpc/64s: Move HMI IRQ stat from percpu variable to paca. 2020-07-29 23:47:53 +10:00
isa-bridge.c powerpc: remove __ioremap_at and __iounmap_at 2020-06-02 10:59:10 -07:00
jump_label.c powerpc: Use a datatype for instructions 2020-05-19 00:10:37 +10:00
kgdb.c maccess: make get_kernel_nofault() check for minimal type compatibility 2020-06-18 12:10:37 -07:00
kprobes-ftrace.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
kprobes.c powerpc: Add a ppc_inst_as_str() helper 2020-07-23 17:41:36 +10:00
kvm_emul.S powerpc/kvm: Add ifdefs around template code 2019-09-14 00:04:40 +10:00
kvm.c powerpc/kvm: Explicitly mark kvm guest code as __init 2019-09-14 00:04:40 +10:00
l2cr_6xx.S powerpc/32: Blacklist functions running with MMU disabled for kprobe 2020-06-02 20:59:11 +10:00
legacy_serial.c tty/serial: Migrate 8250_fsl to use has_sysrq 2019-12-18 15:04:42 +01:00
Makefile Kbuild updates for v5.9 2020-08-09 14:10:26 -07:00
mce_power.c powerpc/powernv: Machine check handler for POWER10 2020-07-23 17:43:30 +10:00
mce.c powerpc/64s: Move HMI IRQ stat from percpu variable to paca. 2020-07-29 23:47:53 +10:00
misc_32.S powerpc/32: Blacklist functions running with MMU disabled for kprobe 2020-06-02 20:59:11 +10:00
misc_64.S powerpc/book3s64/keys/kuap: Reset AMR/IAMR values on kexec 2020-07-20 22:57:59 +10:00
misc.S powerpc/32: Blacklist functions running with MMU disabled for kprobe 2020-06-02 20:59:11 +10:00
module_32.c powerpc: module_[32|64].c: replace swap function with built-in one 2020-05-11 23:15:14 +10:00
module_64.c maccess: rename probe_kernel_{read,write} to copy_{from,to}_kernel_nofault 2020-06-17 10:57:41 -07:00
module.c powerpc: Use MODULES_VADDR if defined 2020-07-27 00:01:30 +10:00
module.lds
msi.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
note.S powerpc: Add PowerPC Capabilities ELF note 2019-08-30 09:40:15 +10:00
nvram_64.c powerpc updates for 5.8 2020-06-05 12:39:30 -07:00
of_platform.c powerpc/eeh: Remove eeh_dev_phb_init_dynamic() 2020-07-26 23:34:19 +10:00
optprobes_head.S powerpc: Add prefixed instructions to instruction data type 2020-05-19 00:10:39 +10:00
optprobes.c powerpc: Add ppc_inst_as_u64() 2020-05-26 23:36:57 +10:00
paca.c Merge branch 'fixes' into next 2020-07-18 22:43:55 +10:00
pci_32.c powerpc/64: Adjust order in pcibios_init() 2019-08-22 23:11:48 +10:00
pci_64.c powerpc updates for 5.8 2020-06-05 12:39:30 -07:00
pci_dn.c powerpc/eeh: Rename eeh_{add_to|remove_from}_parent_pe() 2020-07-26 23:34:21 +10:00
pci_of_scan.c powerpc/pci: Remove pcibios_setup_bus_devices() 2020-01-06 16:25:29 +11:00
pci-common.c powerpc updates for 5.7 2020-04-05 11:12:59 -07:00
pci-hotplug.c powerpc/eeh: Release EEH device state synchronously 2020-05-18 21:58:44 +10:00
pmc.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
ppc32.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
ppc_save_regs.S powerpc: Improve ppc_save_regs() 2020-04-04 21:40:57 +11:00
proc_powerpc.c proc: convert everything to "struct proc_ops" 2020-02-04 03:05:26 +00:00
process.c powerpc/64s: Fix crash in load_fp_state() due to fpexc_mode 2020-08-27 17:41:39 +10:00
prom_init_check.sh powerpc/prom_init: Undo relocation before entering secure mode 2019-10-29 15:12:17 +11:00
prom_init.c powerpc: fix function annotations to avoid section mismatch warnings with gcc-10 2020-07-30 10:50:07 +10:00
prom_parse.c
prom.c powerpc/drmem: Make LMB walk a bit more flexible 2020-07-29 23:47:54 +10:00
reloc_32.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
reloc_64.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
rtas_flash.c proc: convert everything to "struct proc_ops" 2020-02-04 03:05:26 +00:00
rtas_pci.c mm: reorder includes after introduction of linux/pgtable.h 2020-06-09 09:39:13 -07:00
rtas-proc.c proc: convert everything to "struct proc_ops" 2020-02-04 03:05:26 +00:00
rtas-rtc.c
rtas.c powerpc/rtas: don't online CPUs for partition suspend 2020-07-16 13:12:35 +10:00
rtasd.c powerpc/rtasd: simplify handle_rtas_event(), emit message on events 2020-07-16 13:12:38 +10:00
secure_boot.c powerpc/pseries: Detect secure and trusted boot state of the system. 2020-07-16 14:49:53 +10:00
security.c powerpc/security: Allow for processors that flush the link stack using the special bcctr 2020-07-16 13:12:32 +10:00
secvar-ops.c powerpc/powernv: Add OPAL API interface to access secure variable 2019-11-13 00:33:22 +11:00
secvar-sysfs.c powerpc: expose secure variables to userspace via sysfs 2019-11-13 00:33:22 +11:00
setup_32.c mm: reorder includes after introduction of linux/pgtable.h 2020-06-09 09:39:13 -07:00
setup_64.c powerpc/64s: system call support for scv/rfscv instructions 2020-07-22 23:00:27 +10:00
setup-common.c powerpc: Fix P10 PVR revision in /proc/cpuinfo for SMT4 cores 2020-08-17 13:11:22 +10:00
setup.h powerpc/64: Prevent stack protection in early boot 2020-03-25 12:09:38 +11:00
signal_32.c powerpc/signal_32: Simplify loop in PPC64 save_general_regs() 2020-07-15 12:04:40 +10:00
signal_64.c powerpc/signal64: Don't opencode page prefaulting 2020-07-15 12:04:40 +10:00
signal.c powerpc/64s: system call support for scv/rfscv instructions 2020-07-22 23:00:27 +10:00
signal.h powerpc/64/sycall: Implement syscall entry/exit logic in C 2020-04-01 13:42:13 +11:00
smp-tbsync.c
smp.c powerpc/book3s64/kuap: Move UAMOR setup to key init function 2020-07-20 22:57:59 +10:00
stacktrace.c kernel: rename show_stack_loglvl() => show_stack() 2020-06-09 09:39:13 -07:00
suspend.c PM: hibernate: powerpc: Expose pfn_is_nosave() prototype 2019-06-14 10:48:56 +02:00
swsusp_32.S powerpc/32: Blacklist functions running with MMU disabled for kprobe 2020-06-02 20:59:11 +10:00
swsusp_64.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 505 2019-06-19 17:11:22 +02:00
swsusp_asm64.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 505 2019-06-19 17:11:22 +02:00
swsusp_booke.S
swsusp.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
sys_ppc32.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
syscall_64.c Merge branch 'scv' support into next 2020-07-23 17:43:44 +10:00
syscalls.c y2038: syscalls: change remaining timeval to __kernel_old_timeval 2019-11-15 14:38:29 +01:00
sysfs.c powerpc/perf: Add support for ISA3.1 PMU SPRs 2020-07-22 21:56:41 +10:00
systbl_chk.sh treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
systbl.S powerpc/64/sycall: Implement syscall entry/exit logic in C 2020-04-01 13:42:13 +11:00
tau_6xx.c
time.c powerpc64: Break asm/percpu.h vs spinlock_types.h dependency 2020-07-10 12:00:01 +02:00
tm.S powerpc/tm: update comment about interrupt re-entrancy 2019-07-02 21:39:49 +10:00
traps.c powerpc/32s: Remove TAUException wart in traps.c 2020-07-29 21:08:18 +10:00
ucall.S powerpc/kernel: Add ucall_norets() ultravisor call handler 2019-08-30 09:40:15 +10:00
udbg_16550.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
udbg.c powerpc/udbg: Make it safe to call udbg_printf() always 2019-10-11 19:33:25 +11:00
uprobes.c powerpc: Add ppc_inst_next() 2020-05-26 23:36:51 +10:00
vdso.c powerpc/vdso: Fix vdso cpu truncation 2020-07-16 13:12:47 +10:00
vecemu.c powerpc: Define and use get_user_instr() et. al. 2020-05-19 00:10:37 +10:00
vector.S powerpc: re-initialise lazy FPU/VEC counters on every fault 2020-07-16 13:00:24 +10:00
vmlinux.lds.S powerpc updates for 5.8 2020-06-05 12:39:30 -07:00
watchdog.c powerpc/watchdog: Use hrtimers for per-CPU heartbeat 2019-04-30 11:31:02 +10:00