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
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ptrace
syscalls	all arch: remove system call sys_sysctl	2020-08-14 19:56:56 -07:00
trace
vdso32
vdso64
.gitignore
align.c
asm-offsets.c
audit.c
btext.c
cacheinfo.c
cacheinfo.h
compat_audit.c
cpu_setup_6xx.S
cpu_setup_44x.S
cpu_setup_fsl_booke.S
cpu_setup_pa6t.S
cpu_setup_power.S
cpu_setup_ppc970.S
cputable.c	powerpc/kernel: Cleanup machine check function declarations	2020-08-17 14:13:18 +10:00
crash_dump.c
dawr.c
dbell.c
dma-iommu.c
dma-mask.c
dma-swiotlb.c
dt_cpu_ftrs.c	Revert "powerpc/64s: Remove PROT_SAO support"	2020-08-24 14:12:53 +10:00
early_32.c
eeh.c
eeh_cache.c
eeh_driver.c
eeh_event.c
eeh_pe.c
eeh_sysfs.c
entry_32.S
entry_64.S	powerpc/64s: scv entry should set PPR	2020-08-27 17:41:13 +10:00
epapr_hcalls.S
epapr_paravirt.c
exceptions-64e.S
exceptions-64s.S
fadump.c
firmware.c
fpu.S
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head_8xx.S
head_32.h
head_32.S
head_40x.S
head_44x.S
head_64.S
head_booke.h
head_fsl_booke.S
hw_breakpoint.c
idle.c
idle_6xx.S
idle_book3e.S
idle_book3s.S
idle_e500.S
ima_arch.c
io-workarounds.c
io.c
iomap.c	iomap: constify ioreadX() iomem argument (as in generic implementation)	2020-08-14 19:56:57 -07:00
iommu.c
irq.c
isa-bridge.c
jump_label.c
kgdb.c
kprobes-ftrace.c
kprobes.c
kvm.c
kvm_emul.S
l2cr_6xx.S
legacy_serial.c
Makefile
mce.c
mce_power.c
misc.S
misc_32.S
misc_64.S
module.c
module.lds
module_32.c
module_64.c
msi.c
note.S
nvram_64.c
of_platform.c
optprobes.c
optprobes_head.S
paca.c
pci-common.c
pci-hotplug.c
pci_32.c
pci_64.c
pci_dn.c
pci_of_scan.c
pmc.c
ppc32.h
ppc_save_regs.S
proc_powerpc.c
process.c	powerpc/64s: Fix crash in load_fp_state() due to fpexc_mode	2020-08-27 17:41:39 +10:00
prom.c
prom_init.c
prom_init_check.sh
prom_parse.c
reloc_32.S
reloc_64.S
rtas-proc.c
rtas-rtc.c
rtas.c
rtas_flash.c
rtas_pci.c
rtasd.c
secure_boot.c
security.c
secvar-ops.c
secvar-sysfs.c
setup-common.c	powerpc: Fix P10 PVR revision in /proc/cpuinfo for SMT4 cores	2020-08-17 13:11:22 +10:00
setup.h
setup_32.c
setup_64.c
signal.c
signal.h
signal_32.c
signal_64.c
smp-tbsync.c
smp.c
stacktrace.c
suspend.c
swsusp.c
swsusp_32.S
swsusp_64.c
swsusp_asm64.S
swsusp_booke.S
sys_ppc32.c
syscall_64.c
syscalls.c
sysfs.c
systbl.S
systbl_chk.sh
tau_6xx.c
time.c
tm.S
traps.c
ucall.S
udbg.c
udbg_16550.c
uprobes.c
vdso.c
vecemu.c
vector.S
vmlinux.lds.S
watchdog.c