redonkable
/
alistair23-linux
1
0
Fork 0
Code Releases Activity
alistair23-linux/arch/x86/kernel
History
Borislav Petkov 6827d62a86 x86/mce: Make mce_rdmsrl() panic on an inaccessible MSR 
[ Upstream commit e2def7d49d ]

If an exception needs to be handled while reading an MSR - which is in
most of the cases caused by a #GP on a non-existent MSR - then this
is most likely the incarnation of a BIOS or a hardware bug. Such bug
violates the architectural guarantee that MCA banks are present with all
MSRs belonging to them.

The proper fix belongs in the hardware/firmware - not in the kernel.

Handling an #MC exception which is raised while an NMI is being handled
would cause the nasty NMI nesting issue because of the shortcoming of
IRET of reenabling NMIs when executed. And the machine is in an #MC
context already so <Deity> be at its side.

Tracing MSR accesses while in #MC is another no-no due to tracing being
inherently a bad idea in atomic context:

  vmlinux.o: warning: objtool: do_machine_check()+0x4a: call to mce_rdmsrl() leaves .noinstr.text section

so remove all that "additional" functionality from mce_rdmsrl() and
provide it with a special exception handler which panics the machine
when that MSR is not accessible.

The exception handler prints a human-readable message explaining what
the panic reason is but, what is more, it panics while in the #GP
handler and latter won't have executed an IRET, thus opening the NMI
nesting issue in the case when the #MC has happened while handling
an NMI. (#MC itself won't be reenabled until MCG_STATUS hasn't been
cleared).

Suggested-by: Andy Lutomirski <luto@kernel.org>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
[ Add missing prototypes for ex_handler_* ]
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Link: https://lkml.kernel.org/r/20200906212130.GA28456@zn.tnic
Signed-off-by: Sasha Levin <sashal@kernel.org>
 		2020-10-29 09:58:03 +01:00
..
acpi x86: ACPI: fix CPU hotplug deadlock 2020-04-23 10:36:38 +02:00
apic x86/ioapic: Unbreak check_timer() 2020-10-01 13:18:22 +02:00
cpu x86/mce: Make mce_rdmsrl() panic on an inaccessible MSR 2020-10-29 09:58:03 +01:00
fpu x86/fpu: Allow multiple bits in clearcpuid= parameter 2020-10-29 09:57:29 +01:00
kprobes kretprobe: Prevent triggering kretprobe from within kprobe_flush_task 2020-06-24 17:50:52 +02:00
.gitignore
…
Makefile Merge branch 'x86-paravirt-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-07-08 17:34:44 -07:00
alternative.c x86: Correct misc typos 2019-09-02 14:02:59 +02:00
amd_gart_64.c dma-mapping: provide a better default ->get_required_mask 2019-09-04 11:13:19 +02:00
amd_nb.c x86/amd_nb: Add AMD family 17h model 60h PCI IDs 2020-06-22 09:31:17 +02:00
apb_timer.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441 2019-06-05 17:37:17 +02:00
aperture_64.c x86/gart: Exclude GART aperture from kcore 2019-03-23 12:11:49 +01:00
apm_32.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 118 2019-05-24 17:39:02 +02:00
asm-offsets.c x86/paravirt: Make read_cr2() CALLEE_SAVE 2019-07-17 23:17:37 +02:00
asm-offsets_32.c x86/entry/32: Load task stack from x86_tss.sp1 in SYSENTER handler 2018-07-20 01:11:36 +02:00
asm-offsets_64.c Merge branch 'x86-apic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-09-17 12:04:39 -07:00
audit_64.c
…
bootflag.c
…
check.c x86/headers: Fix -Wmissing-prototypes warning 2018-11-23 07:59:59 +01:00
cpuid.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 142 2019-05-30 11:25:17 -07:00
crash.c x86/kdump: Always reserve the low 1M when the crashkernel option is specified 2020-10-01 13:17:18 +02:00
crash_dump_32.c
…
crash_dump_64.c fs/core/vmcore: Move sev_active() reference to x86 arch code 2019-08-09 22:52:10 +10:00
devicetree.c x86/headers: Fix -Wmissing-prototypes warning 2018-11-23 07:59:59 +01:00
doublefault.c x86/doublefault/32: Fix stack canaries in the double fault handler 2019-11-29 10:09:51 +01:00
dumpstack.c x86/dumpstack: Indicate PREEMPT_RT in dumps 2019-07-31 19:03:36 +02:00
dumpstack_32.c x86/irq/32: Rename hard/softirq_stack to hard/softirq_stack_ptr 2019-04-17 15:24:18 +02:00
dumpstack_64.c x86/dumpstack/64: Don't evaluate exception stacks before setup 2019-11-05 00:51:35 +01:00
e820.c x86/e820: Use proper booleans instead of 0/1 2019-07-16 23:13:49 +02:00
early-quirks.c x86/intel: Disable HPET on Intel Ice Lake platforms 2020-01-12 12:21:13 +01:00
early_printk.c efi/x86: Convert x86 EFI earlyprintk into generic earlycon implementation 2019-02-04 08:27:30 +01:00
ebda.c
…
eisa.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 243 2019-06-19 17:09:07 +02:00
espfix_64.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 288 2019-06-05 17:36:37 +02:00
ftrace.c The main changes in this release include: 2019-07-18 11:51:00 -07:00
ftrace_32.S x86/stackframe/32: Provide consistent pt_regs 2019-06-25 10:23:47 +02:00
ftrace_64.S x86/stackframe, x86/ftrace: Add pt_regs frame annotations 2019-06-25 10:23:47 +02:00
head32.c x86/boot: Mostly revert commit ae7e1238e6 ("Add ACPI RSDP address to setup_header") 2018-11-20 09:43:10 +01:00
head64.c x86/boot/64: Make level2_kernel_pgt pages invalid outside kernel area 2019-10-11 18:38:15 +02:00
head_32.S x86/pti/32: Size initial_page_table correctly 2019-11-29 10:09:52 +01:00
head_64.S x86/irq/64: Update stale comment 2019-07-22 10:54:27 +02:00
hpet.c x86/hpet: Undo the early counter is counting check 2019-07-25 12:21:32 +02:00
hw_breakpoint.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
i8237.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
i8253.c x86/timer: Skip PIT initialization on modern chipsets 2019-06-29 11:35:35 +02:00
i8259.c x86/i8259: Use printk_deferred() to prevent deadlock 2020-08-05 09:59:52 +02:00
idt.c x86/idt: Keep spurious entries unset in system_vectors 2020-06-24 17:50:43 +02:00
ima_arch.c x86/ima: use correct identifier for SetupMode variable 2020-02-28 17:22:18 +01:00
io_delay.c x86/io_delay: Define IO_DELAY macros in C instead of Kconfig 2019-05-24 08:46:06 +02:00
ioport.c x86: Lock down IO port access when the kernel is locked down 2019-08-19 21:54:16 -07:00
irq.c x86/irq: Check for VECTOR_UNUSED directly 2019-08-19 23:19:07 +02:00
irq_32.c x86/irq: Move IS_ERR_OR_NULL() check into common do_IRQ() code 2019-08-19 23:19:06 +02:00
irq_64.c x86: fix vmap arguments in map_irq_stack 2020-06-22 09:30:57 +02:00
irq_work.c
…
irqflags.S x86/paravirt: Make native_save_fl() extern inline 2018-07-03 10:56:27 +02:00
irqinit.c x86/irq/32: Handle irq stack allocation failure proper 2019-04-17 15:31:42 +02:00
itmt.c proc/sysctl: add shared variables for range check 2019-07-18 17:08:07 -07:00
jailhouse.c x86: Add "nopv" parameter to disable PV extensions 2019-07-17 08:09:58 +02:00
jump_label.c x86/jump_label: Make tp_vec_nr static 2019-06-25 09:22:14 +02:00
kdebugfs.c Driver Core and debugfs changes for 5.3-rc1 2019-07-12 12:24:03 -07:00
kexec-bzimage64.c Merge branch 'next-lockdown' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2019-09-28 08:14:15 -07:00
kgdb.c x86/apic: Provide and use helper for send_IPI_allbutself() 2019-07-25 16:12:00 +02:00
ksysfs.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 428 2019-06-05 17:37:16 +02:00
kvm.c * s390: ioctl hardening, selftests 2019-09-18 09:49:13 -07:00
kvmclock.c x86: kvmguest: use TSC clocksource if invariant TSC is exposed 2019-02-20 22:48:52 +01:00
ldt.c x86: Convert some slow-path static_cpu_has() callers to boot_cpu_has() 2019-04-08 12:13:34 +02:00
livepatch.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 13 2019-05-21 11:28:45 +02:00
machine_kexec_32.c x86/mm: Remove set_pages_x() and set_pages_nx() 2019-09-03 09:26:37 +02:00
machine_kexec_64.c Merge branch 'x86-kdump-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-07-09 11:52:34 -07:00
mmconf-fam10h_64.c
…
module.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
mpparse.c x86/boot: Fix memory leak in default_get_smp_config() 2019-07-16 23:13:48 +02:00
msr.c x86/msr: Restrict MSR access when the kernel is locked down 2019-08-19 21:54:16 -07:00
nmi.c x86/nmi: Fix nmi_handle() duration miscalculation 2020-10-29 09:57:30 +01:00
nmi_selftest.c
…
paravirt-spinlocks.c x86/paravirt: Use a single ops structure 2018-09-03 16:50:35 +02:00
paravirt.c x86/paravirt: Drop {read,write}_cr8() hooks 2019-07-22 10:12:33 +02:00
paravirt_patch.c x86/paravirt: Standardize 'insn_buff' variable names 2019-04-29 16:05:49 +02:00
pci-calgary_64.c dma-mapping: explicitly wire up ->mmap and ->get_sgtable 2019-09-04 11:13:18 +02:00
pci-dma.c x86/dma: Get rid of iommu_pass_through 2019-08-23 10:11:01 +02:00
pci-iommu_table.c x86/iommu: Use NULL instead of 0 2018-08-02 14:33:19 +02:00
pci-swiotlb.c dma-mapping: fix filename references 2019-09-03 08:36:30 +02:00
pcspeaker.c x86/platform/pcspeaker: Use PTR_ERR_OR_ZERO() to fix ptr_ret.cocci warning 2018-07-24 09:46:42 +02:00
perf_regs.c perf/x86/regs: Check reserved bits 2019-06-24 19:19:24 +02:00
platform-quirks.c x86/i8237: Register device based on FADT legacy boot flag 2018-04-27 16:44:29 +02:00
pmem.c
…
probe_roms.c
…
process.c x86/speculation: Prevent rogue cross-process SSBD shutdown 2020-06-17 16:40:25 +02:00
process.h x86: Use the correct SPDX License Identifier in headers 2019-10-01 20:31:35 +02:00
process_32.c x86/stackframe/32: Provide consistent pt_regs 2019-06-25 10:23:47 +02:00
process_64.c x86/fsgsbase/64: Fix NULL deref in 86_fsgsbase_read_task 2020-08-19 08:16:22 +02:00
ptrace.c x86/ptrace: Mark expected switch fall-through 2019-08-07 15:12:01 +02:00
pvclock.c x86/vdso: Switch to generic vDSO implementation 2019-06-22 21:21:10 +02:00
quirks.c x86/PCI: Remove superfluous returns from void functions 2019-08-20 09:54:36 +02:00
reboot.c x86/reboot/quirks: Add MacBook6,1 reboot quirk 2020-06-17 16:40:25 +02:00
reboot_fixups_32.c
…
relocate_kernel_32.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 230 2019-06-19 17:09:06 +02:00
relocate_kernel_64.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 230 2019-06-19 17:09:06 +02:00
resource.c
…
rtc.c x86: Convert x86_platform_ops to timespec64 2018-05-19 14:03:14 +02:00
setup.c dma-mapping: fix filename references 2019-09-03 08:36:30 +02:00
setup_percpu.c x86/irq/64: Split the IRQ stack into its own pages 2019-04-17 15:37:02 +02:00
signal.c x86: use static_cpu_has in uaccess region to avoid instrumentation 2019-07-12 11:05:42 -07:00
signal_compat.c
…
smp.c x86/smp: Move smp_function_call implementations into IPI code 2019-07-25 16:12:01 +02:00
smpboot.c x86/hotplug: Silence APIC only after all interrupts are migrated 2020-09-03 11:27:06 +02:00
stacktrace.c x86/stacktrace: Fix reliable check for empty user task stacks 2020-08-05 09:59:51 +02:00
step.c
…
sys_x86_64.c x86/compat: Adjust in_compat_syscall() to generic code under !COMPAT 2018-11-01 12:59:25 +01:00
sysfb.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
sysfb_efi.c x86/sysfb_efi: Add quirks for some devices with swapped width and height 2019-07-22 10:47:11 +02:00
sysfb_simplefb.c x86/sysfb: Fix check for bad VRAM size 2020-02-24 08:36:29 +01:00
tboot.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 335 2019-06-05 17:37:06 +02:00
tce_64.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
time.c x86_64: Fix jiffies ODR violation 2020-06-17 16:40:24 +02:00
tls.c x86/tls: Fix possible spectre-v1 in do_get_thread_area() 2019-06-27 23:48:04 +02:00
tls.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 193 2019-05-30 11:29:21 -07:00
topology.c x86/topology: Make DEBUG_HOTPLUG_CPU0 pr_info() more descriptive 2019-04-19 19:42:57 +02:00
trace_clock.c
…
tracepoint.c x86/kernel: Fix more -Wmissing-prototypes warnings 2018-12-08 12:24:35 +01:00
traps.c x86/mm, tracing: Fix CR2 corruption 2019-07-17 23:17:38 +02:00
tsc.c x86/tsc: Respect tsc command line paraemeter for clocksource_tsc_early 2019-11-05 01:24:56 +01:00
tsc_msr.c x86/tsr: Fix tsc frequency enumeration bug on Lightning Mountain SoC 2020-08-21 13:05:36 +02:00
tsc_sync.c
…
umip.c x86/umip: Add emulation (spoofing) for UMIP covered instructions in 64-bit processes as well 2019-09-10 08:36:16 +02:00
unwind_frame.c x86/stackframe/32: Provide consistent pt_regs 2019-06-25 10:23:47 +02:00
unwind_guess.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00
unwind_orc.c x86/unwind/orc: Fix ORC for newly forked tasks 2020-08-05 09:59:51 +02:00
uprobes.c uprobes/x86: Fix detection of 32-bit user mode 2019-08-26 15:55:09 +02:00
verify_cpu.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 230 2019-06-19 17:09:06 +02:00
vm86_32.c signal: Remove task parameter from force_sig 2019-05-27 09:36:28 -05:00
vmlinux.lds.S x86, vmlinux.lds: Page-align end of ..page_aligned sections 2020-07-29 10:18:45 +02:00
vsmp_64.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 346 2019-06-05 17:37:08 +02:00
x86_init.c x86/timer: Don't skip PIT setup when APIC is disabled or in legacy mode 2020-02-11 04:35:52 -08:00