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linux-uconsole/arch/x86/kernel
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Peter Zijlstra 2ea1a37d01 sched/x86: Save [ER]FLAGS on context switch 
commit 6690e86be8 upstream.

Effectively reverts commit:

  2c7577a758 ("sched/x86_64: Don't save flags on context switch")

Specifically because SMAP uses FLAGS.AC which invalidates the claim
that the kernel has clean flags.

In particular; while preemption from interrupt return is fine (the
IRET frame on the exception stack contains FLAGS) it breaks any code
that does synchonous scheduling, including preempt_enable().

This has become a significant issue ever since commit:

  5b24a7a2aa ("Add 'unsafe' user access functions for batched accesses")

provided for means of having 'normal' C code between STAC / CLAC,
exposing the FLAGS.AC state. So far this hasn't led to trouble,
however fix it before it comes apart.

Reported-by: Julien Thierry <julien.thierry@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@kernel.org
Fixes: 5b24a7a2aa ("Add 'unsafe' user access functions for batched accesses")
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-22 07:37:36 +02:00
..
acpi x86/ACPI/cstate: Make APCI C1 FFH MWAIT C-state description vendor-neutral 2018-08-15 00:19:38 +02:00
apic irq/matrix: Spread managed interrupts on allocation 2019-03-05 17:58:45 +01:00
cpu x86/speculation/mds: Add 'mitigations=' support for MDS 2019-05-14 19:17:59 +02:00
fpu x86/fpu: Don't export __kernel_fpu_{begin,end}() 2019-05-02 09:58:59 +02:00
kprobes x86/kprobes: Avoid kretprobe recursion bug 2019-05-16 19:41:28 +02:00
.gitignore
alternative.c x86/alternatives: Lockdep-enforce text_mutex in text_poke*() 2018-08-30 13:02:30 +02:00
amd_gart_64.c x86/dma/amd_gart: Use dma_direct_{alloc,free}() 2018-03-20 10:01:57 +01:00
amd_nb.c x86/amd_nb: Add support for Raven Ridge CPUs 2018-05-13 09:00:27 -07:00
apb_timer.c
aperture_64.c x86/gart: Exclude GART aperture from kcore 2019-04-20 09:15:59 +02:00
apm_32.c x86/APM: Fix build warning when PROC_FS is not enabled 2018-09-15 10:16:25 +02:00
asm-offsets.c x86/entry/32: Enter the kernel via trampoline stack 2018-07-20 01:11:37 +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 x86/asm-offsets: Move TSS_sp0 and TSS_sp1 to asm-offsets.c 2018-07-20 01:11:35 +02:00
audit_64.c
bootflag.c
check.c x86/corruption-check: Fix panic in memory_corruption_check() when boot option without value is provided 2018-11-13 11:08:19 -08:00
cpuid.c x86/cpuid: Allow cpuid_read() to schedule 2018-03-27 12:01:48 +02:00
crash.c kexec_file, x86: move re-factored code to generic side 2018-04-13 17:10:27 -07:00
crash_dump_32.c
crash_dump_64.c
devicetree.c Merge branch 'x86-platform-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-04-02 16:15:32 -07:00
doublefault.c x86/entry: Fix assumptions that the HW TSS is at the beginning of cpu_tss 2017-12-17 13:59:55 +01:00
dumpstack.c x86/process: Don't mix user/kernel regs in 64bit __show_regs() 2018-09-06 14:33:12 +02:00
dumpstack_32.c x86/dumpstack: Unify show_regs() 2018-03-08 12:04:59 +01:00
dumpstack_64.c x86/dumpstack: Unify show_regs() 2018-03-08 12:04:59 +01:00
e820.c Revert "x86/e820: put !E820_TYPE_RAM regions into memblock.reserved" 2018-12-13 09:16:20 +01:00
early-quirks.c On GEM side: 2018-07-20 12:29:24 +10:00
early_printk.c x86/earlyprintk: Add a force option for pciserial device 2018-11-27 16:13:00 +01:00
ebda.c
eisa.c x86/EISA: Don't probe EISA bus for Xen PV guests 2018-09-11 23:36:50 +02:00
espfix_64.c x86/espfix: Document use of _PAGE_GLOBAL 2018-04-09 18:27:33 +02:00
ftrace.c x86/function_graph: Simplify with function_graph_enter() 2018-12-05 19:32:09 +01:00
ftrace_32.S x86/retpoline/ftrace: Convert ftrace assembler indirect jumps 2018-01-12 00:14:30 +01:00
ftrace_64.S Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-01-28 12:19:23 -08:00
head32.c
head64.c x86/mm: Expand static page table for fixmap space 2018-09-20 23:17:22 +02:00
head_32.S x86/pgtable/32: Allocate 8k page-tables when PTI is enabled 2018-07-20 01:11:41 +02:00
head_64.S x86/mm: Expand static page table for fixmap space 2018-09-20 23:17:22 +02:00
hpet.c x86/hpet: Prevent potential NULL pointer dereference 2019-04-20 09:15:59 +02:00
hw_breakpoint.c x86/hw_breakpoints: Make default case in hw_breakpoint_arch_parse() return an error 2019-04-20 09:15:59 +02:00
i8237.c x86/i8237: Register device based on FADT legacy boot flag 2018-04-27 16:44:29 +02:00
i8253.c
i8259.c x86: Don't include linux/irq.h from asm/hardirq.h 2018-08-05 09:53:13 +02:00
idt.c x86: Don't include linux/irq.h from asm/hardirq.h 2018-08-05 09:53:13 +02:00
io_delay.c
ioport.c x86/ioport: add ksys_ioperm() helper; remove in-kernel calls to sys_ioperm() 2018-04-02 20:16:12 +02:00
irq.c x86: Don't include linux/irq.h from asm/hardirq.h 2018-08-05 09:53:13 +02:00
irq_32.c x86: Don't include linux/irq.h from asm/hardirq.h 2018-08-05 09:53:13 +02:00
irq_64.c x86: Don't include linux/irq.h from asm/hardirq.h 2018-08-05 09:53:13 +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: Don't include linux/irq.h from asm/hardirq.h 2018-08-05 09:53:13 +02:00
itmt.c x86/headers: Remove duplicate #includes 2017-12-12 11:32:24 +01:00
jailhouse.c x86: Convert x86_platform_ops to timespec64 2018-05-19 14:03:14 +02:00
jump_label.c x86/alternatives, jumplabel: Use text_poke_early() before mm_init() 2018-07-20 00:02:38 +02:00
kdebugfs.c
kexec-bzimage64.c x86/kexec: Don't setup EFI info if EFI runtime is not enabled 2019-03-13 14:02:32 -07:00
kgdb.c
ksysfs.c treewide: kmalloc() -> kmalloc_array() 2018-06-12 16:19:22 -07:00
kvm.c KVM: x86: WARN_ONCE if sending a PV IPI returns a fatal error 2019-01-31 08:14:38 +01:00
kvmclock.c x86/kvm: Use __bss_decrypted attribute in shared variables 2018-09-15 20:48:46 +02:00
ldt.c x86/ldt: Remove unused variable in map_ldt_struct() 2018-11-27 16:13:08 +01:00
livepatch.c
machine_kexec_32.c x86/kexec: Allocate 8k PGDs for PTI 2018-07-30 13:53:48 +02:00
machine_kexec_64.c x86/mm: Stop pretending pgtable_l5_enabled is a variable 2018-05-19 11:56:57 +02:00
Makefile x86/paravirt: Make native_save_fl() extern inline 2018-07-03 10:56:27 +02:00
mmconf-fam10h_64.c
module.c x86: Treat R_X86_64_PLT32 as R_X86_64_PC32 2018-02-22 09:01:10 -08:00
mpparse.c x86/mm: Don't leak kernel addresses 2019-04-20 09:15:57 +02:00
msr.c
nmi.c x86/speculation/mds: Clear CPU buffers on exit to user 2019-05-14 19:17:55 +02:00
nmi_selftest.c
paravirt-spinlocks.c
paravirt.c x86/paravirt: Fix some warning messages 2018-09-19 13:22:04 +02:00
paravirt_patch_32.c
paravirt_patch_64.c x86/asm/64: Use 32-bit XOR to zero registers 2018-07-03 09:59:29 +02:00
pci-calgary_64.c x86/dma: Remove dma_alloc_coherent_gfp_flags() 2018-03-20 10:01:58 +01:00
pci-dma.c IOMMU Update for Linux v4.19 2018-08-24 13:10:38 -07:00
pci-iommu_table.c x86/iommu: Use NULL instead of 0 2018-08-02 14:33:19 +02:00
pci-swiotlb.c x86/swiotlb: Enable swiotlb for > 4GiG RAM on 32-bit kernels 2018-10-19 07:49:32 +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: Store user space frame-pointer value on a sample 2018-05-25 08:11:12 +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 deadlock on ssb_state::lock 2019-04-27 09:36:38 +02:00
process.h x86/speculation: Avoid __switch_to_xtra() calls 2018-12-05 19:32:03 +01:00
process_32.c sched/x86: Save [ER]FLAGS on context switch 2019-05-22 07:37:36 +02:00
process_64.c sched/x86: Save [ER]FLAGS on context switch 2019-05-22 07:37:36 +02:00
ptrace.c signal: Ensure every siginfo we send has all bits initialized 2018-04-25 10:40:51 -05:00
pvclock.c x86: Convert x86_platform_ops to timespec64 2018-05-19 14:03:14 +02:00
quirks.c x86/mce: Check for alternate indication of machine check recovery on Skylake 2018-06-07 22:22:12 +02:00
reboot.c x86/reboot, efi: Use EFI reboot for Acer TravelMate X514-51T 2019-05-16 19:41:22 +02:00
reboot_fixups_32.c
relocate_kernel_32.S
relocate_kernel_64.S x86/kexec: Make kexec (mostly) work in 5-level paging mode 2018-01-31 08:39:40 +01:00
resource.c
rtc.c x86: Convert x86_platform_ops to timespec64 2018-05-19 14:03:14 +02:00
setup.c pci-v4.19-changes 2018-08-16 09:21:54 -07:00
setup_percpu.c x86/cpu_entry_area: Sync cpu_entry_area to initial_page_table 2018-03-01 09:48:27 +01:00
signal.c rseq: Avoid infinite recursion when delivering SIGSEGV 2018-06-22 19:04:22 +02:00
signal_compat.c signal: Add TRAP_UNK si_code for undiagnosted trap exceptions 2018-04-25 10:40:56 -05:00
smp.c x86/irq: Let interrupt handlers set kvm_cpu_l1tf_flush_l1d 2018-08-05 09:53:13 +02:00
smpboot.c x86/topology: Use total_cpus for max logical packages calculation 2019-01-26 09:32:41 +01:00
stacktrace.c x86/stacktrace: Do not fail for ORC with regs on stack 2018-06-21 16:34:56 +02:00
step.c
sys_x86_64.c compat: Move compat_timespec/ timeval to compat_time.h 2018-04-19 13:29:54 +02:00
sysfb.c
sysfb_efi.c
sysfb_simplefb.c
tboot.c x86/pti: Make unpoison of pgd for trusted boot work for real 2018-01-11 23:36:59 +01:00
tce_64.c
time.c x86/time: Correct the attribute on jiffies' definition 2018-10-14 11:11:23 +02:00
tls.c x86/ldt: Make the LDT mapping RO 2017-12-23 21:13:01 +01:00
tls.h
topology.c x86/xen: Disable CPU0 hotplug for Xen PV 2018-09-12 21:15:02 +02:00
trace_clock.c
tracepoint.c
traps.c x86/speculation/mds: Revert CPU buffer clear on double fault exit 2019-05-22 07:37:34 +02:00
tsc.c x86/cpu: Sanitize FAM6_ATOM naming 2019-05-14 19:17:53 +02:00
tsc_msr.c x86/cpu: Sanitize FAM6_ATOM naming 2019-05-14 19:17:53 +02:00
tsc_sync.c
umip.c signal: Ensure every siginfo we send has all bits initialized 2018-04-25 10:40:51 -05:00
unwind_frame.c x86/unwind: Handle NULL pointer calls better in frame unwinder 2019-03-27 14:14:42 +09:00
unwind_guess.c
unwind_orc.c x86/unwind: Add hardcoded ORC entry for NULL 2019-03-27 14:14:42 +09:00
uprobes.c uprobes/x86: Remove incorrect WARN_ON() in uprobe_init_insn() 2018-06-21 17:11:02 +02:00
verify_cpu.S
vm86_32.c x86/entry: Rename update_sp0 to update_task_stack 2018-07-20 01:11:40 +02:00
vmlinux.lds.S x86/build/lto: Fix truncated .bss with -fdata-sections 2019-05-16 19:41:22 +02:00
vsmp_64.c
x86_init.c x86/tsc: Make use of tsc_calibrate_cpu_early() 2018-07-20 00:02:44 +02:00