Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull misc x86 fixes from Ingo Molnar:
 - topology enumeration fixes
 - KASAN fix
 - two entry fixes (not yet the big series related to KASLR)
 - remove obsolete code
 - instruction decoder fix
 - better /dev/mem sanity checks, hopefully working better this time
 - pkeys fixes
 - two ACPI fixes
 - 5-level paging related fixes
 - UMIP fixes that should make application visible faults more debuggable
 - boot fix for weird virtualization environment

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits)
  x86/decoder: Add new TEST instruction pattern
  x86/PCI: Remove unused HyperTransport interrupt support
  x86/umip: Fix insn_get_code_seg_params()'s return value
  x86/boot/KASLR: Remove unused variable
  x86/entry/64: Add missing irqflags tracing to native_load_gs_index()
  x86/mm/kasan: Don't use vmemmap_populate() to initialize shadow
  x86/entry/64: Fix entry_SYSCALL_64_after_hwframe() IRQ tracing
  x86/pkeys/selftests: Fix protection keys write() warning
  x86/pkeys/selftests: Rename 'si_pkey' to 'siginfo_pkey'
  x86/mpx/selftests: Fix up weird arrays
  x86/pkeys: Update documentation about availability
  x86/umip: Print a warning into the syslog if UMIP-protected instructions are used
  x86/smpboot: Fix __max_logical_packages estimate
  x86/topology: Avoid wasting 128k for package id array
  perf/x86/intel/uncore: Cache logical pkg id in uncore driver
  x86/acpi: Reduce code duplication in mp_override_legacy_irq()
  x86/acpi: Handle SCI interrupts above legacy space gracefully
  x86/boot: Fix boot failure when SMP MP-table is based at 0
  x86/mm: Limit mmap() of /dev/mem to valid physical addresses
  x86/selftests: Add test for mapping placement for 5-level paging
  ...

1 files changed, 9 insertions, 3 deletions

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index df3276d6bfe3..8eed3f94bfc7 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1804,14 +1804,20 @@ config X86_SMAP
 	  If unsure, say Y.
 
 config X86_INTEL_UMIP
-	def_bool n
+	def_bool y
 	depends on CPU_SUP_INTEL
 	prompt "Intel User Mode Instruction Prevention" if EXPERT
 	---help---
 	  The User Mode Instruction Prevention (UMIP) is a security
 	  feature in newer Intel processors. If enabled, a general
-	  protection fault is issued if the instructions SGDT, SLDT,
-	  SIDT, SMSW and STR are executed in user mode.
+	  protection fault is issued if the SGDT, SLDT, SIDT, SMSW
+	  or STR instructions are executed in user mode. These instructions
+	  unnecessarily expose information about the hardware state.
+
+	  The vast majority of applications do not use these instructions.
+	  For the very few that do, software emulation is provided in
+	  specific cases in protected and virtual-8086 modes. Emulated
+	  results are dummy.
 
 config X86_INTEL_MPX
 	prompt "Intel MPX (Memory Protection Extensions)"