Merge branch 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm

Pull ARM updates from Russell King:

 - Initial round of Spectre variant 1 and variant 2 fixes for 32-bit ARM

 - Clang support improvements

 - nommu updates for v8 MPU

 - enable ARM_MODULE_PLTS by default to avoid problems loading modules
   with larger kernels

 - vmlinux.lds and dma-mapping cleanups

* 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm: (31 commits)
  ARM: spectre-v1: fix syscall entry
  ARM: spectre-v1: add array_index_mask_nospec() implementation
  ARM: spectre-v1: add speculation barrier (csdb) macros
  ARM: KVM: report support for SMCCC_ARCH_WORKAROUND_1
  ARM: KVM: Add SMCCC_ARCH_WORKAROUND_1 fast handling
  ARM: spectre-v2: KVM: invalidate icache on guest exit for Brahma B15
  ARM: KVM: invalidate icache on guest exit for Cortex-A15
  ARM: KVM: invalidate BTB on guest exit for Cortex-A12/A17
  ARM: spectre-v2: warn about incorrect context switching functions
  ARM: spectre-v2: add firmware based hardening
  ARM: spectre-v2: harden user aborts in kernel space
  ARM: spectre-v2: add Cortex A8 and A15 validation of the IBE bit
  ARM: spectre-v2: harden branch predictor on context switches
  ARM: spectre: add Kconfig symbol for CPUs vulnerable to Spectre
  ARM: bugs: add support for per-processor bug checking
  ARM: bugs: hook processor bug checking into SMP and suspend paths
  ARM: bugs: prepare processor bug infrastructure
  ARM: add more CPU part numbers for Cortex and Brahma B15 CPUs
  ARM: 8774/1: remove no-op macro VMLINUX_SYMBOL()
  ARM: 8773/1: amba: Export amba_bustype
  ...

1 files changed, 23 insertions, 0 deletions

diff --git a/arch/arm/mm/Kconfig b/arch/arm/mm/Kconfig
index 5a016bc80e26..96a7b6cf459b 100644
--- a/arch/arm/mm/Kconfig
+++ b/arch/arm/mm/Kconfig
@@ -415,6 +415,7 @@ config CPU_V7
 	select CPU_CP15_MPU if !MMU
 	select CPU_HAS_ASID if MMU
 	select CPU_PABRT_V7
+	select CPU_SPECTRE if MMU
 	select CPU_THUMB_CAPABLE
 	select CPU_TLB_V7 if MMU
 
@@ -821,6 +822,28 @@ config CPU_BPREDICT_DISABLE
 	help
 	  Say Y here to disable branch prediction.  If unsure, say N.
 
+config CPU_SPECTRE
+	bool
+
+config HARDEN_BRANCH_PREDICTOR
+	bool "Harden the branch predictor against aliasing attacks" if EXPERT
+	depends on CPU_SPECTRE
+	default y
+	help
+	   Speculation attacks against some high-performance processors rely
+	   on being able to manipulate the branch predictor for a victim
+	   context by executing aliasing branches in the attacker context.
+	   Such attacks can be partially mitigated against by clearing
+	   internal branch predictor state and limiting the prediction
+	   logic in some situations.
+
+	   This config option will take CPU-specific actions to harden
+	   the branch predictor against aliasing attacks and may rely on
+	   specific instruction sequences or control bits being set by
+	   the system firmware.
+
+	   If unsure, say Y.
+
 config TLS_REG_EMUL
 	bool
 	select NEED_KUSER_HELPERS