ARM: spectre-v2: add Cortex A8 and A15 validation of the IBE bit

When the branch predictor hardening is enabled, firmware must have set
the IBE bit in the auxiliary control register.  If this bit has not
been set, the Spectre workarounds will not be functional.

Add validation that this bit is set, and print a warning at alert level
if this is not the case.

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Boot-tested-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Tony Lindgren <tony@atomide.com>

arch/arm/mm/proc-v7.S

@@ -569,7 +569,7 @@ __v7_setup_stack:
 	globl_equ	cpu_ca8_do_suspend,	cpu_v7_do_suspend
 	globl_equ	cpu_ca8_do_resume,	cpu_v7_do_resume
 #endif
-	define_processor_functions ca8, dabort=v7_early_abort, pabort=v7_pabort, suspend=1
+	define_processor_functions ca8, dabort=v7_early_abort, pabort=v7_pabort, suspend=1, bugs=cpu_v7_ca8_ibe
 
 	@ Cortex-A9 - needs more registers preserved across suspend/resume
 	@ and bpiall switch_mm for hardening
@@ -602,7 +602,7 @@ __v7_setup_stack:
 	globl_equ	cpu_ca15_suspend_size,	cpu_v7_suspend_size
 	globl_equ	cpu_ca15_do_suspend,	cpu_v7_do_suspend
 	globl_equ	cpu_ca15_do_resume,	cpu_v7_do_resume
-	define_processor_functions ca15, dabort=v7_early_abort, pabort=v7_pabort, suspend=1
+	define_processor_functions ca15, dabort=v7_early_abort, pabort=v7_pabort, suspend=1, bugs=cpu_v7_ca15_ibe
 #ifdef CONFIG_CPU_PJ4B
 	define_processor_functions pj4b, dabort=v7_early_abort, pabort=v7_pabort, suspend=1
 #endif