[PATCH v4 4/6] arm: Add icache invalidation on switch_mm for Cortex-A15

[Marc Zyngier]

In order to avoid aliasing attacks against the branch predictor,
Cortex-A15 require to invalidate the BTB when switching
from one user context to another. The only way to do so on this
CPU is to perform an ICIALLU, having set ACTLR[0] to 1 from secure
mode.

Signed-off-by: Marc Zyngier <marc.zyngier at arm.com>
---
 arch/arm/mm/proc-v7-2level.S | 10 ++++++++++
 arch/arm/mm/proc-v7-3level.S | 10 ++++++++++
 arch/arm/mm/proc-v7.S        | 23 ++++++++++++++++++++++-
 3 files changed, 42 insertions(+), 1 deletion(-)

diff --git a/arch/arm/mm/proc-v7-2level.S b/arch/arm/mm/proc-v7-2level.S
index 0422e58b74e8..6d81ed7b2cb0 100644
--- a/arch/arm/mm/proc-v7-2level.S
+++ b/arch/arm/mm/proc-v7-2level.S
@@ -40,7 +40,16 @@
  *	Note that we always need to flush BTAC/BTB if IBE is set
  *	even on Cortex-A8 revisions not affected by 430973.
  *	If IBE is not set, the flush BTAC/BTB won't do anything.
+ *
+ *	Cortex-A15 requires ACTLR[0] to be set from secure in order
+ *	for the icache invalidation to also invalidate the BTB.
  */
+ENTRY(cpu_v7_icinv_switch_mm)
+#ifdef CONFIG_MMU
+	mcr	p15, 0, r0, c7, c5, 0		@ ICIALLU
+	/* Fall through to switch_mm... */
+#endif
+
 ENTRY(cpu_v7_btbinv_switch_mm)
 #ifdef CONFIG_MMU
 	mov	r2, #0
@@ -67,6 +76,7 @@ ENTRY(cpu_v7_switch_mm)
 	bx	lr
 ENDPROC(cpu_v7_switch_mm)
 ENDPROC(cpu_v7_btbinv_switch_mm)
+ENDPROC(cpu_v7_icinv_switch_mm)
 
 /*
  *	cpu_v7_set_pte_ext(ptep, pte)
diff --git a/arch/arm/mm/proc-v7-3level.S b/arch/arm/mm/proc-v7-3level.S
index c616afd1b8f4..797053980755 100644
--- a/arch/arm/mm/proc-v7-3level.S
+++ b/arch/arm/mm/proc-v7-3level.S
@@ -54,6 +54,15 @@
  * Set the translation table base pointer to be pgd_phys (physical address of
  * the new TTB).
  */
+ENTRY(cpu_v7_icinv_switch_mm)
+#ifdef CONFIG_MMU
+	/*
+	 * Cortex-A15 requires ACTLR[0] to be set from secure in order
+	 * for the icache invalidation to also invalidate the BTB.
+	 */
+	mcr	p15, 0, r0, c7, c5, 0		@ ICIALLU
+	/* Fall through to switch_mm... */
+#endif
 ENTRY(cpu_v7_btbinv_switch_mm)
 #ifdef CONFIG_MMU
 	mcr	p15, 0, r0, c7, c5, 6			@ flush BTAC/BTB
@@ -69,6 +78,7 @@ ENTRY(cpu_v7_switch_mm)
 	ret	lr
 ENDPROC(cpu_v7_switch_mm)
 ENDPROC(cpu_v7_btbinv_switch_mm)
+ENDPROC(cpu_v7_icinv_switch_mm)
 
 #ifdef __ARMEB__
 #define rl r3
diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S
index 389a7c442058..ba13e4e45c3b 100644
--- a/arch/arm/mm/proc-v7.S
+++ b/arch/arm/mm/proc-v7.S
@@ -232,6 +232,26 @@ ENDPROC(cpu_ca9mp_do_resume)
 	globl_equ	cpu_ca17_do_resume,	cpu_v7_do_resume
 #endif
 
+/*
+ * Cortex-A15
+ */
+	globl_equ	cpu_ca15_proc_init,	cpu_v7_proc_init
+	globl_equ	cpu_ca15_proc_fin,	cpu_v7_proc_fin
+	globl_equ	cpu_ca15_reset,		cpu_v7_reset
+	globl_equ	cpu_ca15_do_idle,	cpu_v7_do_idle
+	globl_equ	cpu_ca15_dcache_clean_area, cpu_v7_dcache_clean_area
+	globl_equ	cpu_ca15_set_pte_ext,	cpu_v7_set_pte_ext
+	globl_equ	cpu_ca15_suspend_size,	cpu_v7_suspend_size
+#ifdef CONFIG_HARDEN_BRANCH_PREDICTOR
+	globl_equ	cpu_ca15_switch_mm,	cpu_v7_icinv_switch_mm
+#else
+	globl_equ	cpu_ca15_switch_mm,	cpu_v7_switch_mm
+#endif
+#ifdef CONFIG_ARM_CPU_SUSPEND
+	globl_equ	cpu_ca15_do_suspend,	cpu_v7_do_suspend
+	globl_equ	cpu_ca15_do_resume,	cpu_v7_do_resume
+#endif
+
 #ifdef CONFIG_CPU_PJ4B
 	globl_equ	cpu_pj4b_switch_mm,     cpu_v7_switch_mm
 	globl_equ	cpu_pj4b_set_pte_ext,	cpu_v7_set_pte_ext
@@ -573,6 +593,7 @@ __v7_setup_stack:
 
 	@ define struct processor (see <asm/proc-fns.h> and proc-macros.S)
 	define_processor_functions v7, dabort=v7_early_abort, pabort=v7_pabort, suspend=1
+	define_processor_functions ca15, dabort=v7_early_abort, pabort=v7_pabort, suspend=1
 	define_processor_functions ca17, dabort=v7_early_abort, pabort=v7_pabort, suspend=1
 #ifndef CONFIG_ARM_LPAE
 	define_processor_functions ca8, dabort=v7_early_abort, pabort=v7_pabort, suspend=1
@@ -694,7 +715,7 @@ __v7_ca12mp_proc_info:
 __v7_ca15mp_proc_info:
 	.long	0x410fc0f0
 	.long	0xff0ffff0
-	__v7_proc __v7_ca15mp_proc_info, __v7_ca15mp_setup
+	__v7_proc __v7_ca15mp_proc_info, __v7_ca15mp_setup, proc_fns = ca15_processor_functions
 	.size	__v7_ca15mp_proc_info, . - __v7_ca15mp_proc_info
 
 	/*
-- 
2.14.2