[PATCH v2 1/6] arm: Add BTB invalidation on switch_mm for Cortex-A9, A12 and A17

[Marc Zyngier]

In order to avoid aliasing attacks against the branch predictor,
some implementations require to invalidate the BTB when switching
from one user context to another.

For this, we reuse the existing implementation for Cortex-A8, and
apply it to A9, A12 and A17.

Signed-off-by: Marc Zyngier <marc.zyngier at arm.com>
---
 arch/arm/mm/proc-v7-2level.S |  4 ++--
 arch/arm/mm/proc-v7-3level.S |  6 ++++++
 arch/arm/mm/proc-v7.S        | 30 +++++++++++++++---------------
 3 files changed, 23 insertions(+), 17 deletions(-)

diff --git a/arch/arm/mm/proc-v7-2level.S b/arch/arm/mm/proc-v7-2level.S
index c6141a5435c3..0422e58b74e8 100644
--- a/arch/arm/mm/proc-v7-2level.S
+++ b/arch/arm/mm/proc-v7-2level.S
@@ -41,7 +41,7 @@
  *	even on Cortex-A8 revisions not affected by 430973.
  *	If IBE is not set, the flush BTAC/BTB won't do anything.
  */
-ENTRY(cpu_ca8_switch_mm)
+ENTRY(cpu_v7_btbinv_switch_mm)
 #ifdef CONFIG_MMU
 	mov	r2, #0
 	mcr	p15, 0, r2, c7, c5, 6		@ flush BTAC/BTB
@@ -66,7 +66,7 @@ ENTRY(cpu_v7_switch_mm)
 #endif
 	bx	lr
 ENDPROC(cpu_v7_switch_mm)
-ENDPROC(cpu_ca8_switch_mm)
+ENDPROC(cpu_v7_btbinv_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 7d16bbc4102b..f6adfe88ead2 100644
--- a/arch/arm/mm/proc-v7-3level.S
+++ b/arch/arm/mm/proc-v7-3level.S
@@ -54,6 +54,11 @@
  * Set the translation table base pointer to be pgd_phys (physical address of
  * the new TTB).
  */
+ENTRY(cpu_v7_btbinv_switch_mm)
+#ifdef CONFIG_MMU
+	mov	r3, #0
+	mcr	p15, 0, r2, c7, c5, 6			@ flush BTAC/BTB
+#endif
 ENTRY(cpu_v7_switch_mm)
 #ifdef CONFIG_MMU
 	mmid	r2, r2
@@ -64,6 +69,7 @@ ENTRY(cpu_v7_switch_mm)
 #endif
 	ret	lr
 ENDPROC(cpu_v7_switch_mm)
+ENDPROC(cpu_v7_btbinv_switch_mm)
 
 #ifdef __ARMEB__
 #define rl r3
diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S
index 01d64c0b2563..0a14967fd400 100644
--- a/arch/arm/mm/proc-v7.S
+++ b/arch/arm/mm/proc-v7.S
@@ -159,18 +159,18 @@ ENDPROC(cpu_v7_do_resume)
 #endif
 
 /*
- * Cortex-A8
+ * Cortex-A8/A12/A17 that require a BTB invalidation on switch_mm
  */
-	globl_equ	cpu_ca8_proc_init,	cpu_v7_proc_init
-	globl_equ	cpu_ca8_proc_fin,	cpu_v7_proc_fin
-	globl_equ	cpu_ca8_reset,		cpu_v7_reset
-	globl_equ	cpu_ca8_do_idle,	cpu_v7_do_idle
-	globl_equ	cpu_ca8_dcache_clean_area, cpu_v7_dcache_clean_area
-	globl_equ	cpu_ca8_set_pte_ext,	cpu_v7_set_pte_ext
-	globl_equ	cpu_ca8_suspend_size,	cpu_v7_suspend_size
+	globl_equ	cpu_v7_btbinv_proc_init,	cpu_v7_proc_init
+	globl_equ	cpu_v7_btbinv_proc_fin,		cpu_v7_proc_fin
+	globl_equ	cpu_v7_btbinv_reset,		cpu_v7_reset
+	globl_equ	cpu_v7_btbinv_do_idle,		cpu_v7_do_idle
+	globl_equ	cpu_v7_btbinv_dcache_clean_area, cpu_v7_dcache_clean_area
+	globl_equ	cpu_v7_btbinv_set_pte_ext,	cpu_v7_set_pte_ext
+	globl_equ	cpu_v7_btbinv_suspend_size,	cpu_v7_suspend_size
 #ifdef CONFIG_ARM_CPU_SUSPEND
-	globl_equ	cpu_ca8_do_suspend,	cpu_v7_do_suspend
-	globl_equ	cpu_ca8_do_resume,	cpu_v7_do_resume
+	globl_equ	cpu_v7_btbinv_do_suspend,	cpu_v7_do_suspend
+	globl_equ	cpu_v7_btbinv_do_resume,	cpu_v7_do_resume
 #endif
 
 /*
@@ -181,7 +181,7 @@ ENDPROC(cpu_v7_do_resume)
 	globl_equ	cpu_ca9mp_reset,	cpu_v7_reset
 	globl_equ	cpu_ca9mp_do_idle,	cpu_v7_do_idle
 	globl_equ	cpu_ca9mp_dcache_clean_area, cpu_v7_dcache_clean_area
-	globl_equ	cpu_ca9mp_switch_mm,	cpu_v7_switch_mm
+	globl_equ	cpu_ca9mp_switch_mm,	cpu_v7_btbinv_switch_mm
 	globl_equ	cpu_ca9mp_set_pte_ext,	cpu_v7_set_pte_ext
 .globl	cpu_ca9mp_suspend_size
 .equ	cpu_ca9mp_suspend_size, cpu_v7_suspend_size + 4 * 2
@@ -548,8 +548,8 @@ __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 v7_btbinv, 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
 	define_processor_functions ca9mp, dabort=v7_early_abort, pabort=v7_pabort, suspend=1
 #endif
 #ifdef CONFIG_CPU_PJ4B
@@ -614,7 +614,7 @@ __v7_ca9mp_proc_info:
 __v7_ca8_proc_info:
 	.long	0x410fc080
 	.long	0xff0ffff0
-	__v7_proc __v7_ca8_proc_info, __v7_setup, proc_fns = ca8_processor_functions
+	__v7_proc __v7_ca8_proc_info, __v7_setup, proc_fns = v7_btbinv_processor_functions
 	.size	__v7_ca8_proc_info, . - __v7_ca8_proc_info
 
 #endif	/* CONFIG_ARM_LPAE */
@@ -658,7 +658,7 @@ __v7_ca7mp_proc_info:
 __v7_ca12mp_proc_info:
 	.long	0x410fc0d0
 	.long	0xff0ffff0
-	__v7_proc __v7_ca12mp_proc_info, __v7_ca12mp_setup
+	__v7_proc __v7_ca12mp_proc_info, __v7_ca12mp_setup, proc_fns = v7_btbinv_processor_functions
 	.size	__v7_ca12mp_proc_info, . - __v7_ca12mp_proc_info
 
 	/*
@@ -688,7 +688,7 @@ __v7_b15mp_proc_info:
 __v7_ca17mp_proc_info:
 	.long	0x410fc0e0
 	.long	0xff0ffff0
-	__v7_proc __v7_ca17mp_proc_info, __v7_ca17mp_setup
+	__v7_proc __v7_ca17mp_proc_info, __v7_ca17mp_setup, proc_fns = v7_btbinv_processor_functions
 	.size	__v7_ca17mp_proc_info, . - __v7_ca17mp_proc_info
 
 	/*
-- 
2.14.2