ARM: 7660/1: tlb: add branch predictor maintenance operations
The ARM architecture requires explicit branch predictor maintenance
when updating an instruction stream for a given virtual address. In
reality, this isn't so much of a burden because the branch predictor
is flushed during the cache maintenance required to make the new
instructions visible to the I-side of the processor.
However, there are still some cases where explicit flushing is required,
so add a local_bp_flush_all operation to deal with this.
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/include/asm/tlbflush.h b/arch/arm/include/asm/tlbflush.h
index 6e924d3..4db8c88 100644
--- a/arch/arm/include/asm/tlbflush.h
+++ b/arch/arm/include/asm/tlbflush.h
@@ -34,10 +34,13 @@
#define TLB_V6_D_ASID (1 << 17)
#define TLB_V6_I_ASID (1 << 18)
+#define TLB_V6_BP (1 << 19)
+
/* Unified Inner Shareable TLB operations (ARMv7 MP extensions) */
-#define TLB_V7_UIS_PAGE (1 << 19)
-#define TLB_V7_UIS_FULL (1 << 20)
-#define TLB_V7_UIS_ASID (1 << 21)
+#define TLB_V7_UIS_PAGE (1 << 20)
+#define TLB_V7_UIS_FULL (1 << 21)
+#define TLB_V7_UIS_ASID (1 << 22)
+#define TLB_V7_UIS_BP (1 << 23)
#define TLB_BARRIER (1 << 28)
#define TLB_L2CLEAN_FR (1 << 29) /* Feroceon */
@@ -150,7 +153,8 @@
#define v6wbi_tlb_flags (TLB_WB | TLB_DCLEAN | TLB_BARRIER | \
TLB_V6_I_FULL | TLB_V6_D_FULL | \
TLB_V6_I_PAGE | TLB_V6_D_PAGE | \
- TLB_V6_I_ASID | TLB_V6_D_ASID)
+ TLB_V6_I_ASID | TLB_V6_D_ASID | \
+ TLB_V6_BP)
#ifdef CONFIG_CPU_TLB_V6
# define v6wbi_possible_flags v6wbi_tlb_flags
@@ -166,9 +170,11 @@
#endif
#define v7wbi_tlb_flags_smp (TLB_WB | TLB_DCLEAN | TLB_BARRIER | \
- TLB_V7_UIS_FULL | TLB_V7_UIS_PAGE | TLB_V7_UIS_ASID)
+ TLB_V7_UIS_FULL | TLB_V7_UIS_PAGE | \
+ TLB_V7_UIS_ASID | TLB_V7_UIS_BP)
#define v7wbi_tlb_flags_up (TLB_WB | TLB_DCLEAN | TLB_BARRIER | \
- TLB_V6_U_FULL | TLB_V6_U_PAGE | TLB_V6_U_ASID)
+ TLB_V6_U_FULL | TLB_V6_U_PAGE | \
+ TLB_V6_U_ASID | TLB_V6_BP)
#ifdef CONFIG_CPU_TLB_V7
@@ -430,6 +436,20 @@
}
}
+static inline void local_flush_bp_all(void)
+{
+ const int zero = 0;
+ const unsigned int __tlb_flag = __cpu_tlb_flags;
+
+ if (tlb_flag(TLB_V7_UIS_BP))
+ asm("mcr p15, 0, %0, c7, c1, 6" : : "r" (zero));
+ else if (tlb_flag(TLB_V6_BP))
+ asm("mcr p15, 0, %0, c7, c5, 6" : : "r" (zero));
+
+ if (tlb_flag(TLB_BARRIER))
+ isb();
+}
+
/*
* flush_pmd_entry
*
@@ -480,6 +500,7 @@
#define flush_tlb_kernel_page local_flush_tlb_kernel_page
#define flush_tlb_range local_flush_tlb_range
#define flush_tlb_kernel_range local_flush_tlb_kernel_range
+#define flush_bp_all local_flush_bp_all
#else
extern void flush_tlb_all(void);
extern void flush_tlb_mm(struct mm_struct *mm);
@@ -487,6 +508,7 @@
extern void flush_tlb_kernel_page(unsigned long kaddr);
extern void flush_tlb_range(struct vm_area_struct *vma, unsigned long start, unsigned long end);
extern void flush_tlb_kernel_range(unsigned long start, unsigned long end);
+extern void flush_bp_all(void);
#endif
/*
diff --git a/arch/arm/kernel/smp_tlb.c b/arch/arm/kernel/smp_tlb.c
index 02c5d2c..bd03005 100644
--- a/arch/arm/kernel/smp_tlb.c
+++ b/arch/arm/kernel/smp_tlb.c
@@ -64,6 +64,11 @@
local_flush_tlb_kernel_range(ta->ta_start, ta->ta_end);
}
+static inline void ipi_flush_bp_all(void *ignored)
+{
+ local_flush_bp_all();
+}
+
void flush_tlb_all(void)
{
if (tlb_ops_need_broadcast())
@@ -127,3 +132,10 @@
local_flush_tlb_kernel_range(start, end);
}
+void flush_bp_all(void)
+{
+ if (tlb_ops_need_broadcast())
+ on_each_cpu(ipi_flush_bp_all, NULL, 1);
+ else
+ local_flush_bp_all();
+}