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ARM: 7660/1: tlb: add branch predictor maintenance operations

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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>
This commit is contained in:
Will Deacon 2013-02-28 17:48:11 +01:00 committed by Russell King
parent 8a4e3a9ead
commit 862c588f06
2 changed files with 40 additions and 6 deletions
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34
arch/arm/include/asm/tlbflush.h
View File

@ -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_tlb_kernel_page(unsigned long kaddr)
}
}
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 @@ static inline void clean_pmd_entry(void *pmd)
#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_page(struct vm_area_struct *vma, unsigned long uaddr);
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
/*

12
arch/arm/kernel/smp_tlb.c
View File

@ -64,6 +64,11 @@ static inline void ipi_flush_tlb_kernel_range(void *arg)
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 @@ void flush_tlb_kernel_range(unsigned long start, unsigned long end)
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();
}