ARM: tlb: don't perform inner-shareable invalidation for local TLB ops

Inner-shareable TLB invalidation is typically more expensive than local
(non-shareable) invalidation, so performing the broadcasting for
local_flush_tlb_* operations is a waste of cycles and needlessly
clobbers entries in the TLBs of other CPUs.

This patch introduces __flush_tlb_* versions for many of the TLB
invalidation functions, which only respect inner-shareable variants of
the invalidation instructions when presented with the TLB_V7_UIS_FULL
flag. The local version is also inlined to prevent SMP_ON_UP kernels
from missing flushes, where the __flush variant would be called with
the UP flags.

This gains us around 0.5% in hackbench scores for a dual-core A15, but I
would expect this to improve as more cores (and clusters) are added to
the equation.

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Albin Tonnerre <Albin.Tonnerre@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

3 files changed, 123 insertions, 30 deletions

diff --git a/arch/arm/include/asm/tlbflush.h b/arch/arm/include/asm/tlbflush.h
index f467e9b3f8d5..3316264916e9 100644
--- a/arch/arm/include/asm/tlbflush.h
+++ b/arch/arm/include/asm/tlbflush.h
@@ -319,6 +319,16 @@ extern struct cpu_tlb_fns cpu_tlb;
 #define tlb_op(f, regs, arg)    __tlb_op(f, "p15, 0, %0, " regs, arg)
 #define tlb_l2_op(f, regs, arg) __tlb_op(f, "p15, 1, %0, " regs, arg)
 
+static inline void __local_flush_tlb_all(void)
+{
+        const int zero = 0;
+        const unsigned int __tlb_flag = __cpu_tlb_flags;
+
+        tlb_op(TLB_V4_U_FULL | TLB_V6_U_FULL, "c8, c7, 0", zero);
+        tlb_op(TLB_V4_D_FULL | TLB_V6_D_FULL, "c8, c6, 0", zero);
+        tlb_op(TLB_V4_I_FULL | TLB_V6_I_FULL, "c8, c5, 0", zero);
+}
+
 static inline void local_flush_tlb_all(void)
 {
         const int zero = 0;
@@ -327,10 +337,8 @@ static inline void local_flush_tlb_all(void)
         if (tlb_flag(TLB_WB))
                 dsb();
 
-        tlb_op(TLB_V4_U_FULL | TLB_V6_U_FULL, "c8, c7, 0", zero);
-        tlb_op(TLB_V4_D_FULL | TLB_V6_D_FULL, "c8, c6, 0", zero);
-        tlb_op(TLB_V4_I_FULL | TLB_V6_I_FULL, "c8, c5, 0", zero);
-        tlb_op(TLB_V7_UIS_FULL, "c8, c3, 0", zero);
+        __local_flush_tlb_all();
+        tlb_op(TLB_V7_UIS_FULL, "c8, c7, 0", zero);
 
         if (tlb_flag(TLB_BARRIER)) {
                 dsb();
@@ -338,31 +346,69 @@ static inline void local_flush_tlb_all(void)
         }
 }
 
-static inline void local_flush_tlb_mm(struct mm_struct *mm)
+static inline void __flush_tlb_all(void)
 {
         const int zero = 0;
-        const int asid = ASID(mm);
         const unsigned int __tlb_flag = __cpu_tlb_flags;
 
         if (tlb_flag(TLB_WB))
                 dsb();
 
+        __local_flush_tlb_all();
+        tlb_op(TLB_V7_UIS_FULL, "c8, c3, 0", zero);
+
+        if (tlb_flag(TLB_BARRIER)) {
+                dsb();
+                isb();
+        }
+}
+
+static inline void __local_flush_tlb_mm(struct mm_struct *mm)
+{
+        const int zero = 0;
+        const int asid = ASID(mm);
+        const unsigned int __tlb_flag = __cpu_tlb_flags;
+
         if (possible_tlb_flags & (TLB_V4_U_FULL|TLB_V4_D_FULL|TLB_V4_I_FULL)) {
-                if (cpumask_test_cpu(get_cpu(), mm_cpumask(mm))) {
+                if (cpumask_test_cpu(smp_processor_id(), mm_cpumask(mm))) {
                         tlb_op(TLB_V4_U_FULL, "c8, c7, 0", zero);
                         tlb_op(TLB_V4_D_FULL, "c8, c6, 0", zero);
                         tlb_op(TLB_V4_I_FULL, "c8, c5, 0", zero);
                 }
-                put_cpu();
         }
 
         tlb_op(TLB_V6_U_ASID, "c8, c7, 2", asid);
         tlb_op(TLB_V6_D_ASID, "c8, c6, 2", asid);
         tlb_op(TLB_V6_I_ASID, "c8, c5, 2", asid);
+}
+
+static inline void local_flush_tlb_mm(struct mm_struct *mm)
+{
+        const int asid = ASID(mm);
+        const unsigned int __tlb_flag = __cpu_tlb_flags;
+
+        if (tlb_flag(TLB_WB))
+                dsb();
+
+        __local_flush_tlb_mm(mm);
+        tlb_op(TLB_V7_UIS_ASID, "c8, c7, 2", asid);
+
+        if (tlb_flag(TLB_BARRIER))
+                dsb();
+}
+
+static inline void __flush_tlb_mm(struct mm_struct *mm)
+{
+        const unsigned int __tlb_flag = __cpu_tlb_flags;
+
+        if (tlb_flag(TLB_WB))
+                dsb();
+
+        __local_flush_tlb_mm(mm);
 #ifdef CONFIG_ARM_ERRATA_720789
-        tlb_op(TLB_V7_UIS_ASID, "c8, c3, 0", zero);
+        tlb_op(TLB_V7_UIS_ASID, "c8, c3, 0", 0);
 #else
-        tlb_op(TLB_V7_UIS_ASID, "c8, c3, 2", asid);
+        tlb_op(TLB_V7_UIS_ASID, "c8, c3, 2", ASID(mm));
 #endif
 
         if (tlb_flag(TLB_BARRIER))
@@ -370,16 +416,13 @@ static inline void local_flush_tlb_mm(struct mm_struct *mm)
 }
 
 static inline void
-local_flush_tlb_page(struct vm_area_struct *vma, unsigned long uaddr)
+__local_flush_tlb_page(struct vm_area_struct *vma, unsigned long uaddr)
 {
         const int zero = 0;
         const unsigned int __tlb_flag = __cpu_tlb_flags;
 
         uaddr = (uaddr & PAGE_MASK) | ASID(vma->vm_mm);
 
-        if (tlb_flag(TLB_WB))
-                dsb();
-
         if (possible_tlb_flags & (TLB_V4_U_PAGE|TLB_V4_D_PAGE|TLB_V4_I_PAGE|TLB_V4_I_FULL) &&
             cpumask_test_cpu(smp_processor_id(), mm_cpumask(vma->vm_mm))) {
                 tlb_op(TLB_V4_U_PAGE, "c8, c7, 1", uaddr);
@@ -392,6 +435,36 @@ local_flush_tlb_page(struct vm_area_struct *vma, unsigned long uaddr)
         tlb_op(TLB_V6_U_PAGE, "c8, c7, 1", uaddr);
         tlb_op(TLB_V6_D_PAGE, "c8, c6, 1", uaddr);
         tlb_op(TLB_V6_I_PAGE, "c8, c5, 1", uaddr);
+}
+
+static inline void
+local_flush_tlb_page(struct vm_area_struct *vma, unsigned long uaddr)
+{
+        const unsigned int __tlb_flag = __cpu_tlb_flags;
+
+        uaddr = (uaddr & PAGE_MASK) | ASID(vma->vm_mm);
+
+        if (tlb_flag(TLB_WB))
+                dsb();
+
+        __local_flush_tlb_page(vma, uaddr);
+        tlb_op(TLB_V7_UIS_PAGE, "c8, c7, 1", uaddr);
+
+        if (tlb_flag(TLB_BARRIER))
+                dsb();
+}
+
+static inline void
+__flush_tlb_page(struct vm_area_struct *vma, unsigned long uaddr)
+{
+        const unsigned int __tlb_flag = __cpu_tlb_flags;
+
+        uaddr = (uaddr & PAGE_MASK) | ASID(vma->vm_mm);
+
+        if (tlb_flag(TLB_WB))
+                dsb();
+
+        __local_flush_tlb_page(vma, uaddr);
 #ifdef CONFIG_ARM_ERRATA_720789
         tlb_op(TLB_V7_UIS_PAGE, "c8, c3, 3", uaddr & PAGE_MASK);
 #else
@@ -402,16 +475,11 @@ local_flush_tlb_page(struct vm_area_struct *vma, unsigned long uaddr)
                 dsb();
 }
 
-static inline void local_flush_tlb_kernel_page(unsigned long kaddr)
+static inline void __local_flush_tlb_kernel_page(unsigned long kaddr)
 {
         const int zero = 0;
         const unsigned int __tlb_flag = __cpu_tlb_flags;
 
-        kaddr &= PAGE_MASK;
-
-        if (tlb_flag(TLB_WB))
-                dsb();
-
         tlb_op(TLB_V4_U_PAGE, "c8, c7, 1", kaddr);
         tlb_op(TLB_V4_D_PAGE, "c8, c6, 1", kaddr);
         tlb_op(TLB_V4_I_PAGE, "c8, c5, 1", kaddr);
@@ -421,6 +489,36 @@ static inline void local_flush_tlb_kernel_page(unsigned long kaddr)
         tlb_op(TLB_V6_U_PAGE, "c8, c7, 1", kaddr);
         tlb_op(TLB_V6_D_PAGE, "c8, c6, 1", kaddr);
         tlb_op(TLB_V6_I_PAGE, "c8, c5, 1", kaddr);
+}
+
+static inline void local_flush_tlb_kernel_page(unsigned long kaddr)
+{
+        const unsigned int __tlb_flag = __cpu_tlb_flags;
+
+        kaddr &= PAGE_MASK;
+
+        if (tlb_flag(TLB_WB))
+                dsb();
+
+        __local_flush_tlb_kernel_page(kaddr);
+        tlb_op(TLB_V7_UIS_PAGE, "c8, c7, 1", kaddr);
+
+        if (tlb_flag(TLB_BARRIER)) {
+                dsb();
+                isb();
+        }
+}
+
+static inline void __flush_tlb_kernel_page(unsigned long kaddr)
+{
+        const unsigned int __tlb_flag = __cpu_tlb_flags;
+
+        kaddr &= PAGE_MASK;
+
+        if (tlb_flag(TLB_WB))
+                dsb();
+
+        __local_flush_tlb_kernel_page(kaddr);
         tlb_op(TLB_V7_UIS_PAGE, "c8, c3, 1", kaddr);
 
         if (tlb_flag(TLB_BARRIER)) {
diff --git a/arch/arm/kernel/smp_tlb.c b/arch/arm/kernel/smp_tlb.c
index c2edfff573c2..5883b8ae77c8 100644
--- a/arch/arm/kernel/smp_tlb.c
+++ b/arch/arm/kernel/smp_tlb.c
@@ -104,7 +104,7 @@ void flush_tlb_all(void)
         if (tlb_ops_need_broadcast())
                 on_each_cpu(ipi_flush_tlb_all, NULL, 1);
         else
-                local_flush_tlb_all();
+                __flush_tlb_all();
         broadcast_tlb_a15_erratum();
 }
 
@@ -113,7 +113,7 @@ void flush_tlb_mm(struct mm_struct *mm)
         if (tlb_ops_need_broadcast())
                 on_each_cpu_mask(mm_cpumask(mm), ipi_flush_tlb_mm, mm, 1);
         else
-                local_flush_tlb_mm(mm);
+                __flush_tlb_mm(mm);
         broadcast_tlb_mm_a15_erratum(mm);
 }
 
@@ -126,7 +126,7 @@ void flush_tlb_page(struct vm_area_struct *vma, unsigned long uaddr)
                 on_each_cpu_mask(mm_cpumask(vma->vm_mm), ipi_flush_tlb_page,
                                         &ta, 1);
         } else
-                local_flush_tlb_page(vma, uaddr);
+                __flush_tlb_page(vma, uaddr);
         broadcast_tlb_mm_a15_erratum(vma->vm_mm);
 }
 
@@ -137,7 +137,7 @@ void flush_tlb_kernel_page(unsigned long kaddr)
                 ta.ta_start = kaddr;
                 on_each_cpu(ipi_flush_tlb_kernel_page, &ta, 1);
         } else
-                local_flush_tlb_kernel_page(kaddr);
+                __flush_tlb_kernel_page(kaddr);
         broadcast_tlb_a15_erratum();
 }
 
diff --git a/arch/arm/mm/context.c b/arch/arm/mm/context.c
index 4a0544492f10..84e6f772e204 100644
--- a/arch/arm/mm/context.c
+++ b/arch/arm/mm/context.c
@@ -162,10 +162,7 @@ static void flush_context(unsigned int cpu)
         }
 
         /* Queue a TLB invalidate and flush the I-cache if necessary. */
-        if (!tlb_ops_need_broadcast())
-                cpumask_set_cpu(cpu, &tlb_flush_pending);
-        else
-                cpumask_setall(&tlb_flush_pending);
+        cpumask_setall(&tlb_flush_pending);
 
         if (icache_is_vivt_asid_tagged())
                 __flush_icache_all();
@@ -245,8 +242,6 @@ void check_and_switch_context(struct mm_struct *mm, struct task_struct *tsk)
         if (cpumask_test_and_clear_cpu(cpu, &tlb_flush_pending)) {
                 local_flush_bp_all();
                 local_flush_tlb_all();
-                if (erratum_a15_798181())
-                        dummy_flush_tlb_a15_erratum();
         }
 
         atomic64_set(&per_cpu(active_asids, cpu), asid);