[PATCH V2 0/2] riscv: Fixup asid_allocator remaining issues

[PATCH V2 0/2] riscv: Fixup asid_allocator remaining issues

[guoren]

From: Guo Ren <guoren@linux.alibaba.com>

The patchset fixes the remaining problems of asid_allocator.
 - Fixup _PAGE_GLOBAL for kernel virtual address mapping
 - Optimize tlb_flush with asid & range

Changes since v1:
 - Drop PAGE_UP wrong fixup
 - Rebase on clean linux-5.13-rc2
 - Add Reviewed-by

Guo Ren (2):
  riscv: Fixup _PAGE_GLOBAL in _PAGE_KERNEL
  riscv: Use use_asid_allocator flush TLB

 arch/riscv/include/asm/mmu_context.h |  2 ++
 arch/riscv/include/asm/pgtable.h     |  3 ++-
 arch/riscv/include/asm/tlbflush.h    | 22 ++++++++++++++++++++
 arch/riscv/mm/context.c              |  2 +-
 arch/riscv/mm/tlbflush.c             | 40 +++++++++++++++++++++++++++++++++---
 5 files changed, 64 insertions(+), 5 deletions(-)

-- 
2.7.4

[PATCH V2 1/2] riscv: Fixup _PAGE_GLOBAL in _PAGE_KERNEL

[guoren]

From: Guo Ren <guoren@linux.alibaba.com>

Kernel virtual address translation should avoid care asid or it'll
cause more TLB-miss and TLB-refill. Because the current asid in satp
belongs to the current process, but the target kernel va TLB entry's
asid still belongs to the previous process.

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Cc: Palmer Dabbelt <palmerdabbelt@google.com>
---
 arch/riscv/include/asm/pgtable.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
index 9469f46..346a3c6 100644
--- a/arch/riscv/include/asm/pgtable.h
+++ b/arch/riscv/include/asm/pgtable.h
@@ -134,7 +134,8 @@
 				| _PAGE_WRITE \
 				| _PAGE_PRESENT \
 				| _PAGE_ACCESSED \
-				| _PAGE_DIRTY)
+				| _PAGE_DIRTY \
+				| _PAGE_GLOBAL)
 
 #define PAGE_KERNEL		__pgprot(_PAGE_KERNEL)
 #define PAGE_KERNEL_READ	__pgprot(_PAGE_KERNEL & ~_PAGE_WRITE)
-- 
2.7.4

[PATCH V2 2/2] riscv: Use use_asid_allocator flush TLB

[guoren]

From: Guo Ren <guoren@linux.alibaba.com>

Use static_branch_unlikely(&use_asid_allocator) to keep the origin
tlb flush style, so it's no effect on the existing machine. Here
are the optimized functions:
 - flush_tlb_mm
 - flush_tlb_page
 - flush_tlb_range

All above are based on the below new implement functions:
 - __sbi_tlb_flush_range_asid
 - local_flush_tlb_range_asid

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Reviewed-by: Anup Patel <anup.patel@wdc.com>
Cc: Palmer Dabbelt <palmerdabbelt@google.com>
---
 arch/riscv/include/asm/mmu_context.h |  2 ++
 arch/riscv/include/asm/tlbflush.h    | 22 ++++++++++++++++++++
 arch/riscv/mm/context.c              |  2 +-
 arch/riscv/mm/tlbflush.c             | 40 +++++++++++++++++++++++++++++++++---
 4 files changed, 62 insertions(+), 4 deletions(-)

diff --git a/arch/riscv/include/asm/mmu_context.h b/arch/riscv/include/asm/mmu_context.h
index b065941..7030837 100644
--- a/arch/riscv/include/asm/mmu_context.h
+++ b/arch/riscv/include/asm/mmu_context.h
@@ -33,6 +33,8 @@ static inline int init_new_context(struct task_struct *tsk,
 	return 0;
 }
 
+DECLARE_STATIC_KEY_FALSE(use_asid_allocator);
+
 #include <asm-generic/mmu_context.h>
 
 #endif /* _ASM_RISCV_MMU_CONTEXT_H */
diff --git a/arch/riscv/include/asm/tlbflush.h b/arch/riscv/include/asm/tlbflush.h
index c84218a..9390319 100644
--- a/arch/riscv/include/asm/tlbflush.h
+++ b/arch/riscv/include/asm/tlbflush.h
@@ -8,6 +8,7 @@
 #define _ASM_RISCV_TLBFLUSH_H
 
 #include <linux/mm_types.h>
+#include <asm/page.h>
 #include <asm/smp.h>
 #include <asm/errata_list.h>
 
@@ -22,9 +23,30 @@ static inline void local_flush_tlb_page(unsigned long addr)
 {
 	ALT_FLUSH_TLB_PAGE(__asm__ __volatile__ ("sfence.vma %0" : : "r" (addr) : "memory"));
 }
+
+static inline void local_flush_tlb_range_asid(unsigned long start, unsigned long size,
+					      unsigned long asid)
+{
+	unsigned long page_add = PAGE_DOWN(start);
+	unsigned long page_end = PAGE_UP(start + size);
+
+	if (size == -1) {
+		__asm__ __volatile__ ("sfence.vma x0, %0" : : "r" (asid) : "memory");
+		return;
+	}
+
+	while(page_add < page_end) {
+		__asm__ __volatile__ ("sfence.vma %0, %1"
+				:
+				: "r" (page_add), "r" (asid)
+				: "memory");
+		page_add += PAGE_SIZE;
+	}
+}
 #else /* CONFIG_MMU */
 #define local_flush_tlb_all()			do { } while (0)
 #define local_flush_tlb_page(addr)		do { } while (0)
+#define local_flush_tlb_range_asid(addr)	do { } while (0)
 #endif /* CONFIG_MMU */
 
 #if defined(CONFIG_SMP) && defined(CONFIG_MMU)
diff --git a/arch/riscv/mm/context.c b/arch/riscv/mm/context.c
index 68aa312..45c1b04 100644
--- a/arch/riscv/mm/context.c
+++ b/arch/riscv/mm/context.c
@@ -18,7 +18,7 @@
 
 #ifdef CONFIG_MMU
 
-static DEFINE_STATIC_KEY_FALSE(use_asid_allocator);
+DEFINE_STATIC_KEY_FALSE(use_asid_allocator);
 
 static unsigned long asid_bits;
 static unsigned long num_asids;
diff --git a/arch/riscv/mm/tlbflush.c b/arch/riscv/mm/tlbflush.c
index 720b443..69588dc 100644
--- a/arch/riscv/mm/tlbflush.c
+++ b/arch/riscv/mm/tlbflush.c
@@ -4,6 +4,7 @@
 #include <linux/smp.h>
 #include <linux/sched.h>
 #include <asm/sbi.h>
+#include <asm/mmu_context.h>
 
 void flush_tlb_all(void)
 {
@@ -39,18 +40,51 @@ static void __sbi_tlb_flush_range(struct cpumask *cmask, unsigned long start,
 	put_cpu();
 }
 
+static void __sbi_tlb_flush_range_asid(struct cpumask *cmask, unsigned long start,
+				       unsigned long size, unsigned long asid)
+{
+	struct cpumask hmask;
+	unsigned int cpuid;
+
+	if (cpumask_empty(cmask))
+		return;
+
+	cpuid = get_cpu();
+
+	if (cpumask_any_but(cmask, cpuid) >= nr_cpu_ids) {
+		local_flush_tlb_range_asid(start, size, asid);
+	} else {
+		riscv_cpuid_to_hartid_mask(cmask, &hmask);
+		sbi_remote_sfence_vma_asid(cpumask_bits(&hmask), start, size, asid);
+	}
+
+	put_cpu();
+}
+
 void flush_tlb_mm(struct mm_struct *mm)
 {
-	__sbi_tlb_flush_range(mm_cpumask(mm), 0, -1);
+	if (static_branch_unlikely(&use_asid_allocator))
+		__sbi_tlb_flush_range_asid(mm_cpumask(mm), 0, -1,
+					   atomic_long_read(&mm->context.id));
+	else
+		__sbi_tlb_flush_range(mm_cpumask(mm), 0, -1);
 }
 
 void flush_tlb_page(struct vm_area_struct *vma, unsigned long addr)
 {
-	__sbi_tlb_flush_range(mm_cpumask(vma->vm_mm), addr, PAGE_SIZE);
+	if (static_branch_unlikely(&use_asid_allocator))
+		__sbi_tlb_flush_range_asid(mm_cpumask(vma->vm_mm), addr, PAGE_SIZE,
+					   atomic_long_read(&vma->vm_mm->context.id));
+	else
+		__sbi_tlb_flush_range(mm_cpumask(vma->vm_mm), addr, PAGE_SIZE);
 }
 
 void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
 		     unsigned long end)
 {
-	__sbi_tlb_flush_range(mm_cpumask(vma->vm_mm), start, end - start);
+	if (static_branch_unlikely(&use_asid_allocator))
+		__sbi_tlb_flush_range_asid(mm_cpumask(vma->vm_mm), start, end - start,
+					   atomic_long_read(&vma->vm_mm->context.id));
+	else
+		__sbi_tlb_flush_range(mm_cpumask(vma->vm_mm), start, end - start);
 }
-- 
2.7.4