This is a note to let you know that I've just added the patch titled
riscv: Improve flush_tlb_kernel_range()
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
riscv-improve-flush_tlb_kernel_range.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit d68ebd8c13fa7dbb70d5b0b57a2fbcadb7c20c2c
Author: Alexandre Ghiti <alexghiti@xxxxxxxxxxxx>
Date: Mon Oct 30 14:30:28 2023 +0100
riscv: Improve flush_tlb_kernel_range()
[ Upstream commit 5e22bfd520ea8740e9a20314d2a890baf304c9d2 ]
This function used to simply flush the whole tlb of all harts, be more
subtile and try to only flush the range.
The problem is that we can only use PAGE_SIZE as stride since we don't know
the size of the underlying mapping and then this function will be improved
only if the size of the region to flush is < threshold * PAGE_SIZE.
Signed-off-by: Alexandre Ghiti <alexghiti@xxxxxxxxxxxx>
Reviewed-by: Andrew Jones <ajones@xxxxxxxxxxxxxxxx>
Tested-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx> # On RZ/Five SMARC
Reviewed-by: Samuel Holland <samuel.holland@xxxxxxxxxx>
Tested-by: Samuel Holland <samuel.holland@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20231030133027.19542-5-alexghiti@xxxxxxxxxxxx
Signed-off-by: Palmer Dabbelt <palmer@xxxxxxxxxxxx>
Stable-dep-of: d9807d60c145 ("riscv: mm: execute local TLB flush after populating vmemmap")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/arch/riscv/include/asm/tlbflush.h b/arch/riscv/include/asm/tlbflush.h
index 170a49c531c6..8f3418c5f172 100644
--- a/arch/riscv/include/asm/tlbflush.h
+++ b/arch/riscv/include/asm/tlbflush.h
@@ -40,6 +40,7 @@ void flush_tlb_mm_range(struct mm_struct *mm, unsigned long start,
void flush_tlb_page(struct vm_area_struct *vma, unsigned long addr);
void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
unsigned long end);
+void flush_tlb_kernel_range(unsigned long start, unsigned long end);
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
#define __HAVE_ARCH_FLUSH_PMD_TLB_RANGE
void flush_pmd_tlb_range(struct vm_area_struct *vma, unsigned long start,
@@ -56,15 +57,15 @@ static inline void flush_tlb_range(struct vm_area_struct *vma,
local_flush_tlb_all();
}
-#define flush_tlb_mm(mm) flush_tlb_all()
-#define flush_tlb_mm_range(mm, start, end, page_size) flush_tlb_all()
-#endif /* !CONFIG_SMP || !CONFIG_MMU */
-
/* Flush a range of kernel pages */
static inline void flush_tlb_kernel_range(unsigned long start,
unsigned long end)
{
- flush_tlb_all();
+ local_flush_tlb_all();
}
+#define flush_tlb_mm(mm) flush_tlb_all()
+#define flush_tlb_mm_range(mm, start, end, page_size) flush_tlb_all()
+#endif /* !CONFIG_SMP || !CONFIG_MMU */
+
#endif /* _ASM_RISCV_TLBFLUSH_H */
diff --git a/arch/riscv/mm/tlbflush.c b/arch/riscv/mm/tlbflush.c
index 88fa8b18ca22..8723adc884c7 100644
--- a/arch/riscv/mm/tlbflush.c
+++ b/arch/riscv/mm/tlbflush.c
@@ -96,20 +96,27 @@ static void __flush_tlb_range(struct mm_struct *mm, unsigned long start,
unsigned long size, unsigned long stride)
{
struct flush_tlb_range_data ftd;
- struct cpumask *cmask = mm_cpumask(mm);
+ const struct cpumask *cmask;
unsigned long asid = FLUSH_TLB_NO_ASID;
- unsigned int cpuid;
bool broadcast;
- if (cpumask_empty(cmask))
- return;
+ if (mm) {
+ unsigned int cpuid;
+
+ cmask = mm_cpumask(mm);
+ if (cpumask_empty(cmask))
+ return;
- cpuid = get_cpu();
- /* check if the tlbflush needs to be sent to other CPUs */
- broadcast = cpumask_any_but(cmask, cpuid) < nr_cpu_ids;
+ cpuid = get_cpu();
+ /* check if the tlbflush needs to be sent to other CPUs */
+ broadcast = cpumask_any_but(cmask, cpuid) < nr_cpu_ids;
- if (static_branch_unlikely(&use_asid_allocator))
- asid = atomic_long_read(&mm->context.id) & asid_mask;
+ if (static_branch_unlikely(&use_asid_allocator))
+ asid = atomic_long_read(&mm->context.id) & asid_mask;
+ } else {
+ cmask = cpu_online_mask;
+ broadcast = true;
+ }
if (broadcast) {
if (riscv_use_ipi_for_rfence()) {
@@ -127,7 +134,8 @@ static void __flush_tlb_range(struct mm_struct *mm, unsigned long start,
local_flush_tlb_range_asid(start, size, stride, asid);
}
- put_cpu();
+ if (mm)
+ put_cpu();
}
void flush_tlb_mm(struct mm_struct *mm)
@@ -152,6 +160,12 @@ void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
{
__flush_tlb_range(vma->vm_mm, start, end - start, PAGE_SIZE);
}
+
+void flush_tlb_kernel_range(unsigned long start, unsigned long end)
+{
+ __flush_tlb_range(NULL, start, end - start, PAGE_SIZE);
+}
+
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
void flush_pmd_tlb_range(struct vm_area_struct *vma, unsigned long start,
unsigned long end)
