[PATCH v5] riscv: mm: execute local TLB flush after populating vmemmap
Alexandre Ghiti
alex at ghiti.fr
Wed Dec 20 13:19:31 PST 2023
Hi Vincent,
On 20/12/2023 03:43, Vincent Chen wrote:
> The spare_init() calls memmap_populate() many times to create VA to PA
> mapping for the VMEMMAP area, where all "struct page" are located once
> CONFIG_SPARSEMEM_VMEMMAP is defined. These "struct page" are later
> initialized in the zone_sizes_init() function. However, during this
> process, no sfence.vma instruction is executed for this VMEMMAP area.
> This omission may cause the hart to fail to perform page table walk
> because some data related to the address translation is invisible to the
> hart. To solve this issue, the local_flush_tlb_kernel_range() is called
> right after the spare_init() to execute a sfence.vma instruction for this
> VMEMMAP area, ensuring that all data related to the address translation
> is visible to the hart.
s/spare_init/sparse_init
>
> Fixes: d95f1a542c3d ("RISC-V: Implement sparsemem")
> Signed-off-by: Vincent Chen <vincent.chen at sifive.com>
> ---
> arch/riscv/include/asm/tlbflush.h | 2 ++
> arch/riscv/mm/init.c | 5 +++++
> arch/riscv/mm/tlbflush.c | 6 ++++++
> 3 files changed, 13 insertions(+)
>
> diff --git a/arch/riscv/include/asm/tlbflush.h b/arch/riscv/include/asm/tlbflush.h
> index 8f3418c5f172..525267379ccb 100644
> --- a/arch/riscv/include/asm/tlbflush.h
> +++ b/arch/riscv/include/asm/tlbflush.h
> @@ -46,6 +46,7 @@ void flush_tlb_kernel_range(unsigned long start, unsigned long end);
> void flush_pmd_tlb_range(struct vm_area_struct *vma, unsigned long start,
> unsigned long end);
> #endif
> +void local_flush_tlb_kernel_range(unsigned long start, unsigned long end);
> #else /* CONFIG_SMP && CONFIG_MMU */
>
> #define flush_tlb_all() local_flush_tlb_all()
> @@ -66,6 +67,7 @@ static inline void flush_tlb_kernel_range(unsigned long start,
>
> #define flush_tlb_mm(mm) flush_tlb_all()
> #define flush_tlb_mm_range(mm, start, end, page_size) flush_tlb_all()
> +#define local_flush_tlb_kernel_range(start, end) flush_tlb_all()
> #endif /* !CONFIG_SMP || !CONFIG_MMU */
>
> #endif /* _ASM_RISCV_TLBFLUSH_H */
> diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
> index 2e011cbddf3a..cc56a0945120 100644
> --- a/arch/riscv/mm/init.c
> +++ b/arch/riscv/mm/init.c
> @@ -1377,6 +1377,10 @@ void __init misc_mem_init(void)
> early_memtest(min_low_pfn << PAGE_SHIFT, max_low_pfn << PAGE_SHIFT);
> arch_numa_init();
> sparse_init();
> +#ifdef CONFIG_SPARSEMEM_VMEMMAP
> + /* The entire VMEMMAP region has been populated. Flush TLB for this region */
> + local_flush_tlb_kernel_range(VMEMMAP_START, VMEMMAP_END);
> +#endif
> zone_sizes_init();
> arch_reserve_crashkernel();
> memblock_dump_all();
> @@ -1386,6 +1390,7 @@ void __init misc_mem_init(void)
> int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
> struct vmem_altmap *altmap)
> {
> + /* Defer the required TLB flush until the entire VMEMMAP region has been populated */
> return vmemmap_populate_basepages(start, end, node, NULL);
> }
> #endif
> diff --git a/arch/riscv/mm/tlbflush.c b/arch/riscv/mm/tlbflush.c
> index e6659d7368b3..d11a4ae87ec1 100644
> --- a/arch/riscv/mm/tlbflush.c
> +++ b/arch/riscv/mm/tlbflush.c
> @@ -193,6 +193,12 @@ void flush_tlb_kernel_range(unsigned long start, unsigned long end)
> __flush_tlb_range(NULL, start, end - start, PAGE_SIZE);
> }
>
> +/* Flush a range of kernel pages without broadcasting */
> +void local_flush_tlb_kernel_range(unsigned long start, unsigned long end)
> +{
> + local_flush_tlb_range_asid(start, end - start, PAGE_SIZE, FLUSH_TLB_NO_ASID);
> +}
> +
> #ifdef CONFIG_TRANSPARENT_HUGEPAGE
> void flush_pmd_tlb_range(struct vm_area_struct *vma, unsigned long start,
> unsigned long end)
Otherwise, this looks good to me and should go to -fixes, you can add:
Reviewed-by: Alexandre Ghiti <alexghiti at rivosinc.com>
Thanks!
Alex
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