Re: [PATCH -next] riscv: Enable HAVE_ARCH_HUGE_VMAP for 64BIT

[Palmer Dabbelt]

On Fri, 04 Jun 2021 22:48:37 PDT (-0700), liushixin2@xxxxxxxxxx wrote:
> This sets the HAVE_ARCH_HUGE_VMAP option. Enable pmd vmap support and
> define the required page table functions(Currently, riscv has only
> three-level page tables support for 64BIT).
>
> Signed-off-by: Liu Shixin <liushixin2@xxxxxxxxxx>
> ---
>  arch/riscv/Kconfig               |  1 +
>  arch/riscv/include/asm/vmalloc.h | 12 ++++++++++
>  arch/riscv/mm/Makefile           |  1 +
>  arch/riscv/mm/pgtable.c          | 40 ++++++++++++++++++++++++++++++++
>  4 files changed, 54 insertions(+)
>  create mode 100644 arch/riscv/mm/pgtable.c
>
> diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> index 4c0bfb2569e9..fb3c48fa96c1 100644
> --- a/arch/riscv/Kconfig
> +++ b/arch/riscv/Kconfig
> @@ -61,6 +61,7 @@ config RISCV
>  	select GENERIC_TIME_VSYSCALL if MMU && 64BIT
>  	select HANDLE_DOMAIN_IRQ
>  	select HAVE_ARCH_AUDITSYSCALL
> +	select HAVE_ARCH_HUGE_VMAP if MMU && 64BIT
>  	select HAVE_ARCH_JUMP_LABEL
>  	select HAVE_ARCH_JUMP_LABEL_RELATIVE
>  	select HAVE_ARCH_KASAN if MMU && 64BIT
> diff --git a/arch/riscv/include/asm/vmalloc.h b/arch/riscv/include/asm/vmalloc.h
> index ff9abc00d139..8f17f421f80c 100644
> --- a/arch/riscv/include/asm/vmalloc.h
> +++ b/arch/riscv/include/asm/vmalloc.h
> @@ -1,4 +1,16 @@
>  #ifndef _ASM_RISCV_VMALLOC_H
>  #define _ASM_RISCV_VMALLOC_H
>
> +#ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
> +
> +#define IOREMAP_MAX_ORDER (PMD_SHIFT)
> +
> +#define arch_vmap_pmd_supported	arch_vmap_pmd_supported
> +static inline bool __init arch_vmap_pmd_supported(pgprot_t prot)
> +{
> +	return true;
> +}
> +
> +#endif
> +
>  #endif /* _ASM_RISCV_VMALLOC_H */
> diff --git a/arch/riscv/mm/Makefile b/arch/riscv/mm/Makefile
> index 7ebaef10ea1b..f932b4d69946 100644
> --- a/arch/riscv/mm/Makefile
> +++ b/arch/riscv/mm/Makefile
> @@ -13,6 +13,7 @@ obj-y += extable.o
>  obj-$(CONFIG_MMU) += fault.o pageattr.o
>  obj-y += cacheflush.o
>  obj-y += context.o
> +obj-y += pgtable.o
>
>  ifeq ($(CONFIG_MMU),y)
>  obj-$(CONFIG_SMP) += tlbflush.o
> diff --git a/arch/riscv/mm/pgtable.c b/arch/riscv/mm/pgtable.c
> new file mode 100644
> index 000000000000..738dc6f3530f
> --- /dev/null
> +++ b/arch/riscv/mm/pgtable.c
> @@ -0,0 +1,40 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +#include <asm/pgalloc.h>
> +#include <linux/gfp.h>
> +#include <linux/kernel.h>
> +#include <linux/pgtable.h>
> +
> +#ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
> +
> +#ifndef __PAGETABLE_PMD_FOLDED
> +int pmd_set_huge(pmd_t *pmd, phys_addr_t phys, pgprot_t prot)
> +{
> +	pmd_t new_pmd = pfn_pmd(__phys_to_pfn(phys), prot);
> +
> +	set_pmd(pmd, new_pmd);
> +	return 1;
> +}
> +
> +int pmd_clear_huge(pmd_t *pmd)
> +{
> +	if (!pmd_leaf(READ_ONCE(*pmd)))
> +		return 0;
> +	pmd_clear(pmd);
> +	return 1;
> +}
> +#endif
> +
> +int pmd_free_pte_page(pmd_t *pmd, unsigned long addr)
> +{
> +	pte_t *pte;
> +
> +	pte = (pte_t *)pmd_page_vaddr(*pmd);
> +	pmd_clear(pmd);
> +
> +	flush_tlb_kernel_range(addr, addr + PMD_SIZE);
> +	pte_free_kernel(NULL, pte);
> +	return 1;
> +}
> +
> +#endif /* CONFIG_HAVE_ARCH_HUGE_VMAP */

Thanks, this is on for-next.