linux-kernel - Re: [PATCH 2/8] riscv: add ARCH_HAS_SET_DIRECT

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Date:   Wed, 04 Mar 2020 16:57:43 -0800 (PST)
From:   Palmer Dabbelt <palmer@...belt.com>
To:     zong.li@...ive.com
CC:     Paul Walmsley <paul.walmsley@...ive.com>, aou@...s.berkeley.edu,
        linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org,
        zong.li@...ive.com
Subject:     Re: [PATCH 2/8] riscv: add ARCH_HAS_SET_DIRECT_MAP support

On Mon, 17 Feb 2020 00:32:17 PST (-0800), zong.li@...ive.com wrote:
> Add set_direct_map_*() functions for setting the direct map alias for
> the page to its default permissions and to an invalid state that cannot
> be cached in a TLB. (See d253ca0c ("x86/mm/cpa: Add set_direct_map_*()
> functions")) Add a similar implementation for RISC-V.
>
> Signed-off-by: Zong Li <zong.li@...ive.com>
> ---
>  arch/riscv/Kconfig                  |  1 +
>  arch/riscv/include/asm/set_memory.h |  3 +++
>  arch/riscv/mm/pageattr.c            | 24 ++++++++++++++++++++++++
>  3 files changed, 28 insertions(+)
>
> diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> index 76ed36543b3a..07bf1a7c0dd2 100644
> --- a/arch/riscv/Kconfig
> +++ b/arch/riscv/Kconfig
> @@ -60,6 +60,7 @@ config RISCV
>  	select HAVE_EBPF_JIT if 64BIT
>  	select EDAC_SUPPORT
>  	select ARCH_HAS_GIGANTIC_PAGE
> +	select ARCH_HAS_SET_DIRECT_MAP
>  	select ARCH_HAS_SET_MEMORY
>  	select ARCH_WANT_HUGE_PMD_SHARE if 64BIT
>  	select SPARSEMEM_STATIC if 32BIT
> diff --git a/arch/riscv/include/asm/set_memory.h b/arch/riscv/include/asm/set_memory.h
> index 936f08063566..a9783a878dca 100644
> --- a/arch/riscv/include/asm/set_memory.h
> +++ b/arch/riscv/include/asm/set_memory.h
> @@ -14,4 +14,7 @@ int set_memory_rw(unsigned long addr, int numpages);
>  int set_memory_x(unsigned long addr, int numpages);
>  int set_memory_nx(unsigned long addr, int numpages);
>
> +int set_direct_map_invalid_noflush(struct page *page);
> +int set_direct_map_default_noflush(struct page *page);
> +
>  #endif /* _ASM_RISCV_SET_MEMORY_H */
> diff --git a/arch/riscv/mm/pageattr.c b/arch/riscv/mm/pageattr.c
> index fcd59ef2835b..7be6cd67e2ef 100644
> --- a/arch/riscv/mm/pageattr.c
> +++ b/arch/riscv/mm/pageattr.c
> @@ -148,3 +148,27 @@ int set_memory_nx(unsigned long addr, int numpages)
>  {
>  	return __set_memory(addr, numpages, __pgprot(0), __pgprot(_PAGE_EXEC));
>  }
> +
> +int set_direct_map_invalid_noflush(struct page *page)
> +{
> +	unsigned long start = (unsigned long)page_address(page);
> +	unsigned long end = start + PAGE_SIZE;
> +	struct pageattr_masks masks = {
> +		.set_mask = __pgprot(0),
> +		.clear_mask = __pgprot(_PAGE_PRESENT)
> +	};
> +
> +	return walk_page_range(&init_mm, start, end, &pageattr_ops, &masks);
> +}
> +
> +int set_direct_map_default_noflush(struct page *page)
> +{
> +	unsigned long start = (unsigned long)page_address(page);
> +	unsigned long end = start + PAGE_SIZE;
> +	struct pageattr_masks masks = {
> +		.set_mask = PAGE_KERNEL,
> +		.clear_mask = __pgprot(0)
> +	};
> +
> +	return walk_page_range(&init_mm, start, end, &pageattr_ops, &masks);
> +}

Reviewed-by: Palmer Dabbelt <palmerdabbelt@...gle.com>