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Message-ID: <20200429095817.GA28631@C02TD0UTHF1T.local>
Date: Wed, 29 Apr 2020 10:58:17 +0100
From: Mark Rutland <mark.rutland@....com>
To: Matthew Wilcox <willy@...radead.org>
Cc: linux-mm@...ck.org, linux-kernel@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org,
Will Deacon <will@...nel.org>,
Catalin Marinas <catalin.marinas@....com>,
Russell King <linux@...linux.org.uk>,
Geert Uytterhoeven <geert@...ux-m68k.org>,
linux-m68k@...ts.linux-m68k.org
Subject: Re: [PATCH 4/7] arm64: Thread mm_struct throughout page table
allocation
Hi Matthew,
On Tue, Apr 28, 2020 at 12:44:46PM -0700, Matthew Wilcox wrote:
> From: "Matthew Wilcox (Oracle)" <willy@...radead.org>
>
> An upcoming patch will pass mm_struct to the page table constructor.
> Make sure arm64 has the appropriate mm_struct at the point it needs to
> call the constructor.
>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@...radead.org>
This generally looks good ot me. I was a little scared that we'd need to
update the EFI mapping code, but I see that already passes its mm into
create_pgd_mapping(), and everything else uses init_mm today.
One small comment below.
> ---
> arch/arm64/mm/mmu.c | 89 ++++++++++++++++++++++-----------------------
> 1 file changed, 43 insertions(+), 46 deletions(-)
>
> diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
> index a374e4f51a62..69ecc83c3be0 100644
> --- a/arch/arm64/mm/mmu.c
> +++ b/arch/arm64/mm/mmu.c
> @@ -88,7 +88,9 @@ pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
> }
> EXPORT_SYMBOL(phys_mem_access_prot);
>
> -static phys_addr_t __init early_pgtable_alloc(int shift)
> +typedef phys_addr_t (arm_pt_alloc_t)(int size, struct mm_struct *);
Sorry to bikeshed, but for consistency with the naming scheme used here
could we please call this 'pgtable_alloc_fn' ?
We generally use 'pgtable' here, and 'fn' makes it clearer that this is
a function pointer rather than data. The 'arm_' prefix is also a bit
unusual here, and I don't think we need it.
With that:
Reviewed-by: Mark Rutland <mark.rutland@....com>
Mark.
> @@ -333,11 +332,9 @@ static void alloc_init_pud(pgd_t *pgdp, unsigned long addr, unsigned long end,
> pud_clear_fixmap();
> }
>
> -static void __create_pgd_mapping(pgd_t *pgdir, phys_addr_t phys,
> - unsigned long virt, phys_addr_t size,
> - pgprot_t prot,
> - phys_addr_t (*pgtable_alloc)(int),
> - int flags)
> +static void __create_pgd_mapping(struct mm_struct *mm, pgd_t *pgdir,
> + phys_addr_t phys, unsigned long virt, phys_addr_t size,
> + pgprot_t prot, arm_pt_alloc_t pgtable_alloc, int flags)
> {
> unsigned long addr, end, next;
> pgd_t *pgdp = pgd_offset_raw(pgdir, virt);
> @@ -355,13 +352,13 @@ static void __create_pgd_mapping(pgd_t *pgdir, phys_addr_t phys,
>
> do {
> next = pgd_addr_end(addr, end);
> - alloc_init_pud(pgdp, addr, next, phys, prot, pgtable_alloc,
> + alloc_init_pud(mm, pgdp, addr, next, phys, prot, pgtable_alloc,
> flags);
> phys += next - addr;
> } while (pgdp++, addr = next, addr != end);
> }
>
> -static phys_addr_t __pgd_pgtable_alloc(int shift)
> +static phys_addr_t __pgd_pgtable_alloc(int shift, struct mm_struct *mm)
> {
> void *ptr = (void *)__get_free_page(GFP_PGTABLE_KERNEL);
> BUG_ON(!ptr);
> @@ -371,9 +368,9 @@ static phys_addr_t __pgd_pgtable_alloc(int shift)
> return __pa(ptr);
> }
>
> -static phys_addr_t pgd_pgtable_alloc(int shift)
> +static phys_addr_t pgd_pgtable_alloc(int shift, struct mm_struct *mm)
> {
> - phys_addr_t pa = __pgd_pgtable_alloc(shift);
> + phys_addr_t pa = __pgd_pgtable_alloc(shift, mm);
>
> /*
> * Call proper page table ctor in case later we need to
> @@ -404,8 +401,8 @@ static void __init create_mapping_noalloc(phys_addr_t phys, unsigned long virt,
> &phys, virt);
> return;
> }
> - __create_pgd_mapping(init_mm.pgd, phys, virt, size, prot, NULL,
> - NO_CONT_MAPPINGS);
> + __create_pgd_mapping(&init_mm, init_mm.pgd, phys, virt, size, prot,
> + NULL, NO_CONT_MAPPINGS);
> }
>
> void __init create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys,
> @@ -419,7 +416,7 @@ void __init create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys,
> if (page_mappings_only)
> flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;
>
> - __create_pgd_mapping(mm->pgd, phys, virt, size, prot,
> + __create_pgd_mapping(mm, mm->pgd, phys, virt, size, prot,
> pgd_pgtable_alloc, flags);
> }
>
> @@ -432,8 +429,8 @@ static void update_mapping_prot(phys_addr_t phys, unsigned long virt,
> return;
> }
>
> - __create_pgd_mapping(init_mm.pgd, phys, virt, size, prot, NULL,
> - NO_CONT_MAPPINGS);
> + __create_pgd_mapping(&init_mm, init_mm.pgd, phys, virt, size, prot,
> + NULL, NO_CONT_MAPPINGS);
>
> /* flush the TLBs after updating live kernel mappings */
> flush_tlb_kernel_range(virt, virt + size);
> @@ -442,8 +439,8 @@ static void update_mapping_prot(phys_addr_t phys, unsigned long virt,
> static void __init __map_memblock(pgd_t *pgdp, phys_addr_t start,
> phys_addr_t end, pgprot_t prot, int flags)
> {
> - __create_pgd_mapping(pgdp, start, __phys_to_virt(start), end - start,
> - prot, early_pgtable_alloc, flags);
> + __create_pgd_mapping(&init_mm, pgdp, start, __phys_to_virt(start),
> + end - start, prot, early_pgtable_alloc, flags);
> }
>
> void __init mark_linear_text_alias_ro(void)
> @@ -547,8 +544,8 @@ static void __init map_kernel_segment(pgd_t *pgdp, void *va_start, void *va_end,
> BUG_ON(!PAGE_ALIGNED(pa_start));
> BUG_ON(!PAGE_ALIGNED(size));
>
> - __create_pgd_mapping(pgdp, pa_start, (unsigned long)va_start, size, prot,
> - early_pgtable_alloc, flags);
> + __create_pgd_mapping(&init_mm, pgdp, pa_start, (unsigned long)va_start,
> + size, prot, early_pgtable_alloc, flags);
>
> if (!(vm_flags & VM_NO_GUARD))
> size += PAGE_SIZE;
> @@ -591,8 +588,8 @@ static int __init map_entry_trampoline(void)
>
> /* Map only the text into the trampoline page table */
> memset(tramp_pg_dir, 0, PGD_SIZE);
> - __create_pgd_mapping(tramp_pg_dir, pa_start, TRAMP_VALIAS, PAGE_SIZE,
> - prot, __pgd_pgtable_alloc, 0);
> + __create_pgd_mapping(&init_mm, tramp_pg_dir, pa_start, TRAMP_VALIAS,
> + PAGE_SIZE, prot, __pgd_pgtable_alloc, 0);
>
> /* Map both the text and data into the kernel page table */
> __set_fixmap(FIX_ENTRY_TRAMP_TEXT, pa_start, prot);
> @@ -1381,9 +1378,9 @@ int arch_add_memory(int nid, u64 start, u64 size,
> if (rodata_full || debug_pagealloc_enabled())
> flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;
>
> - __create_pgd_mapping(swapper_pg_dir, start, __phys_to_virt(start),
> - size, params->pgprot, __pgd_pgtable_alloc,
> - flags);
> + __create_pgd_mapping(&init_mm, swapper_pg_dir, start,
> + __phys_to_virt(start), size, params->pgprot,
> + __pgd_pgtable_alloc, flags);
>
> memblock_clear_nomap(start, size);
>
> --
> 2.26.2
>
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