From: Ard Biesheuvel <ard.biesheuvel@linaro.org>
To: Laura Abbott <labbott@fedoraproject.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCHv2 1/3] arm64: Drop alloc function from create_mapping
Date: Sat, 30 Jan 2016 11:34:50 +0100 [thread overview]
Message-ID: <CAKv+Gu-VTg6m9PNRCEDm07nwku3YVmYkMSs-08p_SigqOdabhQ@mail.gmail.com> (raw)
In-Reply-To: <1454111218-3461-2-git-send-email-labbott@fedoraproject.org>
On 30 January 2016 at 00:46, Laura Abbott <labbott@fedoraproject.org> wrote:
>
> create_mapping is only used in fixmap_remap_fdt. All the create_mapping
> calls need to happen on existing translation table pages without
> additional allocations. Rather than have an alloc function be called
> and fail, just set it to NULL and catch it's use. Also change
s/it's/its/
> the name to create_mapping_noalloc to better capture what exactly is
> going on.
>
> Signed-off-by: Laura Abbott <labbott@fedoraproject.org>
With one nit below:
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> ---
> arch/arm64/mm/mmu.c | 27 ++++++++++++++++++---------
> 1 file changed, 18 insertions(+), 9 deletions(-)
>
> diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
> index 7711554..103ebc0 100644
> --- a/arch/arm64/mm/mmu.c
> +++ b/arch/arm64/mm/mmu.c
> @@ -116,7 +116,9 @@ static void alloc_init_pte(pmd_t *pmd, unsigned long addr,
> pte_t *pte;
>
> if (pmd_none(*pmd) || pmd_sect(*pmd)) {
> - phys_addr_t pte_phys = pgtable_alloc();
> + phys_addr_t pte_phys;
> + BUG_ON(!pgtable_alloc);
> + pte_phys = pgtable_alloc();
> pte = pte_set_fixmap(pte_phys);
> if (pmd_sect(*pmd))
> split_pmd(pmd, pte);
> @@ -158,7 +160,9 @@ static void alloc_init_pmd(pud_t *pud, unsigned long addr, unsigned long end,
> * Check for initial section mappings in the pgd/pud and remove them.
> */
> if (pud_none(*pud) || pud_sect(*pud)) {
> - phys_addr_t pmd_phys = pgtable_alloc();
> + phys_addr_t pmd_phys;
> + BUG_ON(!pgtable_alloc);
> + pmd_phys = pgtable_alloc();
> pmd = pmd_set_fixmap(pmd_phys);
> if (pud_sect(*pud)) {
> /*
> @@ -223,7 +227,9 @@ static void alloc_init_pud(pgd_t *pgd, unsigned long addr, unsigned long end,
> unsigned long next;
>
> if (pgd_none(*pgd)) {
> - phys_addr_t pud_phys = pgtable_alloc();
> + phys_addr_t pud_phys;
> + BUG_ON(!pgtable_alloc);
> + pud_phys = pgtable_alloc();
> __pgd_populate(pgd, pud_phys, PUD_TYPE_TABLE);
> }
> BUG_ON(pgd_bad(*pgd));
> @@ -312,7 +318,10 @@ static void __create_pgd_mapping(pgd_t *pgdir, phys_addr_t phys,
> init_pgd(pgd_offset_raw(pgdir, virt), phys, virt, size, prot, alloc);
> }
>
> -static void __init create_mapping(phys_addr_t phys, unsigned long virt,
> +/*
> + * This function is for mapping using existing sections only.
Could you improve this comment? 'existing sections' does not quite
cover what we expect to deal with imo
> + */
> +static void __init create_mapping_noalloc(phys_addr_t phys, unsigned long virt,
> phys_addr_t size, pgprot_t prot)
> {
> if (virt < VMALLOC_START) {
> @@ -321,7 +330,7 @@ static void __init create_mapping(phys_addr_t phys, unsigned long virt,
> return;
> }
> __create_pgd_mapping(init_mm.pgd, phys, virt, size, prot,
> - early_pgtable_alloc);
> + NULL);
> }
>
> void __init create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys,
> @@ -680,7 +689,7 @@ void *__init fixmap_remap_fdt(phys_addr_t dt_phys)
> /*
> * Make sure that the FDT region can be mapped without the need to
> * allocate additional translation table pages, so that it is safe
> - * to call create_mapping() this early.
> + * to call create_mapping_noalloc() this early.
> *
> * On 64k pages, the FDT will be mapped using PTEs, so we need to
> * be in the same PMD as the rest of the fixmap.
> @@ -696,8 +705,8 @@ void *__init fixmap_remap_fdt(phys_addr_t dt_phys)
> dt_virt = (void *)dt_virt_base + offset;
>
> /* map the first chunk so we can read the size from the header */
> - create_mapping(round_down(dt_phys, SWAPPER_BLOCK_SIZE), dt_virt_base,
> - SWAPPER_BLOCK_SIZE, prot);
> + create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE),
> + dt_virt_base, SWAPPER_BLOCK_SIZE, prot);
>
> if (fdt_check_header(dt_virt) != 0)
> return NULL;
> @@ -707,7 +716,7 @@ void *__init fixmap_remap_fdt(phys_addr_t dt_phys)
> return NULL;
>
> if (offset + size > SWAPPER_BLOCK_SIZE)
> - create_mapping(round_down(dt_phys, SWAPPER_BLOCK_SIZE), dt_virt_base,
> + create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE), dt_virt_base,
> round_up(offset + size, SWAPPER_BLOCK_SIZE), prot);
>
> memblock_reserve(dt_phys, size);
> --
> 2.5.0
>
next prev parent reply other threads:[~2016-01-30 10:34 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-29 23:46 [PATCHv2 0/3] ARCH_SUPPORTS_DEBUG_PAGEALLOC for arm64 Laura Abbott
2016-01-29 23:46 ` [PATCHv2 1/3] arm64: Drop alloc function from create_mapping Laura Abbott
2016-01-30 10:34 ` Ard Biesheuvel [this message]
2016-02-01 12:11 ` Mark Rutland
2016-01-29 23:46 ` [PATCHv2 2/3] arm64: Add support for ARCH_SUPPORTS_DEBUG_PAGEALLOC Laura Abbott
2016-02-01 12:29 ` Mark Rutland
2016-02-01 21:24 ` Laura Abbott
2016-02-02 8:57 ` Ard Biesheuvel
2016-02-02 12:23 ` Mark Rutland
2016-02-02 12:31 ` Mark Rutland
2016-02-02 16:08 ` Laura Abbott
2016-01-29 23:46 ` [PATCHv2 3/3] arm64: ptdump: Indicate whether memory should be faulting Laura Abbott
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