From: Vincenzo Frascino <vincenzo.frascino@arm.com>
To: Andrei Vagin <avagin@gmail.com>
Cc: linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org,
Thomas Gleixner <tglx@linutronix.de>,
Dmitry Safonov <dima@arista.com>
Subject: Re: [PATCH v2 1/6] arm64/vdso: use the fault callback to map vvar pages
Date: Thu, 9 Apr 2020 13:01:12 +0100 [thread overview]
Message-ID: <fd287633-a383-e1ee-2c4a-b961e1b95d66@arm.com> (raw)
In-Reply-To: <20200225073731.465270-2-avagin@gmail.com>
On 2/25/20 7:37 AM, Andrei Vagin wrote:
> This is required to support time namespaces where a time namespace data
> page is different for each namespace.
>
> Signed-off-by: Andrei Vagin <avagin@gmail.com>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
> ---
> arch/arm64/kernel/vdso.c | 24 +++++++++++++++---------
> 1 file changed, 15 insertions(+), 9 deletions(-)
>
> diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c
> index 354b11e27c07..290c36d74e03 100644
> --- a/arch/arm64/kernel/vdso.c
> +++ b/arch/arm64/kernel/vdso.c
> @@ -114,28 +114,32 @@ static int __vdso_init(enum arch_vdso_type arch_index)
> PAGE_SHIFT;
>
> /* Allocate the vDSO pagelist, plus a page for the data. */
> - vdso_pagelist = kcalloc(vdso_lookup[arch_index].vdso_pages + 1,
> + vdso_pagelist = kcalloc(vdso_lookup[arch_index].vdso_pages,
> sizeof(struct page *),
> GFP_KERNEL);
> if (vdso_pagelist == NULL)
> return -ENOMEM;
>
> - /* Grab the vDSO data page. */
> - vdso_pagelist[0] = phys_to_page(__pa_symbol(vdso_data));
> -
> -
> /* Grab the vDSO code pages. */
> pfn = sym_to_pfn(vdso_lookup[arch_index].vdso_code_start);
>
> for (i = 0; i < vdso_lookup[arch_index].vdso_pages; i++)
> - vdso_pagelist[i + 1] = pfn_to_page(pfn + i);
> + vdso_pagelist[i] = pfn_to_page(pfn + i);
>
> - vdso_lookup[arch_index].dm->pages = &vdso_pagelist[0];
> - vdso_lookup[arch_index].cm->pages = &vdso_pagelist[1];
> + vdso_lookup[arch_index].cm->pages = vdso_pagelist;
>
> return 0;
> }
>
> +static vm_fault_t vvar_fault(const struct vm_special_mapping *sm,
> + struct vm_area_struct *vma, struct vm_fault *vmf)
> +{
> + if (vmf->pgoff == 0)
> + return vmf_insert_pfn(vma, vmf->address,
> + sym_to_pfn(vdso_data));
> + return VM_FAULT_SIGBUS;
> +}
> +
> static int __setup_additional_pages(enum arch_vdso_type arch_index,
> struct mm_struct *mm,
> struct linux_binprm *bprm,
> @@ -155,7 +159,7 @@ static int __setup_additional_pages(enum arch_vdso_type arch_index,
> }
>
> ret = _install_special_mapping(mm, vdso_base, PAGE_SIZE,
> - VM_READ|VM_MAYREAD,
> + VM_READ|VM_MAYREAD|VM_PFNMAP,
> vdso_lookup[arch_index].dm);
> if (IS_ERR(ret))
> goto up_fail;
> @@ -215,6 +219,7 @@ static struct vm_special_mapping aarch32_vdso_spec[C_PAGES] = {
> #ifdef CONFIG_COMPAT_VDSO
> {
> .name = "[vvar]",
> + .fault = vvar_fault,
> },
> {
> .name = "[vdso]",
> @@ -396,6 +401,7 @@ static int vdso_mremap(const struct vm_special_mapping *sm,
> static struct vm_special_mapping vdso_spec[A_PAGES] __ro_after_init = {
> {
> .name = "[vvar]",
> + .fault = vvar_fault,
> },
> {
> .name = "[vdso]",
>
--
Regards,
Vincenzo
next prev parent reply other threads:[~2020-04-09 12:00 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-25 7:37 [PATCH v2 0/6] arm64: add the time namespace support Andrei Vagin
2020-02-25 7:37 ` [PATCH v2 1/6] arm64/vdso: use the fault callback to map vvar pages Andrei Vagin
2020-04-09 12:01 ` Vincenzo Frascino [this message]
2020-02-25 7:37 ` [PATCH v2 2/6] arm64/vdso: Zap vvar pages when switching to a time namespace Andrei Vagin
2020-04-09 12:01 ` Vincenzo Frascino
2020-02-25 7:37 ` [PATCH v2 3/6] arm64/vdso: Add time napespace page Andrei Vagin
2020-04-09 12:03 ` Vincenzo Frascino
2020-04-14 17:20 ` Mark Rutland
2020-04-15 2:34 ` Andrei Vagin
2020-04-15 10:05 ` Mark Rutland
2020-04-15 10:16 ` Vincenzo Frascino
2020-04-15 12:27 ` Mark Rutland
2020-02-25 7:37 ` [PATCH v2 4/6] arm64/vdso: Handle faults on timens page Andrei Vagin
2020-04-09 12:04 ` Vincenzo Frascino
2020-02-25 7:37 ` [PATCH v2 5/6] arm64/vdso: Restrict splitting VVAR VMA Andrei Vagin
2020-04-09 12:05 ` Vincenzo Frascino
2020-02-25 7:37 ` [PATCH v2 6/6] arm64: enable time namespace support Andrei Vagin
2020-04-09 12:06 ` Vincenzo Frascino
2020-04-01 6:50 ` [PATCH v2 0/6] arm64: add the " Andrei Vagin
2020-04-01 9:02 ` Vincenzo Frascino
2020-04-09 13:24 ` Vincenzo Frascino
2020-04-11 7:33 ` Andrei Vagin
2020-04-14 9:02 ` Vincenzo Frascino
2020-04-15 16:14 ` Andrei Vagin
2020-04-15 16:35 ` Vincenzo Frascino
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