From: Andrei Vagin <avagin@gmail.com> To: Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will@kernel.org>, Mark Rutland <mark.rutland@arm.com> Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Vincenzo Frascino <vincenzo.frascino@arm.com>, Thomas Gleixner <tglx@linutronix.de>, Dmitry Safonov <dima@arista.com>, Christian Brauner <christian.brauner@ubuntu.com>, Andrei Vagin <avagin@gmail.com> Subject: [PATCH 1/6] arm64/vdso: use the fault callback to map vvar pages Date: Wed, 24 Jun 2020 01:33:16 -0700 [thread overview] Message-ID: <20200624083321.144975-2-avagin@gmail.com> (raw) In-Reply-To: <20200624083321.144975-1-avagin@gmail.com> Currently the vdso has no awareness of time namespaces, which may apply distinct offsets to processes in different namespaces. To handle this within the vdso, we'll need to expose a per-namespace data page. As a preparatory step, this patch separates the vdso data page from the code pages, and has it faulted in via its own fault callback. Subsquent patches will extend this to support distinct pages per time namespace. The vvar vma has to be installed with the VM_PFNMAP flag to handle faults via its vma fault callback. Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Reviewed-by: Dmitry Safonov <dima@arista.com> Signed-off-by: Andrei Vagin <avagin@gmail.com> --- arch/arm64/kernel/vdso.c | 25 +++++++++++++++---------- 1 file changed, 15 insertions(+), 10 deletions(-) diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c index 4e016574bd91..7c4620451fa5 100644 --- a/arch/arm64/kernel/vdso.c +++ b/arch/arm64/kernel/vdso.c @@ -107,29 +107,32 @@ static int __vdso_init(enum vdso_abi abi) vdso_info[abi].vdso_code_start) >> PAGE_SHIFT; - /* Allocate the vDSO pagelist, plus a page for the data. */ - vdso_pagelist = kcalloc(vdso_info[abi].vdso_pages + 1, + vdso_pagelist = kcalloc(vdso_info[abi].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_info[abi].vdso_code_start); for (i = 0; i < vdso_info[abi].vdso_pages; i++) - vdso_pagelist[i + 1] = pfn_to_page(pfn + i); + vdso_pagelist[i] = pfn_to_page(pfn + i); - vdso_info[abi].dm->pages = &vdso_pagelist[0]; - vdso_info[abi].cm->pages = &vdso_pagelist[1]; + vdso_info[abi].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 vdso_abi abi, struct mm_struct *mm, struct linux_binprm *bprm, @@ -150,7 +153,7 @@ static int __setup_additional_pages(enum vdso_abi abi, } ret = _install_special_mapping(mm, vdso_base, PAGE_SIZE, - VM_READ|VM_MAYREAD, + VM_READ|VM_MAYREAD|VM_PFNMAP, vdso_info[abi].dm); if (IS_ERR(ret)) goto up_fail; @@ -209,6 +212,7 @@ static struct vm_special_mapping aarch32_vdso_maps[] = { #ifdef CONFIG_COMPAT_VDSO [AA32_MAP_VVAR] = { .name = "[vvar]", + .fault = vvar_fault, }, [AA32_MAP_VDSO] = { .name = "[vdso]", @@ -376,6 +380,7 @@ enum aarch64_map { static struct vm_special_mapping aarch64_vdso_maps[] __ro_after_init = { [AA64_MAP_VVAR] = { .name = "[vvar]", + .fault = vvar_fault, }, [AA64_MAP_VDSO] = { .name = "[vdso]", -- 2.24.1
WARNING: multiple messages have this Message-ID (diff)
From: Andrei Vagin <avagin@gmail.com> To: Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will@kernel.org>, Mark Rutland <mark.rutland@arm.com> Cc: Dmitry Safonov <dima@arista.com>, linux-kernel@vger.kernel.org, Andrei Vagin <avagin@gmail.com>, Thomas Gleixner <tglx@linutronix.de>, Vincenzo Frascino <vincenzo.frascino@arm.com>, Christian Brauner <christian.brauner@ubuntu.com>, linux-arm-kernel@lists.infradead.org Subject: [PATCH 1/6] arm64/vdso: use the fault callback to map vvar pages Date: Wed, 24 Jun 2020 01:33:16 -0700 [thread overview] Message-ID: <20200624083321.144975-2-avagin@gmail.com> (raw) In-Reply-To: <20200624083321.144975-1-avagin@gmail.com> Currently the vdso has no awareness of time namespaces, which may apply distinct offsets to processes in different namespaces. To handle this within the vdso, we'll need to expose a per-namespace data page. As a preparatory step, this patch separates the vdso data page from the code pages, and has it faulted in via its own fault callback. Subsquent patches will extend this to support distinct pages per time namespace. The vvar vma has to be installed with the VM_PFNMAP flag to handle faults via its vma fault callback. Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Reviewed-by: Dmitry Safonov <dima@arista.com> Signed-off-by: Andrei Vagin <avagin@gmail.com> --- arch/arm64/kernel/vdso.c | 25 +++++++++++++++---------- 1 file changed, 15 insertions(+), 10 deletions(-) diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c index 4e016574bd91..7c4620451fa5 100644 --- a/arch/arm64/kernel/vdso.c +++ b/arch/arm64/kernel/vdso.c @@ -107,29 +107,32 @@ static int __vdso_init(enum vdso_abi abi) vdso_info[abi].vdso_code_start) >> PAGE_SHIFT; - /* Allocate the vDSO pagelist, plus a page for the data. */ - vdso_pagelist = kcalloc(vdso_info[abi].vdso_pages + 1, + vdso_pagelist = kcalloc(vdso_info[abi].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_info[abi].vdso_code_start); for (i = 0; i < vdso_info[abi].vdso_pages; i++) - vdso_pagelist[i + 1] = pfn_to_page(pfn + i); + vdso_pagelist[i] = pfn_to_page(pfn + i); - vdso_info[abi].dm->pages = &vdso_pagelist[0]; - vdso_info[abi].cm->pages = &vdso_pagelist[1]; + vdso_info[abi].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 vdso_abi abi, struct mm_struct *mm, struct linux_binprm *bprm, @@ -150,7 +153,7 @@ static int __setup_additional_pages(enum vdso_abi abi, } ret = _install_special_mapping(mm, vdso_base, PAGE_SIZE, - VM_READ|VM_MAYREAD, + VM_READ|VM_MAYREAD|VM_PFNMAP, vdso_info[abi].dm); if (IS_ERR(ret)) goto up_fail; @@ -209,6 +212,7 @@ static struct vm_special_mapping aarch32_vdso_maps[] = { #ifdef CONFIG_COMPAT_VDSO [AA32_MAP_VVAR] = { .name = "[vvar]", + .fault = vvar_fault, }, [AA32_MAP_VDSO] = { .name = "[vdso]", @@ -376,6 +380,7 @@ enum aarch64_map { static struct vm_special_mapping aarch64_vdso_maps[] __ro_after_init = { [AA64_MAP_VVAR] = { .name = "[vvar]", + .fault = vvar_fault, }, [AA64_MAP_VDSO] = { .name = "[vdso]", -- 2.24.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2020-06-24 8:33 UTC|newest] Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-06-24 8:33 [PATCH v5 0/6] arm64: add the time namespace support Andrei Vagin 2020-06-24 8:33 ` Andrei Vagin 2020-06-24 8:33 ` Andrei Vagin [this message] 2020-06-24 8:33 ` [PATCH 1/6] arm64/vdso: use the fault callback to map vvar pages Andrei Vagin 2020-07-24 17:26 ` Catalin Marinas 2020-07-27 6:45 ` Andrei Vagin 2020-07-27 6:45 ` Andrei Vagin 2020-06-24 8:33 ` [PATCH 2/6] arm64/vdso: Zap vvar pages when switching to a time namespace Andrei Vagin 2020-06-24 8:33 ` Andrei Vagin 2020-06-24 15:18 ` Christian Brauner 2020-06-24 15:18 ` Christian Brauner 2020-06-25 8:25 ` Andrei Vagin 2020-06-25 8:25 ` Andrei Vagin 2020-06-24 8:33 ` [PATCH 3/6] arm64/vdso: Add time namespace page Andrei Vagin 2020-06-24 8:33 ` Andrei Vagin 2020-06-24 8:33 ` [PATCH 4/6] arm64/vdso: Handle faults on timens page Andrei Vagin 2020-06-24 8:33 ` Andrei Vagin 2020-06-24 8:33 ` [PATCH 5/6] arm64/vdso: Restrict splitting VVAR VMA Andrei Vagin 2020-06-24 8:33 ` Andrei Vagin 2020-06-24 8:33 ` [PATCH 6/6] arm64: enable time namespace support Andrei Vagin 2020-06-24 8:33 ` Andrei Vagin 2020-07-05 6:40 ` [PATCH v5 0/6] arm64: add the " Andrei Vagin 2020-07-05 6:40 ` Andrei Vagin 2020-07-14 1:57 ` Andrei Vagin 2020-07-14 1:57 ` Andrei Vagin 2020-07-22 18:15 ` Catalin Marinas 2020-07-22 18:15 ` Catalin Marinas 2020-07-23 17:41 ` Andrei Vagin 2020-07-23 17:41 ` Andrei Vagin 2020-07-23 20:25 ` Thomas Gleixner 2020-07-23 20:25 ` Thomas Gleixner 2020-07-24 11:01 ` Catalin Marinas 2020-07-24 11:01 ` Catalin Marinas 2020-07-24 13:22 ` Thomas Gleixner 2020-07-24 13:22 ` Thomas Gleixner 2020-07-24 13:30 ` Christian Brauner 2020-07-24 13:30 ` Christian Brauner 2020-07-24 14:40 ` Catalin Marinas 2020-07-24 14:40 ` Catalin Marinas -- strict thread matches above, loose matches on Subject: below -- 2020-06-16 7:55 [PATCH v4 " Andrei Vagin 2020-06-16 7:55 ` [PATCH 1/6] arm64/vdso: use the fault callback to map vvar pages Andrei Vagin 2020-06-16 7:55 ` Andrei Vagin 2020-06-16 10:59 ` Mark Rutland 2020-06-16 10:59 ` Mark Rutland 2020-06-18 7:27 ` Andrei Vagin 2020-06-18 7:27 ` Andrei Vagin 2020-06-02 18:02 [PATCH RESEND v3 0/6] arm64: add the time namespace support Andrei Vagin 2020-06-02 18:02 ` [PATCH 1/6] arm64/vdso: use the fault callback to map vvar pages Andrei Vagin 2020-06-02 18:02 ` Andrei Vagin 2020-04-16 5:26 [PATCH v3 0/6] arm64: add the time namespace support Andrei Vagin 2020-04-16 5:26 ` [PATCH 1/6] arm64/vdso: use the fault callback to map vvar pages Andrei Vagin 2020-04-16 5:26 ` Andrei Vagin
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