[PATCH 1/6] arm64/vdso: use the fault callback to map vvar pages
From: Andrei Vagin <hidden>
Date: 2020-06-16 07:56:00
Also in:
lkml
Subsystem:
arm64 port (aarch64 architecture), the rest · Maintainers:
Catalin Marinas, Will Deacon, Linus Torvalds
This is required to support time namespaces where a time namespace data page is different for each namespace. Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Reviewed-by: Dmitry Safonov <redacted> Signed-off-by: Andrei Vagin <redacted> --- 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 4e016574bd91..b0aec4e8c9b4 100644
--- a/arch/arm64/kernel/vdso.c
+++ b/arch/arm64/kernel/vdso.c@@ -108,28 +108,32 @@ static int __vdso_init(enum vdso_abi abi) 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 +154,7 @@ 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 +213,7 @@ 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 +381,7 @@ 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
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