Most of the code for initializing the vDSOs in arm64 and compat will be in common, hence a refactor of the current code is required to avoid duplication and simplify maintainability.
Refactor vdso.c to simplify the implementation of arm64 vDSO compat (which will be pushed with a future patch).
Cc: Catalin Marinas catalin.marinas@arm.com Cc: Will Deacon will.deacon@arm.com Signed-off-by: Vincenzo Frascino vincenzo.frascino@arm.com Tested-by: Shijith Thotton sthotton@marvell.com Tested-by: Andre Przywara andre.przywara@arm.com --- arch/arm64/kernel/vdso.c | 215 ++++++++++++++++++++++++++------------- 1 file changed, 144 insertions(+), 71 deletions(-)
diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c index 23c38303a52a..aa1fb25a9fe4 100644 --- a/arch/arm64/kernel/vdso.c +++ b/arch/arm64/kernel/vdso.c @@ -40,7 +40,31 @@ #include <asm/vdso.h>
extern char vdso_start[], vdso_end[]; -static unsigned long vdso_pages __ro_after_init; + +/* vdso_lookup arch_index */ +enum arch_vdso_type { + ARM64_VDSO = 0, +}; +#define VDSO_TYPES (ARM64_VDSO + 1) + +struct __vdso_abi { + const char *name; + const char *vdso_code_start; + const char *vdso_code_end; + unsigned long vdso_pages; + /* Data Mapping */ + struct vm_special_mapping *dm; + /* Code Mapping */ + struct vm_special_mapping *cm; +}; + +static struct __vdso_abi vdso_lookup[VDSO_TYPES] __ro_after_init = { + { + .name = "vdso", + .vdso_code_start = vdso_start, + .vdso_code_end = vdso_end, + }, +};
/* * The vDSO data page. @@ -51,10 +75,110 @@ static union { } vdso_data_store __page_aligned_data; struct vdso_data *vdso_data = vdso_data_store.data;
+static int __vdso_remap(enum arch_vdso_type arch_index, + const struct vm_special_mapping *sm, + struct vm_area_struct *new_vma) +{ + unsigned long new_size = new_vma->vm_end - new_vma->vm_start; + unsigned long vdso_size = vdso_lookup[arch_index].vdso_code_end - + vdso_lookup[arch_index].vdso_code_start; + + if (vdso_size != new_size) + return -EINVAL; + + current->mm->context.vdso = (void *)new_vma->vm_start; + + return 0; +} + +static int __vdso_init(enum arch_vdso_type arch_index) +{ + int i; + struct page **vdso_pagelist; + unsigned long pfn; + + if (memcmp(vdso_lookup[arch_index].vdso_code_start, "\177ELF", 4)) { + pr_err("vDSO is not a valid ELF object!\n"); + return -EINVAL; + } + + vdso_lookup[arch_index].vdso_pages = ( + vdso_lookup[arch_index].vdso_code_end - + vdso_lookup[arch_index].vdso_code_start) >> + PAGE_SHIFT; + + /* Allocate the vDSO pagelist, plus a page for the data. */ + vdso_pagelist = kcalloc(vdso_lookup[arch_index].vdso_pages + 1, + 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_lookup[arch_index].dm->pages = &vdso_pagelist[0]; + vdso_lookup[arch_index].cm->pages = &vdso_pagelist[1]; + + return 0; +} + +static int __setup_additional_pages(enum arch_vdso_type arch_index, + struct mm_struct *mm, + struct linux_binprm *bprm, + int uses_interp) +{ + unsigned long vdso_base, vdso_text_len, vdso_mapping_len; + void *ret; + + vdso_text_len = vdso_lookup[arch_index].vdso_pages << PAGE_SHIFT; + /* Be sure to map the data page */ + vdso_mapping_len = vdso_text_len + PAGE_SIZE; + + vdso_base = get_unmapped_area(NULL, 0, vdso_mapping_len, 0, 0); + if (IS_ERR_VALUE(vdso_base)) { + ret = ERR_PTR(vdso_base); + goto up_fail; + } + + ret = _install_special_mapping(mm, vdso_base, PAGE_SIZE, + VM_READ|VM_MAYREAD, + vdso_lookup[arch_index].dm); + if (IS_ERR(ret)) + goto up_fail; + + vdso_base += PAGE_SIZE; + mm->context.vdso = (void *)vdso_base; + ret = _install_special_mapping(mm, vdso_base, vdso_text_len, + VM_READ|VM_EXEC| + VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC, + vdso_lookup[arch_index].cm); + if (IS_ERR(ret)) + goto up_fail; + + return 0; + +up_fail: + mm->context.vdso = NULL; + return PTR_ERR(ret); +} + #ifdef CONFIG_COMPAT /* * Create and map the vectors page for AArch32 tasks. */ +/* + * aarch32_vdso_pages: + * 0 - kuser helpers + * 1 - sigreturn code + */ #define C_VECTORS 0 #define C_SIGPAGE 1 #define C_PAGES (C_SIGPAGE + 1) @@ -183,18 +307,18 @@ int aarch32_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) static int vdso_mremap(const struct vm_special_mapping *sm, struct vm_area_struct *new_vma) { - unsigned long new_size = new_vma->vm_end - new_vma->vm_start; - unsigned long vdso_size = vdso_end - vdso_start; - - if (vdso_size != new_size) - return -EINVAL; - - current->mm->context.vdso = (void *)new_vma->vm_start; - - return 0; + return __vdso_remap(ARM64_VDSO, sm, new_vma); }
-static struct vm_special_mapping vdso_spec[2] __ro_after_init = { +/* + * aarch64_vdso_pages: + * 0 - vvar + * 1 - vdso + */ +#define A_VVAR 0 +#define A_VDSO 1 +#define A_PAGES (A_VDSO + 1) +static struct vm_special_mapping vdso_spec[A_PAGES] __ro_after_init = { { .name = "[vvar]", }, @@ -206,37 +330,10 @@ static struct vm_special_mapping vdso_spec[2] __ro_after_init = {
static int __init vdso_init(void) { - int i; - struct page **vdso_pagelist; - unsigned long pfn; - - if (memcmp(vdso_start, "\177ELF", 4)) { - pr_err("vDSO is not a valid ELF object!\n"); - return -EINVAL; - } - - vdso_pages = (vdso_end - vdso_start) >> PAGE_SHIFT; - - /* Allocate the vDSO pagelist, plus a page for the data. */ - vdso_pagelist = kcalloc(vdso_pages + 1, 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)); - + vdso_lookup[ARM64_VDSO].dm = &vdso_spec[A_VVAR]; + vdso_lookup[ARM64_VDSO].cm = &vdso_spec[A_VDSO];
- /* Grab the vDSO code pages. */ - pfn = sym_to_pfn(vdso_start); - - for (i = 0; i < vdso_pages; i++) - vdso_pagelist[i + 1] = pfn_to_page(pfn + i); - - vdso_spec[0].pages = &vdso_pagelist[0]; - vdso_spec[1].pages = &vdso_pagelist[1]; - - return 0; + return __vdso_init(ARM64_VDSO); } arch_initcall(vdso_init);
@@ -244,41 +341,17 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) { struct mm_struct *mm = current->mm; - unsigned long vdso_base, vdso_text_len, vdso_mapping_len; - void *ret; - - vdso_text_len = vdso_pages << PAGE_SHIFT; - /* Be sure to map the data page */ - vdso_mapping_len = vdso_text_len + PAGE_SIZE; + int ret;
if (down_write_killable(&mm->mmap_sem)) return -EINTR; - vdso_base = get_unmapped_area(NULL, 0, vdso_mapping_len, 0, 0); - if (IS_ERR_VALUE(vdso_base)) { - ret = ERR_PTR(vdso_base); - goto up_fail; - } - ret = _install_special_mapping(mm, vdso_base, PAGE_SIZE, - VM_READ|VM_MAYREAD, - &vdso_spec[0]); - if (IS_ERR(ret)) - goto up_fail; - - vdso_base += PAGE_SIZE; - mm->context.vdso = (void *)vdso_base; - ret = _install_special_mapping(mm, vdso_base, vdso_text_len, - VM_READ|VM_EXEC| - VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC, - &vdso_spec[1]); - if (IS_ERR(ret)) - goto up_fail;
+ ret = __setup_additional_pages(ARM64_VDSO, + mm, + bprm, + uses_interp);
up_write(&mm->mmap_sem); - return 0;
-up_fail: - mm->context.vdso = NULL; - up_write(&mm->mmap_sem); - return PTR_ERR(ret); + return ret; }