On Fri, Feb 22, 2019 at 12:24:21PM +0000, Vincenzo Frascino wrote:
> 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@xxxxxxx>
> Cc: Will Deacon <will.deacon@xxxxxxx>
> Signed-off-by: Vincenzo Frascino <vincenzo.frascino@xxxxxxx>
> ---
> arch/arm64/kernel/vdso.c | 208 +++++++++++++++++++++++++--------------
> 1 file changed, 135 insertions(+), 73 deletions(-)
>
> diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c
> index 523e56658b84..c217245768ea 100644
> --- a/arch/arm64/kernel/vdso.c
> +++ b/arch/arm64/kernel/vdso.c
> @@ -41,7 +41,30 @@
> #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,
> +};
> +
> +struct __vdso_lookup_t {
If you want to give this a _t suffix, please use a typedef so that you
don't need to also say 'struct' to use it.
I think this would be better named as struct vdso_instance, or struct
vdso_abi.
Thanks,
Mark.
> + 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_lookup_t vdso_lookup[2] __ro_after_init = {
> + {
> + .name = "vdso",
> + .vdso_code_start = vdso_start,
> + .vdso_code_end = vdso_end,
> + },
> +};
>
> /*
> * The vDSO data page.
> @@ -52,6 +75,106 @@ 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;
> + pr_info("%s: %ld pages (%ld code @ %p, %ld data @ %p)\n",
> + vdso_lookup[arch_index].name,
> + vdso_lookup[arch_index].vdso_pages + 1,
> + vdso_lookup[arch_index].vdso_pages,
> + vdso_lookup[arch_index].vdso_code_start, 1L, vdso_data);
> +
> + /* 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.
> @@ -62,7 +185,7 @@ struct vdso_data *vdso_data = &vdso_data_store.data;
> * 1 - sigreturn code
> */
> static struct page *aarch32_vdso_pages[2] __ro_after_init;
> -static const struct vm_special_mapping aarch32_vdso_spec[2] = {
> +static struct vm_special_mapping aarch32_vdso_spec[2] __ro_after_init = {
> {
> /* Must be named [vectors] for compatibility with arm. */
> .name = "[vectors]",
> @@ -202,15 +325,7 @@ 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 = {
> @@ -225,39 +340,10 @@ 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;
> + vdso_lookup[ARM64_VDSO].dm = &vdso_spec[0];
> + vdso_lookup[ARM64_VDSO].cm = &vdso_spec[1];
>
> - 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;
> - pr_info("vdso: %ld pages (%ld code @ %p, %ld data @ %p)\n",
> - vdso_pages + 1, vdso_pages, vdso_start, 1L, vdso_data);
> -
> - /* 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));
> -
> -
> - /* 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);
>
> @@ -265,43 +351,19 @@ 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;
> }
>
> #define VDSO_PRECISION_MASK ~(0xFF00ULL<<48)
> --
> 2.20.1
>
